Good afternoon everyone, been a minute since I've been on here. This past march I decided to pull the trigger and take the motor out of my '68 442 and have it gone through. Well I just got my block and crank back from the machine shop, the machinist is having a hard time finding some 0.001" under connecting rod bearings and all I can find are ones for a SBC. Does anyone have a lead or information on where to best look? Thanks for any information! Hopefully I can get it back together to actually drive next year

 

I just looked in the Clevite, Federal Mogul and King catalogs and they dont show them. Egge shows them in .001 but I dont know who makes their bearings or the quality.

https://egge.com/product/connecting-rod-bearing-330/

What does the crank actually measure ? If all they did was polish it then it will probably be fine with standard bearings. Its been running like that for 50 years

 

Are you looking for .001 extra clearance or .001 less clearance? And what did he say you have for bearing clearance right now?

 

He did polish the crank, he didn't tell me the measurements other than to find 0.001" under rod bearings. I measured the crank earlier this morning and seem to have misplaced my measurement paper so I will need to go out and remeasure.

 

Let me know what you find. You MAY have options.

 

OK so this is what I have. Per the Service Manual, spec for the 400 on connecting rod bearing is 2.4498"-2.4988". My measurements are between 2.4970 and 2.4985. I am assuming that I could just run standard bearings due to them being in spec? Or should I still look for 0.001" under per the machinist? Thanks!!

 

Ok.
You have issues, crank journals vary .0015, not the best. I’d have it ground .010. Then you can adjust clearances however you want.
And your first numbers aren’t right. I’m guessing you meant 2.4998-2.4988 correct?
Finally, to my knowledge, no one makes a .001 over bearing. In other words one that takes up clearance, not adds to it.

 

Mark beat me to it I assume you meant 2.4988" to 2.4998"

2.497 is almost .002 under the small end of the spec. Even a .001 bearing will be too loose. Way too much range on them. I bet they are probably out of round also.

I agree that the right way to do this is to have the crankshaft reground .010 undersize.

 

I have a set if you want them

 

What do the big ends of the rods measure?
Your machinist just gave his recommendation without giving you what the actual clearances are.
Get a new machinist.

 

Holy guacamole! Thank you for all the information! I will be getting back out to the crank on Thursday so I will be remeasuring and rereading (I have been known to be slightly dyslexic with numbers). Should I drop the crank in the block and measure clearances with plasti gage? I figure at this point I'm probably better off taking it to a new machinist and having it ground as you guys have said just going to check all my bases.

 

What are you using to measure them ?

What got done to the block ?

 

I was using a dial caliper as I cannot seem to find my micrometer set (I know, Harbor Freight carries them but are they trust worthy?) As for the block: hone the cylinders and degrease, removed/installed camshaft bearings, magniflux, replace soft plugs, deridge the cylinders. He also chamfered the oil holes on the crankshaft. On my receipt he states that he ground the crank mains standard and the rods have a note of 0.001 to standard.

 

Dial caliper is not even close to accurate enough for measuring crankshaft journals. You might as well just guess

If he "deridged" the cylinders then the block almost certainly needed to be bored oversize. The only place for a ridge reamer tool is in the dumpster

[QUOTE=ShortSmith;1602935 On my receipt he states that he ground the crank mains standard and the rods have a note of 0.001 to standard.[/QUOTE]

This part makes no sense whatsoever ? You dont "grind" a crankshaft to standard size.

I think you really need to have somebody with a bore gauge and a set of micrometers measure it all for you. I would hate to see you put it together and end up with a smoking, low oil pressure engine after all your hard work.

Now I see how machine shops get such a bad name

 

More than a dial caliper would be.
Like I said, find another machinist.

 

I am guessing he used a "$20 Home Improvement store" DIGITAL calipher. I have never seen a VERNIER or DIAL calipher that would give 4 place (.0001") measurements. Either way, a calipher is not good enough to make close, precise measurements. Unless you measure a .001" feeler gage, you can't even expect "0" is "zero", when you press "Zero reset".