85' Mk2 2.0 OHC Compression

[Urquattro]

Hi there! Here is a quick resume of the story... I'm trying to save a Mk2 mini bus, the van has been sitting outside for over 20 years now.... however the owner claims the the engine was running ok before stopped. The van is pretty solid overall, I popped some fresh petrol, new oil and filter and it started after some time. I drove it around for some time but there is no power, after digging some time I found that the iginition timing was very out so I adjusted and it improved a lot, however there is a lot of blue smoke coming from the exhaust, specially during iddle and low revs... I checked the compression on the cylinders and I got 90-110-120-80 ( dry and wet very similar values). What do you think? Should I start lifting the valve train first or should I just take the engine out for an entire rebuild. Mi idea was to get it running as cheap as possible for now as I have more projects. One thing to mention is that I did the compresion test with the throttle closed, will that change the values? I would really appreciate your input

[metalworker0]

Compression test should be done with throttle wide open ..also all sparkplugs removed.

Brand new it would have been above 130 ish

Perhaps its stood so long that it has a bit of surface rust on the valve seats ..perhaps needing good run .

Also being so old , it may NOT have been fitted with hardened valve seats to cope with unleaded petrol

Unleaded was introduced in 1986.

The head on this engine was cast iron with valve seats cut directly into the cast iron..no separate seats ...the conversion involves a machine shop machining the heads to take separate hardened exhaust valve seats.

Note: there is no way of telling if its had this mod without taking the head off

Note: as the old style valve seats wear out prematurely with unleaded, the valve clearances close up, this causes loss of compression..so valve clearance adjustment will be required.

Also ..valve stem seals harden and will not seal ..that would explain the smoke....or wrong oil grade put in (which is easy to do these days as the older grades are hard to find) ...should be 15w40 in the UK

all the best.mark

[dumper]

Yes agree start with the valve clearance back in the day you could get a tool for the pinto to charge the valve seals with out removing the head .you could put some oil and diesel mix in the bores and let it stand over night it will help free off any sticking piston rings .
No matter if this helps or not it’s important that you change the camshaft oil spray bar used to be a common problem of them blocking up and killing the camshaft and rockers the oil pump drive can also wear and lose drive on the engine.

[Urquattro]

Hi again and thanks a lot for the previous answers. I did make a compression test again but this time dry, without spark plugs and throttle wide open, I got significant better values, 100-125-125-95. I also checked the valve clearances, they didn't seem to be bad, Exhaust had 20 and it should have 25 and inlet should have 20 and they had 15, so I did adjust them but it hasn't improved much. I also replaced the oil for a 20w50 as I had a thinner oil. I'm thinking now of the distributor contacts, when I take off the HV lead on cylinder 2 the engine still running rough but if I put the lead a couple of cms away I can listen to the spark and the engine seems to be running better, so maybe a faulty spark plug? any opinion would be very appreciated. I'm also curious about the compression, do you reckon is low?

[metalworker0]

Cylinder 1 and 4 are low

But because of standing, may have gummed stuck rings , to check this; put a table spoon of oil into each cylinder ..if compression test improves, its the pistons , rings bores ..or simply gumming /stuck rings .

To free stuck rings .
There are various additives that you can add to the oil that will free them up. add a can run at 2500 rpm for 30 mins..than drain and add new oil.
others suggest wd40 in the cylinders for a couple of days-- get all the cylinders level ..add perhaps 100ml to each cylinder.

This fellow had exactly your problem (car left for years) ..and was improved by the additive treatment - he is experimenting with this to see different results. with products - many are USA products - so you'll have to do some research what available here .wynns etc

https://www.youtube.com/watch?v=N1RjnwVSbg8

and again here

https://www.youtube.com/watch?v=-ruifvPjqME

if these treatments don't work ..then it's an engine rebuild time

ps -- dont know if 85 had contact points ..was maybe electronic ignition ..dizzy still there ..but pointless ignition.

The rough running - Could also have an old stale fuel issue ..and rust in fuel filter and tank issue

all the best.mark

[bortaf]

back in the day a good dose of redex down the bores and let it sit for a few days would be the fix for stuck rings ?