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Join Date: Jan 2004
Location: Upstate NY
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3.2 top end so while I'm there time to upgrade
Recently purchased a 1986 3.2 which will need a top end rebuild.
What have you guys done for a hot street 3.2 ? Like to keep the low end pull vs top end power. I won't be tracking the car but maybe an autox here and there. Going to use PMO EFI induction with coil on plug ignition. Still need to do a little research on that part. Looking at both Clewett Engineering and the Rasant Products kit. TIA, Luke Last edited by Luke M; 04-21-2020 at 05:53 AM.. |
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3.2 top end
Glad to see this worked out! Watching this ...
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Join Date: Aug 2018
Location: San Diego, CA
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I'm far from an expert on this, but I recently completed a top end on my 3.2 (heads rebuilt, new head studs (and intake and exhaust studs) and new rings on nikasil P&C's.
Just my opinion, but if I were to increase the performance of the engine (cams, induction, etc) I would want to address the weak link, rod bolts. This means opening the bottom end = slippery slope. I 'think' (hope) that the stock rod bolts can handle stock performance...
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1988 3.2
needed top end wouldnt pass CA smog after shop pulled it apart to do top end I decided, heck while we are this far whats another 6k to do the bottom end at 155k mi I said go for it All stock but polished and balanced and wong chip with no cats and sports muffler couldnt be happier
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I'd go for a stockish rebuild with 964 cams with a Steve Wong chip and use the money saved to build a short ratio gearbox with all the bells and whistles.
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Location: Brisbane, Australia.
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If you haven't already bought the PMO, maybe have a chat to Al Kosmal; he sells a nice alternative from RHD here in Australia.
https://racehead.com.au/product/porsche-bolt-on-6-cylinder-itb-kit-boxer-engines/ |
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Join Date: Oct 2008
Location: Nash County, NC.
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Luke, I don’t see putting more power on the used bottom end is the way to go.
Once you get a valve job done, without new rings, I generally get 175/185# on compression Start banging it harder is looking for problems in the bottom. Even on a top end I open the case to see what is there after 40 years to let the owner know what he owns, change seals, intermediate shaft bearings, chain rails. I consider the appearance of the mains indicative of the rod bearings so I don’t open the rods unless the mains are full of dirt scratches. Bruce |
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Dont think there is a lot of power left on the table by Porsche. Could increase displacement or CR slightly. I think rod bolts can be upgraded without splitting the case. I think compression will be increased slightly as a result of the top end rebuild and machining of the head mating surfaces.
Chris 89 Carrera |
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I dont see the need for ITBs to be honest the factory plenum will support plenty of air flow.
Maybe bump compression, go to a 964 cam and twin plug if you want to get real wild then run it on a mega squirt 3 or aem infinity. keep in mind going to a new ecu will require extensive tuning time to iron out all the little drive-ability bugs to get it to work as smoothly as your car does now.
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FWIW, replacing rod bearings and rebuilding rods isn’t a “bottom end” project. Those parts are accessible with the crankcase intact. Porsche engines are blessed with 8 main bearings supporting the crank with scant history of lower end failures with later Al engines. To compare, a Chevy V8 has four. If oil changes were performed on schedule and no internal grenading, I’d rebuild the rods, replace the rod bearings and upgrade the rod bolts, but it’s your call.
S |
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I received the 3.2 and I'll post a few pics later today.
Looks pretty good from taking a quick look at it. Need to get it mounted on the engine stand and remove a few items. The more I thought about it I'll just split the case and build it all up. I'll upgrade the rod bolts too. I knew that they where a weak point in the 3.2. Any recommendations on a brand other then ARP ? Also I know there was a rash of bad bearings being sold when I was redoing my brothers 3.0 . Any good sources or brands to look for. It's been almost 3 years now since I did the 3.0 . TIA, Luke |
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Rod bearings from Auto Associates.
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Pretty sure my brother purchased his 3.0 bearing set at Auto Associates as well.
I'll have to call them in the morning. So, I'm gonna tear the 3.2 all the way down. The more I thought about it I think I'd like to go with a set of slip in 3.4 MMS p/c's. These here : https://lnengineering.com/products/mahle-motorsports-c-p-sets/porsche-911-carrera-32l-to-34l-1984-1989-motronic-inj-mahle-cylinder-and-piston-set.html I won't be using the Motronic efi but instead PMO Efi kit from Rasant products. Anyone here running these p/c's ? Also which cams? Mainly street driven car with some autox and maybe one track day a year. I plan on upgrading the rod bolts and head studs while I'm there.. |
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Pics..
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I ordered most of the parts and waiting for them to get delivered.
Started tearing down the 3.2. Off came the rockers, cams, housings, cam towers, heads, & p/c's. I'll remove the head studs today then split the case. Question on the oil pump. Should I have the org 3.2 pump gone through or buy a new updated one? What's a good replacement pump that does not require the engine case to be modified for fitment ? Some pics... ![]() ![]() ![]() ![]() ![]() ![]() |
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Luke, if the cylinders are alucil you might desire to open to 3.4.
Bruce |
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Quote:
The current cylinders are Nikasil and look pretty nice. Per the p/o they where replaced by the dealer about 50 thousand miles ago. Old set had a lot of blow by so they were replace with these. I have a set of MMS 3.4 p/c's on order. Should be here next week. |
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Well time to update this..
I'm looking for some cams to make this 3.2 to now 3.4 work. I have the PMO Efi 46, cop kit from Rasant Products. Any one have a similar setup that can give me a real world feedback ? Car will be mainly street driven with some autox/track days. I reached out to John about what he thinks and says the 993SS cams. Anyone running these or other cams that want to share some info? Thanks, Luke |
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What about a 964 oil pump?
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Location: denver
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I have 993SS in a 3,6 and they are kind of boring. Also have Mod S in a 2,7 that's much more fun. Since you have ITB induction you could go with a more aggressive cam like DC40 (mod S), DC44 or DC60.
john |
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