Rods. Use Them or Use Them.

[Pruneman99]

[c77owen]

I have run clearanced factory rods like this on even bigger engines than what you are building with no issues, but they did have upgraded bolts. Not saying it is what I would recommend, but if they are balanced and the bearing clearance measure out correctly, you are not likely to have a failure at the rod anyway. As for the pistons, you will want to run A pistons with a 74mm stroke. Either change the rods to 5.5" if you are going to run B pistons or change the pistons to A's with these rods...Just my opinion

[carguytroy]

I’m thinking that’s a great idea. They actually haven’t messed with the pistons yet so I could take them back and swap out for regulars if needed. Or I could just get a longer rod set I guess. Where they decked the case that would move the cylinders closer to center. Stock rods are, well, stock length so no difference there. Bigger crank moves rod/piston out farther, B pistons move things back closer to the case again. With that being the case it’s possible that I may not need shims depending on how far they milled the side of the case. Or like you say the pistons may be too far in the cylinder hence a longer rod. Yeah... I Better mock up what I have. I’ll post a pic of the case also.

[carguytroy]

Couple of pics of the case sides.

[Chickensoup]

who decked the case?
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Hosea 4:6 "My people are destroyed for lack of knowledge"

[carguytroy]

The VW shop has a place they use. The place I'm referring to has been in business for over 40 years. They really are a good outfit. do a lot of restoration work, engine builds etc. Same guy has owned it the whole time. I like the shop and bought parts etc from them a log time ago when I had my fastback. We just bought the Ghia a couple of years ago so I'm getting back at it after a long vacation from VW's.

[Ohio Tom]

My thoughts on stock rods..
The rod itself is likely fine (even thou it's 40+yrs old).
The bolts are what scare me..
I have seen too many stock rods used on stroker builds that end up failing.

Spend the money on a set of rods with ARP bolts.

Do you put used valves in your new heads?

[Pruneman99]

Wow. When they decked the case, they really DECKED the case! That's a lot of material taken off there. You will need to mock it up and measure. There is no way to know or guess about the length of rod you will need. There are some standards that will get you close, but your case has been worked more than the standard amount.

[carguytroy]

Yeah it’s all flat. Maybe that’s why he said to do the “stroker” pistons. I guess I can just mock up with the B pistons and buy a longer rod if I need to. Once I do that I own em I’m sure so that’s probably the route to take. If there was a way to get close before doing all that it would be cool but probably no way to tell without mocking it up.

[Pruneman99]

Do you have some old parts laying around? If you have a old piston and cylinder you can check and get rough estimate of where you are at before you open the new B pistons you have.

There is probably a way to measure from the case centerline to the new deck surface, IDK how. I'm sure it's child's play for the machinists here. I'd just use old parts and go from there.

[carguytroy]

I actually do have the old crankshaft still assembled and the old cylinders and pistons. They are stock size but I may be able to rig something up. Maybe I’ll try that. Good idea.

[Pruneman99]

Doesn't need to be perfect. Maybe just a thrust and small main bearing, rod with bearing, stock rod, A piston. Bolt the case up, put the piston on, drop the liner and measure. Calculate the difference between the stock crank vs. your 74 and the different pin height. Probably should get you enough info to get the right length rod.

[carguytroy]

Makes sense. If I knew how much was taken off I could do a bit of math and get close. I do think just putting things together a bit is the ticket.

[carguytroy]

I Decided to swap out for the A pistons. I haven’t mocked it up yet but that makes the most sense to me. Even though the case is decked it’s not enough to make up for the B set pin location. Measured parts all day today and that’s what I think is best. Took the others back and waiting on the new set.