BB 383 Valve stem installed height question?

[Road Grabber]

I just had a valve job by an engine builder on BB cast heads. I asked him about grinding the valve stems even and he said he didn't because he could find a spec for it. I paid a lot to have these heads done.
Don't engine shops finish Mopar heads by grinding them even height when finishing the valve job?

Does it matter with a flat tappet magnum cam? Should I bring it back and have him grind them even? To what spec? Is there a max-min height?

My 440 has adjustable pushrods. Should I get a set for this 383?

If I don't grind them even height is there a bigger chance for valve float?

Thanks in advance.

 

[69 Sleeper Bee]

My machine shop ground mine because I remember he commented on them not being the same height.
Don’t know what the stem height is though but I’m sure someone here can tell you.

 

[69Bee]

I would take them back, and have him complete the job correctly that you have paid for. After I grind the valves, I always "Tip the Stems" to correct wear and ensure that they are flat. If necessary, they get a 45^ chamfer if none exists after tipping. It is not necessary to make sure they are even, just new surfaces. After the valve job, and milling of the head, the first check is the "Installed Stem Height" spec. Service manuals tell you to use a tool (not usually available), so I will try to check my specs at work on Monday for you. The machine shop should have the required spec, and correct it. After I measure the valves, I move any from guide to guide to get the best "In Spec" match, then re-tip any that are still too tall over the max height. Next, the "Installed Spring Height" is measured, and springs are shimmed if necessary to get them in spec, and balancing (even pressures). Shims commonly used are 0.030" (silver) or 0.060" (copper), and 0.015" (black) are used for balancing the springs. No more than two shims should be used normally, but have used three (0.015" or 0.030") combos in a pinch. Adjustable push rods make pre-load adjustment easier than trying to get shorter pushrods which are getting harder to get, just make sure the jam-nut is tight. Valve float happens when the installed valve spring height it too tall and the installed pressures (installed & over the nose) is too low, and cannot keep the parts in constant contact, so the valve remains open because it can't close properly before the next rotation of the cam lobe.

 

[66Satellite47]

The guide height depends on the max lift of the cam plus at least .100" with whatever retainers you will use. That needs to be measured, not guessed or assumed "on spec" with what ever spring shims are used.

 

[BSB67]

I just had a valve job by an engine builder on BB cast heads. I asked him about grinding the valve stems even.......

He should make them even.

 

[gtxrt]

on my sheet it say's 2.095-2.125 intake and exhaust, installed stem height. specs from chrysler.

 

[66Satellite47]

With any non stock cam, measure the clearance of retainer to guide. Lack of clearance will cause major damage.

 

[PRHeads]

Be careful of what you ask for.

Not all valves have the tip hardened in the same manor.
Some are heat treated, some have a hardened tip(welded or inserted), some have a welded wafer.
They can’t all have the same amount taken off the tips before you are through the hard stuff.

So, whether or not it’s feasible to make the tips even depends on how uneven they are before the tip grinding begins, and how much can be safely removed from the particular valves in the heads.

If the tip heights vary considerably(say .025” or more), I’d suggest using some sort of adjustable valvetrain and not worry about the tips being even.

 

[BSB67]

Be careful of what you ask for.

Not all valves have the tip hardened in the same manor.
Some are heat treated, some have a hardened tip(welded or inserted), some have a welded wafer.
They can’t all have the same amount taken off the tips before you are through the hard stuff.

So, whether or not it’s feasible to make the tips even depends on how uneven they are before the tip grinding begins, and how much can be safely removed from the particular valves in the heads.

If the tip heights vary considerably(say .025” or more), I’d suggest using some sort of adjustable valvetrain and not worry about the tips being even.

And the shop that did the heads should know, and proceed accordingly.

 

[Mick56]

If you lay a straight edge across the stems, are they all the same?

 

[66Satellite47]

I never considered even stem tip equality to be a significant factor. I check each valve spring for desired pressure at a given height shim accordingly. Then measure the guide to retainer clearance at the desired spring installed height with the lite checking spring and retainer that will be used. Having the tip height equal doesn't seem too important, unless it's way off.

 

[69Bee]

2.095"-2.125" Installed stem height

 

[PRHeads]

One set I had in the shop that comes to mind is a set of 346 heads off a 383 from a 71 Challenger.
They had already been done....... at another performance shop.
They had been done a few years prior, but probably only had a couple thousand miles on them.
The main complaint was it smoked and used oil.
They had the white Teflon seals on them, and there was a period of time where a few brands of those were quite problematic.
I told him to just swap the seals in the car, but he wanted the heads looked over.
They had all new Ferrea valves, new guides, hardened ex seats, new springs/retainers/locks, and a little bit of blending.
All good.... right?
Well...... not exactly.
The exhaust seat install had the seat inserts at rather varying depths, along with them being cut to various depths.
Some of the intake seats(I can only assume) must have been beat to death, and a few intake valves were really sunk quite a bit(from the seats being cut so far).
One one cylinder, the most sunken intake valve was next to the most proud exhaust valve........ to the point where the tip heights between those two valves were off from each other by a whopping .125”!!

The castings weren’t really nice enough to spend the $$$ on correcting them, but they were original to the car...... and he wanted to reuse them.

The new guides had been cut down to where they were very short on the top side.
I replaced them all with flanged bronze guides that had much more length on the top.
I installed 8 intake seats, then I recut the exhaust seats to even them up(equalize the valve drop), then cut the intake seats so the tip heights matched the exhaust.
Then reblended the bowls.

They went back together with the steel jacketed Viton seals.

He said it ran better afterward, but was mostly happy it didn’t smoke anymore.

Those two valves, in the same chamber, on heads that had already been gone through.......with the tip height off .125”........ that’s as bad as I’ve seen.

 

[PRHeads]

2.095"-2.125" Installed stem height

The problem with that is, it doesn’t guarantee the tips will be even.
I’ve seen many factory Mopar heads where the factory spring pads vary in height by .025-.030 or more.
You could have the tip to pad height be exactly the same on two valves next to each other....... and have the tip heights be uneven by .030”.

 

[69Bee]

They don't all need to be exactly the same, but should be close. There is usually enough travel in the hydraulic lifter to work. I had a set too that the valves were way out of kilter. I believe I re-installed larger ex seats to correct the depth, and installed intake seats to correct sunk valves. I also don't use the teflon seals as they are a race only seal requiring frequent replacement. They are not designed for daily street use because of their rigidity, any guide slop will allow oil to pour out as the seal won't follow the valve stem. I also use metal clad Viton seals for proper oil control.

 

[bm02tj]

All non adjustable valve train motors need the valve stem height adjusted