Dial in Bellhousing HELP!

[Julesdm]

Good point, is your short measurement at the bottom by any chance?

Rather agree with Eggbert, this isn't 'alignment', it is 'does not fit' at the moment. Do you have the old bellhousing to check against?

I dont, it was a custom build engine from USA (excluding bellhousing)and i have purchased the bellhousing and Tremec in the UK. Next engine i buy, i will get the builder to mount the flywheel and bellhousing!!

[mylesdw]

Brian from Roadcraft has emailed me as he is on holiday and reckons it could be the Line Boring of the block has caused the crank to move.

I don't follow that. If the crank has moved over 2mm the timing cover oil seal won't work and the timing chain tension will be all wrong. Align boring should not change the crank centreline much if at all. Where is your 'short' measurement, 12 o'clock?.

[dinosoar]

I have seen flywheels out of true by quite a bit but I have not experienced anything like you have there.
Have you checked the flywheel is mounting correctly and it's surfaces run true?
I assume you are using a dti from the flywheel face. It could be worth a check of things without the flywheel for parallel surfaces.
It should be possible to rig a concentricity check without the flywheel also.

KR

A

[Julesdm]

I have seen flywheels out of true by quite a bit but I have not experienced anything like you have there.
Have you checked the flywheel is mounting correctly and it's surfaces run true?
I assume you are using a dti from the flywheel face. It could be worth a check of things without the flywheel for parallel surfaces.
It should be possible to rig a concentricity check without the flywheel also.

KR

A

1. we checked the flywheel ran true and flat to the block.
2. we checked the face of the bellhousing was parallel to the flywheel. It wasnt and so we shimmed and got the face parallel.
3. We checked the offset of the bellhousing to the crank using the Dial in tool mounted on the crank/fly end with NO wobble.
We did this using two methods.
1. 0 gauge @ 12 o'clock then read at 3, 6 and 9 o'clock, taking the opposing readings away from each other and then dividing them by two.
2. watching the DTI needle as rotating the engine. Once the closest point is found, mark the bellhousing, then go to the diametrically opposite position and take a reading. Divide by two and bosh that is your offset and direction of movement needed.

My bellhousing needs to move towards 22.30 on the clock and by 0.087"

I have even removed the straight dowels in the engine and measured......same answer +/- a few thou, now the dowels are removed and i was on my own.

I have found an engineer in Bedford who will make a set of offset dowels for £140!!!! and i guess i would then have to file a slot in each bolt hole to allow the housing to move.

Very confused.com

J

[Julesdm]

I don't follow that. If the crank has moved over 2mm the timing cover oil seal won't work and the timing chain tension will be all wrong. Align boring should not change the crank centreline much if at all. Where is your 'short' measurement, 12 o'clock?.

The short measurement is at 22.30. I did google line boring and it does mention this would move a crank towards the cam shafts, but, yes i do agree....not by 2mm........

[GDCobra]

I don't follow that. If the crank has moved over 2mm the timing cover oil seal won't work and the timing chain tension will be all wrong. Align boring should not change the crank centreline much if at all. Where is your 'short' measurement, 12 o'clock?.

I agree. Even if that reading is TIR it would mean the crank centre has migrated over 1mm, bell housing fit would be the first of many problems. In precision engineer terms this is known as a metric shitload out.

Have you tried fixing the clock to the engine block and checking flywheel runout?

[Julesdm]

I agree. Even if that reading is TIR it would mean the crank centre has migrated over 1mm, bell housing fit would be the first of many problems. In precision engineer terms this is known as a metric shitload out.

Have you tried fixing the clock to the engine block and checking flywheel runout?

We did and it was true......i will double double check again later today.

[aaronjb]

I have found an engineer in Bedford who will make a set of offset dowels for £140!!!! and i guess i would then have to file a slot in each bolt hole to allow the housing to move.

I'm in the wrong line of work.. even for me, I reckon that's about an hours work on the lathe - I think for someone doing lathe work regularly, about 20 minutes! Set up oversize stock in the 4-jaw, machine to size. Turn around, set up in the 4-jaw with desired offset, machine to size. Voila, offset dowel. If you want to get really fancy, set the resulting part up in the mill and use a slitting disc to mill a slot in the top..

I mean for a machine shop, obviously, unless you happen to have a lathe and a mill lying around I was actually planning on making my own offset dowels when I get to that point.. just for the wheeze. What dia are your dowels? No guarantees but I could have a shot at it..

[TINKA]

If you have put wedges that thick under the bellhousing then I'm not surprised that the bellhousing no longer lines up with the crank. can you put the bellhousing on a granit or something to check the faces are parallel. If the issue is not there could gravity be having an effect when your measuring them assembled on the engine ? something seriously wrong there somewhere.

[Julesdm]

I'm in the wrong line of work.. even for me, I reckon that's about an hours work on the lathe - I think for someone doing lathe work regularly, about 20 minutes! Set up oversize stock in the 4-jaw, machine to size. Turn around, set up in the 4-jaw with desired offset, machine to size. Voila, offset dowel. If you want to get really fancy, set the resulting part up in the mill and use a slitting disc to mill a slot in the top..

I mean for a machine shop, obviously, unless you happen to have a lathe and a mill lying around I was actually planning on making my own offset dowels when I get to that point.. just for the wheeze. What dia are your dowels? No guarantees but I could have a shot at it..

dowels are 0.622" in diameter and 1.2" long Aaron