my DIY engine rebuild

[rp17]

Might be a stupid question but about how much does the engine weigh?

[78F350]

Cool tool and great 'DIY clarity'.

Can that cam journal surface be polished or does the cover have to be replaced?

Originally Posted by rp17

Might be a stupid question but about how much does the engine weigh?

Mine was 393 lbs on a bathroom scale rated to 400 lbs.

[epapp]

How many miles are on your car? I checked your first post but didn't see. Everything is so clean on the engine so it can't have that many miles. It doesn't even look like it has the typical browning from heat cycles and age

[flaps10]

Might be a stupid question but about how much does the engine weigh?

Way too heavy to be mounted in the back of a sports car, I'll tell you that. It's a beast. Back in my young and stupid days I used to drop a type 1 VW engine, strip the heater boxes off and carry it in the house. I recall reading that the VW engine would be in the neighborhood of 185 pounds in that trim but I never had one on a scale.

The M96? No idea, but I'm much older, a little bit smarter now and sporting a ruptured disc from about four years ago. I could tell just sliding it out on my makeshift pizza board that there would be a lot of stuff removed, and an assistant before it was going to move to my bench.

Originally Posted by epapp

How many miles are on your car? I checked your first post but didn't see. Everything is so clean on the engine so it can't have that many miles. It doesn't even look like it has the typical browning from heat cycles and age

My car just turned 120K miles. I agree the engine is way too clean. It would appear that it had a cylinder head recently. The valve covers are both marked and the oil scavenge pumps in the heads are also marked so it may have been torn down even more.

This car was what guys older and more southern than me might refer to as a "pig in a poke". I don't know the history of the car and I didn't get a PPI. That of course goes in the face of everything you read about buying a Porsche. You're supposed to walk away from cars like mine. And if you pay someone to work on your 'exotic' car then that's no doubt a smart recommendation.

However I also got my car for about 2/3 of the going rate for an S model, and I also bought the car as a hobby. Maybe I'm an odd one, but I bought a Porsche so I could enjoy ownership, including working on it. I don't enjoy writing big checks as much as some people I guess. In the end if I have to put $5k in parts and machine shop work then I'm still at a break even, and I'll have a car I know I can trust.

Enough blathering.

This morning it was time to clear the decks. I started by clearing my work bench because I hope to have the crank case sitting on it prior to tearing it apart.


Yet another lousy phone pic. You'd think Katherine Hepburn took these. Anyway this is part way through "making a hole".

And then it was time to clear the top and bottom of the engine of anything that moves.


Top side clear. The starter, oil cooler, alternator and crankcase breather apparatus all come off easily. The power steering pump though - what a scream. It's mounted to a pedestal which you would really like to remove in one piece and take the power steering pump still attached to it. But there is one base bolt that is pinned down by a lug on the power steering pump. You can't just remove the power steering pump because first you have to remove the pump pulley and then you'll discover that one of the hard lines is in the way. It's like one of those puzzles with one missing square. I found I could leave the hard line attached and remove the pulley and the four bolts (three from the front and one from behind) that hold the PS pump to the pedestal. By doing that you could get just enough room to sneak a box wrench in and inch the remaining base bolt out. Tedious but it gets you there.

Then you're looking at a pile like this:


Next I carefully tipped the engine up on end and removed the exhaust manifolds. Pretty easy with the help of an air impact wrench. It managed to come up with quite a puddle of oil and coolant it was hiding while I did the work. Then back down to a stable position.


Before anyone asks, the hideous black area on the board is from being used to host some things I spray painted for my woman recently. So far (other than the oil filter and the IMS bearing/shaft) I have only seen clean oil and clean coolant.

[kodabear]

Originally Posted by flaps10

Way too heavy to be mounted in the back of a sports car, I'll tell you that. It's a beast. Back in my young and stupid days I used to drop a type 1 VW engine, strip the heater boxes off and carry it in the house. I recall reading that the VW engine would be in the neighborhood of 185 pounds in that trim but I never had one on a scale.
.

Too heavy to be in a sports car? You might want to educate yourself a bit on engine weights before making such a statement. The m96 weighs significantly less than the old air cooled 911 motors. And comparing it to a type I vw...really? The m96S makes 5 times the horsepower lol. FYI The 3.5 liter cosworth dfv f1 engine only weighs ~30 pounds less than a m96 even with m96 heavy street flywheel. The dfv was not too heavy for Jim Clark.

[flaps10]

I was mostly poking fun at rear engine cars as opposed to mid engine cars not trying to roast the M96 as an oversize boat anchor. I'll try to stay on topic.

[rp17]

Originally Posted by flaps10

I was mostly poking fun at rear engine cars as opposed to mid engine cars not trying to roast the M96 as an oversize boat anchor. I'll try to stay on topic.

Humor is good. Thanks for the pointers so far. Damnit need more popcorn.

[kjc2050]

Originally Posted by flaps10

I was mostly poking fun at rear engine cars as opposed to mid engine cars not trying to roast the M96 as an oversize boat anchor. I'll try to stay on topic.

I took it as humorous. Great thread; keep it up.

[Jake Raby]

Consider reindexing the slots for the exhaust cam sprocket more toward the middle. As they are you have no room for adjustment at a later date. That later date might be really soon.

After its together spin the engine 20 times CW and then recheck cam timing. In most cases a small correction will need to be made.

[Chuck W.]

Originally Posted by Jake Raby

Consider reindexing the slots for the exhaust cam sprocket more toward the middle. As they are you have no room for adjustment at a later date. That later date might be really soon.

After its together spin the engine 20 times CW and then recheck cam timing. In most cases a small correction will need to be made.

Class act Mr. Raby. Class act.

[flaps10]

Originally Posted by Chuck W.

Class act Mr. Raby. Class act.

Indeed. Much appreciated.

I got the lifter carrier off the cylinder head this morning. It would seem that the builder of this engine was certain that gray goo was supposed to be applied to every possible surface in order to keep the oil inside.


Starting to collect a pile.

Getting the cylinder head off was a matter of removing four screws and then the large long bolts. I had neglected to remove the chain ramp pivot bolt but just by wiggling the head it was obvious where the hang up was. Out it came and the head came off.



I was a bit startled to see a stray piece of metal, visible in the coolant passage at the lower left of the picture above.


A close up.

It was that piece of foil that seals every oil and coolant jug we purchase, and somehow this one ended up in my engine. Could have been a really bad thing down the road.

This is a look the other direction:


Out came my oil pump:


And water pump:

[Jamesp]

The metal in the coolant passage is cause for concern, particularly since the engine appears to have had some work in the past. What does the block side of the water pump look like? Failed metal impeller water pumps are legend on this forum.

[kjc2050]

Originally Posted by Jamesp

What does the block side of the water pump look like? Failed metal impeller water pumps are legend on this forum.

Isn't that a picture of the block side of the WP right above your post?

[BFeller]

Originally Posted by Jamesp

The metal in the coolant passage is cause for concern, particularly since the engine appears to have had some work in the past. What does the block side of the water pump look like? Failed metal impeller water pumps are legend on this forum.

The picture does show a foil tab that seals a bottle of some sort. Maybe from the previous owner applying IMS Bearing Repair in a Can.

[78F350]

You call those bearings bad? I bet you could have gotten another 1,000-1,500 miles out of 'em.
Mail them to me, I'll replace mine with it:



:dance:

Great pics and description. I can't wait for the assembly (you too I suppose).
I was going to put my 2.7 in today, but found out I can't get spark plugs locally, so I'm waiting a day or two for shipping rather than doing it with the engine in.

[Nine8Six]

One of favorite thread on 986forum atm. Got to say thanks to the OP for taking the time and throwing those awesome pics at us. Top man x100

quality work, love it. Keep it going man

[hemonu]

I had that twice in my life, but on a motorcycle engine quite a while ago. A few thouhgts.

Root cause is usually a lack of oilf pressure / flow in the bearing. If the engine is very old and worn the gap may be too high to maintain enough pressure. If the engine is not worn, there may be a problem with the oil pump or an oil line is clocked. Both happened to me. I think it should be possible to grind and polish the crank to the next smaller bearing diameter as it looks. But you have to measure first.
If the bearing has really turned inside the piston rod, you have to change the rod. But I'm surprised that the clips at the corner of the bearings are not broken. When it happened to me the engine got totally overheated in a minute and the bearing was complety destroyed.

[flaps10]

Originally Posted by hemonu

snip
But I'm surprised that the clips at the corner of the bearings are not broken. When it happened to me the engine got totally overheated in a minute and the bearing was completely destroyed.

You know, I had put my tools away and gone about my life for a couple of hours when I had the exact same thought. So I went back out and took a careful look.



As you can see, both tabs are knocked off. I'm pointing at one of them still where it is supposed to live. The other one presented itself when I first removed the rod and bearing. It was just sitting on the crank and at the time I didn't know where it came from.

It would appear rods come in sets of six, and they're about $1500. I'd like to think I could get a single rod and have them all balanced as a set.

That I can tell, there are no scratches on the crank that would justify turning it to the next size down (which btw, aren't commonly available for the M96 from my first glance), but would respond well to a polish job.

I'm making a call to a local hot rod shop that has the capacity to do ultrasonic cleaning and do the polish work.

[hemonu]

Originally Posted by flaps10

I'm making a call to a local hot rod shop that has the capacity to do ultrasonic cleaning and do the polish work.

If it is a good shop you can trust, they may be able to polish and balance a set of piston rods at a reasonable price. That might allow to integrate a used one and strength and balance of the engine would be even better than OEM. For the damaged piston they also should be able to measure the wear of pistons and bore and than you can decide to change one or all. But after 120k and engine opened ...

I remember changing a single broken piston ring on the engine of my first car. I was young, still at school and had little money Only a few weeks later the next was broken ;-)

[78F350]

If you haven't already seen it, take a look at the video referenced here:
How to Build a 3.8L Porsche Track Monster
Maybe jump to about 8:20 and 12:00 to highlight some key points.

That shows all new parts going in, but makes me wonder if you can add in a new single rod and piston to the engine if you rebalance all of them across the engine.

There are used rods, but good idea? I don't know.



***EDIT:
A quick read on cracked-rod design/cracked cap technology makes me think that installing a used rod or even reinstalling your old rods/bolts is probably not a good idea. Look at some of the aftermarket products. They are probably better and cheaper than OE. ***