KLLRVET

I got the car back today, and just had to get the head off to examine the damage. It wasn't good, but expected:

Here is what came out of the intake manifold:


here is what the #8 combustion chamber looked like (notice the clean break on the exhaust valve hmmm....):


Here is a shot inside #8 cylinder


And finally a shot of #8 lifter valley (there is a fist size hole...so much for a set of MID sleeves)



I will post more pictures soon, and video too. The thing is, all of the exhaust guides on this head are shot. There is marking on the valves, and #8 has a very black sooty residue in the port, leading me to believe there was a lot of oil coming out not long before the failure.

I have not disassembled the head yet, so I don't have any measurements, but trust me, you can see the movement. The wear is in the direction of the rocker arm movement. with that I will say, this was possibly caused by a geometry issue, but was NOT CAUSED BY A TUNE OR BY DRAG RACING. There is a defect with the car.

Tony

Mopar Jimmy

Best of luck to you bro, I hope you get enough support and breaks to stay in the game!

obzidian

You mentioned that the guides are too short. Can you elaborate on that? These finding are interesting though it took your motor to go... Which sucks!!!

Do you think a taller guide would keep the valve from movng around? Or what would wear out the guide to make the valve move around like that? Is there not enough pressure on the spring to keep in check?

Man, if we can just fine out what exactly is making the valve shift around and hopefully we can come up with a way to reduce this type of failure.

NORTY

Valve train wear? What oil are you using?

KLLRVET

I mentioned the guides were "shot", not "short". however you may have a point. It may be possible that there isn't enough guide length after the CNC porting process.



Tony

KLLRVET

I bought the car with 11,600 miles on it. It had mobil 1 (and I can only assume that it always had Mobile One), and I have since switched to Amsoil 5/30.

Tony

MTIRC6Z

So the guides were shot...while this isn't directed specifically at the OP, I still fail to see how replacing the stock exhaust valves with something that weighs 30% more would have allowed this blow-up to have been avoided. Thus I stand by the point I made in a previous thread, the "cheap, lousy, no good, hollow" stock exhaust valves are NOT the issue and people replacing them without fixing something else along the way are pissin their money away on cheap parts.

I also stand by my previously made point that spending money to upgrade the oiling system on these cars (and I'm NOT just talking about increasing capacity) is money far better spent than money spent to replace the stock exhaust valves with SS exhaust valves.

Cheers, Paul.

sammyv

Looks like an intake valve broken?

1.8t

It could also be a QC issue with the bore size of the guide. Make sure you get measurements. I seriously doubt GM would release an engine with improper geometry from the factory, much less give it a 5yr/100k mile warranty. I am sure Katech could comment on this issue with accurate information.

Painrace

My guess is the valve was tagged and that started the problem. If you are just drag racing and not getting the oil over 240 degrees the 5W30 will probably work. Above that you need a heavier oil.

Good louk and let me know it you want the pistons and how I can help. I got one rod but it was not worth sending to you.

Jim

tjwong

Looks just like one I had in my shop last year, the difference was that it lost 2 cylinders, 7 and 8 respectively. There was over a pound of debris in the intake manifold alone and it shot peices of the piston out the tail pipe! That guy got a complete engine as both heads was wasted, the only things reusble was the covers, and the oil pan.

Painrace

This is what you get when you run a race engine too long:



A nice trophy. It happened at Charlotte Motor Speedway coming out of NASCAR turn 4 in 1986. I was leading by 1.5 laps and still came in third!

Jim

CJ1957

Tony,

Speaking of intake manifolds. It looks like you get mine that you bought on Friday the 7th.

Just in time for the weekend.

0Louis @ LG Motorsports

how long was it run post major engine noise? Notice the sleeve is missing, like I said in the earlier thread.

360jeepboy

I agree with you on this. I really don't think it has anything to do with the actual valve its self. The valve breaking is just a direct cause of a different problem.

KLLRVET

I have never seen 240 degrees of oil temp. I doubt that the valve tapped the piston, one, becuase the exhaust valve is not bent, two, there are no eyebrows on the other pistons, three the pushrods arent bent, and last, how would that wear out the other three exhaust guides?

Tony

360jeepboy

I think that it was caused by geometry as well.

Here are some pics of a rockerarm that is missing the needle bearings. (a stock problem from GM) Notice where the rocker arm engages the vlave changes with the bearings missing, which changes the geometry.

offset intake rocker arm and exhaust rocker arm:

KLLRVET

The motor was only run for a few seconds when the failure occured. If your theory were true why are the other exhaust guides worn?

Tony

360jeepboy

I'm sorry but if anything just kind of sticks out as the problem that is it...

Painrace

Once the valve stem is bent wear starts to occur and the valve starts turning causing more wear. Parts get into the oil and around the other valves causing valve guide wear. The rocker arm will also be slightly off once the stem is bent, hence, bad geometry. It is just a guess on my part. It could have all happened before you owned the car.

Jim