Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:04 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Propellor shaft

Propellor shaft rear section had lumpy universal joints that refused to ease off when greased & the yokes were thumped with a mallet (1kg rubber one is good for this) so new ones were fitted (Quinton Hazell QL2104 for the CF350 model).

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First thing to do is mark the shaft & yokes so that they can be kept aligned the same way when new joints fitted.

Trick when removing rusted-in circlips is to scrub the rust off, apply some easing oil then, with a tube or socket that fits well on the circlip, thump it to shock it in its groove.

Once tapping a narrow point centre punch in circlip eyes will move the ends of the circlip inwards keep working at it until the circlip will spin in its groove. Then circlip pliers can be used to extract the circlip without being overloaded & slipping from the clip.

When all the circlips are out the joint can be removed; I've always found it easier to remove the splined & flange yokes with their joints from the shaft by thumping the shaft yokes to shift the bearing cups, then work on the yokes separately in a vice, clamping across the journal while thumping the yoke to shift the remaining bearing cups.

Most worn journal was the front one but the rear one wasn't as good as it should be - wear pattern could be felt with the fingertips although it was hard to see without me specs on. (I thought I had some pics of this bit but I seemed to have copied later ones over them, probably because I forgot that the camera loses the plot sometimes & resets file names. Rats.)

Fitting new universal joint -

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Yokes need to be clean, especially the circlip grooves. Another trick: once the joint & one bearing cup is fitted, press the cup into the yoke past the circlip groove plus a few mm so that the opposite cup can be fitted more easily with the journal mid-way between the cups then press in the second cup until the journal will stay put. Fit the first circlip & carry on pressing until the first cup meets its circlip (middle pic above), then fit the second circlip.

Circlips can be fitted either way up - they have a rounded edge one side & square edge on the other - & whichever is easiest for pliers used will do provided circlips expand properly to full engagement of their thickness in the grooves. Any circlip with ends closer together than other circlips needs sorting or it could spring out. Usually a tap or two with a punch will make it snap home in the groove but if it doesn't then the cup might need pressing in a tiny bit more.

When all 4 circlips are in any tightness in the joint will ease off if the yokes are bumped over the bearing cups with a mallet.

Finished -

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Grease nipples are 5/16" across the flats & a 1/4" drive socket makes fitting them a bit easier than with a spanner; they have taper threads so will go tight with some thread still showing. Universal joints can be filled with grease (to just swell rubber seals on the bearing cups) before fitting but the spline sleeve is best greased when the propellor shaft is back on the van - excess squirts out from a hole in the cap in the yoke.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:06 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Exhaust repair

This is how the silencers assembly came off the van -

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The tin can and fire putty 'repair' to seal up the join had failed (if it ever worked anyway); not surprising really because once the front of the inter-pipe (pipe with holes in) becomes detached from inside the front silencer the back of the front silencer flexes all the time with taking all the strain and eventually fractures.

The bits cleaned up -

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Failure of the tack weld on the front end of the inter-pipe where it meets the internal baffle in the front silencer is what has caused the problem.

Re-assembled prior to welding -

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A seam weld all the way round wasn't hard to get right first time because the fracture in the front silencer was a clean break with no corrosion thinning the silencer end plate.

Once that was done a length of 6mm rod got to be an external brace to replace the internal weld that failed -

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Note the clean spigot for the tailpipe for when the silencer is refitted to the van. Cleaning the inside of the tailpipe likewise makes fitting a lot easier and needs less fire putty to seal any leaks because it's got something to stick to.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:10 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Bottom end

The damage

Scored cylinder bores -

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Piston (best of a bad bunch) -

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Second ring stuck in its groove & signs of lots of blow-by (dark areas on alloy).

The state of the bores alone requires a rebore; scoring is too deep to hone out & top ring gaps in their bores were all above 1mm.

The fixes.

Spare engine donated by Skoota is in better condition although the piston rings are worn enough to require replacing; top rings are the worst -

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Rings should be rectangular section; these are worn to wedge section, enough to have been pumping oil into the combustion chambers.
Pistons aren't worn though, in fact they're just about spot on.

Bores -

Cylinders all glazed but not very worn (bore size at top of ring travel 95.55mm, new ring gaps 0.38-0.40mm).
In the top image below cylinders 3 & 4 first pass honed with 180 grade stones to show the difference.

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The glaze has to be removed and replaced by a cross-hatch honed finish in order to provide lubrication for the piston rings.
(Google 'cylinder bore honing' - a pile of stuff on the topic just on the first page of hits.)
To stay within maximum ring gap allowed (0.65mm) no more than 0.02mm could be honed off.
All 4 cylinders honed using 180 grade stones (cross-hatch at 30 degrees to block top face) then finished with 280 grade stones.
Finished size 97.57mm (0.03mm over spec.).

New rings gapped at 0.55mm (maximum allowed is 0.65mm) -

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Rings set is Deves (California), standard size, from F W Thornton in Shropshire (see Sources - general list) -

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Top ring is plain; the second ring is a stepped scraper ring with an expander fitted behind it in the piston groove.
Oil control ring has an expander with a spacer between the two thin rings.

Original rings -

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Plain top ring, stepped second ring (but step almost worn away) and one-piece expander/spacer for the oil control.

Ring grooves have to be cleaned out (not my favourite job...) -

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and rings fitted; second and top ring clearances (feeler gauges in gap between ring & groove) were around 0.04mm, near enough spot on.

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One done -

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and 3 more to do...

So, a set of good pistons, near enough 'new' bores with piston clearances in their bores within limits & new rings.
However, a compromise has been made: taper (difference in bore diameters top & bottom) and ovality (difference in bore diameters longitudinally & transversely) has been accepted as found because honing stones follow existing contour.
The finished bores have barely enough taper & ovality to worry about though; how lucky can you get?
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:13 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Crankshaft

Crankshaft from the rattly engine donated by Skoota -

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Main & big end bearings have lost white metal on the thrust areas indicative of poor lubrication (not to be confused with running with timing too far advanced - this can show up as big end bearings being more worn than main bearings & takes a long time to get bad enough to worry about).

Crankshaft journals are oval too, by about 0.03mm, and end float is 0.45mm (way over spec. of 0.35mm max.) so a regrind & polish & under-size bearing shells would be needed.

When the bottom end of cooked engine came apart there was another nice surprise though: crankshaft journals look good and the bearings are barely worn -

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Crankshaft journals measure up fine & end float is minimal at 0.15mm -

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despite apparent wear of thrust washers both sides (integral with the rear main bearing shells by being being keyed to them) -

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Run-out on the main bearings made the dial gauge pointer move barely half a division, about 0.005mm (max. permissible 0.038mm) -

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(This snap was taken after the event, when end float was being checked; snaps taken at the time didn't turn out too well.)

That's a whole pile of lucky breaks. It had to end though and the reason has had me spitting feathers: Payen conversion set comes without the rear crankshaft seal halves. Hmm.

So Gaskets-direct are getting the business although I'm not yet sure how much they'll need glues & stuff to work as well as Payen (OE spec.).

Some sitting on hands waiting for gaskets because the first thing to fit is the crankshaft & that can't be done without first fitting the rear seal halves.

Gaskets conversion set

As received from Gaskets-direct (next day: can't complain about service like that!) -

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EDIT. Gaskets-direct now J&M Gaskets and Seals; I've used them for gaskets (sets and singles) a number of times now and the service has been excellent. See Sources - general list.

First impressions.

The sump gaskets came rolled around a card tube; no bad thing for keeping packaging costs down but it took a day or so under a book before the gaskets started to lie fairly flat.

Sump plug copper washer is a one-trip U-section type formed from thin sheet that do seal ok when new but need replacing first oil change.

There's only one fuel pump gasket: two are needed, one for the plastic insulator and one for the pump itself.

Crankshaft rear seal halves are mighty big for a slant engine -

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but the section looks right & they're graphite-impregnated woven roving on a cord former so should shape to the right curve...

Details of how each gasket & seal performed are in the build.
Last edited by Phil Bradshaw on Wed Dec 11, 2013 6:02 pm, edited 2 times in total.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:15 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Core plugs

Cylinder block has 6 steel cup plugs that can quickly rot on the inside if corrosion inhibitor isn't kept up to strength. (This is the main reason why it's a good idea to renew antifreeze every few years because it should come with inhibitor already mixed in - should say so on the label). Core plugs will rust through in time anyway though so it's a good idea to renew iffy ones when an engine is in bits.

To test core plugs -

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Ding each core plug near the bottom (ding = bounce hammer on punch held on core plug rather than smack it with any force so that the plug moves inwards); if any are weak enough for the punch to make a depression then they're not far off from leaking -

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All the core plugs in the block dinged in so they had to come out. Quickest way I've found is to punch the plugs near their rims so that they twist as they go into the water jacket, when they can be winkled out using vice grips or a lever against the block casting.

Core plugs each side of the cylinder block are best punched in at the top or bottom or they can jam against the cylinder walls behind as they move inwards; rear core plug is best punched in on one side -

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Left side done -

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6 new core plugs come expensive as a set, twice as much as what they can be had singly from an engine shop. Anything matching original GM plugs is hard to find though, metric sizes being the norm these days. Here's how the ones I found shaped up -

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The smallest is easiest to find & cheapest (70p) so I got a handful of these to experiment with along with 3 of the 1.935" ones (actually old stock, no longer available) and found a GM one in with some 1.96" ones I've got lying about.

The smallest diameter plugs, when sunk into the bores the amount that they're shallower than GM ones (which are fitted flush with the block casting), ~0.1", tightened up after a day or two & needed a fair wallop to get them out again. The ones that were removed were then too slack to refit but Loctite 243 threadlocker worked well second time round.

This stuff has good sealing & shear properties as a thin film & also is resistant to water-glycol mixes; after ~24 hour cure time it made the second-trip smallest plugs as hard to shift as the original rotten ones. For belt & braces then, Loctite 243 was used on all the new core plugs that were fitted.

Bores in the block have to be cleaned to obtain a good seal -

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& solvent cleaner used to finish & also clean the new core plugs (acetone is cheap from GRP materials stockists & dries off rapidly).

New core plugs fitted -

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A socket that sits in the core plug with about 1mm all round and a 5" extension make a suitable drift for getting the plugs in square; final adjustment of depth can be easier with a 3/8" (10mm) drift worked around the plug within initial cure time of Loctite 243, about 10 minutes (faster above 25C, slower for larger gaps).

The smallest plugs are fitted right side (inlet manifold side) because that's the easiest to get at with the engine in the van if there's any problems. However, the second-trip ones that were glued up with Loctite 243 & then removed next day were well distorted by the time they moved so I can't see cooling system pressure having any effect on new ones with glue on.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:24 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Fit crankshaft

Build starts with the crankshaft rear seal -

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The manual says use a hammer shaft to roll the seal into its groove, starting from the centre of the seal. Given that most of my hammers have shafts that are a bit knocked about I got a £1 wooden rolling pin; it's easier to use & more even pressure can be brought to bear on the seal so that it won't jam so easily on the edges of the groove; edges tend to dig into the flanks of the seal. Not a problem though once more than half the seal thickness is seated in the groove because the crankshaft will squash it in place & seal regardless.

First thing that had to be done was to chop about 1 inch off the seal half: the excess length (see old-new comparison pic in 'Gaskets: conversion set') kept curling over & getting in the way. Then, despite working at it, the seal seemed not to want to lie evenly in its groove (left pic above).

To be safe & not end up with gaps between the seal ends when the crankshaft is fitted the crankcase half was trimmed off to leave about 0.05" protrusion and then the crankshaft was trial fitted using just the front & rear main bearing caps with shells fitted & oiled & tightening the bolts just to nip & settle the crankshaft without turning it.

This pulled the seal down, to ~0.012" each side when trimmed parallel with the crankcase (right hand pic above) & this is within the 0.020" protrusion allowed so the main bearing cap half of the seal got the same treatment -

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This pic was taken before trial fitting to pull the seal down; slight angle left on the ends came from how the crankcase half pulled down angled t'other way before being trimmed parallel. To get the seal in the groove at all evenly in the cap it's best to secure it in a vice.

Everything ready and spotless -

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I mean spotless too: even the dust sheet (cotton curtain - someone's pride & joy once...) is freshly laundered to minimise chance of forrin bodies getting in where it matters.

Incidentally, every bearing shell was labelled on the back with indelible marker so that they would land back on the same crankshaft journals they came from & also the same way up, i.e. crankase or cap side for main bearings, con rod or cap side for the big end bearings. Tabs at one end of each shell keeps them the right way round.

Crankshaft positioned ready to fit with bearings including rear bearing thrust washer faces, journals & rear seal contact face liberally oiled.

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EDIT. Since this build I've found that foundry grease (graphited grease) is ideal for wiping on the rear seal faces to prevent scuffing when the engine is first started. Comes from following Perkins practice on similar rope seals on the 4.154 diesel engine. Never too old to learn. :D

Once the crankshaft is in position the front & rear main bearing caps need some black RTV sealer (Loctite 598 or similar); faces must be clean & dry -

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Then the front & rear cap lands in the crankcase also have to be clean & dry before the caps can be fitted & before the RTV goes past skinning over, along with the other 3 caps.

Bearing caps are numbered 1 to 5, front to rear, all numbers on the same side as front & rear caps. Outer faces of front & rear caps must be flush with the crankcase faces when tightened but it's rare for them not to land right.

When using the crankshaft pulley bolt to turn the crankshaft it needs washers at least 3mm thick in total as well as the original thick washer to prevent the bolt from bottoming in the crankshaft thread. (With the van being a CF350, there's 2 washers handy on the propellor shaft centre mounting bolts.)

With all the bolts tightened about 1/4 turn from nipping to settle the crankshaft & check that it rotates freely, each cap can be fully tightened down, checking crankshaft rotation each time again. Tightening torque is 83 lbft or 112 Nm; bolt heads are 3/4" AF (& a hexagon impact socket won't slip as easily as a bi-hexagon one).

Leaving the rear cap to torque down last shows up how much the rear seal grips the crankshaft: it needs to in order to form a good seal & once the crankshaft turns the seal lets go its grip as it starts to self-lubricate. It'll settle in well enough when the engine runs & after that there's only age and erosion of the crankshaft seal journal that will make it leak. He says hopefully; there's an amount of erosion on the crankshaft already (see pics above) but it doesn't span the whole seal contact width.

If the crankshaft gets hard to turn at any time before the rear seal grips then ALWAYS take things apart to see what's going wrong; a forrin body under a bearing shell can be enough to cause bearing crush, when the white metal & sometimes the copper alloy backing deforms. Grit on bearing surfaces will score journals. I did say spotless...

Marking on the rear big end journal visible in pics above had me worried when I first saw it, along with marks on the front one: leaving crankshafts oily to prevent corrosion then cleaning them just before fitting hides things like this. I thought I'd managed to clonk the journals somehow but under magnification it's clear that the marks are below the bearing surface & must have been there before the journals were ground & polished. The crankshaft must have run like this until now so should be ok this time. (With this crankshaft having standard size main & big end bearing journals it makes me wonder what else GM-built engines left the factory with...)

Crankshaft front seal can be fitted now or later -

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Seal from the gasket set is rubber coated steel shell type with spring-loaded single taper lip with clockwise scroll: 2.69" outside diameter, 0.39" thick; shaft diameter (for lip diameter, in practice 1-2mm smaller) is 2.04".

Any RTV from the bearing cap/crankcase join that has squeezed out into the seal bore should be removed; leaving fitting the seal for an hour or so for the RTV to cure makes rubbing off excess a lot simpler.

A wipe of LM grease both sides of the seal lip before fitting it is a Good Thing: it'll hang around long enough for the lip to bed in on the crankshaft without scuffing.

Gently does it with some oil on the outer rim of the seal when fitting it: too much of a whack off-centre can start the rubber coating tearing. Ideally the seal should be pressed in but I couldn't find a 1/2" UNF (crankshaft pulley bolt thread) screw that's long enough to go through the 2+1/8" socket that fitted nicely on the seal.

Original seal fits flush with the front face of the crankcase; this one felt like it was oversize on the outside diameter, taking a while to bed down compared with OE spec. seals, & stopped with about 1mm protruding all round.

Hmm. This far there's been a bit more messing about I'm not accustomed to when using Payen gaskets...
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:30 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Fit pistons

Fitting the pistons in pairs saves having to move the lump about too much - it's getting heavier all the time now.

Set up for pistons 1 & 4 -

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Piston ring clamp is a ratchet type, 60-175mm capacity.

Crankshaft rotated so that 1 & 4 big end journals are at bottom dead centre to allow plenty of room for the connecting rods when fitting the pistons.

Normally the top of each cylinder bore is chamfered to allow rings to enter the bore without jamming; this engine is fine for that but sometimes after a rebore the chamfer gets a bit thin. However, it's ok to make it a bit wider again with a half-round file (best done beforehand so that filings can be cleaned out).

Before fitting pistons it's important to check that they have matching connecting rod & cap numbers (all different in an engine set) -

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and also that the bearing shells go back where they came from with being used (permanent marker on the backs of the shells again).

With a piston sitting on the rim of its cylinder bore, the arrow head on the crown needs to point to the front of the engine and piston rings must be fitted correctly with ring gaps spaced as they should be before fitting piston ring clamp -

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Top & second ring gaps should be equally spaced, i.e. 180 degree apart, & best place for the gaps is roughly in line with the piston pin. Deves rings used have their own particular oil control ring setup - http://www.deves.com/oilring_inst.cfm - & the second ring gap should be 180 degree from the oil control top rail gap.

Once the rings check out ok it gets a bit messy: plenty of engine oil needs to be on the rings and also inside the clamp & cylinder bore. The clamp is fitted loose & then wound up (well. it is clock spring steel...) until the piston is held well enough to slip into the top of the bore & not slide from the clamp. With the clamp settled so that it sits evenly on the top face of the block it can be wound up until the ratchet won't click any more. The square drive key is the short length it is to prevent over-tightening...

Once the clamp ratchet stops & the clamp is settled evenly on the top of the block again then, using the end of a hammer shaft, the piston can be tapped gently around its top so that it moves slowly into its bore while keeping the clamp pressed down onto the top of the block.

Golden rule here: never try to force a piston into its bore. If it jams then take it out & find out why & start again if need be; a busted ring will ruin the whole job. I had to re-clamp rings twice when one of the oil control rails clicked out from under the clamp but once it decided to behave it slipped in as easily as the rest.

Once a pair of pistons is fitted the block can be turned to get at the big end bearings -

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Once the connecting rod is aligned to its crankshaft journal the bearing shells & journal can be oiled & the cap fitted. The dowels that keep the caps aligned usually prevent them mating fully with the connecting rod but once the bolts are fitted tightening them evenly will pull everything together.

With 2 caps fitted & connecting rod bolts nipped up the crankshaft should turn but it'll be a bit stiffer now and the rings will make a light scraping noise on honed bores. It's best to torque tighten 1 cap at a time & check crankshaft rotation again before tightening another. It shouldn't get any stiffer than with the bolts nipped up though; if it does then the cap must be removed to see what's gone wrong. Tightening torque is 47 lbft or 64 Nm; bolt heads are 9/16" AF.

All pistons fitted -

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and from the top -

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EDIT. Connecting rod bolts on this engine have 9/16" AF heads so a normal bi-hexagon socket can be used if it's not too worn. On earlier engines the bolt heads have 7/16" AF heads: for these it is necessary to use a hexagon 'impact' or flank drive socket in order to avoid the socket slipping off and rounding of the bolt heads.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:48 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Oil pipe & sump

Oil pipe -

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O-ring is 0.14" round section, 1" outside diameter. New O-ring fitted with a smear of LM grease once pipe boss & groove cleaned. Best tool I've found for cleaning the bore is a small de-coke brush in an electric drill.

Old O-ring came off with a bite out of it, like it had been trapped between the pipe boss & crankcase when fitted. Would play merry hell with oil pump pick-up if it had been letting in air ... could well explain bearings damage in the engine donated by Skoota.

Fitting pipe -

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Pipe slips nicely into its bore in the crankcase with a wipe of grease in the clean bore & will swivel to align the clamp bracket hole with No 4 main bearing cap threaded hole. Clamp bolt is the last one to tighten once retainer & clamp bracket secured.

Sump: everything to hand -

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Dry fit of sump end seals and gaskets -

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Black rubber sump end seals a good fit & gasket holes align with sump screw holes.

Fit sump end seals -

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Black RTV silicone (Loctite 598 or equivalent) again, where the flat ends of the seals meet the crankcase. Seals easiest to fit from one end & then into the slots in the main bearing caps until the other ends can be pressed down; anywhere where a seal lips up in its slot can be poked in with the fingers once the ends stick down.

Sump gasket is cork bonded in a rubber compound & doesn't need any sealer: once the engine runs the rubber component eventually will stick to the crankcase & sump faces (a vulcanisation process).

To hurry things along and also stop the gasket from slipping & squeezing out from the join when the sump screws are tightened Loctite 3020 spray adhesive helps. Spray carpet glue will work if it's a dry-off before sticking down type & usually is cheaper but care is needed to not lay it on in lumps if it spatters instead of spraying.

First each gasket is coated on one side (lay it on a sheet of paper) but with about 1 to 2 inch at each end masked to keep them free of adhesive. After about 10 minutes (tack dry time for Loctite 3020) the gaskets can be fitted from one end while loosely fitting the sump screws so everything lines up -

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Once all the screws are in place the gasket can be pressed down and the sump screws can be removed.

Black RTV silicone needs to be applied at the ends of the gaskets, underneath where they meet the end seals and also on top -

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Gasket face of the sump had a coat of Loctite 3020 as well & after 10 minutes it can be fitted using just the 4 end screws to level it up & start pulling it down -

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Once the sump starts to pull down the rest of the sump screws can be fitted (note position of clutch cable clip) -

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Even tightening of the screws involves 3 or 4 passes around the lot & when the integral lock washers are felt to bite is when to stop. For now anyway: a re-tighten is normal once the engine has been running.

This used to be part of the GM PDI, pre-delivery inspection, when I started in the motor trade & more often than not every sump screw would go 1/2 a turn or so. These days different gaskets & lots of silicone RTV like on Isuzu diesels means fit & forget.

Sump plug washer from the gasket kit was rejected - pic 1 below; new one is 3/4" inside diameter, 0.8" thick solid copper & sits well on the taper of the plug just under its head - pic 2.

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Pic 3: annealing (softening) new washer; one of the few good things about old electric hobs! Annealing process requires the washer to cool down slowly; leaving it on the hob ring while that cools down is fine.

Sump plug is 1" AF head (3/4" x 20 tpi thread) & doesn't need tightening any more than 1/4 turn from contacting the washer.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 3:52 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Auxiliary shaft, crankshaft pulleys

Nothing wrong with the auxiliary shaft apart from a busted thrust plate (cast iron) -

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Good thrust plate off the cooked engine though and the front & rear bearings are fine.

It's a lot easier to fit the shaft with the engine out so that it can be up-ended -

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Simple enough: fit thrust plate to shaft then drop shaft into its bearings (oiled) so that the plate locates on the dowel. Pic shows dry fit of the plate to prevent camera flash glare on oil so that the dowel shows up. Oil seal lip greased as with the crankshaft front seal.

The seal is a close tolerance interference fit because it's the retainer for the shaft, trapping the thrust plate against the crankcase. When working on an engine in a van the trick to stop the plate from falling away from the dowel & then jamming against it when the seal bears against the plate (why so many plates come out broken I reckon) is to stick the plate to the crankcase with grease. Once the seal is in squirting some oil past the seal lip will do for initial lubrication.

It's ok to start the seal in its bore by tapping round the shoulder so that it enters straight before bumping it in with a tube or large socket. Once the seal is flush with the front of the crankcase the last bit needs to go gently until the seal contacts the thrust plate. I've found that working a 5/16" punch around the face of the seal shell makes it easier to feel when the seal is trapping the plate & stop there; too much welly at this point also can crack the plate.

Oil seal is a steel shell single spring-loaded plain taper lip type, 2.504" diameter & 0.375" thick; shaft diameter (for lip working diameter) is 1.75".

Shaft end float check -

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End float should be 0.05 to 0.20mm; 0.07mm will do quite nicely.

Crankshaft pulleys

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The guide plate without a keyway slot that fits on the boss of the cam belt pulley should be a tight fit; if it isn't then gasket glue will do to stick it onto the pulley while it's being fitted, after which the plate is trapped against the shoulder of the crankshaft.

Fitting -

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A wipe of oil on the crankshaft and in cleaned bores of the pulleys helps with assembly & also deters rust that can make removal later a bit difficult.

The cam belt pulley should slide onto the crankshaft until it meets where the shaft diameter is slightly larger; sometimes it will push home but if it sticks then fit the outer guide plate then the crankshaft pulley & bump them along the shaft until the bolt can be used to press the lot on.

Then remove the crankshaft pulley and outer guide plate; pulley gets in the way until it's time to fit the cam belt and the pressed steel type easily can be bent meanwhile when moving the lump about.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: A cooked engine

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Post by Phil Bradshaw » Club admin » Wed Dec 11, 2013 4:03 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3825
Cylinder head

A good third of the budget for the job went on this -

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4 exhaust valve seats for LPG fitted, re-cut inlet valve seats, reface all valves & lap in; 8 valve guide sleeves (K-Line); gasket face surface grind. Exhaust valve finished stem height 1.06 inch.

The reasoning behind not fitting inlet valve seats is based on the fact that the inlet valves run cool enough to make use of the original seats re-cut. That and another £100 or so...

Valve head numbering is to ensure that valves stay with the seats they've been lapped to; numbering here is from the back of the head rather than the front.

From the top -

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This being the first CF head that John at J&E (see Sources - general list) has done, a bit of experimenting with the cracked head was in order to determine the best seats to use and also confirm that valve guide liners could be fitted rather than ream out the guides & fit valves with over-size stems, if they could be found.

Like so -

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Inlet counterbore (larger one) has been over-bored as far as breaking into the water jacket to check wall thickness when bored to fit a seat. Pass.

EDIT. Jon at J&E has done a few more Vauxhall OHC heads since this build and, although he has a whinge every time about setting the valve stem heights :) , he can set the heights within +/- 0.001 inch of spec (1.06 to 1.07 inch according to condition of tappet adjuster screws). A proper engineer accustomed to restoring older engines and a pleasure to work with as well: not many about these days.
Last edited by Phil Bradshaw on Thu Sep 08, 2016 7:59 am, edited 1 time in total.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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