Thread: 383 SBC build questions (there's lots commin')

Tweet

Okay instead of posting a bunch of questions separately I decided to put them all in one in case someone else needs the info. So far I've aleady learned a bunch:

1. KB hypereutectic pistons need a large gap, mine were .026.
2. Shiny ring on top, cast grey second, oil scraper third. I believe these are a standard gap of 0.004 for every inch of displacement.
3. Second ring has a bevel that goes down and dot goes up. If the top ring is beveled it goes up.

Now I got all the pistons in and the rod caps in place just gonna run to the store to get a 12 point socket. I bolted on the cam chain with the cam at 6 o'clock, crank at 12 o'clock and keyway at 2 o'clock. Next the weird thing. I rotated the crank a number of times to see where it hits the cam lobes, then I'd grind the bolt heads down. Well nothing, it was pretty stiff with all the pistons in but nothing hit???? It's a Scat 9000 assembly and the caps are chamfered a bit as well it uses bolts instead of studs. Is this possible or am I missing something again(direction of rotation...). I've read so many things on needing to clearance it, apparently the block didn't need any work either. Oh yea it's a Comp xe268h flat tappet.

Thanks for the input so far,
Sean

i make up a long feeler gage out of cardboard a bout 060 thick or abit thicker and turn it thru by have i do one hole at a time with no rings on the pistons if every thing you have clears the rods if scat could be the they used a short bolt and this will give you more room so you do not have to nip the bolt heads you with a thru bolt rod want to TQ them up so you know the end of the bolt will clear the oil pan rail to this is what we have to do to get them big cranks to swing thru

Thanks Pat, I'll try the cardboard. I was surprised nothing hit, do the rods you use have the edge chamfered where you're doing the clearancing in the pictures. I wanted to take pictures but my camera battery is dead. Maybe tomorrow.

Next question is about push-rod length. I consulted this link that shows the checker I bought from Summit.

http://www.thedirtforum.com/pushrodlengths.htm

From this I got my max lift of .48 subtracted from .60 is .12, divided by 3 gives me .04 gap. With the preload adjustment of .021 My total is .061" total.

So I measured with the lifter fully down but not compressed and I have a gap between the pushrod and the measuring tool of .039. So I guess that means my pushrods are .039" too short??? I'll have to measure the total length and go buy some longer ones tomorrow then do I??? I have comp roller rockers and AFR heads if that makes any difference. Also am I doing this right???


Thanks,
Sean

the checker you have is the type i do not use any more with lot of rocker arms you have a good chance it maybe off i check it at mild lift and the rocker arm i use for the engine plays in to the right length pushrod and not working off a checker

Well here it is so far, I have to tighten down the rockers and then I'm gonna flip it back over and button up the bottom end after checking the cam clearance with cardboard. I should've done that sooner but I didn't read it until after I was working on the top. A friend came over today and we took out all the inner valve springs for the break-in. Gotta go back to work tomorrow, just when I was havin' fun.

Sean