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Old 01-24-2026, 10:34 PM   #1
Brian
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Join Date: May 2010
Location: Masterton, New Zealand
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Default .030"-.004 rod bearings

Did ford or any aftermarket manufacturer, ever make .030" -.004" 81A 6211 full floating rod bearings? I know Ford made .030"-.008", but I'm looking for something a bit smaller on the o/d.
Long story; I'm building an engine and supplied everything to the engine balancing outfit to balance; all nos stuff, apart from the crank which is ground .030 under on the throws. He rings me advising the rods were mismatched weightwise too much, and asked if I had any more. I sent some more, although they were nos, they were a bit rusty in places....In due course he rings me telling me the job is done. When I get there to pick up the job, we're going through everything, it's all good until he says we bead blasted the rods. WTF!!?? i don't believe in bead blasting engine components; if you examine the surface with a microscope you'll observe abrasive material imbedded into the surface, which can potentially come loose and circulate through the engine in the oil doing untold damage, however, the bigger issue in this case is that the big end of the rod is a bearing surface; it rotates/reciprocates on the o/d of the bearing, and is now of a bead blasted texture. I pointed this out to him, he agreed they had stuffed up! So, now they are going to run the big end of each rod through a Sunnen hone to provide a suitable bearing surface. I told him I can allow .001" oversize [don't really want to run even that much, but fear it's going to take more than .001" to clean up the bearing surface].
There is a reason I use nos stuff in my builds...unstressed, and those parts are to factory specs. The only way I can see to remedy this particular situation, is going to be to hone the rods out to a size to suit rod bearings with an oversized o/d. I don't really want to have to hone brand new o/s stock conrods out .008" in order I can achieve factory clearances. I mean, why? brand new rods having to go out to maximum oversize through the incompetence of a 'professional' machine shop.
In my opinion, the only 'real' way to do this job properly, would be to balance up another set of rods to the same specs, as what has already been done. I'm in New Zealand, all the components in this engine have been imported from the USA at considerable expense, including two sets of 21A con rods in order to get a matched set.
Alternatively, import a set of rod bearings that are oversized on the o/d and size the existing rods to suit [which are still contaminated with imbedded abrasive material with the potential of coming loose].
Any helpful comments? Thank you, rant over.
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