Engine failure questions (pics)

[matt dunn]

Surely the "professional workshop" would've checked the timing before/during the transplant, especially if they changed the ignition system

Was running fine for a week or more and then got progressively slower and lower on power. Eventually stopped going and opened up to discover the following.

Would suggest that the ign timing and cam timing was correct when it left the workshop, and developed a problem after a week or so, and the owner just drove it to death.

[Lloyd]

Well thats how I'm seeing it also. I would have thought they would pick up on it. Seemingly they reckon cam timing and everything was correct when the covers came off but I really cant see how that would be the case.

[Mr Revhead]

who actually pulled it apart?

so, they are saying they pulled it apart and all looked perfect untill the head came off?
yeah right.

[rollaholic]

agree with cambelt failure theories.

personally i would never put a secondhand engine in a car without replacing the cambelt etc, the professional workshop you speak of is just trying to shift the expensive looking blame. they took a secondhand engine, fiddled with the ignition setup, changed the ECU and expect you to take the blame when it goes pear shaped?

tell them to take a flying leap imo.

[Mr.Phreak]

Would suggest that the ign timing and cam timing was correct when it left the workshop, and developed a problem after a week or so, and the owner just drove it to death.

I agree, so I can't see it being any liability on Lloyd's part....Hell, a lot of wreckers only offer a start up warranty, why should you expect more from a private sale.

[KinLoud]

Bits of #4 found in #1 cylinder - most likely that bits were fired out the intake ports once the valves broke and then got sucked into #1 cylinder.

Ewan (10k20v) had a very similar result when his modified 4age 20v silvertop dropped a valve due to dodgy modified valvestem. Engine outfit who reground the cam for him welded extra material onto the end of the valve stem in order to make up for the smaller base circle... this broke eventually and dropped the valve into the cylinder.
trying to find a pic of it...



Ken
Ham
021 408 863

[Alex B]

Would suggest that the ign timing and cam timing was correct when it left the workshop, and developed a problem after a week or so, and the owner just drove it to death.

I agree, so I can't see it being any liability on Lloyd's part....Hell, a lot of wreckers only offer a start up warranty, why should you expect more from a private sale.

Because the shop in question is saying it has the wrong pistons. The engines new owner knew from day one it had GZE pistons.

[Mr Revhead]

seems the shop in question isnt familiar with 4age turbos with 20v heads.

[Pelo]

It sounds similar to what happened to my 16v gze moons ago. The crank timing woodruff key slowly wore away to nothing due to the oversize pulley, over about 4 days it got slower and slower until it wouldn't start one morning. The key had disappeared by then.
On a 16v it just stops but with a 20v I guess the consequences would look like this!

[sergei]

It sounds similar to what happened to my 16v gze moons ago. The crank timing woodruff key slowly wore away to nothing due to the oversize pulley, over about 4 days it got slower and slower until it wouldn't start one morning. The key had disappeared by then.
On a 16v it just stops but with a 20v I guess the consequences would look like this!

if it was stock silver top it would just stop as well, but being a hybrid it changes everything. Although a blacktop would fail in similar way.

[gepsk8]

its buy beware, with private sales, its a risk he took. that all of us take!
did give him warrenty?
motor been pulled apart by a bais party so u can't stand by what been said.

[Flannelman]

FIRST question - this doesnt happen quietly. or gradually!! did you hear this mechanical disaster take place?
If you didnt then it was like it before you got it. or it happened outside your earshot.

Im not familiar with the hybrid turbos, but to me it looks as if both intake and exhaust valves have touched the piston.
Does someone know what the valve-to-piston clearance is? repeated hitting on the limiter or timing belt stretch under full acceration - full de-acceration could cause the indents on all pistons. may do if the belt is old... If the clearance is too close its a posiblity

Timing belt failure would be easy as the belt is broken, and jumped tooth would only have been found on dis assembly of the engine. Who took it apart? Was anyone looking for these things?

is the head intact? as to say are the cams still in it? taking the buckets (think thats what they are called - the piece that the cam touches) off the valves to reveal the retainers and keepers. on the failed valves are all of these present? this is checking to see if it was a "dropped valve"

With any failure like this, looking at it an ruling all posiblities out are the only way to find what caused it. and so it can be prevented next time.
Hope these things help out to find what caused this.

[Lloyd]

Read the thread again, this isn't my motor. It was mine and I sold it to someone who drove it for a while and came to have these issues.

Cambelt wasn't broken. Went and looked at the motor in person today but didn't have a good look at the belt as I was a bit pressed for time.

The other suggestion that has been made to me is valve stretch, though it is a lot of valves to all stretch at the same time, though the 20Vs are well known for it apparently.

Everyone who looks at the pictures is saying over rev

Have learnt today that it was driving around fine for 2 months with a 5500rpm limited and only running about 5psi boost as he was wanting to be nice to it for the first little while. Issues came around after about a week or driving it on the new tune with a 7000rpm limited and running 10psi


And no Revhead, I don't think they are familiar with them as the owner of the business kept saying they are the wrong pistons and there would have been clearance issues. I told him I had seem many setups with a standard head and standard GZE bottom end bolted together like this with no issues. He said to me that they must just all be lucky.

gepsk8, no warantee offered. It was running fine in my car and then was sold as a running engine. Was installed in his car with different plenum, fuel system, ignition system and ECU. Ran fine like that too for a couple of months until it was again tuned and thats when the issues seem to have started. Having said that, it looks to have been running nicely inside as far as the valve colours etc go

[Mr Revhead]

The other suggestion that has been made to me is valve stretch, though it is a lot of valves to all stretch at the same time, though the 20Vs are well known for it apparently.

new one on me

[sergei]

And no Revhead, I don't think they are familiar with them as the owner of the business kept saying they are the wrong pistons and there would have been clearance issues. I told him I had seem many setups with a standard head and standard GZE bottom end bolted together like this with no issues. He said to me that they must just all be lucky.

It sounds to me that mechanic is full of shit, and does not know what he is talking about.
As with over rev and valve stretch (that is some thing new), the silver top could stay at 8000rpm all day long without any valve train issues.
With one valve coming out from it's place you would get hit only on one cylinder (maybe another cylinder, like some one mentioned above), but it will not leave marks like all valves hits in every cylinder as I can see on your pic.
This could only happen if cambelt or cam gear (tensioner or crank sprocket broke it's key) fail.

[Lloyd]

Yeah, have been told the valve stretch happens, more so on the black tops I think but cant be sure on that. And as you say, its unlikely that it would happen to every valve or to the extent that it has.

I still want to think cambelt, though the place who did all the work has had the head off and therefore I cant see if the belt was right or not. They say it was spot on...

[matt dunn]

Then ask them why the valves hit the pistons.

If they say wrong pistons,
(which is a load of crap, it common to use 16V pistons with 20V head)
then ask why did it not hit and break the valve the first tim they ran it,

it's not like the piston to valve clearance can change over time.

[fivebob]

Valve stretch is just BS, if it happens then it's a few thou at the most and would simply cause the valve clearance to close up. It won't happen to all valves at the same time, and certainly not to the extent that all the exhaust valves hit the pistons, that takes several mm of movement and the valve stems will not elongate to that extent without breaking first.

It's obvious to anyone not trying to cover up faulty workmanship that this engine failed due to incorrect valve timing and lack of mechanical empathy on the part of the driver. If an engine lost as much power as this one would have, then it shouldn't be driven, and it must have been making a lot of noise before it failed.

It is not your responsibility to fix someone else's problems and if it was me I'd tell them to take a hike, and I'd see them in court if they wanted to take it any further.

[Jdawg]

Valve stretch is just BS, if it happens then it's a few thou at the most and would simply cause the valve clearance to close up. It won't happen to all valves at the same time....

This will sound stupid, but I assumed, never having seen this type of piston before, that 6 eyebrows were standard, cyl 1-3 do not look to have been damaged, as looking at the picks I took it that only cyl 4 was showing damage. This was why I thought it may have been a valve problem specific to Cyl 4, either stretched or seized valves.

[Lloyd]

6 not standard, there should be 4 cut outs as its a 16V bottom end. The exhaust valves in the 20V sit a bit further out than the 16s