73.5 offset bore how much
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73.5 offset bore how much ?

is the two pair of cylindars off set 0.010 to the outside

or is there new thinking now adays by going a shade more

as far as im aware there are two ways of thinking, lining the bores up with the gasket or lining them up so the gap/meat between bores is the same between each 3 pairs.

I havent decided which is better yet as im still to test my own which is matched to the gasket.

I've seen the future and tbh its Pie

Visard's information is a little vague. In his white book it says to offset pairs of cylinders 1+2 and 3+4 awau from each other by 10thou each thereby increasing bore centers by 20 though, but, also to off set all cylinders towards the push rods by 15 thou. Having said that there is no mention of the last operation in the yellow book except for the overbored small bore blocks.

I just had mine offset the 10 though, but looking at it last night maybe i should have done the other as well. Might try this on the next big bore build. That is unless some one says no Because.....................................?

right gents iam going to give my pet machinist some rules after your advice and having a natterwith nic who called tonight

and brought me a fantastic plenum chamber hand crafted this workmanship is just excellent!

iam going to post some pics shortley

be warned! anything i say could cause fatal disaster!!

thanks for a great evening though!

i have one of those plenums too spot on.

Gents,

For me this is not clear enough......i'm a blond sorry.

Are you guys offsetting THE pairs of cilinders, so 1+2 and 3+4 to THE outside OR only THE Center 2 cilinders, cilinder 2+3 to THE outside.......

Please advice.....

Greetz Bas
A blond novice!

Bas, this is an old post buddy

what it is all the bores are rebored and honed to 73.5mm ........ the correct size is stamped on the top of the pistons for correct piston skirt clearence .... so wait till you get the pistons bas.

the two center bores 2 & 3 are bored and honed the same size ....BUT...... the are each offset bored 0.010" thou of an inch to the outside of the block .... so leaving more material in the centre of 0.020" thou or in metric 0.5mm

the outside bores 1 & 4 are NOT offset bored........ just bored and honed

i hope this makes sense bas

Manny thanx Steve.....

Just Try to understand how to create THE perfect bore.

Cylinder 1 and 4 should also be offset.

Vegard in the past I have offset 1&4 0.015" but...... its pointless!

Every bit helps? By doing this you can go 74mm in the future.

maybe offset them all 0.015" you may have a point V

What are we talking About in THE metric world......0.3809 mm to THE outside?

Any modifications nessecary on crank?

Cheers bas

0.254mm = 0.010" thou

0.381mm =0.015 thou

nothing special in the crank department, unless you want a full blooded track race engine bas,

having the crank,flywheel, backplate,damper ballanced is very worthwhile bas.

why dont you come over to the Benross HQ again bas and i will sort all the engine out for you ......... pm me buddy

Steve, i know that it's been a wile nog....

But you already die THE crank and flywheel and pressureplate and THE hole shabang for me......

I was sitting at your dinner table with you and ann having lunch......

I know your old butt this........