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Machine STD con rods to narrow journal?

PostPosted: Sun Aug 18, 2019 7:08 pm
by Plus2soon
Dear Listers,
I just bought a narrow journal 77,62 mm steel crank. The idea is to use it for the street and be able to rev up to about 7800 rpm without spend money on ex Carrillos . Has any one machined 125 E rods to narrow spec with success? Any thoughts are appreciated.

Johan

Re: Machine STD con rods to narrow journal?

PostPosted: Sat Jan 04, 2020 9:21 am
by ceejay
Depending how much you have to machine off each side... might be an issue with the roll pin locaters for the big end caps...measure carefully before proceeding. Not hard to machine the forged steel rods.

Re: Machine STD con rods to narrow journal?

PostPosted: Sat Jan 04, 2020 10:21 am
by nmauduit
I should have a set somewhere but never tried it (there are also inexpensive H-beam steel conrods these days, though I'm not sure if the cheap ones are good enough). Interesting topic : please post update when you have experienced it.

Re: Machine STD con rods to narrow journal?

PostPosted: Sat Jan 04, 2020 10:32 am
by ceejay
If you are referring to the maxspeeding brand (No commercial connection), I have spoken to several Aussie pro engine builders and they speak highly of them, good for race engines or for building a high HP reliable fast road engine, but of course if you want the best, look at Farndon, Cosworth, Arrow, SCAT, etc, etc.

Re: Machine STD con rods to narrow journal?

PostPosted: Sat Jan 04, 2020 12:18 pm
by promotor
Plus2soon wrote:Dear Listers,
I just bought a narrow journal 77,62 mm steel crank. The idea is to use it for the street and be able to rev up to about 7800 rpm without spend money on ex Carrillos . Has any one machined 125 E rods to narrow spec with success? Any thoughts are appreciated.

Johan


As already mentioned the roll pins for locating the two halves together would be an issue. Possibly the cutouts for the bearing tangs would cause issue also as these would have to be re-cut in a new position.

There is someone on Ebay who was selling old stock Farndon GAF rods with narrow journals - I can bet he still has a few sets left too as he's got a ridiculous amount of useful stuff. The only problem is I can't remember his user name! Sorry!

Re: Machine STD con rods to narrow journal?

PostPosted: Sat Jan 04, 2020 12:28 pm
by promotor
This is the seller :

https://www.ebay.co.uk/itm/Lotus-Twinca ... 4182155217

The rods he had for sale were a good price if I remember correctly!