Billet main cap alignment questions

[Jerryl]

First question;
What does your machine shop charge for; Labor to install 2 center billet mains.
Just looking for a reference to make the decision from there.

Second question;
So, let's "ass-u-me" it is done right; Line bore, line hone, the center if moved up 0.005", shorter timing chain, verify deck height, etc. etc.
Is there a concern with misalignment of the converter pilot and transmission input shaft?
I realize that the converter pilot to trans input shaft is not a real high precision deal, but any added misalignment is not a good thing in my book.
So, something to worry about or no?

 

[dr_frankenstein]

yes, i would say in my opinion jerry that it is very very important.

Runout in the bellhousing area is something that happens all all the time and nobody really ever pays attention to it.

but there is a solution,

They make offset adjustable bellhousing dowel pins.

these allow you to slightly adjust the bellhousing to the ideal location.

I hope this helps Jerry.

Lakewood Suspension 15907 - Lakewood EZ-Adjustable Bellhousing Dowel Pins

:biggrin: A.j.

P.S. I finally got my 5 speed man buick pulled apart, Runout had been a problem, I can send you a pic of my pilot bearing that occured from me not checking the bellhousing and just putting it together cause it fit. THAT was a bad idea.

 

[charlief1]

Post them on here Aj. It may not be an auto but it is good info.

 

[Chuck Leeper]

My $.02..

These are a MUCH more "user friendly" dowel set, than the Lakewoods..
besides the guy is a super dude to do business with.
He also has some neat fuel filters. that I use, and recommend.
RobbMc Performance Products - Bellhousing Alignment Dowels

 

[TURBOELKY]

I dont have billet main caps, I plan on a girdle. But do know my machinist charges $150 per cap, and I dont believe that includes the line bore and align-hone. Hope that helps.:smile:

 

[charlief1]

I was actually thinking about pinning the caps instead of a girdle or billet caps. I think it was Smokey that said it was the most effective way to keep the caps from walking. What ever I do the block needs to be align bored so it's good info.

 

[Jerryl]

Thanks fella's.
How would you verify the converter to pilot to input shaft alignment?
I can see it with a fixture .......... but with a dial indicator it would be tough.
What do you guys think?

 

[charlief1]

You could use a manual bell housing and mount the dial indicator on the flexplate to check for concentricity. Or if you have an old tranny shell you could hack it up to make a center fixture. Since you're just south of me I might be able to loan you one of my bell housings to check. I'm a little more that 30 miles north of Waco.

 

[dr_frankenstein]

You could use a manual bell housing and mount the dial indicator on the flexplate to check for concentricity. Or if you have an old tranny shell you could hack it up to make a center fixture. Since you're just south of me I might be able to loan you one of my bell housings to check. I'm a little more that 30 miles north of Waco.

my computer is a real pile now that work has it all locked down, can i send you the pic to post Charlie?

A.j.

 

[charlief1]

Send it to me Aj. I'll be glad to.

 

[dr_frankenstein]

OK! Got my comptroller working a little better. Thanks Anyways Charlie!

So Here we go....

Here is a perfect example of excessive bellhousing runout. This was not caused by not the align bore, but plain bellhousing being off from the factory dowel location.

Now those aftermarket dowels that were shown should cure my problem. And after an align-hone has been done, they should be used to correct the bellhousing in relation to the crank for an automatic trans as well.

here are the pics

This shows the distortion of the pilot bearing. The pic indicates the cracks that are found everywhere in the bearing.

This photo shows just how worn out the pilot bearing has become from the bellhousing being misaligned.

Needless to say........... imma gonna pay attention to what ima doing next time.

But here is a process is for an automatic....... stupid amount of work.... but possible.
First take an old transmission, and gut it completly- and cut the case to gain access to the front pump bore from the back. Once the case is aligned to the engine's crank, mark which way the offsets were and install your working trans with the offset dowels. While it's more trouble than most people want to go through, the process does offer accurate alignment. In any case, boring and sleeving the dowel pins on the case of your automatic should be done if the dowels are loose. This sounds to be the only approach to alignment, But i do question the validity of the alignment unless the bells of the 2 transmissions were measured to ensure they were identical.

A.j.

 

[charlief1]

No prob Aj. I didn't get to see them until I got home from work today. Kinda shocking.

 

[dr_frankenstein]

No prob Aj. I didn't get to see them until I got home from work today. Kinda shocking.

it was so distorted it took 2 1/2 hours to get it out! alot of grease and damn near machining a mock input shaft to hydraulicly force it out, I couldnt get any 3 finger bearing puller to hold onto it!

A.j.

 

[charlief1]

All you needed is a good chistle or a die grinder with a very course bit for soft metal. I've had to do one like that before. You have to be gentle but you can do it if you're careful. I've also used a bolt that won't quite go in and then used an impact to drive it in and the bearing will back out on the bolt.

 

[Jerryl]

...........
But here is a process is for an automatic....... stupid amount of work.... but possible.
First take an old transmission, and gut it completly- and cut the case to gain access to the front pump bore from the back. Once the case is aligned to the engine's crank, mark which way the offsets were and install your working trans with the offset dowels. While it's more trouble than most people want to go through, the process does offer accurate alignment. In any case, boring and sleeving the dowel pins on the case of your automatic should be done if the dowels are loose. This sounds to be the only approach to alignment, But i do question the validity of the alignment unless the bells of the 2 transmissions were measured to ensure they were identical.

A.j.

Agree. :smile:
You need a cut up core, and hope it has the same tollerances as the final unit.

From the looks of it though, no one else (from "The BIG Boy Clubs") seems to be concerned about this, or this is one of those secrets. :redface:

 

[dr_frankenstein]

Well I guess not Jerry, but apparently it seems to be an issue.

Doing some research last night I found that alot of circle track guys are concerned with this, claiming it robs up to 15hp and shortens driveline life by 30%.

I suppose if you ran a large shop building engines, it would be nice to have cores already premade to use as an alignment tool... but might be a little much for the average home builder.

I myself am going to try and take this on, AFTER I compare 6 or 7 200's to see what the tolerances are like between themselves. if there are all fairly close to each other, than I feel it would be ok to use one core as the jig. The great part is that a tool like this is excellent GM piece, as it fits Bowties and BOP's. lots that can be aligned from one core.

I dunno, Good post though... got me thinking.

:biggrin: A.j.

 

[joe_schindler]

I’ll skip the pilot bushing thing as that’s been kind’a covered here; but the cut up a transmission case and use it to line up another transmission is not going to work.

Well; unless both transmissions are identical (as has been mentioned above); and that’s the idea behind using non-adjustable pins between the block and transmission in the first place.

If the case you use to set your pins is not the same case you are going to run; what are you gaining? You are setting an adjustment to the one item that will not be part of the car when you are done.

You can empty your transmission case; and then try to rig something that will float on the flywheel and give you run-out based on the front pump seal surface; but I don’t think that will be any fun; and probably hard to keep everything lined up while you build the transmission. If your front pump is not perfect to the seal surface; all bets are now off again.

Luckily; the tolerance of the torque converter to pump to input shaft and stator support is pretty high. I haven’t seen too many torque converters that were ruined by bad transmission/engine line-up. Most of the pilot bushings that I’ve seen go bad were from other causes also.

I’m not saying you shouldn’t keep things straight; there’s just some things that won’t make much difference. A bore shift of 0.005” at the crank gives about 0.04 degrees of bend in an input shaft on a manual transmission. That alone won’t wear out a pilot bushing in the life of a clutch.

 

[charlief1]

I’ll skip the pilot bushing thing as that’s been kind’a covered here; but the cut up a transmission case and use it to line up another transmission is not going to work.

Well; unless both transmissions are identical (as has been mentioned above); and that’s the idea behind using non-adjustable pins between the block and transmission in the first place.

If the case you use to set your pins is not the same case you are going to run; what are you gaining? You are setting an adjustment to the one item that will not be part of the car when you are done.

You can empty your transmission case; and then try to rig something that will float on the flywheel and give you run-out based on the front pump seal surface; but I don’t think that will be any fun; and probably hard to keep everything lined up while you build the transmission. If your front pump is not perfect to the seal surface; all bets are now off again.

Luckily; the tolerance of the torque converter to pump to input shaft and stator support is pretty high. I haven’t seen too many torque converters that were ruined by bad transmission/engine line-up. Most of the pilot bushings that I’ve seen go bad were from other causes also.

I’m not saying you shouldn’t keep things straight; there’s just some things that won’t make much difference. A bore shift of 0.005” at the crank gives about 0.04 degrees of bend in an input shaft on a manual transmission. That alone won’t wear out a pilot bushing in the life of a clutch.

Pretty much sums it up but I'll add if you have the engine assembled and a way to turn the engine upside down, you could attach the tranny case without guts and set the dial indicator up so you can see it move. Then you can figure out how close it would be. After you did this then put the guts in minus the torque convertor and set the dial indicator to go off the input shaft.

 

[charlief1]

And Aj, most circle guys run manuals so it is different as far as tolerance.