ISO: 3.2 to 3.4 (or 3.5) engine build checklist / spreadsheet + heat backdate help?

[famoroso]

Greetings all,

I've searched both the engine building forum and this technical forum, for a checklist, but couldn't find anything. I also posted this entreaty for help on the engine build forum and didn't get a response, so, here I go again...

I am working with Jae Lee at Mirage International to define the scope of an engine rebuild for my 1987 911 M491 coupe. The engine has 105k miles on it and is burning a quart of oil every ~265 miles. Engine feels pretty strong still and is running Sal Carceller's modern MAF & injectors + ECU, as well as a Dansk pre-muffler and Dansk 84mm sport muffler. All of which I plan to retain on the build, although I have a Bisimoto Pulse Chamber "muffler" that I may play with post engine build.

Jae and I are kicking around a top end rebuild, or perhaps a full rebuild and we're discussing a few options at this stage.

I'd like to build something a bit more rev-happy than stock, so considering Pauter rods and a lightweight clutch pressure plate to help in that area. I'm planning on using Mahle Motorsports 98mm pistons & cylinders, but haven't decided on a CR yet (I'm saddled with crap CA gas here in San Diego). Also considering Web 20/21 cams (I have them in my other 911 and I'm happy with them). Jae is suggesting we consider a GT3 crankshaft, if we end up splitting the case, to net the 3.5 liter displacement. I wonder how that will affect my rev-happy goals though.

Anyway, I want to ensure that I'm covering all the build bases, hence why I'm looking for a parts checklist, or the like. So, does anyone have a checklist / spreadsheet they can share?

Also, I would like to incorporate a heater backdate as part of the above. Does anyone have a part number for the right duct, that fits without modifications? The reviews here make me wary... https://www.pelicanparts.com/More_Info/93010632101V2PH.htm?pn=930-106-321-01-V2-PH

I'd do the Classic Retrofit electrocooler too, but my stock AC is working so well (pic attached), I don't wanna mess with it.

Thanks!

Pic of the business end of the patient...



Glorius vent temps...

[Cevan]

So a GT3 crank nets you an extra .1 liters of displacement?

[famoroso]

Originally Posted by Cevan

So a GT3 crank nets you an extra .1 liters of displacement?

I don't recall the precise figures, but as we were talking, Jae busted his calculator out and figured something less than 3,400 CCs for just 98mm P&C's and something over 3,500 CCs for 98mm P&C's + GT3 crank.

[3rd_gear_Ted]

Originally Posted by famoroso

I don't recall the precise figures, but as we were talking, Jae busted his calculator out and figured something less than 3,400 CCs for just 98mm P&C's and something over 3,500 CCs for 98mm P&C's + GT3 crank.

But, the GT3 crank will spin to 9K

[fred cook]

Originally Posted by famoroso

I don't recall the precise figures, but as we were talking, Jae busted his calculator out and figured something less than 3,400 CCs for just 98mm P&C's and something over 3,500 CCs for 98mm P&C's + GT3 crank.

Or, you can use KN Engineering "slip fit" cylinders and Mahle 100mm pistons and still get approximately 3.5 liters. The pistons and cylinders are pricey but should not be as much as a new crankshaft. If you go the twin plug route you can run up to 11:1 or a bit more and still use pump gas. I would plan on using aftermarket connecting rods rather than the original 3.2 rods especially if you plan on going over about 7000-7500 rpms!

[Lyle O]

If you plan to spin above 7000 regularly, you might want to consider different cams (20/21). They really drop off after about 6900 or so (I know ‘cuz I’ve got em)...Great cams, but not meant for power above 7000.

[Jeff Alton]

If you are working with Jae, listen to what he has to say. Discuss with him your needs/wants/budget. You are in good hands. Plus, if he is building the motor, then let him deliver what you want, he will.

Cheers

[winders]

@famoroso

If you want this engine build to last for another 100,000 miles, you don't want a high RPM motor. Keep the revs under 7000RPM for longevity and reliability.

[famoroso]

Thanks everyone.

I'm totally listening to Jae.

I'm not looking for a high revving motor, per se, but one that revs (and drops revs) a bit more freely than the stock 3.2. Hence, the motivation for lighter Pauter rods and aluminum clutch pressure plate. Sub 7,000 RPM is good for me.

I am a list guy though, so just looking for a parts checklist.

Also, any suggestions for heater backdate parts?

[Helix8]

maybe consider Carillo rod set and AASCO lighweight flywheel - many use 964 profiled cams (not saying this is the best only frequently used) ?

[famoroso]

Originally Posted by Helix8

maybe consider Carillo rod set and AASCO lighweight flywheel - many use 964 profiled cams (not saying this is the best only frequently used) ?

Jae uses / recommends Pauter, so we'll go with them.

3.2 Carrera single mass flywheel is already pretty light (relatively speaking anyway) and I don't want to tempt / invite any idle issues. G50 stock steel clutch pressure plate is pretty heavy though, so the thinking is to lighten things up there with a Kennedy or Sachs Sport aluminum unit.

Thanks for everyone's thoughts. Still looking for a checklist.

[1989Carrera]

Listed below are the parts I used to backdate the heat on my 1988 Carrera. Based on price, I purchased all but the Left Hot Air Duct from Sonnen Porsche. The Left Hot Air Duct was purchased from Pelican Parts. The prices listed are from July 2018. I had to buy the Front Tin without Hole used.

930.106.321.02 Left Hot Air Duct (930 version - better clearance) $105.95
911.106.327.00 Right Hot Air Duct $140.50
911.106.331.00 Right Hot Air Duct Support $ 8.50
911.106.036.00 Right Hot Air Duct Cover Plate $ 52.61
911.106.827.00 Right Hot Air Duct Closing Plate $ 12.30
901.106.825.00 Left Tin for Hot Air Hose $ 48.73
901.106.826.00 Right Tin for Hot Air Hose $ 48.73
911.106.083.01 Left Tin $144.73
901.106.084.00 Right Tin $121.35
901.106.085.05 Front Tin without Hole NLA
999.591.592.40 Plastic Nut (for hole in Left Hot Air Duct) $ .64
999.703.044.50 Rubber Plug (for hole in Left Hot Air Duct) $ 3.53

Best of luck with your build!

Dall

[shoooo32]

Pelican sells the heater backdate parts - they are the only ones to my knowledge that have modified the left duct to minimize interference with the distributor.

As for a checklist, the closest thing I've seen is in Wayne Dempsey's engine rebuilding book. It identifies all the components (by P/N) that need to be replaced, and the different paths to upgrade. It's older but there's a ton of knowledge there. $20 on Amazon.

There are lots of threads in the engine building forum discussing good streetable power with a 3.2 carrera. IMO, the low hanging fruit for modification are replacing heavy G50 PP/flywheel, more aggressive cams (964, 993ss), free flowing muffler and a Steve Wong chip. ARP rod bolts are a must on 3.2 motors if you're staying with stock rods. These mods are game changers for a street car, making it way more playful/rev happy.

Beyond that, having your cylinders bored to 98mm is not terribly expensive (roughly $2.5-$3k including new pistons & rings) and is a no brainer if your stock stuff is not in spec.

Based on everything I've read for street motors, I'd avoid heavier valve springs and titanium. It's not necessary and limits longevity. I'm sure one of the guys that builds these for a living can chime in on the specifics.

[Helix8]

If you do have your cylinders bored and plated make sure to specify RA (no more than 6-10) and have this verified afterwards. AMHIK

[fred cook]

Since you asked, here is a list of components that I used in my 3.3SS engine build:

Kept and reused:
engine block
crankshaft
conn rods (rebuilt by Ollie)
oil pump
flywheel

Replaced/new:
KN 100mm slip fit cylinders
Mahle 100mm 10.1:1 pistons
Carrera heads machined for twin plugs and matching cam housings
valve job on heads by Xtreme Cylinder Heads in Florida
Early large port CIS air box, rubber connector hoses and intake runners
964 camshafts
timing chains
crank and rod bearings
gasket set
Electromotive XDi twin plug crank fired ignition
Plug wires for 12 plugs
Sealants
small fastener kit (misc. nuts, washers and bolts)
miscellaneous vacuum hoses and connectors
aluminum clutch cover
3.2 rear engine mount modified to work w/3.0 block
engine mounts
black crinkle paint for rocker covers
probably some other misc small parts
engine stand, hoist, Porsche camshaft tools
all labor done by me.

The end result was an engine that can sit for a month and fire right up! Runs great after a short warm up period. I modified the CIS to be more like the original 1973 1/2 system and added a 7th injector that adds fuel only at full throttle. Compression wound up being about 10.8:1 because of some machining done on the heads. Runs great on 91 or 93 octane pump gas.