Chads996

Hey folks...

Upon speaking to various vendors and individuals, it has dawned on me that there are MANY different philosophies and solutions for rebuilding a motor. From (as the term goes) "mild to wild", I have seen an amazing diversity in what can be done. With that said, I have been researching rebuilding the engine in my 1989 944 S2 (147K on the motor). While I love the idea of finding every ounce of power (and torque - ) I am not trying to build a sprint motor. I want some reliability. So onto my questions:

- Where do I start? Head? Block?
- What level do I go? Full rebuild or partial?
- What should I consider for a budget?
- Should I consider lightening the crank? Flywheel?
- Who should rebuild it? Local or others?
- Can I rebuild it? (finding vendors for machining of course) - if so, how difficult? (FWIW- I have gone as far as rebuilding lower ends on motors and assembling my own suspensions. Not a novice...with that said )

Any thoughts or "been there and done that..." advice would be GREATLY appreciated. Thanks...

Chad

phlip

The only thing a little tricky about an S2 engine is your going to need a couple of dial indicators and special holders for them to properly set the cam timing. The rest is pretty straight forward,
although my take on it may be a little simplistic.

993944S2

If is was me I would crate my current motor and ship it to Karl. For a couple of reasons
-I want it to make as much power as possible but still be CR legal.
-He has a reputation for building quality motors.
-He knows all the "secrets".
-Do a full rebuild. Don't cut any corners. A significant part of an S2 rebuild is pulling and reinstalling the motor. Those hours add up. I would not want to do it twice in a short period of time.
-Most importantly, and a big question you need to answer for yourself, I work 60-70 hours per week and would have no time to do it myself. Also, if I did, and screwed it up I would be way behind the game.

Lemming

Chad, I say get it ready quickly and get out racing, the season is upon us (there are at least 4 events next month and that's just counting Barber and RA). Do the rod bearings, seals, and front end and go have fun. Ok, here's the crazy part, look for a second engine this summer and begin a quality rebuild to swap in after the 2009 season. Then plan on rebuilding engine #1 in 2010 to drop in the car in 2011. This also assures that if you blow an engine, you have a second to drop in quickly (like overnight if you blow an engine on Saturday at an RA event). Our engines are relatively cheap and having a spare is handy.

From your posts it appears that you like to work on your car, so why not do the rebuilds yourself. Yes you may not get the last few HP's out of it, but you should be able to come close and will have the satisfaction of knowing that you did it.

J richard

First off is this a racecar or a de car? two totally different ways to go...

Second, +1 on what tim said, then you'll have a better idea of what's important in your new motor. I'm not sure if the S2 motors revised the oiling from the earlier motors, but rod bearings/oiling/oil cooling are critical to get life out of the early motors...I'd get an oil temperature guage installed if you don't have one yet, buy the time the water temp tells you you've pushed too far the oil temp is already beyond it's limits.

Chads996

Tim that is some great advice. Finding another motor is likely to be the challenge. Thanks for all the advice guys. I appreciate it. Good point to chew on...thanks.

C.

Van

Don knows his S2s... That being said, there are other fine builders that you could also consider. (Nothing against Karl - just saying you have other options, too.)

333pg333

I didn't know Karl was an engine builder?

DHinkle

I biased but Karl's results stand head and shoulders above anyone else's with S2's.

Willard Bridgham 3

John Milledge is great with in-line 4 cars, especially if you are looking for class-winning engines.

http://www.jmengines.com/index.htm

RedlineMan

Well...

If you think about it, these are production cars, eh? Do you think the factory spends ooodles of time making sure everything is 100% optimized when they put these together? No, they don't. They pull the parts out of the bin and stick them together. It is a testament to Porsche engineering that they are as great as they are.

If you have all the bits and they are at factory tollerance, then there is no real trick to putting one gether right. Again, if everything is to tollerance, then everything will fit as it should without undue fuss. You should certainly check things to make sure, but it's 98% that everything can just be slapped together without any tweaking. Works just fine for street engines.

Track engines are only slightly different. The big thing is keeping the rod bearings happy. Cooling the bearing and journal is the key, and getting enough oil volume through the bearing is what accomplishes that, so you want to make sure that you are not tight on the rod bearing tollerances. The spec for rod bearing radial clearance is .00133" - 00362". You'd be better off toward the "loose" end of that scale to keep oil volume plentiful.

Another thing that I am convinced is vitally important is to have the rods resized. It stands to reason that any 100k+ engine does not have "round" journals any more. If you put a new "round" full tolerance bearing into a high mileage journal environment, you're asking for trouble. An engine that has prophylactic bearing replacement done without resizing the rods will likely have a bearing failure sooner than if it were left alone.

You need to check the cylinder bores for roundness, and then likely have the bores reconditioned. This can only be done by shops having the proper tools and knowledge. Many better engine shops can do this, but you need to be certain they have the specific knowledge to work with the alusil honing process. To get max perofmance from there, you need to size your pistons and rings to that new bore size.

Those are the biggies in my book.

Robert W. Bausum Jr.

See, if you just bought mine, you'd already have two engines...

(shameless plug...)

Lemming

Not as hard as you think, I've managed to easily find 3 968 engines and passed on many good ones.

Chads996

But it's a turbo...(slight difference.)

C.

M758

944 spec does not allow for fancy rebuilds and that is where my experience is. My take is do a stock rebuild to start with. If you want hp it will cost $$$$$$$$$$$ to do it. Even then it won't be much seat of the pants change.

A stock simple rebuild would be fresh head (nothing fancy, just cleaned up and make sure the valves seal), new rod & main bearings, fresh rings in stock untouched bore. Then bolt it back up. I have done multiple rebuilds similar to this with good results.

The motors take well to fresh seals, gaskets, fresh bearings, and light headwork to restore stock performance. They won't make big hp like this, but should run like a tank!