Cam choice

[GH85Carrera]

My 85 Carrea 3.2 engine had numerous oil leaks. I did a reseal on ever easily replaceable seal just last year. I noticed one head was a little wet. I really wanted to believe it was just the oil leaks that got on the area. After 4,000 miles the head was still wet. Out comes the engine again and this time I start on "just a top end" but the while I am in there syndrome set in.

I ended up going all the way and the case is split. The good news is the Nikasil cylinders are virtually as good as new. I do feel better about the full rebuild when I found a little wear on one rod. It was just starting to have a little mar. The piston rings are worn and the valve guides were shot. I only burned 1.5 quarts on a 4,000 mile road trip to Michigan last summer.

Anyway the point of this post is to ask opinions about changing the cams to a 964 grind. I want to stay with the stock Motronic fuel injection. Will the 964 grind cause any problems at all? I want a engine the idles and runs like it was meant to, but with just a little more pep.

What say you?

Any problems caused with a 964 grind?

[GH85Carrera]

Before



After.

The one head was leaking and had to be fly cut to get a good seal. If one is cut, they all have to be cut. If yer gonna do that while yer in there ya might as well port and polish em all. New giudes of course, clean up the seats, clean up the valves.

[KTL]

No problems with the 964 grind on a stock 3.2. Makes for a nice upgrade that seems to pull a bit harder on the top end. No issues with idle or any other negatives. It's basically a no-brainer upgrade.

While you're in there i'd recommend a set of 12 steel studs to get those pesky dilavar studs out of there. Those dilavars are most likely the reason for your head leakage.

Nice job on the heads. They look great. All new valves too? Usually when the guides are toast, the valves are pretty worn too.


Also take a look at the chain idler arms and the pivot posts. Make sure the bushings aren't showing any wear you can feel with your fingernail.

If getting new or reground cams (can regrind 964 on Carrera cam w/out any welding needed) it's advisable to have the rockers resurfaced. Talk to Craig at G2 (cgarr on the forums) for that. He does a fantastic job.

[GH85Carrera]

Thanks.

The valve seats were just cleaned up a bit as were the valves. The guides are replaced.




The case is now boat-tailed if that is the proper term.

[GH85Carrera]

As you can see the case studs are out and will be replaced.

[Eagledriver]

When you say the valve seats were "cleaned up abit". I hope you mean they were recut after replacing the guides. The new guides will have a different center location (no matter how small) that will make the valves not seat unless the seats are cut with the new guides inplace.

-Andy

[GH85Carrera]

That is what he does. After honing the guide bores.

[KTL]

Originally Posted by Eagledriver

When you say the valve seats were "cleaned up abit". I hope you mean they were recut after replacing the guides. The new guides will have a different center location (no matter how small) that will make the valves not seat unless the seats are cut with the new guides inplace.

-Andy

Yep. Andy is 100% right. Any time the guides are replaced the seats should always be re-cut to get your valves sealing & seating properly. Remember, the seat not only seals the combustion chamber but also relies on good contact with the valve to cool it.

[GH85Carrera]

The heads are done. As soon as the racewear rod bolts and head bolts come in the assembly will begin. It should be done this weekend.

[CaptainCalf]

Nice project...subbed

[DSPTurtle]

Those are sexy heads!!! But collapsible oil return tubes?

[GH85Carrera]

Originally Posted by DSPTurtle

Those are sexy heads!!! But collapsible oil return tubes?

Those were on the for the last ,18 years. They are billet aluminum and high quality. Might as well reuse them.

[GH85Carrera]

The rod bolts and head studs finally came in.

Those are purdy. Dilivar is in the trash.

[KTL]

Yeah those are nice looking studs. Definitely got a good seal on the engine case- plenty of orange 574 goo squeeze out.

[GH85Carrera]

I really hope to have a DRY engne for a while. I have owned my 911 for 18.5 years and it has always had some leaks. It got real bad last year.

Each one of those studs got a nice dose of red loctite.

[Lapkritis]

...is it a but sick that I want to build another engine whenever I see pics with new studs? Even if I don't need one.

[GH85Carrera]

Making some progress.

[GH85Carrera]

Is it bad to have extra parts?

With a little luck (and these parts) the engine will be back together this weekend.

[KTL]

When you gonna wipe that extra orange goop off? It's not gonna dry.......

Nice job.