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valves , time to sort them out .

Post by johnnyonions » Subscribing Member » Thu Nov 26, 2015 2:10 pm
Joined: Tue Apr 28, 2015 11:33 am
Posts: 308
The old van hasn't been running right for quite a while overheating , sooty plugs the usual script , but with a box of clean plugs and usually get there and back
The latest run out on a 30 mile round trip New plugs started out reasonably well but lacking that va va boom ! Not that it had much in the first place well in the last couple of mile it was a bit of a pain with the van running really rough with the odd backfire which ain't quite a good thing at the moment ,
I've had the van for 15 years . Not had all that much of a problem with it , biggest one was the gearbox going earlier on in the year and the the front near side brake seizing up .
So decided to look at the valves and camshaft as they had never been adjusted the whole to me I've had it , had a look at last year putting a camshaft cover gasket on and noticed that no 4 exhaust valve was at the maximum adjustment so left it at that with the thought of putting an undersize adjuster screw in at a later date , .......well that date has arrived , I'm going in! :o .

Re: valves , time to sort them out .

Post by johnnyonions » Subscribing Member » Fri Nov 27, 2015 12:12 pm
Joined: Tue Apr 28, 2015 11:33 am
Posts: 308
Took some gap readings none are close to correct.

Cold engine readings .021. .013

Front to back ......pot one. Exhaust .030 inlet. .005
pot two. Exhaust .014. inlet .009
pot three. Exhaust .000 inlet. .005
pot four. Exhaust .000. inlet .010
I couldn't get my feeler guage under the exhaust valves of three and four cylinder s,
The adjuster screw in number three exhaust seems to missing altogether ? So will have to remove the camshaft housing to investigate further .

John

Re: valves , time to sort them out .

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Post by VDUB384 » Club admin » Sat Nov 28, 2015 9:58 am
Joined: Wed Sep 12, 2012 9:01 am
Posts: 1396
Hi John it looks like you've found your problem,those exhaust valves that are reading 0000 with engine cold are going to be slightly open when the engine warms up that's why it's running crap, you might get away with removing the cam box and sorting out the adjusters. If however it's been running like this for a while I think your valves will need reseating for the best performance.
Dave
Whilst good maintainece is the best prevention"If its not broken don't fix it."
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Re: valves , time to sort them out .

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Post by Phil Bradshaw » Club admin » Sat Nov 28, 2015 3:14 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3818
Once the camshaft housing is removed try a cylinder compression test.

If you get reasonable figures from the iffy cylinders then the affected valves may seal well enough to run them with slack clearances to see whether they will hammer into their seats and restore compression.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: valves , time to sort them out .

Post by johnnyonions » Subscribing Member » Sat Nov 28, 2015 10:29 pm
Joined: Tue Apr 28, 2015 11:33 am
Posts: 308
Thanks for the feedback


Going to try and get the correct settings /gaps then I'll have the cam housing off . The housings got to come off anyway due to the adjuster screw in cylinder number three exhaust wotsit missing or something , had a squint down the hole and couldn't see the Allen key hole. ??? to adjust it.
Should I clean the hydraulic cam followers when I take the housing off ? Seen a few videos youtube , seems an easy job , or just leave them alone ?
Got the grill and front off , radiator removed cambelt cover off , the Cambelt tensioner was really stiff to turn oiled it up a bit and freed it. Will get another cambelt and use the old one as a get you home spare.

Noticed the the horizontal elements on the radiator are starting to crumble at the bottom , that looks a bit concerning , might be looking for a spare rad in the not too distant future. Replace or repair that is the question. It's a long time since I had one repaired .

John

Re: valves , time to sort them out .

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Post by Phil Bradshaw » Club admin » Sat Nov 28, 2015 11:30 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3818
If you can't see the blind end of No. 3 exhaust tappet screw in the hole in the tappet opposite to the notch in the top then the screw may be broken; even when the blind end is as far as the tappet wall and trying to jam against the housing the hexagon still should be accessible from the notched side of the tappet.

Tappets on the Vauxhall OHC engine aren't hydraulic; it's the Opel CIH and Holden 3.3 litre engines that have those.

Radiator horizontal fins do crumble away before the vertical tubes start to leak: leave alone if the radiator isn't leaking or too heavy once dry (much more than 6.4kg indicates sludge accumulation inside).
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: valves , time to sort them out .

Post by johnnyonions » Subscribing Member » Tue Dec 01, 2015 2:01 pm
Joined: Tue Apr 28, 2015 11:33 am
Posts: 308
Hello
I have just taken.the camshaft housing off the engine for a closer inspection , pot three and four exhaust valves are at the end of there adjustment , a problem adjusting no' three pot adjuster , I thought the adjuster screw was broken but on pulling it out found that whoever put the screw in , put it in the wrong way round ie from the un- notched hole (I wasn't aware there was another hole :oops: ) so learned something new . Having g re read Phil's previous post It should have dawned on me what he meant by “blind hole“the
A question can I file the adjuster screw to give me some more adjustment ? , I have one underside screw I bought a year ago from ABC which cost about £8 which is the next size up but don't think it's enough or should I just dig into the coffers and get two max size sent .
I know the valve/valve seats might be worn but that's another story .

John

Re: valves , time to sort them out .

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Post by Phil Bradshaw » Club admin » Tue Dec 01, 2015 3:15 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3818
Adjuster screws can be ground on the taper face but the taper angle should be altered if a lot of material is removed.
More information in Vauxhall OHC (slant) Camshaft Assembly Overhaul and Vauxhall OHC (slant) Cylinder Head Overhaul in the Reference Library. :thumb:
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: valves , time to sort them out .

Post by johnnyonions » Subscribing Member » Thu Dec 10, 2015 11:48 am
Joined: Tue Apr 28, 2015 11:33 am
Posts: 308
Put on an oversize camshaft housing gasket 1.5 and have got a good amount of adjustment without having to put underside adjuster screws in gave it a run of about 30 miles but need the gaps closing slightly less . waiting for 1/8 adjuster tool to arrive from eBay . can't bugger about with an Allen key anymore it's just too fiddly.
Next on the shopping list is a compression tester :thumb:
John

Re: valves , time to sort them out .

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Post by Phil Bradshaw » Club admin » Thu Dec 10, 2015 3:09 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3818
There's no harm in running with valve clearances on the slack side (1 click anyway, about 0.003 inch) after being too tight.
This will allow room for the valves to hammer their seats back into shape, especially the exhaust valve seats, and gradually improve cylinder compression.

Whether you adjust to spec. or slack you'll have to check the clearances fairly soon anyway (about 1000 mile) and also monitor cylinder compression to be sure that no lasting damage has been done to the valve seats.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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