Going from girdled to non girdled Machining required?
- Thread starter Sleeper
- Start date
Thanks Neal
Time to resurrect this thread.
Long story short...I had a 4.1 NA block machined for a stroker setup (3.625 stroke crank, 6.350 rods, 4.000 forged pistons) ended up that the deck height was taller in the NA block vs the Stage 1 block where the setup originally came from, so the pistons were too far in the hole yielding a really low comp ratio. I managed to get my hands on the original Stage 1 block
and now want to transfer over the rotating assembly from the NA block to the stage block.
Question is... Can I use the NA caps on the stage block that originally ran a girdle without a line hone?
Long story short...I had a 4.1 NA block machined for a stroker setup (3.625 stroke crank, 6.350 rods, 4.000 forged pistons) ended up that the deck height was taller in the NA block vs the Stage 1 block where the setup originally came from, so the pistons were too far in the hole yielding a really low comp ratio. I managed to get my hands on the original Stage 1 block
and now want to transfer over the rotating assembly from the NA block to the stage block.
Question is... Can I use the NA caps on the stage block that originally ran a girdle without a line hone?
- Joined
- Aug 1, 2003
no you cant just pop em on and go , they will bolt up but anytime you go swapping caps especially on a block that was already line bored you will need a line bore , a hone usually wont do it
..and std caps on a stage block (2 bolt mains) is a waste of a good block
you can run the standard #1 and #4 caps but unless hp goals are low at minimum i would get a pair of center billet caps installed and then that block will be ready for future hp needs
..and std caps on a stage block (2 bolt mains) is a waste of a good block
you can run the standard #1 and #4 caps but unless hp goals are low at minimum i would get a pair of center billet caps installed and then that block will be ready for future hp needs
Good to hear. I'm in the process of building a 273 cu. in. 291 and am leery about the thin deck. I'm only removing enough to clean the deck to a nice smooth surface. Did you remove any of the head bolt threads in the deck?
.025" is right at the thickness of 5 or 6 sheets of paper. It's not like taking off 1/4'' of meat.
I knocked a couple threads out and got rid of all the sharp casting flash in all the deck holes. When I started building my 4.1 I didn't know they blocks were taller than 109's so it was a surprise to me. That's why I'm working with a race piston manufacturer to tool up for Buick slugs. That way I can just more the wrist pin down .035" and leave the meat on the deck (and not have to machine it in the first place)
I knocked a couple threads out and got rid of all the sharp casting flash in all the deck holes. When I started building my 4.1 I didn't know they blocks were taller than 109's so it was a surprise to me. That's why I'm working with a race piston manufacturer to tool up for Buick slugs. That way I can just more the wrist pin down .035" and leave the meat on the deck (and not have to machine it in the first place)
ek02
Well-Known Member
- Joined
- Jan 31, 2008
If you get the block decked, have it square decked if at all possible. Mine have been off from .005-.007 end for end. Also, the 4.1 has a reputation for cracking between the head bolt holes and the water passages. I believe it has to do with the bolts or studs pulling on the deck surface. Like Earl said, take out a thread or two if you deck it. I had no problem with a factory deck for years, but when I had that block decked .010 on a rebuild, it was cracked the next time I pulled the heads.
291? How much power?
