I think I had this answered before but I can't find my info anywhere Anyways, I will be doing a SE204/SE 1.725 rocker arms/.030 head gasket change to my 96" in the next couple months. Headwork will only involve valves/light intake port clean-up/equalizing CC's. Can I use my stock pushrods with this configuration? I do have a new set of SE tapered adjustables (with grade 8 machined lock nuts) available but would like the safety/simplicity of the stockers if they would work. Thx for any input, Troop

 

You can use the stock push rods with the SE204. But any milling of the heads or changing the head gasket throws things off a bit. Your safe bet is to go with the adjustables.

Jim

 

If the head gasket change is the only dimensional change in the valve train stackup height, you are good to go. The lifter end of the pushrod will just be a tad deeper into the lifter which is not bad thing. If the heads have been decked, you need to do the math on the stack up height and see how much travel is left in the lifter.

What size are the machined adjustor nuts? 5/16" or 3/8"?

 

Actually I believe they are 1/2"

 

Depends how much they take off the heads. I had a set of heads decked .037 and .038 and used .030 hg and it worked. Just mock it up. If your lifters bleed down and you can spin the pushrods you will be good. It is too early for my mind to think so not sure how much diff the 1.725 vs the 1.625 would make. Personally I would use the SE tapered adj as they are very nice. Actually I think the adjustables are simplier especially if you have to mess around in the cam chest again.

 

I doubt it. IIRC, the jam nuts that come with the SE pushrods are 5/16" x 20. 3.8" x 20 is hard to find; have to jump to 7/16" x 20 to find the correct pitch. Someone was offering machined, G8 5/16" x 20 and I was wondering if that was your source. I have a set of SE tapered pushrods but two nuts have cracked and I won't use them again unless I can find some 5/16" x 20 ajustors.

 

Lift has nothing to do with pushrod length. Adjusted properly, the stock pushrods should sit .100" into the lifter body which leaves .100" of travel. Decked heads and thinner head gaskets will sink the pushrod deeper into the lifter body and limit the remaining "cushion" travel in the lifter. Some guys adjust pushrods by bottoming out the lifter travel and backing of whatever number of turns they choose. The lifter needs some travel in the event a shift is missed, engine overreved and valves float. In this situation, a lifter with no travel remaining can cause valve to piston contact.

Cam base circle is also a factor in determining pushrod length. Troop doesn't have that issue as he using the SE204 cam. However, many aftermarket cams are ground on a smaller base circle which affects the valve train stack up height.

The SE tapered adjustables are nice but unless the quality of the adjustor nuts has improved, the adjustors can be a problem. I have had two come loose and back off; they cracked from the inside under torque and came loose; bad juju.

Apoligies if you already knew all this; just trying to clear up what seems to mystify many.

 

He said he had new jam nuts which I have used in the past as well but also never had an issue with the stock ones. It really does not matter where the pushrods actually sit in the lifters as long as they are not bottomed out or on the converse not flopping around lol. If the rocker arm is longer it would push the rod further into the lifter I would think, maybe not tho.

 

Well, could be. I bought the pushrod set new/unopened from a v-twin forum member. He bought the lock nuts from another v-twin forum member who was machining/selling them to use with the SE tapered adjustables. I went back to the ad and it said 1/2" but he could have mispoke. The package is still sealed up so I haven't actually tried threading the nuts on to the adjusters..

 

They person I buy them from machines 9/16-3/8- 24 grade 8 nut and machined down to 1/2-3/8-24 which are the se tapered adj size needed.