grumpy...please help with main bolt question???

NYH1

Member
My machinist align honed the mains on my 2 bolt block. He did it with ARP main bolts installed. I'd like to use studs so I can use a good windage tray. My question is, will it change anything if I use the studs instead of the bolts he align honed it with?

As alway's, thanks! ;)
 
will you change the clamp loads and change the block dimensions, by changing from use of a dry clean thread to use of a thread lubricant on the threads?
yes you will, but will it be enough of a change to effect your engine clearances and alignment?
thats a (MAYBE /MAYBE-NOT) in most cases adding studs adds extra clamping pressure to the main caps, but that's not always enough to significantly change clearances, you can check and be reasonably sure its ok or not,by installing the crank in the block and lubricating the bearings after checking bearing clearances with either the snap gauges and mics or plasti-gauge, lay all the upper saddle bearings into the block and lube them with a mix of oil and moly assembly lube ,lay the crank into the upper bearings ,then starting with the center main cap,and use a decent torque wrench,tighten it to about 40 ft lbs then work out ward alternating first to #2 then #4 then #1 then the rear main cap and each time spin the crank,once all the mains are tightened to 40 ft lbs, it should increase in the effort needed to spin it, as you tighten each main cap, but the drag should remain consistent, thru all 360 degrees and never require more than about 10-15 ft lbs to start the crank spinning in the bearings, go back and tighten each main cap to specs, and spin the crank as you tighten each main cap,the effort should still be less than about 10-15 ft lbs to start the crank spinning in the bearings,if not the cranks bent or the mains are distorted, if it spins easily, and your clearances remain in spec. you should be ok.
if you experience problems turning the crank alone in the bearings the mains probably require a line hone or the cranks bent, a machine shop can quickly tell you which, is the case.
its been my experience that a properly machined block will NOT usually distort ENOUGH with that change to make a significant difference in clearances but the chances are fairly high that it can.
obviously a correctly machined crank with journals that are strait and not tapered, the correct bearings, and having both plasti-gauge and a dial indicator and snap gauges and precision mics will help here
READ THESE RELATED THREADS
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arpultratorque.jpg

In any application where your tightening a nut on a stud , such as on the outer threaded ends of main cap studs or head bolt studs, youll want to use a lube on the threads that gives consistent torque reading from your torque wrench indicating the correct bolt or stud TENSION, oil and MOLY assembly lube and various thread sealants do not always do that,the end in the blocks course threads have thread sealant, the fine threads on the outer end require a totally different lubricant

TWO BOLT MAIN CAP BLOCK
2boltcapbn.jpg

4 bolt SBC block


3504bolt.JPG

READING MATERIAL, yes its a bunch to read but you'll gain a great deal of useful info if you take the effort

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http://www.pro-gram.com/catalog.jsp

viewtopic.php?f=50&t=989

viewtopic.php?f=53&t=2728

viewtopic.php?f=50&t=50&p=5604&hilit=+studs#p5604

viewtopic.php?f=53&t=2726

viewtopic.php?f=53&t=1138

viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=89

viewtopic.php?f=59&t=1026&p=4328&hilit=plasti#p4328

viewtopic.php?f=51&t=1014&p=3831&hilit=splayed#p3831

I was asked," whats the differance between 2,4, and a splayed bolt block"

138maincap.jpg


SBC
bbccrank.jpg

BBC

on a normal chevy engine with 4 bolt main caps the caps look like this, notice the front cap on the sbc is a two bolt main cap which is normal even on four bolt block sbc where all the other caps have four bolts




on a two bolt block all the caps look like the front cap like this block below
10051181b2.jpg

]
typical2bolt350.jpg

typical two bolt cast crank 350

racing blocks have SPLAYED 4 bolt main caps like this

splayed3.jpg

24502503a.jpg


which are even stronger
 
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