NEED 2.7L VALVES! timing belt disaster
03-14-2006, 10:51 AM
#17
Captain Obvious
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Are these valves same as the '85-'86 32V 928 valves? I have a spare head for my 928 that has some bent valves and some that are still good. IF they are same I might be willing to sell the good valves out of it.
Ahh never mind, at first glance I didn't realize this was a 2 vavle head. Now sicne it is an 8V head, would any of the 928 heads have the same sized valves? There are alot of 2V 928 heads out there.
Ahh never mind, at first glance I didn't realize this was a 2 vavle head. Now sicne it is an 8V head, would any of the 928 heads have the same sized valves? There are alot of 2V 928 heads out there.
03-14-2006, 12:21 PM
#18
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Originally Posted by Imo000
Are these valves same as the '85-'86 32V 928 valves? I have a spare head for my 928 that has some bent valves and some that are still good. IF they are same I might be willing to sell the good valves out of it.
Ahh never mind, at first glance I didn't realize this was a 2 vavle head. Now sicne it is an 8V head, would any of the 928 heads have the same sized valves? There are alot of 2V 928 heads out there.
Ahh never mind, at first glance I didn't realize this was a 2 vavle head. Now sicne it is an 8V head, would any of the 928 heads have the same sized valves? There are alot of 2V 928 heads out there.
944 NA Intake Valve 2.5L: 928 105 409 02
944 NA Exhaust Valve 2.5L: 928 105 410 04
Though it has a 928 part number, the 928 uses a different part number for both the intake and exhaust valves (as well as being different between the 32v and the 16v)
The 2.7 NA part numbers are:
Intake: 944 105 409 03
Exhaust: 944 105 418 00
03-14-2006, 01:41 PM
#20
Hates Family Guy
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A 2.7 head will be just about impossible to find - all the guys are using them on the 3.0l turbos.
Does anyone have an exhaust valve from a 2.7? What makes them different? I'll acknowledge they have a different part number, but how are they different? Diameter is the same. Stem size is the same. They use the same guides and keepers. So either the height is different, the profile of the head is different, or the composition is different. Someone show me the two valves side by side.
Campeck I can send you a bent 2.5 valve to compare to your bent 2.7 valves, if that helps. I've got 4, inherited them with one of the parts cars. Otherwise take Eyal up on his valves, or if you have another head laying around pull a valve from it.
Does anyone have an exhaust valve from a 2.7? What makes them different? I'll acknowledge they have a different part number, but how are they different? Diameter is the same. Stem size is the same. They use the same guides and keepers. So either the height is different, the profile of the head is different, or the composition is different. Someone show me the two valves side by side.
Campeck I can send you a bent 2.5 valve to compare to your bent 2.7 valves, if that helps. I've got 4, inherited them with one of the parts cars. Otherwise take Eyal up on his valves, or if you have another head laying around pull a valve from it.
03-14-2006, 01:58 PM
#21
Race Car
It doesn't matter what rmp the engine is running (to a certain point) since that is what valve springs are for. The only way for valves to stay open during high RPM when they are NOT SUPPOSED to be open is when the valves are floating. This would happen if you have broken valve springs in all 6 valves or you WAY over revved your engine. That has only happened to one car I have seen, a spec racer's car I worked on when he mis-shifted into 2nd instead of 4th sending the rpm to about 12k rpm. Even then, he had way below minimun thickness shaved head (shaved all the way to the exhaust valve-only way to shave more is to angle mill it) with only 4mm clearance between the piston and lowest point of the exhaust valve. I have replaced more than 50 heads due to bent valves and only one case of more than 3 valves bent without the timing belt being installed improperly.
BTW, one of the reason why I wouldn't run a 2.7L engine is the rarity of the parts. I was told by my supplier that these valves are being discontinued (they are not making any more) thus the $110 price PER VALVE.
BTW, one of the reason why I wouldn't run a 2.7L engine is the rarity of the parts. I was told by my supplier that these valves are being discontinued (they are not making any more) thus the $110 price PER VALVE.
Last edited by Legoland951; 03-14-2006 at 02:33 PM.
03-14-2006, 04:28 PM
#22
Originally Posted by PorscheDoc
I show the following part numbers:
944 NA Intake Valve 2.5L: 928 105 409 02
944 NA Exhaust Valve 2.5L: 928 105 410 04
Though it has a 928 part number, the 928 uses a different part number for both the intake and exhaust valves (as well as being different between the 32v and the 16v)
The 2.7 NA part numbers are:
Intake: 944 105 409 03
Exhaust: 944 105 418 00
944 NA Intake Valve 2.5L: 928 105 409 02
944 NA Exhaust Valve 2.5L: 928 105 410 04
Though it has a 928 part number, the 928 uses a different part number for both the intake and exhaust valves (as well as being different between the 32v and the 16v)
The 2.7 NA part numbers are:
Intake: 944 105 409 03
Exhaust: 944 105 418 00
03-14-2006, 04:30 PM
#23
Originally Posted by rockfan4
Campeck I can send you a bent 2.5 valve to compare to your bent 2.7 valves, if that helps. I've got 4, inherited them with one of the parts cars. Otherwise take Eyal up on his valves, or if you have another head laying around pull a valve from it.
03-14-2006, 06:27 PM
#24
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Originally Posted by aribop
We have plenty of 2.5L valves but thanks for the offer.
BTW, it isn't impossible to bend a bunch of valves. All you have to do is have some teeth strip off the timing belt, or have it start to come apart but not completely fail, the timing gets messed up and they'll all get bent. In the pic below there's 4 exhaust and at least one intake valve bent.
Last edited by Kurt R; 03-01-2013 at 06:47 PM.
03-16-2006, 01:49 AM
#25
Campeck Rulez
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Thread Starter
Originally Posted by Legoland951
It doesn't matter what rmp the engine is running (to a certain point) since that is what valve springs are for. The only way for valves to stay open during high RPM when they are NOT SUPPOSED to be open is when the valves are floating. This would happen if you have broken valve springs in all 6 valves or you WAY over revved your engine. That has only happened to one car I have seen, a spec racer's car I worked on when he mis-shifted into 2nd instead of 4th sending the rpm to about 12k rpm. Even then, he had way below minimun thickness shaved head (shaved all the way to the exhaust valve-only way to shave more is to angle mill it) with only 4mm clearance between the piston and lowest point of the exhaust valve. I have replaced more than 50 heads due to bent valves and only one case of more than 3 valves bent without the timing belt being installed improperly.
BTW, one of the reason why I wouldn't run a 2.7L engine is the rarity of the parts. I was told by my supplier that these valves are being discontinued (they are not making any more) thus the $110 price PER VALVE.
BTW, one of the reason why I wouldn't run a 2.7L engine is the rarity of the parts. I was told by my supplier that these valves are being discontinued (they are not making any more) thus the $110 price PER VALVE.
well then i geuss you have seen one now.
the belt stripped while being driven down the highway. 4exhaust and atleast one intake bent.
bump.
03-16-2006, 11:34 AM
#27
Race Car
I am sure the belt slipped, some valves were bent, and the person who owned the car tried to start again and again, somehow catching some part of the belt that still had teeth to bend the rest of the valves. Most people who knows what compression (or lack thereof) sounds like would immediately STOP CRANKING THE ENGINE. The belt had to catch again with WRONG TIMING to bend the rest, which is my whole point. I am not even sure how someone can "recatch" the belt after it stripped enough to bend valves. I rest my point unless someone can show me at any time 6 valves can stay open without wrong timing.
