Engine Rebuild Advice Requested
 

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Greetings all,

I am posting this here and on Rennlist with the hope of some of this groups amazing knowledge.

I have a 1983 911SC Cab. The motor is being pulled out by my mechanic this week for the purpose of a rebuild.

As of right now he is guessing the top end needs a rebuild and nothing more. If the bottom looks good when he has it apart he wants to swap the CIS for PMO carbs.

I have read that the PMOs are great for power and streetability and so I am not too scared by that. What I was thinking was throwing in the 964 cams, however that means keeping the CIS.

I am curious as to what everyone here thinks!

My opinion ,-No way,!! carbs are for cavemen, go with a modern standalone system and you can run all sorts of cam and ignition. Carbs were once the hot set up but just nostalgia anymore. carbs are for those who have not herd of electromotive ,S.D.S. and the like.

Also, there's no reason to use 964 cams only with CIS, however if you have carbs it does open up a world of other cams that you can use that normally the CIS system not like.

964 cams and PMO carbs will work fine. Any carbs (including PMOs) will reduce you milage and "streetablility". You'll have to crank the engine several times while pumping the gas to start it and it won't idle for the first couple of minutes. If you've ever driven a car from the 70's with carbs you'll know what it's like.

You can't beat the power though. If you put on 40mm PMOs and SSIs or early exhaust you should get around 220-230 HP. The 964 cams are good for a couple more and for racing 46mm Carbs will give even more.

-Andy

Wow, good stuff so far.

So, when I spoke to him he was thinking we could avoid cracking the bottom half open. I am not certain, but I think replacing the P's and C's require cracking open the bottom.

The car has the upgraded tensioners, 930 vc's and has headers (no mufflers, or heat exchangers (it really sounds like a race car!) There is NO inspection here in florida (emissions or otherwise).

My goal is too not invest a ton of money as I am not really a cab fan, and I think I will end up with a 997 in two years (ok 3-4). I really just want to start the car and go riding. The car has also had the AC removed (and I am thinking about having one re-installed).

So, basically inexpensive and reliable.

Thanks!!

t.

Replacing P/Cs does not require opening the case. EFI is also an option for upgrading your CIS. Do a search on this site for "Tbitz" or "Bitz EFI" to get all of the info you need on the kit. It is actually cheaper than PMOs. Or you could just go here:

http://www.bitzracing.com/index.html

Good luck!

if you are going with EFI , go wth one that will manage your spark too! gives you more doors and options for later

wow. more good info. so i dont need to opeen the case, thats awesome!
i will check out bitzracing now

so in general do most think i should stay away from carbs and keep the cis or stay away from carbs and go to another FI, or just keep CIS?

thanks again.

t.

Cis is simple sweet reliable..carbs suck (lol) truly they will need lots more attn then cis or efi. You asked for opinions, I would keep the cis over carbs . efi over cis, a complete management sys over efi.

The Bitz kit can manage spark, being of the Megasquirt variety, but that requires more work on your part.