schwank

This weekend I plan to get the track car back into the garage for some in depth maintenance. Last year the car performed admirably, but with 157K on the bottom end I'd like to get the bearings swapped out for peace of mind. Would suck to have all the rest of my hard work destroyed by a thrown rod. So I have pushed aside the long term 951 project and now is the time to re-focus on the track tool.

I'm just gonna drop the whole front end, and do front control arm bushings and such while I am in there. I just swapped out the suspension and pulled the front steering so things will be even easier as half the damn thing is already apart.

The top end was already done 2 years ago and only has this summer's track mileage on it to date. The clutch is only a year old as well. Pretty much everything else in the engine bay is already new.

So I'm looking at main and rod bearings, pan gasket, FMS & RMS, and since I'm pulling the motor, AOS and balance shaft seals. Finally she'll be getting an upgrade to a turbo oil filter mount with an external Mocal oil cooler. Oh yeah, will Magnaflux the crank and drill the 2 & 3 mains.

Questions:

1) Anything else I missed in the while the motor is out category?
2) Can I do all this work with the top end still installed? I assume the cylinders to be in good condition or the head work would not have proceeded when it did. I figure I can always review them from the bottom side, no?
3) Any reason the thing can't be put on an engine stand and rotated to make the work easy?
4) What special tools do I need for this job, other than a ring compressor?
5) Will the early lower balance shaft front cover fit the late motor? I ask as it is a bit lighter due to no extra provisions for the power steering pump, which I have deleted. I could swap the one in from my spare 83 motor.
6) How many hours would you guys estimate this would take in total. For some of you, I know to add 50% to cover my OCD.

I guess that's all for now. Undoubtedly I'll have more in the future. I have pulled a motor from a 44 before, but that was my parts car. This time I need to do it fast and do it right. And it will be my first time taking apart the bottom end too. I've got the shop manuals and clarks to guide me... hopefully I'll come out ok by my early March deadline.

Thanks. Once this is done my car is gonna be awesome, with every component tweaked to perfection. Can't wait to get it back on track this year!

944 guy

You can't pull the pistons out the bottom due to a sizeable ledge at the front and back of the cylinders. You'll have to pull the head if you want too. Considering you have to pull off the timing belt anyways, you may want to spend the extra hour or 2 on that since it will drastically lighten it all up facilitating mobility of the engine on the stand.
You might want to get a 12 point socket (one with a '3 square' layout instead of a '2 hexagon' layout which is standard for normal nuts 'n bolts, don't know the real terms) for the conrod nuts. A standard '2 hexagon' will work if it's in perfect condition, but it's not the best tool for the job.
I don't know much about the balance shaft covers, I'm actually curious if you could put the upper shaft cover on the lower shaft, they seem so identical
The main bearings are generally in good condition and usually don't need replacement (they don't take near as much punishment as the conrod bearings). Just get a measuring tool and measure crank play (radial, axial) with the auxiliary equipment disconnected to determine if those need to be replaced (you break open lots of oil channels when you remove the bottom end and have to reseal them all upon reassembly, PITA). Our engine bombed on track last september (yes, conrod number 2), and except for what looked to be scoring from the bearing material floating around, the main bearings looked pretty good. We're not replacing the bearings in our new second hand bottom end since the play was well within tolerance.

jwade944

I put the Lindsey Racing baffle kit in mine. It takes me a couple of days to do the rod bearings but that is leaving the engine in the car.
1. Yes.
2. Yes.
3. Just make sure you have something to catch all the oil and coolant.
4. Flywheel lock. (Loosen the crank bolt before you remove the engine!) Balance shaft spanner. Alignment tool for the oil pressure relief valve. Gear puller. Unless you plan to do the rings, I would leave the pistons in the bore. I originally said not to do the main bearings, but if you are pulling the crank anyway, I would probably go ahead and do them.
5. I don't know the answer to this one.
6. 30 hours to do the work. 100 hours of cleaning 21 years of crap off the engine. Three parts orders- minimum.

schwank

Good tips. I really don't want to pull the head if I can avoid it. If that is the case I'd be better off just building my spare motor which is out and on the floor, already disassembled, and then just doing a direct swap when it is finished.

I have a late pan that is already baffled, so that is ok. I have the flywheel lock and a complete set of Arnnworx tools... only thing I don't have is the OPRV alignment tool. As long as I can leave the pistons in the cylinders while the motor is upside down, I think that is what I'll do. I know it's cutting a corner, but the motor does not need a full rebuild, it has great compression and leakdown. It sucks, but I'm only doing this to prevent any issues... have not had any to date.

Unless the things are mint, which I doubt after 157K, I'm doing all the bottom end bearings. I do NOT want to open this thing up again soon. I need to work on the turbo too! Luckily the car is damn clean as I've spent the last year sorting it out, and most of the engine bay is already spotless.

FRporscheman

Then why don't you want to do the rings as well?

KuHL 951

If you aren't doing the head I would skip the mains. Have you ever heard of a main bearing failure? Pulling the crank opens Pandoras box as far things that can go wrong. If all you need is a rod bearing refresh just do it in the car and save yourself a lot of work. If you pull the engine and build it on a stand, do it right and install rings, mains, and full upper and lower seal sets. You said the head is fresh so you are good there.

luckett

+1 don't touch the mains and then do it in the car.

Have you considered:
- A 3 pc. cross member so you can check the bearings much more easily next time? I was going to have one done locally but it would take too much time to get it set up and cost too much. I was thinking of posting up to see if there would be interest in doing a run of them to spread the jig/setup costs out.

-An Accusump or even a proper dry sump setup since you're messing with all the same parts. That would take care of any oil starvation issues.

KuHL 951

Chris, you can count me in if the price and quality is good. I'll even throw in a couple spare crossmembers so people don't have to send theirs in as a core or have to wait for theirs to get back.

JerryW

I agree with this -- And a little design change with some locating pins as well as the bolts if it can be worked out.
Some discussions on the 944Challenge forums imply the current style may have some issues when used in Race cars.

luckett

Did you already have any ideas for the design?

I have two crossmembers also. I'm thinking it would probably take about 10 or so to get it to a good price. Of course, more means cheaper. I talked with the guy already and he said he would be interested, but we didn't talk details yet. Initially he would need enough pieces to make it worth his setup and fitting time. Once he has the jig ready, he would be able to crank them out for a fixed rate.

Jerry, can you put a feeler out to the spec guys and see if there is interest?

FRporscheman

I now have a spare crossmember that came with the 951 engine. I won't say 'count me in' until I know what price to expect but I'm interested as well.

reno808

save your self the trouble and just buy it at Lindsey Racing.

JerryW

I'll post a question and link to this thread, as well as design changes they recomend.

JerryW

Thread started athttp://www.nasaforums.com/viewtopic.php?f=40&t=19947

M758

I suggest doing the Mains.

Here is why. The main bearing clearnaces are critical to provide oil flow to the rod bearings. The way the system works is the oil galleys in the block feed the main bearings. The excess oil that is feed to the mains gets send throught the crank to the rods. If the main bearings are old and worn they will leak more oil and the more oil they leak the less that is available to go to the rods. Of course old worn rod bearings leak too and the reason you change then is to reduce the clearances and thus how much oil is needed to float the surface and prevent metal to metal contact.

You can do just rods in a pinch, but doing the mains on a 157k motor is a good idea inspite of all the work. I have heard fo old motors with fresh rod bearings still fail. I believe this was due to worn mains and wide open clearances there thus not supplying enough oil to maintain even fresh rod bearings.


Now balance shaft covers. These are match set to the engine block. They cannot be moved from one engine to another engine nor moved from top to bottom. If you notice carefully you will see a stamped 3 or 4 digit number on the block and on the balance shaft cover. These are the match set numbers.

Now the forward covers where oil seals sit are not matched and can be swapped from engine to engine.

Also when you put the engine in the engine stand make sure you allow plenty of time to allow the oil to drain. Don't turn the motor over full of oil as then oil could seep into the combustion chambers.