To replace bellhousing dowel pins or not?

[A98Coupe]

Firstly Happy New Year to everyone!
I’m hoping this is an easy question to answer. Last month I received my new Shelby 427 FE stroker from Survival Motorsports and I am now preparing it for installation into my Kirkham. The first job is to align my Lakewood bellhousing with the crank centre. I checked the alignment and found it to be 0.038” TIR, which means I need to move the bellhousing approx. 0.019”.
I already have a Lakewood dowel pin & weld bush kit and plan to open up the dowel pin holes in the bellhousing to 1- 1/16” diameter to allow enough movement to centre the bell before welding the bush in place.
My question is about the longer dowel pins which were supplied with the kit. When I put the bush over the existing dowel pins and press it up hard against the block plate, the pin is almost to the end of the bush. The exact distance from the end of the pin to the end of the bush is 0.062” top right & 0.055” bottom left. See photos below



It would seem to me that there is ample engagement between the dowel pin & bush, so I don’t see the point trying to tackle the potential nightmare job of replacing the existing dowel pins in the block?
Do you think I can go with the existing dowel pins?

[Grubby]

I think you have enough engagement. If in doubt remove and replace the bell housing a few times and check your run out. If it goes on the same a few times then you are good.

John

[LMH]

Why don't you use offset dowel pins instead?
Larry

[A98Coupe]

Originally Posted by LMH

Why don't you use offset dowel pins instead?
Larry

Thanks Larry,
I have thought about using the offset pins, but they are not a permanent fix for aligning the bellhousing, and I would be faced with trying to remove the existing pins which can be a real pig of a job unless you've got the right tools. So I've decided to go the welded bush route as recommended by Kirkham.

Thanks Grubby,
I agree, I think I have enough dowel pin engagement so will leave the existing pins in place.

Thanks
Stuart

[Jac Mac]

I would drill the bell housing dowel holes to ~13/16" then use a lathe to turn a step on the bush in pic in the area of the 45° champher to 3/4" dia. That should leave enough material for a good weld once you get the bell housing indexed.
Drilling to 1,1/16 might create a problem with the bush vs shape of bell housing.

[Karmann]

I have a bored/stroked Shelby 427(527) from Survival Motorsports as well. I used offset dowel pins to get the bellhousing aligned. It wasn't that hard to get the stock dowels out. I welded an allen head bolt to the pin. Putting a wisegrip on the bolt stem and an allen key on the bolt head, managed to twist them out fairly easy.
Just saying

[A98Coupe]

Originally Posted by Jac Mac

I would drill the bell housing dowel holes to ~13/16" then use a lathe to turn a step on the bush in pic in the area of the 45° champher to 3/4" dia. That should leave enough material for a good weld once you get the bell housing indexed.
Drilling to 1,1/16 might create a problem with the bush vs shape of bell housing.

Thanks Jac Mac but the 1-1/16 dia. drill is what Lakewood actually recommend in their installation instructions. Also, Kirkham Motorsports show a step-by-step photo story of aligning and welding in the 1" bushings in a Lakewood and they seem to have no problems with the shape of the bell.

Karmann, thanks for the advice about removing the pins, but I don't really trust the offset pin method, especially if the bellhousing bolts relax tension after the first 100 miles or so. I'm going to stick with the welded bush method - it's a more permanent method of alignment - I hope

Thanks again everyone for the advice

[Xack]

Lakewood Bellhousing... I had serious issues with the Lakewood for my 460. Check to see that the hole for the transmission is indeed round. Mine was not round and it was too big. I took it to a machine shop. We located the center or what was likely the center of the hole that existed. Made a temporary jig to mark that center. Welded up the hole to machine out a true circle to actually fit the transmission. Don't trust the hole in the Lakewood to be round, have it checked. If it's not round it'll be very difficult to center your dowels. If the hole is too big, your work to set the dowel pins is for nada.

[SSSammy]

Originally Posted by A98Coupe

Attachment 23189
It would seem to me that there is ample engagement between the dowel pin & bush, so I don’t see the point trying to tackle the potential nightmare job of replacing the existing dowel pins in the block?
Do you think I can go with the existing dowel pins?

Stuart, the engagement has to include the thickness of the bell housing, as well as the block plate. Set the housing in place on top of all that and see how short the stock pins are. The "bushing" is really a collar .. it goes on top of a slightly enlarged hole, not pressed into it. The bevel is for the weld bead

Sam