Re: My New CF

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Post by Phil Bradshaw » Club admin » Fri Sep 14, 2018 12:51 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
The ideal for split propellor shafts with centre bearing is for the vertical angle of the front shaft being the same as the angle of the axle pinion shaft. (Took a while: long time since I thought much about Hooke joint theory and suchlike.)

Fudge factors apply with having the CV plunge joint on the rear shaft and range of alignment of the centre bearing cushion. Confounder is vertical arc of movement of the pinion nose as the rear springs flex on acceleration.

There's no spacers or anything else different about overdrive mountings according to GM parts listings, just a flange yoke instead of a sleeve yoke at the front.

Try it as it is first, keep the original centre bearing position then worry about what to adjust if something looks obviously wrong or the shaft vibrates.

One thing to watch for is judder or thudding on starting off which, with the engine mountings and torque reaction bar sorted, may be the centre bearing cushion being bashed to death because the front shaft angle is incorrect.
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: My New CF

Post by MattA24 » Subscribing Member » Fri Sep 14, 2018 9:51 am
Joined: Wed Jan 15, 2014 9:06 pm
Posts: 203
Thanks Phil, I'm going to sit and digest that and see if it goes in.

I had a feeling that whatever I did might end up being a bit hard on the centre bearing (and the last one has a hard life, it looks like), which is why I bought a £13 Transit bearing not a £69 OEM one ;)

Re: My New CF

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Post by Phil Bradshaw » Club admin » Fri Sep 14, 2018 11:54 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
There you go -

Image

Support bracket for centre bearing changes with model and variant. Bearing lateral alignment is in line with transmission tailshaft regardless of front shaft inclination to horizontal.
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: My New CF

Post by MattA24 » Subscribing Member » Fri Sep 14, 2018 11:45 pm
Joined: Wed Jan 15, 2014 9:06 pm
Posts: 203
One big question that keeps bubbling up to the top of my mind is the cylinder head.

The plan is to stick my LPG kit on this van, which would of course require hard valve seats. I'm guessing there's no good way to know whether the van has already had some fitted?

On the one hand, it's obviously had plenty of money spent on it over the years, so I'd not be surprised to find it had been converted. It runs very nicely for something that's lived in a hedge.

On the other hand, there was an empty fuel additive bottle in the wardrobe.

I guess the only way to be sure is to pull the cylinder head? Even then, is it that easy to spot the new seats? :?:

Or I could set the valves nicely, then drive around a bit on LPG and see what happens to them? :?:

PS: thanks for the prop shaft diagram Phil, its finally starting to make sense... :thumb:

Re: My New CF

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Post by Phil Bradshaw » Club admin » Sat Sep 15, 2018 1:18 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
Check the valve clearances.

If the exhaust valves already are tight then chances are it's a bog standard head.

If the clearances are not too far out then adjust as normal and note (a) mileage, (b) which valves need adjusting and (c) by how much (number of clicks or full turns of adjusting screws) so that you have a reference point.

After about 1000 mile check exhaust valve clearances, note mileage etc. and compare with previous results.

If any exhaust valve clearances are closing up then standard head is more likely; if none are closing up then hardened seats may be fitted.

Seat recession depends a lot on how hard the engine is driven so check clearances again at 3000 mile and then every 3000 mile until it is apparent that the head needs hard seats, or the head is fine and longer intervals are adequate.

If running on petrol then use lead replacement additive until hard valve seats confirmed: seat recession in cast iron cannot be prevented, only slowed down a bit (as was the case then leaded petrol was all the rage).

If running on LPG then use Flashlube or similar intake lubrication system: even if hardened seats are fitted the valves still need protection.

Propellor shaft

Whatever transmission is fitted to a Vauxhall OHC engine the alignment of the transmission tailshaft and axle pinion shaft to horizontal remain parallel (with engine mountings fixed, that is!).

Bearing carrier should be attached to the support bracket without flexing the cushion, i.e. carrier and bearing both perpendicular to the front shaft axis.

So the answer is to change the angle of the dangle of your centre bearing support bracket to keep the front shaft in line with the transmission shaft.
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: My New CF

Post by MattA24 » Subscribing Member » Sat Sep 15, 2018 8:42 pm
Joined: Wed Jan 15, 2014 9:06 pm
Posts: 203
Phil you talk good sense I guess! The temptation is to try and settle the cylinder head question now because I'm about to change the radiator and timing belt and whatno, so while I had all the ancillaries off it seemed like a great time to dig in a bit further but provided the valves aren't already well out of cock I'll just fettle them and keep records.

Re: My New CF

Post by MattA24 » Subscribing Member » Tue Sep 25, 2018 7:00 pm
Joined: Wed Jan 15, 2014 9:06 pm
Posts: 203
Since last posting, I've mostly been looking sadly at the van sat out in the rain, but the sun is out again, so...

Fuel line out:

Image

Lots of different bits of pipe including some weirdy greeen stuff, some filters, a "fuelsaver", an electric pump, and a knackered mechanical pump. All to be replaced with a nice new bit of pipe and the glass-bowl-type mechanical pump off the donor van.

Radiator has seen better days:

Image

I'm reasonably sure the rad had all it's fins intact when I checked the van over before buying it and driving it home. I think they must have corroded to a fine lacework while it had been sitting in it's field, and got blasted away on their first journey in years.

I've also got the prop back in on a home-made centre bearing bracket. It's not pretty, so I'm telling myself it's a temporary bracket, just to check I've got it in the right place...

I noticed today that all the wires have fallen out of plastic multi-plug that goes into the back of the alternator, leaving me with no good way of working out which one went where. Anyone got any clues or a picture? (It's a '78 petrol) The wiring diagram in the member's area doesn't really help I don't think... :?:

I'm also puzzling over a fuel gauge that always reads full, but I've found another thread for that, so I'm off now to measure some Ohms.

Cheerio!

Re: My New CF

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Post by Phil Bradshaw » Club admin » Tue Sep 25, 2018 10:08 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
Which alternator is fitted?

Might not be original Lucas ACR or Delco DN460: a photo will help.
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: My New CF

Post by MattA24 » Subscribing Member » Wed Sep 26, 2018 7:45 pm
Joined: Wed Jan 15, 2014 9:06 pm
Posts: 203
Hello!

Phil, the alternator I've got fitted looks like this:

Image

(The thing in the foreground is the connector block that should be on the end of the wiring)

Here's the wires that fell out of the block and/or the back of the alternator:

Image

Does that give you any clues? :?:

***

I found another non-glass-bowl-type fuel pump in my spares box today. Then I sat for ages wondering why the actuator arm was such a different shape to the busted one off this van, I realised it had been intentionally cut off (presumably because the pump was busted, and was only stuck back on the van to block the hole in the crankcase). Spot the difference:

Image

***

I took a look at the fuel sender today too. I cleaned up all the earth contacts in the hope that was the problem, but it was still resolutely reading over-full. Next I took the sender out and wiggled it around, and Hurrah! - the fuel gauge seemed to move up and down as I would hope. A bit more experimentation and I noticed that it seems to work fine between zero and a quarter-tank, but reads extra-full at anything above that. I must have never gotten down to under a 1/4 tank on my drive home.

I guess this means the little coil of wire in the sender is broken somewhere along it's length. I guess I should pull the sender out of the parts van, but apathy is tempting because I'm planning to run the van mainly on LPG anyhow.

***

One strange symptom from the drive home that I'd entirely forgotten about until today is the oil pressure. When you start the van up from cold the pressure light comes on for a second or three then goes out once everything is primed. Once the van starts to warm up the light can come on at idle, but goes out when you rev up. As it gets warmer and warmer, the amount of revs needed to keep the light out gets higher and higher, until the light is permanently lit.

I remember reading somewhere ages ago that this could be the pump, or the pickup in the sump, or the oil pressure sensor itself.

Hoping it would be the latter (because it should be the easiest thing to test) I took the sensor from the parts van with the intention of swapping it over, however no amount of might could get the suspect sender to shift.

Annoyingly (and unlike the one from the parts van) it is designed such that a socket can't be put over it, thanks to a sticky-out bit on top.

A rummage in my parts box turned up a spare oil pump. Is it worth swapping this over? Or is there a better way to diagnose this problem before I pull the distributor out? :?:

The spare pump I found is one I remember working okay last time it was in a van, but on examination I noticed there was some little holes in the casting at the tail end of the bolts that hold the bottom cover on. Does this compromise the pump at all? :?:

Image

***

Also, while I'm in a questioning mood, what is this thing clamped to the back end of one of my rear leaf springs? :?:

Image

Cheerio!

Re: My New CF

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Post by Phil Bradshaw » Club admin » Wed Sep 26, 2018 9:10 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
Alternator wiring -

Image

Moulded sockets can be deleted if each wire has a new terminal and insulator sleeve fitted.

If the alternator turns out to be faulty then replace with any later '2-wire' type thet will physically fit. Peel back harness tape to reduce wires to one each thick brown, brown+yellow and thin brown; discard brown+yellow loop-back wire. Bend back thin brown wire into harness and insulate: it's redundant for 2-wire installations.

Connect thick brown and brown+yellow to alternator output and warning terminal respectively. If 2-wire alternator has a terminal on the case itself then connect an earth lead as thick as the thick brown lead between the case terminal and engine.

Oil warning: if the engine doesn't rattle any more than usual when the light is on then switch probably is dying (and may be starting to leak as well); replace switch.

To remove switch with hexagon below switch body: snap off body then wedge (or bash) a tight fit socket on the switch hexagon: use a hexagon socket rather than bi-hexagon which may slip. Apply long bar with feeling.

Oil pump: cover screws are in threaded through holes.

Tank unit: if the resistance wire is intact then suspect poor connection at pivot for the float arm due to corrosion.

Spring thing is a (sort of) adjustable assistor which may or may not prevent reverse bend of the taper leaf spring when van is laden. With coil assistors as well that may mean a history overloading...
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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