EN40B 1071 Crankshaft mod

[fc1071]

Hi,
i have not been on the forum for a long time.
can anyone tell me if they know, or they know someone who can do the work for me in modify my hybrid 1071 cc engine (A+ block and an EN40B 1071 crankshaft).
The mod that i am at present tackling is in the crankshaft, i want to improve the response and extend the rev rang.
I have purchased this engine at end off season, from a father and son team who were racing it in an under 1100 cc class/formula (i think).

I now wish to take it to the next level so to speak, i can do a lot of the work myself, but i would need expert help in lightening the crankshaft at the big ends/pins area of the crankshaft externally and internally.
There have been lots of companies that i have approached who are willing and able to help me that would be able to lighten the crankshaft externally the problem is the internal removal of material from the crankshaft big end that present the difficulty.
I am looking for someone who is able to make this type of modification and that enjoys a challenge.

Most Crankshaft manufactures that i have approached prefer to sell one of there own units instead of modifying mine is there anyone that can help.
Thanks

[mk1]

The best person to talk to about this is Simon at Southam Mini & Metro. If the work can be completed, he will be able to do it.

However, you are in a "If you want to get there, you don't want to start here" type scenario. Rather than screwing up, sorry, I meant modifying, an original S crank, you should be starting off with a South African 1100 crank. These will fit straight into your GT type block, without mods & are EN16, rather than the much harder EN45 steel. This is easier to machine & I & many other people have had fully wedged, lightened, counterbalanced cranks made from these South African examples. The result would be less expensive & probably better than using an S crank.

The SA crank is pretty much bullet proof to boot.

I'll have to check, but I think I still have a few SA cranks from when I was importing crates of them a few years ago, but I'd have to check.

[fc1071]

Hi Mark, thanks for responding so quickly. yes your quit right about molesting a 1071 S crank any further is not nice, thou it has been raced and as it stands it is different to standard.
So your suggesting that a substitute crank would be kinder and is a feasible option. Can you then check and let me know if you have a spare S.African crank available.
Can you tell me if the cranks you received, are they just a rough casting or did you receive them as a finished 1071 S crank.
In the mean time thanks for the sign post to Southam mini & metro, i'll give them a call and see what they say.
Thank you Mark.

Regards

Frank

[mk1]

Hi Frank,

The SA cranks are all second hand units, a lot were in superb condition, but I may only have "dregs" now. As they are EN16 they are easier to machine than the EN40B ones. Makes for a more economical crank in the end.

I am sure that Simon would be able to do your EN40 crank, but with it being so hard, it will be more difficult.

[fc1071]

Hi Mark,
so have you had sufficient time to look for a suitable S A crank? if so can you let me know what condition is it in, would it need to be re-machined and then re-hardened or not? and what would it cost to buy if that is your intention.

Regards

Frank

[mk1]

Sorry, No, I'm at work. Will have a look this weekend.

M

[Richspec]

Are these the ones you use to make an overbored 1275 or something?

[mk1]

No, they are within a mm or so of a normal 1071 crank, but have GT sized bearings.

[fc1071]

Hi mark, did you have time to look at S/African cranks over the w/end.
Regards frank

[mk1]

Hi Frank,

Yes, I had a look & apart from one I am keeping for myself, I don't have any useable ones left. Sorry.

M

[fc1071]

Hi Mark,
Oh that's fine, and thanks for looking.

Regards

Frank.