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EP3 BARE ENGINE SHOWING 1 HIGH 1 LOW AND 2 SAME COMPRESSION READINGS

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9
I have recently bought an engine from a car breakers. I have just done a compression test by turning the starter motor over by putting a power pack on it . The readings show ( left to right) 10bar. 6bar 7bar 7bar . Is there something I’m doing wrong? I know they’re supposed to be all the same but with it being a bare engine with no exhaust mani gearbox and air filter etc should that affect the results?
If there’s anything you think I’m doing wrong please let me know thanks.
 
Yes you're meant to have the throttle wide open to allow full air into the cylinders, otherwise it is working under a partial vacuum trying to pull air through the closed throttle and can give varying readings. Let's hope it comes back as okay when you try again.

Sent from my Mi MIX 2 using Tapatalk
 
Yes you're meant to have the throttle wide open to allow full air into the cylinders, otherwise it is working under a partial vacuum trying to pull air through the closed throttle and can give varying readings. Let's hope it comes back as okay when you try again.

Sent from my Mi MIX 2 using Tapatalk

Hello, thanks for your input . I’ve just tried with the throttle open and it’s come back with the exact same readings and they all hold their pressure. Not sure where that leaves me now. It’s looking like a dodgy engine.
 
If you're keeping the engine/car long term, give it an overhaul and rebuild to make it right, and make it last.

If you're not, and/or you're on a budget - bounce it back to the seller.

A leakdown test could also give you some more insight.
 
If you're keeping the engine/car long term, give it an overhaul and rebuild to make it right, and make it last.

If you're not, and/or you're on a budget - bounce it back to the seller.

A leakdown test could also give you some more insight.

It’s for a trackday car , oil surge ruined my last engines bottom end shells and scored the crank. I was informed that machining the crank and buying bigger shells would work but only for so long. So was advised to find a new engine.

The breakers sold me the engine saying it was a great runner but going off them readings it doesn’t sound like it will be.

Problem with these breakers is you can’t even take anything off to see what could be causing it because of the paint they smear all over the bolt and gaskets and once they see it’s been opened they void the warranty. Looks like it’s going back. Thanks everyone for your input.
 
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