advice on 2.4 cis top end rebuild

ezraman · 01-28-2008, 07:02 PM

I have a Smokey slightly missing 73.5 cis motor. I bought some used heads in good condition that I intend to send over to Ollie's to have them cleaned up and gone through. I know I will need to replace the rings not sure about the P&C's. If I decide to replace the P&C's what size and brand should I use where Horse power and reliability are concerned. Should I be considering Cams? I intend to use this car solely for street use. I'd like as much HP within the 2,000 dollar price range and also I would like stay in the top end rebuild area not quite ready to try opening up the case yet.

Thanks

Eagledriver · 01-28-2008, 08:59 PM

Unless you are going to lose the CIS, you are limited in cam choices. You could put in 90mm pistons and cylinders and use SC or 964 cam profiles.

-Andy

ezraman · 01-28-2008, 09:22 PM

What would be the HP bump with 90mm pistons and 964 cams? Also should I have the heads polished as well? I am thinking that I like the CIS system for smooth performance and also I have replaced alot parts on it rebuilt fuel distributor and pressure regulator.

Thanks

rvanderpyl · rvanderpyl's Garage

You can't use 90mm P/C if you are just doing a top-end as you have to have the case spigots bored bigger. And if you crack the case your $2000.00 budget is gone. 964 cams won't work unless you get them custom ground as they are 4 bearing and your current cams will be 3 bearing. Customs cams will cost you $800.00. New 2.4 Mahle P/C don't even seem to be available. You can probbaly get your cylinders bored out and a set of JE pistons made up, but I don't think you are going to stay in your budget for that. So, best bet is to re-ring your pistons if they and the cylinders are in spec, otherwise find a good used set and use them. CIS P/C should be cheap. Then accept that staying with CIS you will have to accept what your HP is.

dtw · 01-29-2008, 08:05 AM

The very first and very last T motors - the 2.0T and 2.4T CIS are two of the least upgradeable engines, unfortunately. Ditch the CIS for some MFI or carbs and you can at least start talking cam and compression upgrades.

Is $2k your overall budget? If so I have even more bad news...