964Andrew

Found a used cam online, has some pitting. Picture below. Is this acceptable? appears to be 1mm in diameter.



Thanks!
Andrew

964Andrew

More progress. Heads are off and soon to be shipped for rebuild. I was hoping for head gaskets since the service history was partially missing, but no luck












Thanks!
Andrew

964Andrew

One GIANT setback today. Take a look. I'm gonna go pour myself a big glass of "goddammit!"

jstyer

So sorry to see that... Huge bummer. I say cut your losses and go for 3.8

964Andrew

Haha, 3.8 would be nice. If I'll have any more setbacks I might extend the build and go for it. For now I'm wondering what are the criteria to match single cylinder - piston combo.




Mine have A2 W2 markings on all of them. I can find A2 W4, A2 W6, etc... online. They look identical to mine , but are they still useable? Do I have to match the numbers exactly?

Thanks!
Andrew

ilko

Ugh, so sorry to see that

A buddy has a set of very nice P&Cs with 60K miles on them left over from his build. Those may be an option...

964Andrew

Fixed!



Hahaha...

John McM

This is from the manual. Not sure it helps

GTA_G20

subscribed

964Andrew

Thanks for the info. Here is what my cylinder stamps show. There is more than one corresponding number to a weight group. Can anyone confirm that I am reading them correctly?



Thanks!
Andrew

964Andrew

OK, let's talk cam grind. I've been offered a grind and polish service that would get rid of the pits.

If I'm not mistaken the shop will remove a very thin layer of the lobe metal surface on all lobes on both cams. This will change the cam's weight and lobe hight. How this will impact the car's performance or can it be corrected by adjusting the lifters?

Thanks!
Andrew

Jacke2c

If it is a reputable shop, that is the way to go. It will not change the profile (unless asked to do so) and you will need to break them since they will be "as new". The last 911 engine (1979 911SC) I built, I had my cams ground to 964 specs. That was 12 years ago and it is still going strong...

964Andrew

Oh the little differences. I have ordered a matching numbers and matching height and dimension group barrel to replace my cracked one. The barrels were about 14 months difference in production date. The condition appeared to be similar to mine. It wasn't too expensive and it came with a piston.

Right from the start I noticed the piston has different proportions in ring-land. OK, no problem If the barrel is identical to mine I should be able to reuse my old piston. I proceed to measure the barrels and was happy to see they match... except for one thing: slight offset in the cooling ribs.

Please see for yourself:

Left - OLD / Right - NEW




What do you think, use it or not?

964Andrew

Time for some ultrasonic cleaning...

jstyer

I know nothing of piston/cylinder group sizes, but if the offset cooling fins truly are the only difference then I say bolt that puppy on there. It's going to be under the cooling shroud anyways...

Ultrasonic cleaning is absolutely the way to go! There's nothing like assembling clean engine components.

Keep the picks coming!