More 3.2 Short Stroke horrors

[cstreit]

As some may know I am rebuilding a really trick short-stroke 3.2L motor.

It's got 98mm Max Moritz pistons, an early 3.0L Carrera case, 2.7 Crank, Titanium valve train, etc..

The engine was partially assembled by a non-Porsche mechanic and so upon tear-down of this zero hour motor I found a number of horrors including:

1. Curil-T used as case sealant
2. Silicone everywhere
3. Broken rings
4. Overtorqued bolts,

etc....

Well I just started re-assembling the thing (With Souk's help as always, THANKS Souk) and found this! One of the wrist pins they used was the wrong size. Probably from a 3.0L motor, too short, and not nearly as beefy.

PHILISTINES!

[911pcars]

Hi Chris,
The shortcomings of DIY anything. One doesn't know the person's threshold level of skill, thoroughness, patience or ineptitude. There's less chance of a pro doing this, but not unheard of. Hope all else is okay w/o damage.

Sherwood

[MotoSook]

Ummm..did you wipe all my drool off the engine already?

Dang! This is the engine I want! 3.0C case and 2.7 crank (same for stock 3.0C), with Max Moritz 98MM p/c's! Who ever buys this motor better treat it right or I'll be sending my Posse after them.....and if that person sells the car...I get right of first refusal! I bled on this thing...it has my DNA on it!

Seriously, this is the engine Wayne is building...close.

My greatest fear is that the engine wll disappear and we'll never know what happened to it.

It's funny, the back ground of the engine..Chris can tell....It's just the least likely thing!

I REALLY want this engine! I'll give you one of the boys for it Chis

[Bobboloo]

Amazing.

Your "non-Porsche" mechanic should really be called a non-mechanic. A mistake with the case sealant might be understandable with a mechanic who had never worked on a Porsche motor but broken rings and over torqued bolts qualifies him not as a mechanic but a hack.

Did you have the case checked out for a straight line bore and have the spigots decked? If the above mistakes were made I would start at ground zero and assume nothing was done right.

[Wayne 962]

I'll chime in here. I can't think of any way to determine if bolts were over torqued. Static torque is way different than dynamic torque, and you can't accurately determine if the bolts were overstretched without some advanced measuring equipment. Simply backing them off with a torque wrench will not tell you anything...

-Wayne

[Shuie]

Chris, is this thing going in #15 or is it going to be sold?

[cstreit]

Bobboloo... Yes.

Wayne: Yeah, you're probably right, but with a case perimeter bolt, I definitely got the feel that they were over te 18 Ft/Lbs or so... But that's the least of the offenses here.

Schuie: It belongs to number 119 here which is going "on the auction block" as soon as the car is finished. (Motor, suspension, more fiberglass)

[TimT]

A little off topic to the non-mechanic assembling the engine

There is a method to determine the actual torque in a fastener. You need a dial type torque wrench with a tell-tale. You simply apply torque to the fastener until the nut or bolt moves
(about 5°). Then read the tell tale.

This method is recognized by groups such as AISC, ASTM etc.

BTW Chris when your done sorting out the engine I have a good home for it

now back to your regular programing

[911pcars]

Wayne is correct. The torque reading applied to a fastener as it's loosened is NOT necessarily the torque applied when it was tightened. There's a breakaway torque; usually higher than the applied torque to tighten. There's also thread corrosion and sealer that must be overcome to loosen as well. However, if it takes 100 ft lbs. to remove an otherwise clean and sealerless "18 ft.lb bolt", then it probably was too tight.

Because of the static friction, one cannot verify the torque on a previously tightened fastener by reading the torque wrench at the spec value. To be accurate, the fastener must rotate while tightening. Thus, in order to re-torque a fastener to spec, it must first be backed off (loosened), then tightened to spec.

BTW, what was the result of using Curil-T sealant on this particular engine?

Sherwood

[cstreit]

Sherwood,

THe engine was never actually run. I received it "partially assembled" from the guy. The deal was, I am going to put the car back into turn-key racing condition this winter for sale this spring.

Since the motor was only partially assmebled, I decided that since my name goes on it, and because it was such a special one, that I had better make darn well and sure it was done right.

It wasn't...

As far as my "scientific method" for overtorqued bolts go... I haven't one. Call it a "feel"... It's inconsequential to the other issues anyway.