Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - Rod Bolt to Block Clearence
View Single Post
  #10 (permalink)  
Old 05-03-2013, 07:22 PM
BogiesAnnex1 BogiesAnnex1 is offline
Registered User
Join Date: Apr 2007
Posts: 9,608
Wiki Edits: 0

Thanks: 18
Thanked 226 Times in 182 Posts
Originally Posted by ChevroletSS View Post
Cap screws are what Im using sorry guess i worded it different. I didnt have to take off much, Ill still be able to use a socket to get them off. It still seems close tho.
What do you mean by still able to use a socket to remove them? Normal practice is to remove material from the pan rail rather than the bolt head. Typically the upper part (shank) of a cap screw rod will clear the spigot extensions of the cylinder bore, but typically when a clearance issue is found here the bottom of the cylinder is clearanced. The only grinding on the rod or head of a conventional rod bolt (of bolt and nut design) is to clear the cam.

The clearance is usually pretty tight .050 inch is commonly used. One can see that if you loose a rod bearing, perhaps not even severe enough to do more to the rod than spin the bearing, the crankcase and cam are going to get hit.

Not that I think that taking a little material off the wrenching end of the cap screw's head is going to cause you problems other than getting a wrench socket on the bolt, but this isn't usually where material is deleted for clearance. At the other extreme one has to be careful about grinding on the pan rail or cylinder spigot as it's all to easy to discover coolant. To that extent the Vortec 880 block is somewhat easier to deal with because the cylinder wall so called spigot on the bottom does not extend as far into the crankcase as it does on other blocks. Because of this, the 880 block is better run with hypereutectic cast pistons, or if forged, the high silicon 4032 rather than the slightly stronger low silicon 2618. Because high silicon content pistons can be run with tighter skirt clearance so the thrust side reversal at BDC can't use the wider clearance of less thermally stable piston material to accelerate the piston to where the skirt gets cracked or snapped off.

Building an engine, even a simple engine, these days is not an easy task. Newer design elements for new materials have made several subtle but significant design changes to the Gen I and II SBC as well as the same kind of thing happening over at the Chrysler and Ford houses. So it's easy to stumble into previously unheard of problems simply by mixing parts from different years of technologies. Most of this stuff is not published and many engine building books out there are now many years behind the state of art that was incorporated into the last production years of the old SBC. When you arrive at the Gen III motor it’s a whole different world where in a lot of the ways you see the kind of kludged together ideas that show themselves in the Gen II LT1 an 4 of the 1990's become refined and defined in the extraordinary LS series engines of today.

Reply With Quote