I am planning on getting .090 taken off my 1986 hydraulic head, has anyone done this and can confirm that I will not have a clearance issue or will it really depend on the cam lift?

Someone suggested to me that I should look into adjustable rockers for a specific cam I may decide to use, are these avail for a late model slant six head?

I am pretty sure that the older style rocker shaft cannot be used cause of oiling issues but Id like to confirm this.

Maybe there are aftermarket units avail that will allow me some adjustment?

BTT

When using hydraulic lifters it is very important that when the head is done all the valve stems be the same height. You "adjust" your preload with pushrod length. At .090" off the head you will probably need shorter pushrods, but it will also depend on what camshaft you use too.

There was a good discussion ln this a while back started by Rick Covalt.

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Thanks, how about adjustable rockers, are these or were these even avail?

Not that I am aware of. I have never seen any other than factory stamped steel.

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CJ and a few others on here have done a group buy on some aftermarket aluminum adjustable rockers before. They were available in the stock ratio and 1.6, but think the wait time and other issues made the experience not worth it.

You'll need to inform the machine shop the engine will be non-adjustable so they can get all the valve tip heights the same as Slantzilla said, or you will have problems.

When cutting that much off of the head and/or block, an adjustable checking pushrod tool can help determine how to re-establish the correct length for regaining the right lifter preload adjustment.

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There's no such thing as too much cam....only not enough engine!

Thanks for the tips, yes I have read that I can take an old pushrod, thread it to make the tool. Have not got that far yet though.

How would the machine shop not get all the valve tips the same height, in other words would do they need to watch for in what specific machining process?

Knowing this will help me to better understand and explain to them what they may want to watch out for.

Thanks

The rockers Ceej did were for mechanical lifters.

Any good machine shop should be able to get the tips at the same height, especially if they are doing a big valve install. Make sure to check when you get it back to make sure they haven't ground the stems and gotten the space above the locks too short.

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Will do, so is it safe to assume that you guys generally stay clear of the hydraulic heads/cams.

I read alot about milling .100 + on these heads and no issues but I guess I am on almost new ground here with the late head as far as valve problems.

If the machine shop is modernized it should be common practice to get the tips the same height and all the seat depths the same, but never assume they are. If they are outdated and using less modern tooling and equipment like stone grinding the seats, then you will get some variations if they don't stay on top of it. But like Slantzilla said, check to verify before you load it up at go home with it.

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There's no such thing as too much cam....only not enough engine!

Yes, I believe they are pretty up to date. They have a excellent reputation here. Safe to assume I just need to lay a machinest rule across the top. of the keepers and see that they are fall in line.

Is that the way to check?

Check it across the valve tips themself.

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There's no such thing as too much cam....only not enough engine!

There are some guys running hydraulic cams, but cam choice is fairly limited.

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The thing about hydraulic slant six engins, is the the valve gear is very specialized. The lifters get their oil from the top end- it goes through the rocker shaft, the rockers, & down through the pushrods to the lifters. So any non-stock rocker for a hyd slant is going to be custom.

I ran a moderately stout hyd. cam in a mech cam engine, but didn't understand all the oiling differences from mech to hyd, so ended up with a couple lifters that would collapse when conditions lined up right. (that cam's in the Parts for sale section)

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