sonic test SBC

RedRacer · Post by **RedRacer** » Wed Sep 07, 2005 7:29 pm

when sonic testing a SBC block (010 style if it matters), what is the limit you guys are giving for how thin is too thin, and where are the typical thin spots on these blocks? Talking about a 550HP, 13.5:1 steel head late model type engine. Thank you, ron

SupStk · Post by **SupStk** » Wed Sep 07, 2005 8:40 pm

On unfilled blocks, for your application, my minimum is .200" on the major thrust side. Other areas can be thinner. Every block is different but usually the thinest spots are between the cylinders. We have made 550 HP with thinner blocks but the ring seal usually don't last as long.

CNC BLOCKS · Post by **CNC BLOCKS** » Wed Sep 07, 2005 10:02 pm

We sonic test every block that comes in the shop and we shoot for .195 on the skirt sides and on the wrist pin side we shoot for a minimum of .110 so far that has worked for us on these blocks we only bore .040 over as we find very few blocks that will bore .060 over and be safe.

Wolfplace · Post by **Wolfplace** » Thu Sep 08, 2005 12:53 am

CNC BLOCKS wrote:We sonic test every block that comes in the shop and we shoot for .195 on the skirt sides and on the wrist pin side we shoot for a minimum of .110 so far that has worked for us on these blocks we only bore .040 over as we find very few blocks that will bore .060 over and be safe.

=
Just want to add the .195-200 minimum is what you want from about the center of the cylinder up on the thrust side.
You will find the cylinders get a lot thinner at the lower part on a lot of blocks & this is not a problem.
It would be nice to see .195 everywhere but it will be a pretty rare block that is this thick down low.
I have seen a lot of 350's & 400's in the low .100's to as thin as .080 at the bottom of the bores.
Again, I don't feel this is a problem, built a lot of them & they are still fine.

CNC BLOCKS · Post by **CNC BLOCKS** » Thu Sep 08, 2005 7:20 am

Thats why we check every block at .040 over we like to see at .180 plus on the skirt sides or we don't bother putting splayed caps on and most likley we will kieep it for a 2 barrel circle track block or a street performance application.

SupStk · Post by **SupStk** » Thu Sep 08, 2005 8:46 am

Carl, This might belong in a differnt thread but what machine do you use in cutting registers and drill/tapping for splayed caps? Seen CNC Blocks and was just wondering. Also is there anyway to check lifter true without doing the whole set-up? Thanks

CNC BLOCKS · Post by **CNC BLOCKS** » Thu Sep 08, 2005 3:06 pm

SupStk wrote:Carl, This might belong in a differnt thread but what machine do you use in cutting registers and drill/tapping for splayed caps? Seen CNC Blocks and was just wondering. Also is there anyway to check lifter true without doing the whole set-up? Thanks

To cut the registers we use a 2.500 shell mill and then we use a 1/2 inch end mill a 10 degrees to make a flat in the register, Center drill it, Drill with the letter U drill and use a 7/16 spiral tap and your done the whole process takes just under 20 minutes to do.

The next block I do I will take some pic and post them.

Thanks for your interest

RedRacer · Post by **RedRacer** » Tue Sep 13, 2005 1:48 pm

Thanks guys for the help, one other question: when testing the block, how many spots do you test? I have been pulling the tester from the bottom to the top in 4 spots. Both skirt sides and inline with the wrist pins,
Red

SupStk · Post by **SupStk** » Tue Sep 13, 2005 3:03 pm

Red, Sounds like you and I are doing it the same. The exception is when I find a thin area, I'll do several to determine the extent. On the siemeesed blocks I check at different locations. I know this isn't high tech but when testing I talk to a tape recorder and later print out the results on the computer along with any revelant information. Seems to save time for me.