.060-.065".. The pistons are .040-.045 in the hole. They are TRW 406 flat tops. No reliefs at all. The heads are C4ae G heads with 75CC chambers. Not ideal I know.

FWIW, I have 2 sets of FM rod bearings I keep trying to use, over a few builds now, they always come up loose, one set had a chunk of something embedded in it.  Bought a set of narrowed Clevite, and it's like a production shop assembling the rods.  Once I got a combo for one rod, every other one was the same.

You weren't kidding about the rod bearings. Mic'd my crank up and it came in around 2.4280.. Gave me .0035-.0037" clearance. I even checked the clearance using another set of rods and had the same results. So for grins I threw in the .030" under Muskegon bearings and checked them at 2.4080" and got .0025-.0027"..

I have Clevite Rod and mains on the way. I messed around with the mains tonight and still am not happy. Tried dressing up some of the halves and swapping them around. The upper halves were pretty consistent, maybe .0002" off from the front to back of the shell. The bottoms were another story with .0005-.0008" front to back. Checked the main bores and the are dead true.

 It's too bad we cant find a better source for more consistent bearings. Maybe I will take take the FM bearings to work and strip the coating off and see if I can plate them and hold a tighter tolerance. I used to work with a guy who raced carts back in the 70's. He said they used to take the cages for the crank bearings and silver plate them.. I wonder what they coat race bearings with..

Fred

Checking main bearing clearance last night and I have a couple bearings with some pretty healthy taper. The block has been align honed and and I'm checking clearances using a bore gauge. Even when I move the bearing halves to a different cap/saddle I'm still seeing about .0005" of taper. This is using a 125M10 bearing. It's not all bearings only 2 sets out of 5. When I was putting together an engine last year I seem to recall the same issue with the 125M. I had to use Cleveland bearings to get clearance then and it solved the taper issue also. I need to gain a little clearance on this one but I cant seem to find .011" Cleveland bearings. The mains without taper are .0018-.002.. The mains with taper are .002-.0025 and .0025-.003. The crank is a fresh grind and checks out within .0002" across all 5. I haven't Mic'd the bearings yet. Is anyone else seeing this with FM bearings? I hope its not just me!


Fred

Good idea making a punch out of an old valve stem.... Crazy question.... Do you have the head dowels in place?

I run .040" cometics on my stroker with the pistons @ .001"- .002" out of the hole. I turn it to 7000-7200 rpm and have never had an issue. Any time I've pulled the heads the quench pads are clean and there are no "kiss" marks of the piston to head. I'm not sure what is to be gained with going any tighter or looser. I'm going to be putting a 406 together for my summer daily driver in the following weeks with true flat tops and C4ae-g heads(75CC chambers). I'm not sure where the pistons will land in the hole but at 0 it puts me at 10.8:1 compression. I'm going to be trying to run 93 octane so I'm curious to see if running tighter quench will help with detonation or run a thicker gasket to knock the compression down but have a larger quench. This will be with an edelbrock pro flo EFI and a comp 270s cam.

My wife is a program manager at Thales In-flight Entertainment division.  They build seat-back LCD units for airliners.

As you can imagine they are hurting badly!  Just yesterday they told everybody to expect a 30% pay cut until things get rolling again.  We're relieved since we really expected a furlough.

The Plating/surface finish company I work for does a lot of work for Thales and Boeing. We also do a lot of other military/aerospace work. We haven't seen any slow downs in production....yet.

I have a set on my 451". Very nice quality stuff. Make sure you check the chamfer on the thrust cap where the bearing sits in. I had to hit mine with a file to allow the bearing to sit in the cap 100%. I also wish I drilled and tapped mine to use a slide hammer to remove the thrust cap.