Bent Valves Without A Misshift???

[Blue Bomber]

Is this possible? My mechanic called me today and said the machine shop he sent the head to to swap all the parts over to my P&P head said I had two bent valves. He originally thought the problem was a blown head gasket. The last time I drove the car I was driving on the Parkway for about 15 min doing 60-70 in 5th and 6th. Didn't hit lift or go over 5000 before that, and I didn't hit lift on the way to my destination, either (about 30mi). The engine lost power and died all of a sudden, so I pulled over to the side, restarted, and continued on my way home. It happened again a couple minutes later, and this time the CEL came on when I restarted the car. The engine also felt weaker, but it sounded perfectly fine. There wasn't a noise or anything else out of the ordinary to indicate anything had broken.

:confused:

[EasyC]

blue bomber is asking a question???? im astounded!

[Blue Bomber]

Originally posted by EasyC
blue bomber is asking a question???? im astounded! It happens. :rolleyes:

[2k2gts6]

sure its possible. not likely to happen often, but possible.

[Bing]

Originally posted by EasyC
blue bomber is asking a question???? im astounded!

:werd: haha!

Anyways, I think it's possible. Are you running PFC or any other piggyback system? Maybe knock caused the valve bent.

[Blue Bomber]

Nope, stock ECU and internals. The only engine mod was a modded eBay CAI.

[EasyC]

was that a blue bomber modded CAI....cuz if so, theres your culprit!. the ridges caused by cutting the pipe up created turbulence inside the intake pipe. This in turn created short bursts of air inside the intake manifold (due to the mini vacuums from the ridges) which in turn forced a couple of your valves down while the piston was in its compression stroke.

Solution: get a tpr intake.

btw wat oil do u use?

[Blue Bomber]

Originally posted by EasyC
was that a blue bomber modded CAI....cuz if so, theres your culprit!. the ridges caused by cutting the pipe up created turbulence inside the intake pipe. This in turn created short bursts of air inside the intake manifold (due to the mini vacuums from the ridges) which in turn forced a couple of your valves down while the piston was in its compression stroke. LOL, I smoothed the edges before I installed it. :chuckles
Originally posted by EasyC
btw wat oil do u use? Mobil 1 every 3000-4000 w/ Toyota filter.

[EasyC]

i guess a more important question....has toyota ever touched the car lol. I managed to bend all 16 valves when i first got the car back from them cuz they rebuilt the head wrong.

[Blue Bomber]

Yes, they've touched the car, but not the engine. ;) Last time they saw my car was about 70K+ ago.

[S|Lv3rBu||et]

Originally posted by EasyC
blue bomber is asking a question???? im astounded!

Ahhh chris.... always can be counted on to be a smarta$$ ;)

Originally posted by Bing
Maybe knock caused the valve bent.

^^This sounds like it might be your culprit.

[Bing]

How many miles do you have on it?

[Tikked Again]

Originally posted by Bing
Maybe knock caused the valve bent.

That would have to be a hell of a lot of pre-detonation. Hard to miss the noise that would make. Perhaps a VVTi malfunction.....

[mithrandir167]

:crazy2: so many TPR sigs in one thread :crazy2:

[stein]

Just guessing but valve float if your downshifting I suppose could cause it.

[Zensoku]

Do you ever over-rev to land lift?

[Blue Bomber]

Originally posted by Bing
How many miles do you have on it? Almost 100K.Originally posted by Zensoku
Do you ever over-rev to land lift? Nope.

[clayrush]

It happened to me. 3 months after a miss shift. lol

[jway83]

Originally posted by Tikked Again
That would have to be a hell of a lot of pre-detonation. Hard to miss the noise that would make. Perhaps a VVTi malfunction.....

it's a gt-s

[Blue Bomber]

Originally posted by jway83
it's a gt-s GT-S' have VVT-i, too. ;)

[Red01GTS]

Originally posted by Blue Bomber
Is this possible? My mechanic called me today and said the machine shop he sent the head to to swap all the parts over to my P&P head said I had two bent valves. He originally thought the problem was a blown head gasket. The last time I drove the car I was driving on the Parkway for about 15 min doing 60-70 in 5th and 6th. Didn't hit lift or go over 5000 before that, and I didn't hit lift on the way to my destination, either (about 30mi). The engine lost power and died all of a sudden, so I pulled over to the side, restarted, and continued on my way home. It happened again a couple minutes later, and this time the CEL came on when I restarted the car. The engine also felt weaker, but it sounded perfectly fine. There wasn't a noise or anything else out of the ordinary to indicate anything had broken.

:confused:

On the two bent valves, were they in the same hole or different cylinders?

If in different holes, were they both on the same cam (int/exh - high/low)?

What cylinder(s) exactly were the bent valves at?

How bad are the valves bent and what kind of leak down ratings did he get while doing the compression check?

Is there damage to the top of the piston?

Is there damage to the valve seat?

Another question I have is about weather. What kind of weather conditions did you encounter just before the engine started acting up?



It's hard to "just bend a valve" driving down the street. The information above will help us figure what happened....as much as we can.

[jway83]

Originally posted by Blue Bomber
GT-S' have VVT-i, too. ;)

that never occurred to me before since it doesn't have the L in it, but now that i think about it, it makes sense... i've said it before: i'm just dumb sometimes :gap: