5 replies to this topic

[lenny20]

Hello
Can anyone help. My sons 998 engine blew up and we replaced it with an engine from ebay sold as a runner. Having had it fitted the mechanic could not get it to start and using a compression tester it is showing 150 on 1, 45 on 2 and 120 on 3 & 4. They have put oil down the bores and it has improved the readings on 1,3&4 which they say means no2 cylinder piston ring has gone and the engine is no good. They also say there is no way the engine was a runner before it was sold to us. I still have the cylinder head from his old engine so is it worth trying this head (bottom end problem before) or do you agree that it is the piston ring that has gone and if so could it have been a runner before. Obviously the person that sold the engine is now ignoring my emails. Any help would be brilliant.

[Ethel]

You could ask why they never did a compression test before fitting it.

It could be a head gasket or valve problem and you have nothing to lose by pulling the head off to find out if you can't sort it out with the seller. Afraid you always take a big risk buying an engine you can't at least see running.

[blacktulip]

i second what ethel has said.

[Scruffs]

Hello
Can anyone help. My sons 998 engine blew up and we replaced it with an engine from ebay sold as a runner. Having had it fitted the mechanic could not get it to start and using a compression tester it is showing 150 on 1, 45 on 2 and 120 on 3 & 4. They have put oil down the bores and it has improved the readings on 1,3&4 which they say means no2 cylinder piston ring has gone and the engine is no good. They also say there is no way the engine was a runner before it was sold to us. I still have the cylinder head from his old engine so is it worth trying this head (bottom end problem before) or do you agree that it is the piston ring that has gone and if so could it have been a runner before. Obviously the person that sold the engine is now ignoring my emails. Any help would be brilliant.

Third from me to what ethel said

Since it wasn't hot then the compression readings won't be particularly accurate anyway, but to what degree I don't know...

If oil improves a cylinder's compression that shows the rings/bores are worn in that cylinder only, as it bungs up the ring gaps and any scores in the bore. What happened to the reading on 2 when the oil went in?

I bought my current engine as an 'absoluter minter' (that phrase alone should've raised suspicions..), cleaned it up, painted it, dropped it in and found the gearbox wouldn't select gears. So yeah, risky business!

al

[dklawson]

As above, contact the seller, it appears you were mislead.

Google the subject of "leak down testers" and after you're more familiar with that they can tell you, ask the garage to perform a leak down test on the engine. That will very quickly tell you if its worth pulling the head or not and will be ammunition in any dispute you have with the seller.

[ginigwunkle]

ive just done my compressions and i got

1 - 180
2 - 169
3 - 172
4 - 175


i thought mine were out, haynes says if more than 15psi out between two valves then either the rings or valves are gone......

check the head out otherwise its just new piston rings not neccesarily a new engine!