Ok, heres the deal. I recently got my type R engine built. Ported B18C5 head, Toda 82mm pistons, Toda B cams, Toda timing belt, Toda valve springs, Toda cam gears. I'm about 800 miles into break-in, and when I'm idling in a parking lot one day, my car just dies and shuts off.

We open up the head, and this is what we find:



The head is busted, so is one of the pistons. Any ideas how a valve can break like that? The garage guys say they've never seen a valve break up like that. All the other valves are in good condition.

Also, the garage guys say they have a B18 non type R head they could use in my car. I'm not sure which it is, but they say it has higher compression, and the intake manifold fits downward on it, so they'd have to modify my intake manifold. Any idea which head this is?

 

How in the hell did you do that? Do you have higher compression pistons? It looks like the thing got bent and then snapped at the top and the piston might have broke the head off it. several things might have caused something like that. bad valve adjustment, timing belt off by a tooth or 2, bad timing, etc etc...The main thing is you should probably make SURE the cylinder wall is all screwed up. You might end up reboring the cylinders and getting new pistons. Also I would take the oil pan off and see if there's any metal in it. I don't know about anybody else but a valved thats messed up like that one is pretty catastrophic to me

 

Redlineracer

I do have high compression pistons, about 12.6:1

Since my engine was just built, I was in a break-in period. Not much tuning was done to it. And I noticed that the ignition timing was jumping all over the place, it'd be like 16 deg, 12 deg, 19 deg, 16 deg etc.

The mechanic said this should be ok until it gets dyno tuned. Could this have something to do with it?

 

yeah it sounds like one of the cam gear screws were loose or the timing belt was put on wrong.

 

But wouldnt that cause the valves to bend and not break?

Also wouldnt all the valves be bent? instead of just the one?

 

You would think but hell, I've seen stranger stuff happen. did you check the other valves? Is their any scoring on the cam(s)? What happened to the retainer and spring from the valve? Was the valve properly seated? did you have the valve seats replaced?

Million things could have gone wrong. The important thing is to figure out what happened by process of elimination. You don't want to just slap another head on their and say "it should work this time." Obviously, something went wrong. Maybe the retainer just fell off that valve but that doesn't explain the jumpy timing. A bent valve is a bent valve. Sometimes they bend so slightly you can't even tell with your eye so you have to take them out and check it by another means. Something smells about this, how aggressive were the cams you put in?

 

what valve it it, intake or exhaust?, the eratic timming is prob due to the ecm adjusting because of the high compression and bigger cams. also what fuel are you using?

 

The bigger cams and higher compression isn't going to affect the ECU's manipulation of the timing at all.

 

It was the exhaust valve on cylinder #2 that broke. The retainer on the valve was fine, I'll have to check on the keepers though.

From what I've gathered so far, it seems the consensus is that my garage installed something incorrectly, especially given the erratic timing. Besides timing belt slip, what else will cause that jumpy timing I had?

Garage claims that the valve was faulty, in other words not their fault, I feel really shortchanged tho. They say since it broke into pieces, and since it was only 1 valve, it must be that valve. Of course thats also a possibility, but seems like an excuse to me. How do I argue with them about this mess?

 

The higher compression could of forced it to break.. but Im doubtfull.. Valves just dont snap like that.. I might have to go with the "garage guys" here and say their was an impurity in that valve.

 

i have seen many valves(esp. Type R) with the heads pulled off. Small valve stem diameter plus excessive spring pressure, equals head off valve. if it was a stock gsr or b16 valve it might not have happened. I went worth a couple of heads with the old crower springs, pulling the heads off type R and REV valves.

 

maybe your mechanic just dropped a 10mm socket in there or 10mm bolt in there to get you to come back and spend more money!!

 

Have a metallurgist look for lueder lines at the fracture near the top of the valve stem. If they are there, than it is a fatigue fracture of the upper stem. That is a valve quality problem. The lower damage, head off, stem bent, could all be subsequent damage after the valve dropped.

 

Did you replace the valve guides when you rebuilt the head??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigMoose &raquo;</TD></TR><TR><TD CLASS="quote">Have a metallurgist look for lueder lines at the fracture near the top of the valve stem. If they are there, than it is a fatigue fracture of the upper stem. That is a valve quality problem. The lower damage, head off, stem bent, could all be subsequent damage after the valve dropped.</TD></TR></TABLE>

^ He knows whats up

 

Thats good advice, but where exactly do I find a metallurgist? Especially since I live in Hong Kong haha.

These garage guys work with TODA stuff everyday, so I want to see if the valve is indeed faulty, cuz I doubt they installed stuff incorrectly. Anyway, they ordered a new piston for me and are working on a B18C1 head. I'll have an update soon. Thanks for all the responses.