Just a couple of questions regarding an 1100S(1275) block rebuild that I am undertaking at the moment....

1. What thread is the temp sender? I need to tap it out, but the one I took out was a bit crossed up and I cant tell what it should be.

2. In the Vizard book they recommend that you drill and tap the gearbox bolt holes to 5/16 and use bigger bolts. Is this necessary or just a waste of time? If a good idea then do I need to use hardened bolts or will other ones suffice?

Thanks everyone in advance!!

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68 Mini
70 Moke

Q1. 5/8-18 UNF or 5/8-16 UNS thread, depending which guru you talk to. I tap them with the former, you can actually buy taps here this size.

Q2. I had an ex-race Mk1 S motor with the block tapped out to 5/16 UNF. I believe it's a waste of time unless:
a.It's a race motor and
b. It's an early thin flange block.

I've never had an oil leak problem there with the stock 1/4" bolts in 1100S blocks, these bolts are Grade 5 and quite adequate. If you want stronger, buy Grade 12 Unbrako socket head bolts instead.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks Doc.

Oh yeah the other question was also vizard related.

What thread should I tap out the oil gallery plug holes?

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68 Mini
70 Moke

whatever thread you can get a good supply of bolts in, but given it's a cast iron block, UNF would be the go

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did I tell you that I won a trophy?

The holes are 1/2" now. 9/16" UNF would be nice, (I even have a tap) but 9/16 UNF grub screws are unobtainium.
You could drill out a bit and use 5/8" UNF ones.
I'm probably tapping mine 14mm next time- instead of just turning up new brass ones and bashing them in.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks guys

Also what length unbrako gearbox 1/4 inch bolts should I buy (dont actually have any to compare against.

Do the oil gallery plugs need to be tapered? or will just ordinary do with a bit of sealant of some sort?

sorry for the dumb questions but I wont know the answers untill I ask the questions.

Regards
Smarty

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68 Mini
70 Moke

Not sure of the bolt lengths, but there are several you will need. Fronts longer than the backs, and 2 near the crank pulley are shorter still.

Parallel thread hex plugs are fine, just smear a bit of Loctite on them to seal. Do NOT use teflon tape, it'll get into places it shouldn't.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.