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Old 08-31-2013, 04:46 AM   #1
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What would you do while rebuilding an engine?

I have my 2003 3.2L M96.24 engine completely torn down due to a "gentle" IMS failure, no other engine damage. I've replaced the main bearings, thrust bearing , rod bearings (what the heck, I'm in there anyway) had the heads re-worked and am starting to rebuild the engine from the ground up.

I found a stock IMS with bearing on E-bay (very hard to find) and am using it over the dealer part to avoid the oversized IMS bearing issue. I'm going to go with the LN bearing after completing the rebuild as the clutch is still good.

The engine had 120K at failure, all the journal bearings were shot, but everything else is in amazingly good shape.

What performance mods / upgrades / part replacements would you put into the engine if you were rebuilding from scratch?
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Old 08-31-2013, 05:42 AM   #2
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Perfect excuse for a 3.6 swap.

Otherwise, start here:http://www.lnengineering.com/store/catalog/index.php
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Old 08-31-2013, 11:09 AM   #3
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If you have the engine town down, don't do the LN IMS retrofit, send them your whole shaft and get the triple bearing IMS (which can't be done through the case hole, but involves them having the whole shaft at their facility), or, better yet, do the IMS Solution.

If you are re-using the factory rods, you need to check clearances, and use new rod bolts.

If you're on a budget, you can certainly do a rebuild using stock parts, but, if you want added performance and reliability, have LN sleeve your 3.2 out to a 3.6 with their JE pistons, get their R&R rods with ARP hardware, have the heads lightly ported and cleaned up.

If you're planning a stock rebuild, I would very carefully inspect and measure your cylinder bores.

Also note that the last time I checked, new piston rings from Porsche were almost as much as new pistons from JE!!

Obviously you're going to need a complete gasket kit, and the bolts in the bearing carrier are one time use stretch bolts, so you'll need to replace those, and note that they have a slightly weird, very specific torque procedure.

Either way, I'd use the billet IMS tensioner paddle with the updated tensioner, replace the rest of the chain guides, replace the VarioCam solenoids. Something else to look at, especially with 120k on the clock, are the intake cam's bearing sleeve (that aluminum thing on the driven end of the cam) and the little sealing rings inside it (that ride in grooves on the cam). You likely have wear on on the rings, and possibly that bearing sleeve, and what happens when those leak is you'll get laggy VarioCam response, as you're leaking oil past those rings and it's not getting to the vane cell to move the cam.

Do you have all the engine assembly and timing tools?
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Old 08-31-2013, 12:18 PM   #4
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A 3.6 swap is definietly in the cards for the future. Right now I'm headed towards a stock 3.2 with minor upgrades.
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Old 08-31-2013, 01:12 PM   #5
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Modern chain guides, lifters, rod bolts, journal IMS bearing, clean up the head ports and coolant passages. I would go ahead with a 3.6 option while I was in there. Anything else??
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Old 09-01-2013, 04:57 AM   #6
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AOS, water pump, thermostat, pulley, belt, hoses, plugs, coilpacks, all the little things that are so much easier when the engine is out. The connections for the expansion tank and oil filler tank.
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Old 09-02-2013, 05:02 AM   #7
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I'm just completeing my rebuild of a M96 24.
I would liked to have used new JE pistons and rods but was informed the only way I can do that is if I sleeve the cylinders. My cylinders, pistons and rods were good so I went with new Porsche rings(I think there must be gold, titanium or some metal from mars in these rings because of their price).
I went with ARP bolts thought it was the logical replacement (rebuilder agreed) but I have since read where some rebuilders have had experience with ARP coming loose???
I went with the LN triple row bearing but if I could have got the IMS solution that would have been my choice.
I used the LN billet IMS tensioner paddle and all new chain guides and other paddles, new chains. I'm not totally convinced the billet tensioner paddle is necessary (I'm not a mechanic), I don't track the car.
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Old 09-02-2013, 05:33 AM   #8
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Thanks everyone for your insight and thoughts. Keep the posts coming! I'm making a list for the rebuild and will post what ended up in the engine as well as the cost and results after completion.
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Old 09-02-2013, 01:19 PM   #9
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Quote:
Originally Posted by pjq View Post
I'm just completeing my rebuild of a M96 24.
I would liked to have used new JE pistons and rods but was informed the only way I can do that is if I sleeve the cylinders. My cylinders, pistons and rods were good so I went with new Porsche rings(I think there must be gold, titanium or some metal from mars in these rings because of their price).
I went with ARP bolts thought it was the logical replacement (rebuilder agreed) but I have since read where some rebuilders have had experience with ARP coming loose???
I went with the LN triple row bearing but if I could have got the IMS solution that would have been my choice.
I used the LN billet IMS tensioner paddle and all new chain guides and other paddles, new chains. I'm not totally convinced the billet tensioner paddle is necessary (I'm not a mechanic), I don't track the car.
ARP rod bolts are a must! If they came loose it's probably from using ARP torque spec but not ARP thread lube for proper stretch load. Or you can use the LN R&R steel rods which include ARP bolts, are rebuildable, & should be 50 grams lighter per rod. Maybe more since factory rod weights vary alot.
All rotational parts should be precision balanced including flywheel & pressure plate. Consider having a 2nd flywheel & pressure plate balanced while you have the crankshaft balanced as it is difficult to do without the crank.
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Old 09-03-2013, 03:32 AM   #10
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I came across the OBX throttle bodies kit the other day. I'd be tempted to work that in if you had the time an money whilst the engine is already in pieces.
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