Getting adapter pcd's concentric

TIMBERWOLF · Post by **TIMBERWOLF** » Tue Sep 14, 2004 11:00 am

Ok, I'm making an adapter to mate a volvo b23 engine to an 021 tranny. I'm using a ring of 1" thick steel (a big pipe flange) 31cm inside dia about 35cm outside. I can get the volvo attach bolts into a pcd about 32cm (on the ring) 021 pcd is less than 31 so I'm going to weld on lugs to one side of the adapter. Question is how do I make sure the two pcd's are perfectly concentric without a lathe or such?

volkdent · Post by **volkdent** » Wed Sep 15, 2004 11:51 am

As much as I admire your do-it-yourself thoughts, please just save up some $ and buy them. Unless you know exactly what your doing, wheel adapters can be very dangerous. You mentioned welding, and I can tell you right off the bat your into some questionable territory. Welding on thick metal requires special planning and heating, not to mention I've never heard of any sort of welding having to do with the lugs. The forces acting on each bolt and lug are supposed to be very similar.

Many manufacturers will build you adapters to your exact specifications.

For example: http://www.spurverbreiterung.de/

Jason

ecdez · Post by **ecdez** » Wed Sep 15, 2004 12:10 pm

I believe he's making an engine adapter.

I would have to agree with volkdent on his general line of thought though. This part would be a critical component in your car. Depending on your skill level, I would have to guess that the adapter plate would be difficult, and the flywheel near impossible without the proper machining tools. If you're confident in your fabrication abilities, then I say go for it

. As far as how to make sure everything is concentric.... good question.

TIMBERWOLF · Post by **TIMBERWOLF** » Sat Sep 18, 2004 1:30 pm

Thanks guys for the replies. Ta ecdez, Mr Volkdent, I aint talking wheel adapters here, I'm talkin engine to gearbox as in Volvo b23 to Vw 021 tranny.

Fly wheel machining's done - just needed turning down to 270mm dia. Adapter plate needed to be 310 inner dia, also done. Guy in next town with a lathe and 50 beer tickets. I can drill the holes for the engine and gearbox I just wondered if there was any geometrical, mathematic, measuring type way to see if all was concentric without parting with more potential beer tickets.

The Volvo gearbox bell housing has a machined lip on it about 2mm inside the adapter dia, which i can eye ball an alignment to about +/- 0.5mm accuracy, is this close enough? I know the vw box has some run out in the input shaft and runs in the flywheel pilot bearing, so is it self aligning at these sort of tolerances?

Guest · Post by **Guest** » Tue Sep 21, 2004 12:26 am

Ok, been talking it through with a friend. I'm going to try an accurate mdf plug in the adapter (which has the engine mounting holes drilled accurately concentric - by measurement of the machined rim on the block) the mdf will be like a very squashed top hat, with one disc to go in the adapter hole and a smaller one to go in the machined part of the tranny bell housing, the two will be bolted together at there centre point. If the mdf is routered accurately and a tight fit the two (adapter and tranny) will be concentric.

Any comments on this idea?, I haven't done it yet.......

I'll post pics if it all works- it'll be a cheap, strong adapter (free apart from £50 of machining work), maybe others could copy.

TIMBERWOLF