Converting to non-interference engine
#31
Now now, don't get your G string all twisted.
It has nothing to do with how low you consider yourself either. It was just the idea of maching on the Pistons still in the engine.
Give me a break!
It has nothing to do with how low you consider yourself either. It was just the idea of maching on the Pistons still in the engine.
Give me a break!
#32
Nordschleife Master
There's more than one reason to replace the belts regularly. I've had to replace rollers too, and I wouldn't have caught that without the belt job.
There aren't many things we can do better than the Porsche engineers.
There aren't many things we can do better than the Porsche engineers.
#33
Rennlist Member
Originally Posted by Peckster
There aren't many things we can do better than the Porsche engineers.
Oh, and what about those impossibley-complicated spring-clips holding the distributor cap in place. And while I'm at it, how about that damn oil filter that vomits all over the place everytime you change the oil....
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Dwizle (07-18-2021)
#34
Addict
Rennlist Member
Rennlist Member
Originally Posted by m42racer
It has nothing to do with how low you consider yourself either. It was just the idea of maching on the Pistons still in the engine.
Give me a break!
Give me a break!
Tools:
http://www.iskycams.com/category_tem...ategory_id=133
Procedure:
http://www.forcefedhighperformance.com/tech_Isky.htm
Sam
#35
Rennlist Member
Sam, thanks for that post. The second link, showing yet another use for duct tape, actaully looks like an effective way to keep the scrap metal shavings out of the motor. I image one of those kits would work or could be adapted for the 951. Who's going to be out guinea pig?
#38
m42racer,
Let me know the name of your shop where you take your car so I can sneak in at night with my drill and grinding stones and go to work on your pistons. I would be honored to have your car as the first with the new flycut pistons. It would be an inspiration to us all. Your apology is accepted for criticizing my idea of flycutting pistons in the engine which turned out to be an old and commonplace procedure. You should have done your research first before you started whining. Looks like you learned something after all. I'm proud of you, son.
Let me know the name of your shop where you take your car so I can sneak in at night with my drill and grinding stones and go to work on your pistons. I would be honored to have your car as the first with the new flycut pistons. It would be an inspiration to us all. Your apology is accepted for criticizing my idea of flycutting pistons in the engine which turned out to be an old and commonplace procedure. You should have done your research first before you started whining. Looks like you learned something after all. I'm proud of you, son.
#41
JNS,
Everyday I try to live down the reputation we 951 owners have. Then we debate the merits of machining Pistons while still in the Block.
Just how many professional engine builders would do it this way, I'm wondering?
Everyday I try to live down the reputation we 951 owners have. Then we debate the merits of machining Pistons while still in the Block.
Just how many professional engine builders would do it this way, I'm wondering?
#42
Addict
Rennlist Member
Rennlist Member
Yes, it's old and commonplace to flycut pistons in-block. I know engine builders who have done it for longer than the 951 has been around - back then you had to braze your own cutting tools out of a piece of carbide and an old valve, noone made them.
Sam
Sam
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Jay Wellwood (06-13-2021)
#43
Rennlist Member
Originally Posted by m42racer
Not me!! I rather chance the belt not breaking than risk my cylinders with some stray shavings.
#44
Addict
Rennlist Member
Rennlist Member
Thread Starter
Ingeniously simple, a true sign that it has been around for a long time. Tom, I think you are right for pistons (with outer periphery) flush with the deck, it seals the gap and the other cylinders from the shavings, but it also fixes the piston, so it doesn’t wobble in the cylinder while cutting, although a dedicated plastic wedge in the gap would probably do a better job.
I would imagine it was designed for people converting to high lift and wide cams.
Thanks, excellent references Sam.
I would imagine it was designed for people converting to high lift and wide cams.
Thanks, excellent references Sam.
#45
Once a crank has been knife-edged, the reciprocating assembly is re-balanced--if it is my car. This is "commonplace." Maybe fly-cutting was done on other models, but not on any making 15 lbs. of boost.
Wes: I just dropped a huge amount of money with your company. How would it seem if I installed all of it, undertook an untested procedure, grenaded something and came back to you with complaints? Not a good idea.
My 2.8 records show it was re-balanced after crossdrilling and a new flywheel installed. It will continue to get that type of care. At 400hp and 7000rpm, I am leaving my combustion chamber and balancing alone until any results are available. Oh, and changing belts. Compared to 928's, it is cheap and easy.
Jeff
'86 951 2.8. Lots of extra stuff. Most from Lindsey.
'87 928 S4. Some extra stuff (Murf SC in progress).
'92 968 Cab. Mostly stock and staying that way.
Wes: I just dropped a huge amount of money with your company. How would it seem if I installed all of it, undertook an untested procedure, grenaded something and came back to you with complaints? Not a good idea.
My 2.8 records show it was re-balanced after crossdrilling and a new flywheel installed. It will continue to get that type of care. At 400hp and 7000rpm, I am leaving my combustion chamber and balancing alone until any results are available. Oh, and changing belts. Compared to 928's, it is cheap and easy.
Jeff
'86 951 2.8. Lots of extra stuff. Most from Lindsey.
'87 928 S4. Some extra stuff (Murf SC in progress).
'92 968 Cab. Mostly stock and staying that way.