T-10 conversion...Crankshaft bolts to flywheel

[Doug Bowen]

I just got back on the forum after a couple days doing "other things" and found the above. Wow. What a great idea. I just can't believe the useful info you get from this site. Thanks a lot guys. Tap the crank flange. Wow. If you had the crank out it would be a cake walk for a machine shop. That will go in the memory banks.

[3x2stude]

Opps, I meant "FARTHER", my bad.

[3x2stude]

One step farter

I had my motor out and apart so this was way easy but still do-able without rebuilding. I had my engine machine shop enlarge the flywheel hols to accept SBC flywheel bolts to pass through from the clutch side and also drilled and tapped the crank. For ever after now I can mess with the fltwheel and never touch the oil pan.

JK

[kmac530]

64 Challenger,
The bolts I took out of AT crank are 3/8"-24 and 15/16" long. The MT bolts were about 1/4" longer, so 1-3/16" long. Both sizes are special bolts with a thin, round head with a angle cut out to hold it from turning when you tighten it .

[64 Challenger]

Hi,

I'm getting ready to put my short block (259 pumped up to 299) together and I am going with a 4 spd. also-how long are the bolts that are mentioned above? The drivetrain I'm using is non-matching and not original to my car. The 1963 Chassis book lists(pg. 519 under Jet Thrust equipment) what I think are the bolts as part 195227 screw to flywheel 3/8" - 16 x 7/8" correct?

Thanks.

[starliner62]

I've done a couple of cranks that way. Gotta have some sharp taps and patience.

I don't know if any have done this before but I have and have seen it done many times. That is to cut the old auto bolts off and tap the crank. Then one can use bolts from the flywheel side. Not saying this is right or better but I didnt note any failures with higher than stock hp. This was done even with the crank on a new rebuild.

[kmac530]

You mentioned 3 speed, so I hope you are talking about a T85, and not a T86. If T86, the flywheel is gonna be the least of your problems. You'll go thru at least 25 tranny rebuilds before ever having to even think about the clutch, let alone the flywheel

I wish...T86 here.
I am aware it will not last....part of the fun isn't it?
The truck is so light in the back I actually doubt I will have trans trouble without putting some weight on the rear.
The whole truck weighed in at 3300 lbs and that was with the front wheels on a tow dolly and weighing the dolly...at least 400 lbs I would say, so roughly 2900 lbs without a bed and with a v8 conversion. With the V8 in the front, and that so far out over the front axle, the back end is very light.

[JoeHall]

Joe, I really appreciate the technical specifics on dimensions for the counterbored flywheel approach. As I said above, it really intrigued me. After reading Jeff Rice's post (above) I pulled out my flywheel and took a look. Picturing that the flywheel was "about an inch thick", I got cold feet when I saw how thin the flange counterbore area was. I was guessing (without checking actual dimensions) that there would only be about .125" left. Now that I have your dimensions, I don't think that .275" of meat left would be so bad. I would really appreciate any pics you might have if you can get them posted. Thanks again...Doug

Doug I just PM'd you. If you wanna send me your email I will attach and send you pix.

Joe H

[JoeHall]

Joe,
I have a 3 speed and I plan on "burning rubber"...

Not sure I will have a choice with 289, big cam, bumped compression, porting....all on a truck with 5.30 rear gears and NO bed so it is really light in the rear...I am thinking wheel spin is going to be inevitable...cool.

You mentioned 3 speed, so I hope you are talking about a T85, and not a T86. If T86, the flywheel is gonna be the least of your problems. You'll go thru at least 25 tranny rebuilds before ever having to even think about the clutch, let alone the flywheel

[Doug Bowen]

Joe, I really appreciate the technical specifics on dimensions for the counterbored flywheel approach. As I said above, it really intrigued me. After reading Jeff Rice's post (above) I pulled out my flywheel and took a look. Picturing that the flywheel was "about an inch thick", I got cold feet when I saw how thin the flange counterbore area was. I was guessing (without checking actual dimensions) that there would only be about .125" left. Now that I have your dimensions, I don't think that .275" of meat left would be so bad. Actually you have proved it by logging over 200,000 miles on the modification. I am going to still pull the engine to do the necessary concentricity check/corrections/pinning, but I really would like not to have to break apart a currently bone-dry engine just to replace the darned flange bolts.

I am going on 63 and just don't see myself running this girl at the drags. Neither have I ever been the guy who likes to try to pave the township roads with my hard-paid-for tires to impress the girls (at 63 this isn't a concern anyway!)..I just love going through the gears. All automatics, quite frankly, bore the hell out of me. (don't mean to offend anyone)

I would really appreciate any pics you might have if you can get them posted. Thanks again...Doug

[kmac530]

Joe,
I have a 3 speed and I plan on "burning rubber"...

Not sure I will have a choice with 289, big cam, bumped compression, porting....all on a truck with 5.30 rear gears and NO bed so it is really light in the rear...I am thinking wheel spin is going to be inevitable...cool.

[JoeHall]

I forgot to mention, the OD of the countersunk holes is .805". This allows room for a six-point socket to slip fully onto the nut.

Also, maybe this mod won't hold up for you since you are installing a 4-speed, and many who like 4-speeds also like to burn rubber Even so, the mod will probably still hold up just fine, it's just that I have never tested that way, so can't say for sure.

I will post pix here, if I ever take the time to figure out how to.

[JoeHall]

Thanks Guys...you have confirmed that my gut feel was correct. I'll yank the engine! (...although I really was intrigued about counterboring the flywheel for the shorter bolts!)
D

Funny you mentioned this, and maybe a little more info may help you. Just this morning, I removed the flywheel (which was modified for the shorter bolts about 250,000 miles ago) from the engine I am swapping out in the GT. Before removal, I took a few pix. Then later today, after having the flywheel resurfaced, I snapped a couple more pix. I also reviewed my notes from yester-decade, and took some measurements that may be helpful: First, though the automatic tranny bolts are .250" shorter, the countersinks only need to be .180" in order to allow the nut to fit flush with the end of the stud. This is accomplished by using .030" thick "wave" washers, instead of the original .100" lock-washers. (Of course, always use red Lock-Tite also.) The flywheel is .455" thick in the bolthole area; the countersinks leave .275" of "meat" there to hold the flywheel in place. This has proven more than enough in my GT, which has towed several 56Js a total of around 5,000 miles, and U'Haul trailers, loaded to the gills, about 5,000 miles. I have never abused the car however, i.e. "burnt rubber". To me, it is inconceivable that anyone would pull the engine to swap those bolts, when any competent machinist can modify the flywheel for few dollars. But as many others say here, your car your money; I would add, and your labor.

[Doug Bowen]

Thanks Guys...you have confirmed that my gut feel was correct. I'll yank the engine! (...although I really was intrigued about counterboring the flywheel for the shorter bolts!)
D