Most common rebuild mistakes

[jonesb930]

quote:
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Originally posted by jgparker
I have to agree that Jim Sims answer is the probably the most common mistake. Everyone seems to think they can do a rebuild for $3000 until they get deep into it.

JP
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I am in the 15K neighborhood now. Of course that inlcludes a ton of machine work, Carrillo rods, P&C set, Motec M600, New Cams, etc. I still have more to go. I figure I will be near 20K by the time I am done. Of course my rebuild is an exception as I opted to just go all out and spare no expense. Looking back, I could have did a basic rebuild for about 4K or so.

[ischmitz]

Originally posted by jonesb930
I am in the 15K neighborhood now. Of course that inlcludes a ton of machine work, Carrillo rods, P&C set, Motec M600, New Cams, etc. I still have more to go. I figure I will be near 20K by the time I am done...

What's it gonna be when you are done?? What exactly are you building?

Ingo

[markwemple]

It's amazing what can constitute a rebuild. My main reason for creating this post, however, was to have a list of dos and don'ts from real life experience for all of us to refer to. Wayne's book is an excellent primer but we are all human and I'm hoping this will prevent some headaches.

Looks like Jones will have one incredible engine!

[jonesb930]

I have also heard that people have mixed up the springs for the oil check valves.

As far as my motor goes. It will be a streat car for the most part. We estimate it should run in the 550+ HP range. The case has been boat tailed, Knife edge crank, Carrillo rods, New Big Bore P&C set(3.2L 7.5:1), C2 Oil pump, Larger Turbo, Full bay intercooler (under construction), 3.2 EFI intake, 75mm TB, Motec M600, GT2 Evo Cams, performance valve springs, Euro exhaust, and an Aeromotive fuel system.

Bill

[ChrisBennet]

Originally posted by jonesb930
I have also heard that people have mixed up the springs for the oil check valves.

As far as my motor goes. It will be a streat car for the most part. We estimate it should run in the 550+ HP range. The case has been boat tailed, Knife edge crank, Carrillo rods, New Big Bore P&C set(3.2L 7.5:1), C2 Oil pump, Larger Turbo, Full bay intercooler (under construction), 3.2 EFI intake, 75mm TB, Motec M600, GT2 Evo Cams, performance valve springs, Euro exhaust, and an Aeromotive fuel system.

Bill

Is that a C2 (964) or a C2 Turbo pump? I thought a 964 pump was smaller than a 930 pump. I've got a 964 pump on the bench at the moment if you want me to take a picture or measure it.
-Chris

[Tinker]

Chris,

It looks like he started with a 77 930 which has the smaller 911 pump.

Tinker

[ChrisBennet]

Originally posted by Tinker
Chris,

It looks like he started with a 77 930 which has the smaller 911 pump.

Tinker

If I was making a 500hp Turbo I'd want a nice big Turbo pump - which is probably what he's doing anyway. I was just curious.
-Chris

[sayah]

Getting back on the topic. one of the big reasons prompting my current rebuild:

The previous rebuilder forgot or didn't think it was necessary to include "o" rings on the through case studs. They just relied on some sealant to do the job. Naturally over time they leaked!

[Tinker]

Chris,

I was under the impression the C2 pump and the turbo pump are relatively similar in terms of overall performance, with the C2 pump having a higher scavenging volume?

Is the C2 turbo pump different from the normal C2 pump? I have never seen one.

I just bought a 3.3 pump, so I could compare your measurements.

Tinker

[ChrisBennet]

I just measured a 964 oil pump. It is ~ 8 1/8" from the tip of the input shaft to the other end of the pump casing or about ~8 1/4" if you measure to the ends of the studs.
-Chris

[Tinker]

3.3 pump is ~7 5/16" from the housing end to end and ~8.5" from the tip of the input shaft to the end of the housing.

Tinker

[aigel]

Originally posted by Wayne at Pelican Parts
As I mention in the book, you can indeed sometimes get away with a $3K rebuild if the following is true:

- Aluminum case
- Reusable pistons & cylinders (Nikasil)
- No broken head studs or broken parts (bearings, etc just wore out)
- You do all the work yourself

-Wayne

But how likely is that? If the engine has 150+k miles, it will need pistons. If it died earlier than 150k miles it will have broken parts.

I will baby my 3.0 along and am starting to save for the 3.6!

George

[Tinker]

"I will baby my 3.0 along and am starting to save for the 3.6!"

Those 3.6's aren't getting any younger. The youngest being 5 years old. Eventually they will all require a rebuild so our choices will be between rebuilding or taking a chance on used 3.6 with mileage. The cost difference could be substantial.

Tinker

[Wayne 962]

Originally posted by aigel
But how likely is that? If the engine has 150+k miles, it will need pistons. If it died earlier than 150k miles it will have broken parts.

I will baby my 3.0 along and am starting to save for the 3.6!

George

The example I point out is applicable for relatively low-mileage motors with a broken head stud.

-Wayne

[aigel]

Originally posted by Tinker
"I will baby my 3.0 along and am starting to save for the 3.6!"

Those 3.6's aren't getting any younger. The youngest being 5 years old. Eventually they will all require a rebuild so our choices will be between rebuilding or taking a chance on used 3.6 with mileage. The cost difference could be substantial.

Tinker

Tinker:

Correct. If I buy a 3.6, it would come apart for inspection and refreshing. I would not put it in blindfolded, unless it was very well documented low mileage and I could hear it run etc.

I am dreaming at this point in time. I would like to recreate a setup built by JW that one of the club members has: A 3.6 with higher compression, hefty cams and carburetors. Carrillo rods and all the works. The engine I am talking about dynos at 320 horse. I'ts bullet proof and pulls like a freight train! For a lot of folks JW is too conservative. I like his approach. If you don't overrev such an engine, it will last you a decade.

George

[aigel]

Originally posted by Wayne at Pelican Parts
The example I point out is applicable for relatively low-mileage motors with a broken head stud.

-Wayne

You should have said so. You are correct, that is a great example for a low budget rebuild. A top end may be all that's done it that case. I have even read about folks that did this for $300, leaving everything alone, since their engines had well under 100k.

Cheers, George

[markwemple]

All the machine shops I spoke with (mentioned in Wayne's book) believe that the sc is young even at 130-150k and that baring something noticably wrong with the bottom end, a top end is fine. They all told me to wait for a full rebuild until 250k+.

[fastfredracing]

How about using the right machinist and his advice, my first 3.0 Litre was a nightmare( well, not that bad) Would have never happened if I had known about this board

[ficke]

case half leak I should have paid a little more attention. Every thing else is great. Parts $6000, machine shop labor $2500. I did not replace P.C.s or valves, I went into it because PO's mech. did not shim cams well and wore thrust bearing and I caught it before the crank was damaged so my crank was STD./
STD.$$ went to updates on an old engine while I was in there. No HP. increase to speak of. Just a sweet running 2.OS

[911pcars]

The most common mistake, IMHO, is having false assumptions. Assuming something is either installed, measured, rebuilt, tightened to spec, machined, cleaned or adjusted will eventually lead to the realization one or more of the aforementioned wasn't and often not realized until it's way past the point of correcting it.

Sherwood