On 2" inch main 1275 engines the use of main studs gives a solid improvement over the
stock bolts.
On the 1275 Mini there is something to look out for that doesn't arise on an inline
engine.
Due to the proximity of the gear box webs at both ends, there is not enough clearance for
the nut.
There are a couple of ways to deal with this:
1/. is to leave out the washer and then sink the stud a little deeper in the
block.
2/. shorten the studs if you have a lathe available.
The following photo's should help show the steps to take.
All engine fasteners from APT are manufactured by ARP,
the most respected and well known name for performance fasteners.
Here is what the studs look like when installed for a Sprite or
Midget, which is fine.
For a Mini this setup needs to be changed, as outlined in the text.
Here, you can see how little room there is.
All checking is done without gaskets between the flange faces.
When your complete design is done around a
1 3/4" dia. Crank, and then you change to 2" dia. This is what you end up with!
First step is to remove the locating rings. The pliers shown are
made to pull plug wires off spark plugs, but seem to work well for this application
also!
Tap all holes right to the bottom.
Use the correct tap as shown, which, confusingly, is called 'bottom' or 'plug' depending
on which country you are in!
These instructions apply to APT Main Stud Kit part number
MSA54 only
