512 B Underway

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Decked it to 9.970" . J.Rob

20210330_160506.jpg
 
Kind of looks like the deck was not flat front to rear, but also maybe twisted, or lowest at the top rear area? Maybe I am not seeing it right.
Thanks for posting your real world builds. No-bull-crap technical threads like this are always my favorites.
 
Bobzilla said:
Kind of looks like the deck was not flat front to rear, but also maybe twisted, or lowest at the top rear area? Maybe I am not seeing it right.
Thanks for posting your real world builds. No-bull-crap technical threads like this are always my favorites.
Click to expand...

Yes this was .003" removal, wanted to show how messed up the deck was. J.Rob

20210330_160621.jpg
 
Bewy said:
Ramm,
I have heard of, & seen, inexplicable thrust failures...on many engine brands. I am not sure if anybody really knows the cause. Some engines with GM T400 trans seem to suffer more than those with GM T350. One line of thought is some form of pressure problem in the T400 cooling cct, that causes back pressure & some builders put a restrictor in the coolant line. many theories out there....

I do not think you are properly thinking through this mod. The mains supply that you have drilled into also supplies two rod brgs. Any bleeding off of that supply reduces oil getting to those rod brgs. If you look at used t/brgs, you see wear on both sides. Thrust clearance on Ch engines is 0.002 - 0.010". If the clearance is on the larger side & the crank is away from the thrust brg on the hole side, you have a large 'leak' through a 0.010" gap. The t/faces already get pressurised oil without extra holes, which is probably why no engines have extra holes.
Click to expand...
“Inexplicable”. Love it
 
Wanted to show what I feel is important and easily overlooked. Using studs everyone knows to drill out the #3 cap holes to 17/32" in order to give the thrust cap some fore/aft movement, but sometimes in the machining process it just gets torqued down and off we go. I've been guilty of this a time or two. It's not critical to align the thrust faces when just line honing but its still nice to do--If you are line-boring and doing anything with the thrust face it becomes critical. Here I just torque the cap to about 50ft/lbs and tap it back and forth with some aluminum rod until I can't feel the cap to block interface. Here the ARP studs call for 110ft/lbs after alignment. After a bunch of cap and block prep the main bores are honed to 2.8178"-2.818"--crank should spin nicely. Oh and its also a good time to address the sharp edge at the bottom of the bores left after boring. J.Rob

Setthrust.jpg


Linehone.jpg
 
Ramm. Thanks for that on the thrust cap. I've got a block going in next week that's getting studs but I'm going to guess that he wouldn't know to open the cap holes up on #3.
 
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