AO

I worked at TRW until late 2008 and at that time we still didn't have valve manufacturing in China - and as far I know, didn't have plans to start there. So if they are indeed from China and are stamped TRW, they're not real TRW product, which wouldn't surprise me.

Manfred

I'd look into this again--there's gotta to be more to this story.

mark kibort

can we get the entire story Brian??? thanks! details!!!!

Bill Ball

I've lost valves on other motors and the piston/rod took a beating but held up pretty well. Didn't disapppear like this one. But they weren't 928s. First was a 76 Westfalia. Crank and rod checked out OK. Replaced bearings, cylinder and piston and had heads done. Other was a worked-over 40 flathead Ford. Vastly different motor but similar result in terms of damage.

Where are the piston and rod??? Back on the track?

Very nasty. Sean, other people encountering all the failures you have had in such a short time would have concluded by now that it's way too much trouble trying to track a 928.

Then there's Kibort....why no failures? I've long thought it's racing style/technique. His driving is much smoother and less abrupt than other drivers. I saw that the first time I watched him race. A few others think the same. It's definitely not just Amsoil. Gotta watch that engine braking stuff. I don't think Kibort even does that at all. It's another way you can starve the pickup when you see all the sump area that is forward of the pickup. I've ridden with other drivers who turn racing into a E-ticket ride, tossing me all over the car from all the abrupt inputs, slamming the brakes on, crazy direction changes, tires constantly squealing. A hoot, but probably not good for motor survival.

IcemanG17

MK
I don't have anymore information.....other than a dropped exhaust valve from #8....the rear most valve....

We did find a large chunk of piston among the destruction....but the blown motor still hasn't be opened to figure out exactly what happened..... The goal is to get a running stock engine back in.....

Neil Forn

Hey, if this was supposed to be a newly built motor why is there still cosmolene on the underside of the block? Or whatever that stuff the factory sprayed allover the under side of our cars is.

Aspkiller

Guess I ought to read all the words next time. Somehow thought you blew up the Estate.

And I agree with Bill that how you drive in and out of corners can have a big time affect engine oiling. Just watch Kibort and notice that the shift is just prior to actually needing the gear. Something I'm working on but haven't gotten there yet. Years of aggressive street driving with compression braking is a hard habit to break.

GregBBRD

Let me reword that..what I know about where they are made is indeed "second hand"....perhaps you can enlighten us.

Mike Simard had a TRW 968 intake valve break at the keeper grooves. Inspection of the grooves with a magnifying glass reveals that the keeper grooves are incredibly "chattered" and appear to have been cut by someone with the equipment and technology that Fred Flintstone had. The chattering in the keeper grooves is an obvious "stress riser" and lead to Mike's failure. Further inspection of TRW 968 intake valves (from different suppliers) revealed the same problem (meaning the problem was not isolated) and we are unable to install these valves in any engines...and still sleep at night. We have been forced to buy all of our valves directly from Porsche and pay their "huge" prices to get quality parts. BTW....inspection of other valves (including exhaust valves) reveals the same problem, in the keeper grooves.

Mike Simard researched this and found that there is an identification mark on the valves that shows they were made in China. He told me that the valves that were marked with what appears to be "lazer etching" and that say "TRWF" are made in China. (The whole part number is TRWF 30288.)

Doesn't really matter where they were built....junk is junk....and these qualify. If you indeed have contacts at TRW, I have a couple brand new sets of 968 intake valves here, that I'd love to put in someone else's trash can....

You might send Mike an email, for further details...he did the reasearch into where they were made.

Bill Ball

And go break that one? Sorry if I sound like a party pooper, but what is going to be different this time? It would seem worthwhile to try to understand this failure, as well as the earlier ones, and come up with something that might mitigate this.

I honestly think it would be worthwhile to have Kibort hitch a ride with Sean and make some observations. It could be very helpful. Now, I'm just suggesting. I haven't watched Sean drive, and I could be all wet about this driving style thing, but it's the main thing that jumps out at me when I watch Kibort go around and around the track and not kill the car. It's probably not the quality of the motor build - I helped him finish the stroker.

mark kibort

Yes, i do want to go for a ride. I cant believe my holbert transmission picked a terrible time to break after 10 years! really effected my ability to work with Sean and figure some stuff out. Thanks for the complements. I dont really think im doing any thing special, and I get pretty rough on it, in races, but you see the videos, so maybe there are some subtle differences that might be helping me. (or the motor) . I dont know if the approach t the turns is what is doing it, or the different gearing , or selection of gears.

Now, Bill you are a good friend and an angle! if you EVER need anything, make sure you call me! Bill has donated several days between the stroker install and the transmission replacement and I certainly couldnt have done it with out him

Now, back to sean. Help me understand, I thought we just blew a motor in the widow last time out? no? did you blow it again? who is bulding the motors? and why dont we try a stock build with no screens or scrapers and just take that motor and make it like mine, or like the holbert engine
Nothing you can do if the failure was a dropped valve, but thats another discussion. i am surprised that the motor wasted itself due to that.

anyway, Sean, lets find some time to hang out at the track and figure this stuff out and get the car set up right too. (ride height , alignment, etc) we can get it all very close and then give it to darrell andersons master alingment guy, Tim who is always at the track with us and the SCCA weekends dialing in the top mazdas and the top ITE cars

Bill Ball

I just talked to Brian - the next motor is in and running. It's bone stock. I think Sean plans to race this weekend. Hope Sean and Mark can connect for some seat time. And Mark, your driving style is clearly more smooth than others. Even though I don't race at all on the track, I learned about "smooth" from Keith Code's superbike motorcycle school and his book, a Twist of the Wrist. He advocates very deliberately smooth application of throttle, brakes and steering. You seem to behave that way, at least on the track.

James Bailey

Kibort..."Nothing you can do if the failure was a dropped valve, but thats another discussion. i am surprised that the motor wasted itself due to that." Just shows how little experience you have with engine failure which is a good thing. Overrev an engine on a down shift and it floats the valves, then bends them, then breaks off the head, which then explodes the piston and bits of piston can fly up into the intake ending up in other cylinders since there is no valve in the way...BTDT just not with a 928. The wife's 79 split a cylinder because of a very small bolt from an intake boot clamp imagine how much larger the head off a valve is...and how little it is going to compress !

IcemanG17

UPDATE.....we got the used stock S4 engine in a running pretty well.....we had to make some fuel pressure adjustments, but near stock S4 pressure has it purring nicely..... Sean was just about to dyno it when I had to head home... it was running a bit hot, due to bubbles and a possible sticky thermostat.... however Sean said it ran strong in a brief test drive....

I got some better pics of the destruction....it was the #4 cylinder and it sucked the inboard exhaust valve... Sean was a bit emotional thinking about the engine destruction......then the widow on the dyno & finally a flashlight into the #4 cylinder

Bill Ball

That last picture looks more like the inside of Fukushima #4

IcemanG17

agreed...however the inside of your open diff has to be a bit worn too!!!