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Hopefully I'll be able to start stripping down my turbo lump in a few weeks.

Whilst it's in kit form it makes sense (to me anyway) to do an 11 stud conversion, now the numty question; does anyone know what size threads the head studs are and what diameter I need to drill the holes before I tap them?

Also I've heard about people using bigger studs to connect the engine to the gearbox (5/16th sounds familar) has anyone got any views on this, good bad indifferent? Again the numpty question, what size studs and what diameter holes?

3/8 unc into the block, 3/8 unf on the top

1/4 unf is the usual size of sump bolt, peolpe do upgrade to 5/16th but its only really needed on very high reving engines IMO. Personally i do it to my engine as its a simple and cheap mod.

I've seen the future and tbh its Pie

the tapping drill size for the 3/8 unc block studs is 8.1mm prefered!

8mm is fine use a 2nd tap and the plug tap

drill 25 mm down on the left hand side one and on the water pump side 14mm max depth

no more then tap the block

make sure the hole is not drilled on the pi$$

no cutting fluid is required on cast

Oh! an only torque the water pump side head nut down to....... no more than 25ftbl

as there is not too much meat over the pump housing

if the blocks going to distort it will happen there

or even may crack the block over this area if torque figures are set over this

the left hand side one is the same torque figure as the rest
55ftbl for a turbo motor

the block to gearbox fastners IMHO are up to the job!

but others may disagree

In my opinion, if your doing the sump bolt mod, drill and tap for M8 rather than 5/16th.

Far easier to get the right sort of bolt. I found it a pain in the arse getting a spanner in to a normal headed bolt, I was after the Cap head bolts but couldnt find any where that stocked them in short notice.

I presume the spaner clearance issue is why Visard in his book recomends cap heads or the ARP multi point bolts. You can get these type of multi point bolts from Aero fastner suppliers but ar MEGA expensive for what they are doing.

Metric bolts of all types are freely available and do the same job at much the same size for far less penies. Next block I mod will be metric sump bolts. I learned the hard way.

People that are in the RAF, know people in the RAF can usualy get access to those fancy multi point bolts in UNF.

Edited by Sprocket on 22nd Jul, 2006.

Cheers guys.

:EDIT: Just got my new engineering ruler in the post, and it's got all the dill sizes for both metris & imperial drills on the back :) All I need to do now is finish the MG and start on the Mini.

Edited by Rob H on 29th Jul, 2006.

I done the gearbox to engine in m8,and used allenkey bolts

Metro turbo weekend driver,Mini turbo in the making again!