Jump to content
The mkiv Supra Owners Club

Stood engine, low compression 4 cyclinders....valves or head gasket?


n boost

Recommended Posts

Ok guys, probably posted this in the wrong section but as title............if a engine has been out of a car for 8 mths and then fitted/started and u find low compression in 4 adjacent cyclinders............how would u know if it was valves or headgasket without removing head?

 

I know u can't be 100% sure until removed,but must be some ways to give u a rough idea.

 

Basically bought a engine of a guy who had it removed over 8 mths ago and when fitted, we found compression low in 4 cyclinders( 1+2/4+5).......3 & 6 were ok.

 

The guy i bought it off insists, their was nothing wrong with it as it was removed from his own car but then again they all say that.

On the m3's it cause's the car to det badly which can be heard whilst driving in gear very easily although in neutral everything is perfect.

 

So any pointers in trying to identify the problem without ripping the engine apart?

Already squirted oil down cyclinders and no change in compression, so rings ok.

 

P.s..the engine is for a bmw m3.

 

Thanks in advance.

Link to comment
Share on other sites

Leakdown test will tell you if its rings or valves, i'd be supprised if you've got headgasket failure across 4 cylinders.

 

I've seen this engines with headgasket cracked between each and every cyclinder before!

 

Their is like 5 mm between each cyclinder, so they can crack quite easily.

 

Its just that the guy who sold it (who i've threatened to take to court) insists it was fine as it came out of his own car and having only 40k miles seems a bit odd for the headgasket to let go.

They normally go around 100k but a mate mentioned something about damp/moisture causing rusting around the valves which may not be seating properly.

TBH its most likely the gasket as i can't see valves in 4 cyclinders all not seating at the same time.

Link to comment
Share on other sites

sorry mate were did you here that the head gasket goes at 100k. that surlely is not the case

 

 

Not on all m3's but i have personally heard/seen 7 cars that have had this issue and all their mileages were over 100k but again i know of m3's with over 175k and still on original gasket.

Link to comment
Share on other sites

Isn't the cam chain tensioner run via oil pressure a bit like a hydraulic lifter, so if its been stood for 8 months the oil coil have drained out enough to cause the tensioner to slack right off letting pistons hit valves ?

 

Did you crank it over without running it to get the oil pressure up ?

Link to comment
Share on other sites

Isn't the cam chain tensioner run via oil pressure a bit like a hydraulic lifter, so if its been stood for 8 months the oil coil have drained out enough to cause the tensioner to slack right off letting pistons hit valves ?

 

Did you crank it over without running it to get the oil pressure up ?

 

Oil pressure's fine..........had the engine running hot prior to doing the compression test.

 

I think the guy who sold it knew the headgasketwas gone and pulled a fast one.

Will be speaking to trading standards to get some advice and might end up taking it to small claims court.

Link to comment
Share on other sites

I cant see why a head gasket would fail just because the engine hadnt been used for ages. I can imagine valves sticking though.

 

 

I know.............the prick who sold it must have known the gasket was goosed and being from rural wales had fcuk all garages around to do the work for him, so flogged it.

 

I bought it through ebay and paid partly by gaypal thinking i would atleast be protected for this amount but gaypal fcuked me up and said i couldn't claim a refund because i had picked it up!

Ebay themselves are a bunch of clowns who have all this buyer protection bullshit but really its just the same as paypal.

When paypal refused to refund i contacted ebay under their pritection policy and they said paypal had told them not to open this case........i mean WTF is the buyer protection about then!

Link to comment
Share on other sites

I know.............the prick who sold it must have known the gasket was goosed and being from rural wales had fcuk all garages around to do the work for him, so flogged it.

 

I bought it through ebay and paid partly by gaypal thinking i would atleast be protected for this amount but gaypal fcuked me up and said i couldn't claim a refund because i had picked it up!

Ebay themselves are a bunch of clowns who have all this buyer protection bullshit but really its just the same as paypal.

When paypal refused to refund i contacted ebay under their pritection policy and they said paypal had told them not to open this case........i mean WTF is the buyer protection about then!

 

The best thing you can do is ignore the lot of them and go straight through small claims. There's lots of good stuff on the net about the sale of goods act, distance selling and your rights, so Google that and do some reading first if you haven't already

Link to comment
Share on other sites

Oil pressure's fine..........had the engine running hot prior to doing the compression test.

 

I think the guy who sold it knew the headgasketwas gone and pulled a fast one.

Will be speaking to trading standards to get some advice and might end up taking it to small claims court.

 

I dont doubt it is now but for a few vital seconds when it was first started was it ?

With any engine thats been stood that long or on a new build you'd crank it over with the coil lead and plugs out to get the oil pressure light out, then fire it up ?

 

If your right which it sounds like your 100% its headgasket just take the head off and then it'll be quite obvious, then the guy wont have a leg to stand on.

Edited by Dnk (see edit history)
Link to comment
Share on other sites

I dont doubt it is now but for a few vital seconds when it was first started was it ?

With any engine thats been stood that long or on a new build you'd crank it over with the coil lead and plugs out to get the oil pressure light out, then fire it up ?

 

If your right which it sounds like your 100% its headgasket just take the head off and then it'll be quite obvious, then the guy wont have a leg to stand on.

 

The guy i bought it off isn't answering his phone now and yesterday said he would send £200 towards the repair costs, which proves he must have known about the fault.

 

Only problem i have is, i picked the engine up from a garage and dont have this guys home address.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.