Jesel rocker bar bolts too short!

When i mounted the rocker bars back on the heads, the bolts going into the ports under the intake rockers just didn't feel right to me when i torqued them to 45 ft lbs, actually three ft lbs shy of recomended 48 for aluminum threads. So i measured the actual thread engagement and found i was only getting .375 thread engagement for the 7/16/14 x 3/4 long bolts. I do have to say i have .060 shims undeer the bars, but called Jesel and asked about that before running it, and was given the OK to do so. Even with the extra .060 without the shims, at .435 thread engagement i didn't feel that was a great plan. I ordered the bolts from Jesel in one inch length, and gained thread engagement to .685, which brought the bolts a little proud in the port, but about .030 ground off the bolt fixed that. I decided to use 45 ft lbs torque, and all felt normal.

I am not sure why the pictures loaded sideways and upside down, they are ok in my phone. The long bolt in the pic already had a bit of grinding, just enough to be even with the port ceiling.

I've installed several new sets of Jesel rockers on BBC's and they come with bolts in 3 different lengths. 8 long for exh. and 2 different (8 each) lengths for int. It is rare for me to use the shortest ones though.

Brian

Thanks for sharing that

Good idea. I like to use as much aluminum threads as I can access.

Sean, it dawned on me something wasn't right as it felt mushy at 45 ft lbs, when usually you feel more resistance as you approach the listed torque spec. Now it feels right, for what that is worth.

Typical when having to use a shim....My question would be why the need for the shim??

Somehow i ended up with pushrods that were too long, the shim is cheap, even after paying $40 for long bolts.
But even without the shim, too little thread engagement for my taste. Not to mention a .225 deep hole in the port roof, 7/16 diameter.

Won't that extra .060 stand height throw your rocker to valve tip location off if it was correct before?

My T&D paired shaft rockers were shimmed .060" as well. The trend pushrods I had were too long. I calculated the additional sweep across the rocker. it was .011" compared to T&D's exact speck height.
The cam has .799" lift w/o lash. Ran it 8 years and over 750 passes like this. Then had to mill the heads and deck the block. It now has a .075" shim. Over 200 passes. Never had any valve train issues. I will say when the bed plates were mountd on the -1 heads the end studs that supplied were shorter than I liked. They were replaced with longer studs from ARP .
Doug

Doug, thanks for the input on sweep and your changes. Good to hear so little additional sweep as a result of using shims on these setups. My guess is velocity changes from changing rocker height would be insignificant at these levels of shims, and it is good to hear you have had good life out of your valvetrain.

I ran into the same issue on a set of -1 heads. Good catch!

Understand and assumed that was the reason. Guess there is a reason I have probably 20 sets of pushrods here. Just went through this with and engine I acquired, Had shims under the rocker stands, because the [pusjrods were to long, poor sweep on the valve tip and the WRONG exhaust rocker. From a name shop as well.

I use up all thread that's there after shimming, and have bought longer and/or larger diameter fasteners if the real estate is there to do so depending on the project.

After talking to a Jesel rep, it didn't seem to be a big concern. But as shimming gets greater than say .100, it might be a great idea to have all the specs on its effect.