Center Main Straps
Turbo Mini Forums

That's pure class ! lol. I've even managed to get a new sig from it.

WWW.TURBO-MINI.COM

another experienced qote from me now,lol.

when i was used DON on the hills i built the engine without a centre strap and used it for a season,

wjen i pulled it apart i found a small trace micro fretting between the cap ,
and block, .

i was turning up to 9k during the season, although now a mega power motor,

so i foitted a strap to try hold thing in place and have not seen any fretting since,

even now on the DON engine i'm rebuilding.


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Well have just been to a tuning company in my area to get some work done and got laughed at when i said i was gonna run high boost and only use a center main strap. i was told i would need a strap on each cap else i would get too much crank flex! Please tell me im being fed tuner bollox as i declined!

sounds like a load of bollocks to me

boost has little correlation to crank flex, it is rpm related which generally turbos dont suffer from as they dont need to rev that high

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Leicester? Well, i guess its one of two companies beginning with the letter M ???

Anyone got a pic of a 4 bolt strap setup?

Edited by Jason G on 17th Jan, 2008.

Thats what i thought joey! Yes leicester and the supposedly better tuning company with the lette M! ha ha

cheers vegard

the catch is that you have to line bore the 4 bolt cap ..that is neither easy nor cheap to have done properly.

I'm still at odds with the whole strap thing..when i look at a A+ cap it just seems wrong to mill a big chunk off.

then add a strap so you need longer bolts (with more stretch). ''Judging''
from what i have seen used on some very powerfull jap engines i would say that the strap itself should be up to the job providing it does stay put.
I'll just take my chances and stress relieve the original use shorter ARP bolts, tightly fitting dowels and proper torque methods and hope for the best (NA @ 7800 rpm).

Oh a certain MF member advocated cutting valve seats with a coutersink drill..

That sir, is not rust, it is the progressive mass reduction system

http://aseriesmodifications.wordpress.com/

4 bolt seems abit OTT to me. Alas, I'm still learning and I'm a quite few horses down of 200!

Four bolt caps stiffen the cock em, Block

Hi,
I've seen a Toyota touring car engine , 5 caps all with straps!
So yes you can, but don't ask me to fit the gearbox after
Cheers,
Gavin :)

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My Mini build diary

Just got the 2 bolts here...think I'll stick to it.

Some of the older ford cosworths have the same lay out gav.

Back once again like a renegade master

Yes, but as Gav says there's no gears in the sump!

I know at least one of the miglia builders do not use eiter 4 bolt caps or straps at all. He just stress relieves the original caps. seems to work.

I was thinking about this today

Im about to order some 30mm square bar to make up a strap, then i thought to my self, would aluminum bar suffice?

Looking at most modern engines, albeit 5 bearing engines, they use alloy blocks/caps, and 30mm squared would surely be adequate if not overkill?

Anyway, im gonna stick to the usual steel bar, but thought id raise the point for debate if anyone interested?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

has this ally been heat treated?

Dont be a cheap skate and just buy one, fastcarl makes these up

Edited by Sprocket on 19th Nov, 2008.

A decent ally like 6061 T6 could do the job and potentially be better than a dubious origin 'putty-steel'.

It'd be a good weight saving - and at the end of the day, what exactly does a strap do anyway? You weaken the original cap by machining 20% of it away, then sit a piece of somewhat solid material on top...

Very Strange.

4 bolt main is the only way to go imo, It is a far better idea and I don’t get what the fuss about line boring and engine all my Race prepped blocks are line bores and honed it is really not that expensive and a hell of a loot cheaper than a new crank ect.

I'm not too sure aluminium would be a good choice, its rate of expansion is greater than steel so may have a tendancy to stretch the bolts as it goes throuh many heat cycles,

i think its inportant to use similar metals so that the caps and bolts all expand at a similar rate, keeping torque values somewhere near what they shoud be,

even TI would be a bad idea although i'm tempted,

can anyone tell us how much a mains bolt stretches with 60lbs ft torque on it,


carl


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

I'm not too sure aluminium would be a good choice, its rate of expansion is greater than steel so may have a tendancy to stretch the bolts as it goes throuh many heat cycles,

i think its inportant to use similar metals so that the caps and bolts all expand at a similar rate, keeping torque values somewhere near what they shoud be,

even TI would be a bad idea although i'm tempted,

can anyone tell us how much a mains bolt stretches with 60lbs ft torque on it,


carl


carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE