strokers are fine i agree with the Miniman

i have had a turbocharged A+ motor with an offset ground 1100S crank inmy mini for over 5 years the crank is fine and i take it 7500 every opportunity i get (if the clutch can handle it)
standard "S" rods 4 bolt centre main bearing cap and its all great, as i said its been in since 99 when i built it, bottom end will outlast the rings thats for sure and bores i reckon.

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100% Pure A Series Turbo
Morris - The Original RedBull Racing

Grant, are you running the A+ `turbo' main bearings or stock 1275?

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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.

I spoke to Jack? yesterday and it looks like my motor is going to Brisbane. It needs another crank as it is 020 so I may as well stroke it. It will finish at 1415 I am told.




'

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Chris

Everything I like is either
illegal, immoral or fattening.

Doc, the normal A series bearings all round in mine. have never really heard much on the later ones though

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100% Pure A Series Turbo
Morris - The Original RedBull Racing

Yeah that's what I'm fitting. I have been told the later turbo ones can starve the big ends at high rpm, as the oil feed is intermittent (no groove in bottom bearing shells).

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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.

ahh interesting hey, so you would need to have either A series main caps or aftermarket ones then, or i guess you could always machine a tag lip in the A+ main caps too.

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100% Pure A Series Turbo
Morris - The Original RedBull Racing

You need to get the main bearing journals crossdrilled to avoid the oil starvation issue when using turbo mains. You also need to have new bearing locating tang grooves machined in the main bearing housings. Turbo main bearings have the locating tang in the centre rather than at the edge of the bearing shell. I have been told you can get turbo type main shells with the edge tang. Not sure if this is correct.

Regards
RonR

Ron,
Was it only the turbo had these main shells, or all A+ 1275's?
Dunno wot Barney's got in him- it's an A+ block out of a UK 1275GT..

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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.

Hi Kevin,
I don't know if the turbo main bearings became standardised. I am trying to remember if the centre tang was only on the half shell without the groove. It would make sense if this was the case to avoid installing them incorrectly. This motor was done about 10 or so years ago and it's still waiting to get a run. I did a new motor for my S and made a BIG booboo in using friction modified oil for the first fill and this motor was to be a big bore stroker 1425cc 73.5 mm bore to replace the S motor. The S motor came good - initial oil consumption was horrendous - 100 miles per litre. I pulled the head to check the bores and found the rings hadn't seated as the bores were coated in a light brown coloured highly glazed coating. Cleaned this off with 400 grade wet and dry and it seemed to work. Had nothing to lose really. So the big bore stroker is still waiting in the wings.

Regards
Ron

Next week, I'll have my spare 1100S big journal (std/std) crank stroked..
No it's not for my current `1275 auto block' engine build- it's going into the next one. Which will probably then sit in the corner, like Ron's is!

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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.

The crank I'm getting put into my rebuilt 1430cc has been crack tested, stroked, wedged and hardened, which Cono (WA Mini Mechanic) highly recommended.

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Jonathan
http://photobucket.com/albums/y64/FatMaserati/

Yeah I want to get this one Tuftrided, but some people reckon they distort when this is done.
I'm going to wedge it first... then decide.

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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.

Nearly all the turbo & vandenplas & a lot of the std issue MG metro 1275 blocks were fitted with centre tang bearings,,,heaps & heaps of the donks that i have imported over the last 8 years have centre tang bearings,,,i`d almost go to say that it bacame the norm on all the later blocks to save time & money in production

all the hardening treatments do tend to distort/bend cranks to certain degrees(they also grow somewhat),,,we normally will grind to a size just over what we need & then allow the bend to occure during hardening process & then re-machine the entire crank straight agin,,,other people tend to simply grind to the size they want , harden it & then linish the bearing surfaces clean to size,,,but, obviosly alot of those guys are driving around with bent cranks & will have a shortened life span.

quality time spent (& a bit of experienced knowledge) here can either make or "break" your expensive donk ,,,pun intended

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

A lot of the 1300 racers with destroked cranks are running soft ones- not wanting to take the risk of the crank distorting.
Doesn't seem to matter much to them- the motors come apart for maintenance so often anyway.

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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.