Low compression on 1980 carb. VW Rabbit engine

[Gene]

My nightmare started last fall when the temp dropped to 80

Topic

[johnzcarz]

Can you confirm what the compression reading was right after installing the head gasket (but before it started to act up)?
60PSI is very low, I would think you need to be at least in the 100-120psi to run.

You need to find out where the compression is leaking to. The way to do that is using a leakdown tester.

This should give you an idea of what to do:

http://www.youtube.com/watch?v=WgrfT0LFMhc

BTW- you don’t actually need a leakdown tester to do this – you should be able to find a sparkplug adapter at the parts store that allows you to hook up your air compressor hose and pressurize the combustion chamber. Then just listen (and look) at where the air is escaping and you will have your answer.

[dreamer2355]

Welcome to the forums.

+1 on the above post.

You have to make sure when you are doing your compression test that you are doing it at WOT.

Did you do a cooling pressure test or use a block tester to confirm you have a head gasket issue?

Are you loosing coolant? Does your radiator fan work?

Here is a video Eric made on diagnosing a overheat issue –

http://www.youtube.com/watch?v=hUzOTnsWImI

And another on bleeding air out of a cooling system. Air in cooling systems can array to alot of issues –

http://www.youtube.com/watch?v=zUpXgAJ1 … ure=relmfu

Next time the vehicle does not start, i would look to see if your missing spark or missing fuel.

Keep us posted.

[kevzo01]

i can confirm that johncarz is right you would need at least 120 psi at minimum to start i (been a vw mk2 golf owner for around 7 years now)….before i try to help you could you verify;
timing is correct (we all make mistakes),
which engine is is it?
before renewing the headgasket was the cylinder head skimmed and pressure tested?
if you dont have a spark or fuel issue does the manifold pre heater work?
if it does run, do you have any bubbling in the coolant?
did you bleed the cooling system beforehand?

early mk1’s did suffer from engine cracking but when they did it was obvious.

• if you do suspect a crack in the engine and unable to pressurize the sytsem with tools or by cranking try this;

with the engine switched off and spark plugs removed, fill the coolant to the max and re-cap tightly, and by hand; pump the pipes for about ten minutes inspecting the the cylinders and around the engine for leakage and check if the coolant level drops (this might not be accurate for hair line cracks but will work for severe cracks).

[Matt]

Quoted From dreamer2355:

You have to make sure when you are doing your compression test that you are doing it at WOT.

Winner.

[EricTheCarGuy]

Yes make sure you do the compression test properly for starters but I didn’t see you mention anything about the cylinder walls when you replaced the rings, it could be that the cylinders are worn out and you need to bore it out and install larger pistons in order to gain compression again. For now I would recommend you do a leak down test so that you know where the compression is going first.

[Trcustoms719]

Yup, 60psi is about half of what you should have.
No sense in adding any more info at this time, everyone else beat me to it.T)

[Author]

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