Dowels for Block to Bell Housing

[miked]

Guys,

Re; Dowels on twink to alloy bell housing.

Can anybody help me out here, I am kind of drawing a blank. I picked up a really nice alloy bell housing for my project car from my mate. We have tried to trace its origin but failed, so am forgetting that route.

I have not really taken much notice of dowels in the past, they sit there in the block and never usually come out. I noticed that mine were missing on the block of the engine (that an amount of work on it). I also noticed that my new bell housing has metric threads and also slighltly larger holes for the dowels.

I have a new set of dowels for the standard old twink and they measure about 12.73 mm dia' on my caliper. The holes they go into on a normal heavy bell housing are about 12.75 ish. So they engage with a close fit. The holes on the new alloy housing are about 13.05 mm dia'. Looks like I need some form of stepped dowel. Will I need to make these or has someone else had this problem and knows some one who makes these.

Everything else about this bell housing looks right save the thread and these dowel holes.

Suggestions welcome!



Polite ones


regards Mike

[gerrym]

For engine to alloy bellhousing dowels, try Burtons (they sell the alloy bell housings). Otherwise Tony Thompson or QED.
Regards
Gerry

[cliveyboy]

Mike
Appears that you have imperial dowels on engine and metric holes on bell housing.
The 12.7mm dowels are 1/2" . Your 13.05mm hole is slightly big but about right size for clearance on a 13mm dowel.
You could as you suggest use stepped dowels. Some one might sell them otherwise someone with a lathe can knock them up easily.
An alternative you might be able to do yourself is to replace the dowels with 13mm ones. This means removing the 1/2" ones and reaming the holes bigger and installing 13mm dowels. (A very easy straightforward job for someone with a machine shop). This would mean the engine would then not mate up to an original box if you wanted to revert back without some more machining.
If you sent the bell housing to a machine shop you could always get them to drill the dowel holes larger and put sleeves in to accept 1/2" dowels and at the same time possibly get the metric threads changed back to imperial. You then have a standard fit housing
Obviously easiest option for you would be if you can get some stepped dowels.

Cliveyboy

[GrUmPyBoDgEr]

Seems like you're struggling a bit on this one Mike.
If you can't find anyone locally put a few 13mm dowels in a Jiffy bag together with a sketch of what you want & I'll turn the req'd length to 1/2" dia.

Cheers
John

[miked]

Thanks Guys

Gerry, I tried all those boys but they could not help out.

Clive, I think you are right I will go for stepped dowels, it is the easiest option and I am not altering anything. The metric threads cause no problem, the bolts go through fine.

John, My old South bend project is still waiting the worn counter shaft back yet. Also I am a learner so will take you up on your offer, if you don't mind. I will get some of the metric dowels. Will give you a shout.


Thanks Mike

[GrUmPyBoDgEr]

Oh, I forgot to mention that if anybody is considering fitting an MT 75 G/box or the conversion I did; Zetec onto Elan G/box, those stepped dowels will also be necessary.
A major business oppertunity there?

The mix of UNF & Metric bolts works without modification.
A set of "Metrinch" spanners in the boot is also a good idea.



Cheers
John

[billwill]

Thanks Guys

Gerry, I tried all those boys but they could not help out.

Clive, I think you are right I will go for stepped dowels, it is the easiest option and I am not altering anything. The metric threads cause no problem, the bolts go through fine.

John, My old South bend project is still waiting the worn counter shaft back yet. Also I am a learner so will take you up on your offer, if you don't mind. I will get some of the metric dowels. Will give you a shout.


Thanks Mike

Golden Rule of modifying anything:
where you have a choice put the modifications on the least expensive bits.

[miked]

Sorted!

Cliveboy made me some stepped dowels. Put it together yesterday. Thanks Clive.

Just some info' for anybody else regarding the alloy bell housing I picked up that was new (second hand). Having studied it against the old heavy one it appears to have been copied from the old one with the same ribs and casting marks etc. The only difference is the thread parts in the housing which are metric and the dowel holes are also slightly bigger (being metric). I also found that when I offered it up the flywheel ring gear touched the left side of the interal casting in one place. Bit of a fettle.

I was a bit of a silly boy, starting with the dremmel and then keep offering it up with the gearbox. I did not want to take the clutch fork off and thrust bit with the clips. After an hour and a good old sweat and a hump back I decided I had had enough and took the housing off the box. I gave up with the dremmel and had ago with the drill grinding wheel and also the small disc cutter wheel. Soon sorted.

Anyway. It all went together. Moral of the story I suppose is offer up the casting to the engine before you bolt it all up to the gearbox.

I would be interested if anybody else comes across this type of bell housing. The other castings I have seen have a different rib casting pattern inside. Just wonder were it originates from.


Mike