Con Rod bushes

[pwhitehouse]

Thanks to those who responded to my recent con rod post. Having now sourced some replacement rods for the bent ones I found previously (particular thanks for someone who regularly posts on this forum for his assistance), I have now attempted to rebush the smallends, a job which should be straightforward and one I have done before. The replacement bushes are ACL RB902 which will fit lots of pre crossflow Fords ie very common. These have been pressed in without trouble and today I attempted to ream to size (pistons are Omega, gudgeon pins are standard size). I was surprised to find how much material had to be removed. I used a straightforward expanding reamer doing it by hand. It was necessary to remove about 12 thou off the diameter (!) and in fact this removed all of the phophor bronze lining in places revealing the steel backing.

I stopped at this point and compared a bush that I had previously removed and which had no discernable play in it. I weighed an unused new bush (16gram) and compared this with the old bush (12 gram) indicating that I would have to remove 25% of the total metal to get to the right size, no wonder I was down to the backing. Also on close inspection the old bush (FoMoCo stamped on ths back) had backing metal of significantly less thickness and consequently more phosphor bronze bearing material, totally the opposite of the new replacements.

I am totally puzzled. There seems to be little point in continuing when the likelihood is that I shall face the same problem with the other rods, they measure the same internal diameter. Significant quantities of these ACL bearings must have been sold (my well known supplier has sold many recently from the same batch with no comeback) and I have never experienced this problem before neither have I heard of anyone else.

Until I can sort out the problem, I am trying a different supplier although I suspect that they will come from the same source with potentially a similar outcome. In desperation I had thought of using oilite bushes, machined to the right dimensions although clearly I don't really want to be forced down this road.

I can't believe that such a straightforward simple job can have developed in the way it has. Any ideas anyone?

Peter W

[PeterK]

Any difference between the s/e bearing from the bent rod and the new one ?

[RichardHawkins]

Peter,
I struggled to find small end bushes last year. I was having work done by Coventry Boring and Metalling.

Eventually Coventry Boring and Metalling found some, I was unable to.

I have spoken with Roger at Coventry Boring and Metalling and they could supply you with a set for ?35.

Roger's phone number is 02476 672372

I have also googled Buton Performance & QED Motorsport. Both show small end bushes, which I presume to be correct.

Regards,
Richard Hawkins