Opinions requested on motor rebuild.

[Zeke]

Here's the situation: I have a numbers matching S motor in my '71 S, a 2.2 MFI motor that is showing little or no compression on one cyl and pretty low on another. I also have a 2.4 T motor on the garage floor that needs rebuilding. Before discovering the problems on the 2.2 (I knew they were there, I just didn't want to know the details yet), I had planned on building the T motor to a "high compression E" and using it as the powerplant for my track time and what little street driving I do. Prolly would see some good numbers on a motor like this. I have the 2.2 E pistons and some in spec biral cylinders on the bench for this motor. And a brand new E MFI pump.

I could go two ways on this and I want to do it on a reasonable budget. Knowing that a perfect job would provide me with a motor that would go for 200,000 to 300,000 miles with some maintenance, at the present rate of my anual mileage, I would be dead about 30 years before that occurs. And that's with me living for 20 more and still driving. So, something that will last a while will be in order for me. With that in mind, I may very well look over the lower end of whichever and put it back together if all is in spec after doing the oil bypass mod.

I had planned to do the high comp E before removing the S so I would be "down" for the least amount of time. Then, I would have held on to the S for a later rebuild or simply for posterity while wearing down the HCE at my paltry rate of DE's along with to and from and a bit of recreational driving (something that is becoming less fun in SoCal every year).

But, the word budget keeps dogging me and I don't have $10,000 to spend going all out. And, building two motors is false economy. All money spent on one or the other would make more sense. I think you know where this is going, so I'll cut to the chase.

Option A: Remove the S and build it as right as necessary and part out the T. Or maybe "stroke" the S with the later T crank (my understanding is that all 2.4 cranks are counter balanced and the same) and find some rods and use the trick rod bolts.

Option B: Start right in on the T now and get a few miles out of the S before making the switch. Little down time and store the S when it is retired for whatever may be in store for the future. One other advantage to this, I am a carpenter by trade with a fairly extensive background in bodywork, painting, general mechanics and some fabrication. I have built only a couple of other types of motors in my career, no 911 flat 6's. If I am to learn something by mistake (hopefully with this BBS and all the aids like Wayne's book, that would not necessarily be the case), it might as well be on the first motor with the S as number 2 and backup.

I'm sure there are other considerations that I have not addressed, either because of space here or neglect. I'll leave it to you guys (and gals) to bring those concerns up.

Now, in my shoes, what would each of you do? I could have started a poll, but there are no cut and dry choices, eh?

[randywebb]

B

[Brother]

The S motor would be cool.

Does the T motor run?

You could put the T motor in the car while you rebuild the S. Then switch them out when you are done and sell off the T motor. This would keep you at the DE's and then you would have some change to buy the wife something nice to make up for all the time you were working in the garage.

[pwd72s]

I vote for B as well...use the T case as your "learning experience" engine. Save the "S" engine for whatever, whenever.

[Early_S_Man]

Milt,

My best SWAG is that the S has a few broken rings due to the substandard California Panther Pi$$ masquerading as gasoline ... and my strong suggestion is not to drive it any longer and risk further piston/cylinder damage!

How about an option 'C' ??? Use the 'T' block, crank, rods ... 'S' cams & Biral cylinders bored out to 85 mm, JE 9.5:1 85 mm pistons, 'S' heads, 'S' MFI ... save all of the remaining parts ('T' MFI heads can be ported to 'S' specs if need be due to detonation damage [cracks, etc.] on any of the 'S' heads) ...

Of course, there is always an option 'D' to do a short-stroke 2.5 with the 'S' engine, or ...

Option 'E' ... 2.7 or 2.8 on the 'T' core with 'S' MFI components and heads ...

It really isn't a simple choice with all of those components laying around!

[JeremyD]

I like Warren's take - If you are going to be a bear - be a grizzly!

[Zeke]

Originally posted by Early_S_Man
Milt,

My best SWAG is that the S has a few broken rings due to the substandard California Panther Pi$$ masquerading as gasoline ...

Man, ain't that the truth! None of our cars are running right this month. The 90's variety of FI in my truck and our junker, parking lot, grocery-getter Cadillac will hardly run smooth at idle with any load, i.e., AC.

The rest is duely noted, Warren. I wiil do a leak down to verify that theory. Thanks.

And, no, the T is only a core, but it could possibly be a good core only requiring a top end job to put it on the road. But, I'd have to slap those pistons in there and that new E pump just because I can.

[Grady Clay]

Milt,

Option C.

1. Find a “loaner” carbureted 2.0 or 2.2T that runs to keep the 911S mobile.
2. Take the best of both engines and build one good MFI 2.4S with 9.5:2 CR.
3. Sell the remaining parts (keep the 2.2S case if you don’t use it in the engine.)

The 2.4 will have the long stroke (70.4 mm) crank and rods. You have the P&Cs (you will need to be careful because the pistons are cut for E cams and the S cam needs more clearance.) Use the S cams and the best of the 24 rockers and shafts. Pick the better oil pump, jackshaft, sprockets, cam housings, valve covers, flywheel, pressure plate, pump sprockets, etc. If you use the 2.4T case, you will need to re-curve the T distributor. If you use the 2.2S case you have the right distributor. You will need to use the 2.2S oil cooler, hoses, etc.

The big expense is all the new parts and machine work that any rebuild requires. Both Dempsey and Anderson have good lists to start from. Type up your own list and post it. Start pricing all the items. Once you have this priced you will have a low-end figure for the project.

Sell the leftovers on Pelican. Anything that doesn’t sell, I hear there is a company that will pay top dollar for useable junk – M&J, M&K, ML, M… or something like that.

Regardless of what you decide, remember Murphy is in charge – it will always cost more than what you think.

Best,
Grady

[Wayne 962]

Buy a running 2.0 2.2 2.4, etc, and install it in the car for six months. THen rebuild the 'S' and then sell the temporary motor for what you paid for it...

-Wayne

[patkeefe]

Zeke:
My theory may apply to you also. I have reached the point where I realize that I have a limited shelf life. 300k durability means, as you stated, half of those miles will be put on in the afterlife. Go for the fun now.

Put together the most HP you can now, which you feel will be most reliable. Don't worry about rebuilding mistakes, there is lots of help available on this board so that you can't get yourself into too much trouble. Sell the leftovers to finance the rebuild.

Pat

[Zeke]

Originally posted by randywebb
B

Randy, I wish you weren't so indecisive!

[anthony]

What about option D? -sell everything and go for a 3.0L SC or 3.2L Carrera engine. The costs for rebuilding are pretty much the same for a 2.2 as they are for a 3.2 so you might as well have a 3.2 in the end.

[Zeke]

Anthony, the value of the orginal motor in the car, still in the car and built to original specs is too hard to let go. A 3.2 wasn't what Warrren suggested as option "D" anyway. Then, there's the classification aspect of having a motor such as a 3.2 when time trialing or autocrossing. I'll save the 3.2, 3.6 idea for the next car.

[nostatic]

rebuild the 2.2S. It's peaky and fun. Sell the 2.4.

[bigchillcar]

zeke,
go with what makes your hairs stand on end when you wind it up. i'd love to know what a 2.2 or 2.4 either one sounds like..being in the sticks of arkansas i have never even seen or heard either of what has always sounded like to me to be two absolutley thrilling motors. i'm envious of your dilemma. go with your gut on this one..
ryan

[ttweed]

Milt-

If you are going to track the car, I would put the "numbers-matching" engine into "preservation mode" on a stand in your garage and build the 2.4 T into a hotrod motor according to Warren's suggestions. This is exactly what I'm doing with my 2.0 S motor in the '67, as I am getting nervous about destroying it after two seasons of autox, even though it is showing no ill effects at all from occasional severe duty cycles. You want that original case to go with the car if you ever sell it, and if you have a rod go and saw thru the casting, it's too late. Unlikely, but possible. Better safe than sorry is my approach.

TT

[JeremyD]

I would rebuild the s - do it right. Use the 2.4 crank - you'll need to recalibrate the MFI - but would make for a nice - period correct engine that you can drive the piss out of. use decent rod bolts and start acquiring parts to do it right. Use the right components and you can build a pretty bullet prrof engine.

[BURN-BROS]

Milt, you should have started a poll... B is what I would go with.

[techweenie]

C.

I'm with Wayne on this one.

[Zeke]

Originally posted by techweenie
C.

I'm with Wayne on this one.

I'm looking.

Meanwhile, I am gonna tear into the 2.4 to evaluate what I have as a "core." Per Warren's suggestion (does Warren ever make "suggestions?" ), I have parked the car.