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Stock rods are way too old & standard pistons are in the same boat , but with the greater disadvantage of being too heavy ( late 1970's / early 1980's technology )
Do not get me wrong , I have the greatest respect for these ( nowadays ) very old critical engine components , but its these components that let go in old age with modified ( higher boost ) 951 engines & when they let go they take the block ( crankcase ) with them , along with the crankshaft , terrible" avoidable" waste
Stock rods are way too old & standard pistons are in the same boat , but with the greater disadvantage of being too heavy ( late 1970's / early 1980's technology )
Do not get me wrong , I have the greatest respect for these ( nowadays ) very old critical engine components , but its these components that let go in old age with modified ( higher boost ) 951 engines & when they let go they take the block ( crankcase ) with them , along with the crankshaft , terrible" avoidable" waste
Aren't these engines built more robustly compared to newer designs, which thanks to more advanced CAD/CAM technology, designed and built to last the length of the warranty and not one minute longer? Components of all kinds are also designed to be lighter for emissions; lightweight cars pollute less than heavy cars. They also use less fuel, for those all important fleet MPG averages.
Its just metal fatigue , the more the engine revs & the more power it produces the quicker its accelerating to oblivion , its just a matter of when
You would need to know the exact hours of operation the engine had already done
You would need to know how many times previous owners had mechanically over-reved it ( even for a split second ), this is the one that has destroyed more 911 engines than just about anything else , meaning metal fatigue of a conrod or more importantly the conrod bolts
You would need to know how many kms/miles the car has actually done with all its previous owners & how many times the odometer stopped working before it was fixed again ( if at all )
Its a lot cheaper in the long run to fit 4 "NEW" quality aftermarket rods ( minimum requirement )& to get the best out of the engine ( if there are scratches in the bores ) , bore it out and use quality aftermarket pistons , we see so many that have deep bore scratches we often have to jump an oversize and go straight to 2nd oversize , this is also benificial in regards to piston to cylinder clearance as the standard ( street ) piston clearance was quite tight & with higher boost levels this causes issues with the old standard pistons
I'm of the opinion that the stuff the factory built back in the 80's was superior to today's components, better build quality without the environmental restrictions of today. Agreed they were built heavier and for some serious power situations lighter is better but for reasonable builds I see no benefit of using new. Saying that, it's good insurance if you are using old rods, pistons or other vital components, to have them measured for spec and ndt tested for damage.
The 944 engines are a sort of "freak" of durability considering the time they were designed and built in.
What is often the death sentence of an engine (scored alusil) is also the reason why they are so long lived otherwise.
How many other 80s sports cars will run 300k miles without an engine overhaul?
I think that newer stuff will be more durable than older stuff largely because of improved metallurgy and stress-testing of components via computer.
Only BMWs are built to expire 10 minutes after the lease...
If the bores are nice & if you are not going to the track , meaning its just a street car , then just a set of "4" only good quality "NEW" con-rods is a very good insurance policy in the light of a larger turbo going on the engine & higher boost levels
I do not know the age of you're 951 , but lets say you're 951 is a 1987 year model , then the old con rods are 30 years old
What are the real world failure rates of stock 951 rods in a street engine making under 400whp? Assuming it was never really mechanically overrevved and nobody has used them to try and make dangerous levels of power in the past. Fatigue is a factor but under a certain threshold, the number of cycles should be pretty damn high.
What are the real world failure rates of stock 951 rods in a street engine making under 400whp? Assuming it was never really mechanically overrevved and nobody has used them to try and make dangerous levels of power in the past. Fatigue is a factor but under a certain threshold, the number of cycles should be pretty damn high.
02-21-2017, 04:03 AM
951 engine, what will break first?
