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Thank you very much for the added detail to the history of X51. I guess I need to edit my question: I don't understand why, once Porsche had identified the M96 weak points and made efforts to address them, they didn't just start building them all that way. A cam is a cam, a head is a head. Essentially zero cost to Porsche.
The forthcoming 996 Turbo and it’s engine requirements must have entered the equation at some point ...
The Mezger development provided the basis for a bullet-proof roadgoing Turbo engine AND racecar engine, and they knew the aircooled bottom end was pretty much bullet proof even at high horsepower numbers.
996-104-906-00 - Cylinder Head 4-6 (M >> 683 00433)
996-104-910-00 - Cylinder Head 4-6 (M 683 00434 >> - big price difference between these bank 2 heads
So what is the actual difference between these heads? I know the 00434 is roughly twice the price, but don't know anything more than that
So what is the actual difference between these heads? I know the 00434 is roughly twice the price, but don't know anything more than that
The more expensive one/later one has two of the holes in the head for the scavenge pump drilled offset so it can't be installed wrong, and uses the "997" scavenge pump with slotted holes that can be used on earlier 996's
Picture of the scavenge pump that fits on ALL the m96/7 engines..
So basically you are paying $3k for two holes to be drilled and threaded "offset" ,....supply and demand??
Last edited by Porschetech3; 05-17-2024 at 09:27 PM.
You can get most of the X51 parts, but you cannot get the AC compressor suction pipe (996.573.980.00) which is different. The standard AC compressor suction pipe will not clear the X51 intake (ask me how I know) so you have to modify the pipe or not use the AC.
Mark
The more expensive one/later one has two of the holes in the head for the scavenge pump drilled offset so it can't be installed wrong, and uses the "997" scavenge pump with slotted holes that can be used on earlier 996's
Picture of the scavenge pump that fits on ALL the m96/7 engines..
So basically you are paying $3k for two holes to be drilled and threaded "offset" ,....supply and demand??
so can you confirm that’s the only real difference between the two head PNs? 906 vs 910.
I because I’m in need of one due to an internal crack. I have a company looking for a 910 in Europe somewhere as we have none in the US that we can find. its been a long journey to find one and if we could be looking for two parts numbers vs just one that may improve the odds. I’m dying to get the most famous 40th anniversary edition, 1374, back in the road.
thanks a lot.
so can you confirm that’s the only real difference between the two head PNs? 906 vs 910.
I because I’m in need of one due to an internal crack. I have a company looking for a 910 in Europe somewhere as we have none in the US that we can find. its been a long journey to find one and if we could be looking for two parts numbers vs just one that may improve the odds. I’m dying to get the most famous 40th anniversary edition, 1374, back in the road.
thanks a lot.
Have you tried to contact HOFFMAN AUTOMOTIVE MACHINE, INC.
Maybe no need for a new head.?
Len Hoffman is THE 996 head expert and fixes most cracked heads perfectly. pt3 has been driving one for decades now iirr. For maybe < half the money a new head would cost.
so can you confirm that’s the only real difference between the two head PNs? 906 vs 910.
I because I’m in need of one due to an internal crack. I have a company looking for a 910 in Europe somewhere as we have none in the US that we can find. its been a long journey to find one and if we could be looking for two parts numbers vs just one that may improve the odds. I’m dying to get the most famous 40th anniversary edition, 1374, back in the road.
thanks a lot.
Yes I can confirm that the only difference is the 910 can only use the updated 997 scavenge pump whereas the 906 can use the 996 or 997 scavenge pump although either pump can be installed wrong on the 906 head due to the symetrical bolt holes...MUST pay attention to the orientation..
Also if you have to source a used x51 head make sure to get the matching cover and cam caps....they are machine and number matched as a set..
LIke Allcool said Len Hoffman can successfully repair most head cracks on M96 engines... There is one crack that is deep in the SAI ports that cannot be successfully repaired . Have you confirmed the exact location of the crack?
Yes I can confirm that the only difference is the 910 can only use the updated 997 scavenge pump whereas the 906 can use the 996 or 997 scavenge pump although either pump can be installed wrong on the 906 head due to the symetrical bolt holes...MUST pay attention to the orientation..
Also if you have to source a used x51 head make sure to get the matching cover and cam caps....they are machine and number matched as a set..
LIke Allcool said Len Hoffman can successfully repair most head cracks on M96 engines... There is one crack that is deep in the SAI ports that cannot be successfully repaired . Have you confirmed the exact location of the crack?
I don’t have the exact location of the crack but it’s a deeper exhaust port crack. Coolant is weeping through it. I spoke with Jake Raby a bit about it. I was thinking about reaching out to Hoffman as well. It’s worth a shot.
Also, what is the outcome of installing the scavenge pump incorrectly? What issues will is cause?
thanks for the tip about the cam cap and cover.
i would like to utilize the current head as the engine has 500k miles on it and I’d be worried that a newer “tighter” head could cause issues.
Also, what is the outcome of installing the scavenge pump incorrectly? What issues will is cause?.
If an oil scavenge pump is not oriented correctly , it will not return oil to the sump ( Integrated Dry Sump) ...This will lower the oil level in the Sump while running to a dangerous level and also will overfill the head with oil that is more likely be sucked up by the AOS System..
I don’t have the exact location of the crack but it’s a deeper exhaust port crack. Coolant is weeping through it. I spoke with Jake Raby a bit about it. I was thinking about reaching out to Hoffman as well. It’s worth a shot.
Also, what is the outcome of installing the scavenge pump incorrectly? What issues will is cause?
thanks for the tip about the cam cap and cover.
i would like to utilize the current head as the engine has 500k miles on it and I’d be worried that a newer “tighter” head could cause issues.
If an oil scavenge pump is not oriented correctly , it will not return oil to the sump ( Integrated Dry Sump) ...This will lower the oil level in the Sump while running to a dangerous level and also will overfill the head with oil that is more likely be sucked up by the AOS System..
Yes, it’s my late father’s car. You can view some
of his milestones on the 40th AE thread here. Unfortunately he passed just before hitting 500k.
I was looking into a small coolant leak this spring when the crack was identified.
I have sold one of my 996s and my early aero 996 is about to be up for sale as well.
I plan to drive the 40th as long as possible and as much as possible see how far the original engine can really go without a rebuild.
04-16-2022, 09:04 AM
- big price difference between these bank 2 heads
