LA motor - Snapped off trans alignment dowels

[72 Challenger]

Hi Guys,

I was working on my buddies car a 69 Barracuda 340 with a 727. We are removing the engine to spruce up the engine bay with plans of putting it back in because it's a good strong running motor and trans set up. We removed the engine and both Trans alignment dowels/ pins area is snapped off the block, no ability to weld them back in. They have clearly been gone for awhile. The trans still bolts into the trans mount and the normal 4 bolts on the top of the engine. How bad is this really? I know it's not ideal but I am saying this engine is still completely useable.

Opinions? Its not a high performance set up, if that matters. 340 with bolt on's 300 ish HP? stock trans with rebuild.

[Cuda Cody]

Did the dowels break or the castings around them?

[72 Challenger]

Castings around them.

[Cuda Cody]

On a 4 speed it's very important to make sure the dowel pins are perfectly aligned and that's why they sell offset dowel pins that allow a person to adjust it thousandths of an inch.  However, I do not know if it matters as much with an Auto trans? 

[RUNCHARGER]

Hmm: Well, I guess it was running when you pulled it. Can you epoxy in some tubes that would hold dowels? My thought is if you could epoxy in some tubes, check bellhousing alignment and get it right that it would work fine. If bellhousing alignment is off it won't work as well.

[72 Challenger]

I could maybe weld in a dowel on one side with what is left of the casting but I am not too positive how structural it would be. As long as I can make sure the bell housing is aligned when it goes back on I don't see the issue? After installation the effect of those pins must be fairly negligible?

[RUNCHARGER]

Yes: My thought are that the dowels place the bellhousing and if they are tightly fit with no runout there won't be much force on them. Problems happen when there is runout and if a bolt or dowel is loose it will wallow out.
If lugnuts on a wheel are tight no problem, When the lugnuts are loose, instant wallow.
If you weld on the block you risk the chance of running a crack away from where you are welding, I wouldn't do it.

[1 Wild R/T]

On a 4 speed it's very important to make sure the dowel pins are perfectly aligned and that's why they sell offset dowel pins that allow a person to adjust it thousandths of an inch.  However, I do not know if it matters as much with an Auto trans? 

It matters...  But while a manual should be held within a .003 an auto will survive within .010-.012 but guys who are serious drag racers will dial it in to reduce drag....

[Chryco Psycho]

can you deepen the holes & use longer dowels ?? it matters almost as much with an auto trans , yoou damage the from pump area with the converter snout not centered or destroy flex plates

[72 Challenger]

The casting area on the block which held the lug is pretty much gone. So putting in longer dowels would do nothing.

I'm thinking when the engine goes back in since it's going in exactly where it came out of the trans can be aligned back onto the engine as best we can and extra care is required when bolting in the trans to engine bolts to ensure proper alignment.

[Chryco Psycho]

Ideally I would rotate the engine with everything bolted up but the belhousing bolts loose so the crank will center the trans but the only way I can see this working is to have the engine standing vertically on the crank centerline with the trans standing on top or hanging while tightening the bolts & I bet it will still move under load .

[RUNCHARGER]

I've thought about this and there is a bit of a solution. You could tighten up the tolerance on the bolts to bellhousing and center it using the bolts. I would play with it using shim stock on sides of the bolt holes. When you figure you have it dialed in epoxy the shim stock to the holes and do a final test of runout.
To give a good idea how close it is for your initial test install the bellhousing (trans case) to the block and tighten all the bolts down, Do a runout check and in the offchance it is within specs undo 1 bolt and see how centered it is in  the trans case. Then if it is good, tighten it back down and check another one and so on. If you are really lucky you could carefully drill the holes out a bit larger and sleeve them to fit the bolts tightly. If not you will have to add shim stock to tighten it up.
This type of stuff takes a lot of time though.
As I said, it was running before.....

[Brads70]

Ideally I would rotate the engine with everything bolted up but the belhousing bolts loose so the crank will center the trans but the only way I can see this working is to have the engine standing vertically on the crank centerline with the trans standing on top or hanging while tightening the bolts & I bet it will still move under load .

If you could somehow get it centered, what about drilling /reaming for new smaller dowels say 1/4" in 3-4 different places along the flange? 

[Chryco Psycho]

I wanted to see what @Brads70  would suggest being a machinist .
Cast can be welded with the correct process but the block would have to be stripped , heated & welded with high nickle rods & cooled then remachined , nothing else seem to work in my experience , or you could transfer all the parts into another block obviously .
Possibly drilling new holes with new pins will work as well but the pin would need to be smaller as there is no extra width in the flange , I really feel you need something to hold it in place without movement !
You would have a engine & trans that will have to stay together once new pins were added  of course .

[72 Challenger]

Pictures are worth a thousand words so I took some when I go to home.

First is drivers side. You can see where the pin once was. Casting basically gone.
Second is passenger side. I shoved a dowel pin in from a scrap block I had kicking around.