Dart Is No Longer Line Honing The Shp Blocks

[CNC BLOCKS]

We just got 4 SHP blocks in and just was going over them and noticed they are NO LONGER line honing the cam tunnels or the main lines HMMMM

[want-a-be]

How did they check out size wise? Hmmm I'd rather see line honing then line boreing for the finish machining.

Thing is though...it's one thing for us to catch something like that when we know to check...and can machine it ourselves. What happens when those who trust a finished product gets out to them?

Don

[CNC BLOCKS]

The sizing seem to be in the middle or just under a tenth or two on one of the blocks and some times when we clean and relube and torque we some times see them tighten up up to .0003 and all the blocks we machine we take them to 2.6415.

The best line boring jobs I have seen is on the Bowtie Sportsman block as they leave a mirror finish.

[Dart Vader]

This is correct, we don't line hone new SHP blocks, we bore them to a tolerance.

This decision was considered carefully before changing the production process. It's important to note that the main bore tolerance on these blocks is 2.6376 to 2.6395.
A new SHP block is still a fiinished block and will be ready for use after the end user gives it a finish bore (which is neccessary for any new block).

Please feel free to post any further questions about this here.

[lun40119]

At what serial number did you stop line honing these blocks.

[Dart Vader]

At what serial number did you stop line honing these blocks.
Not sure what specific number we stopped at, it was right after the first batch of them I believe. If you really need the number I can likely track it down, let me know.

[lun40119]

I talked to Carl, and he has one that is alot lower than mine, I will just assume mine wasn't. It isn't that big of a deal, I am switching to studs for my windage setup anyway, but it would have been nice to know this.

[CNC BLOCKS]

This is correct, we don't line hone new SHP blocks, we bore them to a tolerance.

This decision was considered carefully before changing the production process. It's important to note that the main bore tolerance on these blocks is 2.6376 to 2.6395.
A new SHP block is still a fiinished block and will be ready for use after the end user gives it a finish bore (which is neccessary for any new block).

Please feel free to post any further questions about this here.


The correct tolerance on the mains is 2.6406 to 2.6415 and some cataloges I have seen 2.6416 for the high side

[lun40119]

I talked to Carl, and he has one that is alot lower than mine, I will just assume mine wasn't. It isn't that big of a deal, I am switching to studs for my windage setup anyway, but it would have been nice to know this.


He also mentioned that I should use the stud kit for the small journal crank SBC's. With a windage tray, 134-5501 would be the part number. Is this correct????????

[Dart Vader]

The correct tolerance on the mains is 2.6406 to 2.6415 and some cataloges I have seen 2.6416 for the high side

SHP blocks numbered 1P to 399P (This should answer your question also Lun) were machined to the tolerances I listed above (2.6376 to 2.6395) and then line honed to tolerances you listed (2.6406 to 2.6415).
Sorry, I grabbed those tolerances off of the sheet here without checking to see if they were for the new serial numbers or the old ones!

All new SHP blocks are machined to 2.6407 to 2.6415.

Also, you should inquire with ARP about the proper stud kits for this. I'm not sure if that's the correct one.

- Moved this thread to general discussion.

[Awesome Bill]

Actually a machined finish is a tighter quality finish that can be measured and controlled better than honing. We are on our #9 block and I have not found 1 block under spec! This is a good thing, because I have had to redo countless Little M's and Big M's and Iron Eagles. They are always .001-.0003 tight, never big. With the cranks being on the large side from with the import line, we always aline hone this little difference out and have to use the X series to get our required race proven clearance we use. Personally, the machined finish is a ton better and all blocks should be done this way. With the CNC machine, we can keep this within .0002 with cutting speeds and feeds. Surface finish is crystal!