trackday killed the engine - ideas please

[Daz Clio Cup]

Hi,

I killed my engine at the weekend on a trackday, or so i thought

I missed 3rd gear and possibly over reved. engine cut out and wouldn't restart, but turns over like the plugs are out. suspected no compression / bent valves. no compression confirmed by testing. Prepared myself for the worst.

however, i did some more tests, pressure tested the cylinder, through the spark plug hole with an airline, and if i get the engine in the right place on each cylinder, it holds pressure! the pressure will even rotate the engine. however i did notice it only rotated it a small amount before the inlet or exhaust valves open and let the pressure out.

now i'm stuck for ideas as if i had bent my valves it wouldn't hold pressure. is there a possibility the cam timing is wrong, eg just jumped a tooth or pulley slipped on the cam? or something else?

thanks Daz

 

[Jay Payne]

worth checking the timing by the sounds of it.

You wont need the tools to do a quick check. Just take the blanking caps out and line up the tdc mark on the gearbox/flywheel. If its out more than a little you will see it by eye.

As you say if its holding a presur at a certain ponit then maybe the valves are ok. Dont you run different cams?

 

[Daz Clio Cup]

yeah 422 catcams. surely with that cam and high comp pistons, if the cam timing was out, i'd have valve/piston contact?

 

[Jay Payne]

You'd think so yea. check the timing and go from there

 

[Riley!]

if its slipt one or two teeth you might of got away with it. And yes this is possible from missing a gear

 

[Daz Clio Cup]

if its slipt one or two teeth you might of got away with it. And yes this is possible from missing a gear

and cause zero compression on all cylinders?

 

[Riley!]

the more teeth it has slipt the more likely it is to give a zero compression reading. Shame that only spotted you turning off pelham bridge other week. Think you saw me too.

Take the two cam seals out and see if you can get them to line up

 

[Riley!]

have you tried turning it over by hand? see what it feels like . . .

 

[Riley!]

if the cams do line up. Time to check the bottom pulley. Not un-heard of them slipping round

 

[Daz Clio Cup]

Checked the timing..............bottom pulley at TDC, Exhaust cam 1 tooth out and Inlet cam 90 degrees (sommat like 8 teeth) out! When turning over by hand there is piston to valve contact but only just.

So i retimed it ( gonna change belt and tensions before i start it) and both cams seem to be about 1/2 tooth out. Whether this is due to it not being properly timed before or the pulleys have slipped.

mmmmm


Daz

 

[sammyhale22]

How do you remove those blanking caps without destroying them? Last time i took one out i had to puncture a hole in the centre and pull it out that way.

Samuel

 

[rich-6]

TBH mate if theres been valve contact with the pistons i wouldnt refit another belt and start it up again, It will tap its tits off and in time drop the valve which will make it a more expensive repair than you have already!

 

[mark123]

Take the cam cover off

Don't think you can.

 

[f0xy]

you just have to undo the first few rows of bolts slightly to raise the cam cover at that end and you will be able to pop them out undamaged.

 

[Riley!]

thought they are meant to be replaced everytime

 

[Daz Clio Cup]

TBH mate if theres been valve contact with the pistons i wouldnt refit another belt and start it up again, It will tap its tits off and in time drop the valve which will make it a more expensive repair than you have already!

The valves aren't damaged because it does a leak down test fine

 

[mark123]

Maybe with your pistons the valves can't really bend and all the force is fed to the lifters and they've collapsed?

 

[ben_p]

How the f**k did it slip if you missed a gear? mine used to bounce off the limiter all the time and had no issues.

Didn't you say you were down on power a while ago, running only 210hp? Maybe its been a gradual thing?

 

[f0xy]

his limiter is like 8200 isnt it daz?....what was yours ben...

 

[ben_p]

7800 with 421's

going to 7950 with 422's

 

[f0xy]

aye daz mentioned his was 8200 when it happened

 

[Daz Clio Cup]

lol i wish. my soft cut (ignition) is at 8k. my hard cut (fuel) is at 8.1k.

I missed 3rd, nailing it out of a bend keeping up with an expensive TVR, and he wasn't getting away! basically floored the throttle from about 6 - 6.5k thinking i had got third, but i'd hit in between 1st and third! so no grinding gear to make me think i wasn't in! I couldn't tell you what revs i hit, because i've never floored it in neutral before, but believe me it revs quick enough just touching the throttle!

yes my power was down and the exhaust cam nut was loose too! haven't got the cap of the vanos pulley yet, it's too tight! (meant to be torqued to sommat like 15 ftlbs!)

so i'll keep plodding on and see what other horrors i find!

 

[Daz Clio Cup]

How do you remove those blanking caps without destroying them? Last time i took one out i had to puncture a hole in the centre and pull it out that way.

Samuel

That's how i take them out, they are £12 from stealers for the pair!

Take the cam cover off

Don't think you can.

you just have to undo the first few rows of bolts slightly to raise the cam cover at that end and you will be able to pop them out undamaged.

true, but then you have to reseal the cam cover, and i'd rather waste £12 than disturb that, cam belt, both pulleys etc, etc. cos you can't get the cover off without taking the pulleys off, and you may not get a good seal without doing so

thought they are meant to be replaced everytime

That's what i thought

 

[f0xy]

i was told by quite a few people on here if they are undamaged when removed (ie removing whole top cover) they can be reused without a problem

but meh! I guess its only £12. Mine are re-used and they have been fine.

 

[Daz Clio Cup]

i was told by quite a few people on here if they are undamaged when removed (ie removing whole top cover) they can be reused without a problem

but meh! I guess its only £12. Mine are re-used and they have been fine.

Yes i agree if you are taking the top end apart and they are undamaged, then why not, i'm not, just doing cambelt change and timing so i have to replace them

 

[Riley!]

so you still sticking with the plan of timing it all back up and hoping for the best?

 

[Fred@BTM]

i'd be surprised if that works! sounds like some decent damage, i'd pull the head off

 

[Daz Clio Cup]

I'm not 'hoping for the best', it will get done properly, TBH if it had been done properly in the first place this may well of never happened, but that's a different story.

Prepare to be suprised.........maybe. TBH i don't know what has been done yet. the engine still tuned over by hand with no resistance eg valve contact and the cylinders are sealing with no leaks.

the valves cannot be bent if it's sealing and it turns over freely by hand , so no contact.

we'll see

 

[bing_17]

You said in an earlier post that; turning over by hand you can feel the valve's just touching the piston? But you've just said the opposite.. so which is it? Personally i'd whip the head off and ivestigate, no more turning it over, even by hand. Thats just me though.

 

[shadowsun]

I have no idea what you guys are on about, but it sounds serious

 

[ben_r1]

You said in an earlier post that; turning over by hand you can feel the valve's just touching the piston? But you've just said the opposite.. so which is it? Personally i'd whip the head off and ivestigate, no more turning it over, even by hand. Thats just me though.

Sounds like damage is already done lol, turn it over all ya want.

Does it start? or turn over on the motor?

I havent a clue what it could be just interested on how this ends up...

 

[Daz Clio Cup]

You said in an earlier post that; turning over by hand you can feel the valve's just touching the piston? But you've just said the opposite.. so which is it? Personally i'd whip the head off and ivestigate, no more turning it over, even by hand. Thats just me though.

Sorry i do apoligise, i got confused with the resistance felt at the top/bottom of the piston stroke and actual valve contact

 

[Daz Clio Cup]

Sounds like damage is already done lol, turn it over all ya want.

Does it start? or turn over on the motor?

I havent a clue what it could be just interested on how this ends up...

I hate to say this, but read your last sentance first and then ask yourself why you stated the other 2 comments....... It doesn't start, it has no cambelt on it! There has been no sounds to indicate damage! and i will turn it over all i want because even if there was damage, it aint going to make it worse!

I can't understand you guys sometimes, if you'd come across an engine, unknown history, good compression, runs fine etc, would you waste best part of £500 stripping it to make sure it's ok? Surely if i have good compression, I can't have done any damage?

 

[bing_17]

I hate to say this, but read your last sentance first and then ask yourself why you stated the other 2 comments....... It doesn't start, it has no cambelt on it! There has been no sounds to indicate damage! and i will turn it over all i want because even if there was damage, it aint going to make it worse!

I can't understand you guys sometimes, if you'd come across an engine, unknown history, good compression, runs fine etc, would you waste best part of £500 stripping it to make sure it's ok? Surely if i have good compression, I can't have done any damage?

I wasn't having a go mate, but just from what you have said in earlier posts about what happened and the problems you had. Even if it now tests ok compression wise *I* would still have it apart.
What ever happened wasn't good and the next thrashing it has may well be fatal for the engine.
Like i said not having a go, just my 2p

 

[Daz Clio Cup]

I wasn't having a go mate, but just from what you have said in earlier posts about what happened and the problems you had. Even if it now tests ok compression wise *I* would still have it apart.
What ever happened wasn't good and the next thrashing it has may well be fatal for the engine.
Like i said not having a go, just my 2p

i know mate, np

 

[ben_p]

I would re time it up on the old belt, give it a good 10 turns by hand, see if it feels ok.

If not, strip it down!

If all is good then wip a new belt kit on, only cheap!

 

[Daz Clio Cup]

i'm in the middle of timing it with old belt and new belt is on it's way. Trying to get a camera to look down cylinders this weekend

 

[Gary172cup]

Fingers crossed for you !

 

[Daz Clio Cup]

Right a bit of an update:

Got the new belt on, and running - however top end really tappy, and knocking noise from down below on overrun. buggar

got the cams out again, to find, all the lifters had locked solid! sorted that, back together again, tapping has gone but knocking is still there!

come on then whats yours guesses and i'll tell you what else i've found without taking anymore of the engine apart ( a clue)

 

[Russ_16v]

how low is the knocking noise? its gotta be top end related im guessing if you havent stripped it down further