Hello. I'm finally getting around to restoring my 1967 Barracuda. I rebuilt the engine 45 years ago and had intended to replace the conrod. I bought a new conrod from the ex BSA dealer in Taunton who told me that it was an improved part for a later model to help prevent conrod failure. They told me that some machining would be required and I presume that this would have referred to the crankshaft flywheels. I didn't use the new rod and rebuilt the engine with the original part.
I now want to rebuild the engine using the new conrod. I believe that my original item is part no 40-0908 and the new part is 70-9911. Does anyone know of any information available showing what work needs to be done so that I can use the new rod?
You will find some useful information on this and much more in Rupert Ratios Unit Single Manual Volume 1 The engine.
http://www.ratiopublishing.co.uk/The-Rupert-Ratio-Unit-Single-Manual-Volume-1
The new part is a conrod that fits the OIF B25. I'll have a look after lunch into what RR says on the subject if you don't have a copy but the good news is that both types of conrod use the same bearing shells (40-0907 - standard) which probably means the big-end part of the conrod is the same for both. One obvious difference is that the C25 conrod used a small end bush, whereas, the OIF B25 did not.
According to RR, in order to fit the later OIF B25 conrod to an earlier crankshaft needs a bit of metal removed from the inside of the 2 x flywheels to provide enough clearance for the conrod. Although not ideal, the job looks as though it can be done by hand using a file.
Thanks for the info guys. I've now ordered a copy of the Rupert Ratio book. I had guessed that the job might involve removing material from the inside of the flywheels. There are a couple of other machining jobs to be done so I'll probably ask the machine shop to skim them as necessary. Thanks again.