Machine Shop Did not Shim Valve Springs

[dibbons]

I'm in Mexico, so perhaps "blueprinting" a Mopar is too much to ask. I asked the machine shop to install the new 340 factory style springs with dampers at installed height of 1.650". However, when I picked up the cylinder heads with valves/springs already installed they just told me all the final installed height measurements are not the same. No effort made to use shims to even things out for me.

I built my first small block 50 years ago, but an not familiar with shimming the valve springs. I notice some shims for sale on this forum called '31 VS! 303 which I assume fit a factory unmodified spring seat. Don't know how thick the shims are or if they come in various thicknesses.

Can anyone suggest a thread here that explains what one needs to know in a situation like mine? Or perhaps a video? Thank you. (Cylinder heads are 915 with 1.88 intake valves). Valves, retainers, springs, locks are all new stuff.

 

[RustyRatRod]

While the spring heights are important, IMO, the valve STEM height is equally as important and they all should be even. The shop should have done that FIRST.

 

[dibbons]

How would you change that? Grind the top end of the valve stem?

 

[teringer]

Yes slight changes can be made with grinding the tips ,and if to bad replacing valve Seats or by installing new valves that have never been ground ,a spring slim has no effect on valve height

 

[RustyRatRod]

How would you change that? Grind the top end of the valve stem?

VERY slight changes can be made there, but they really should be evened out by the valve job.

 

[Killer6]

I'm in Mexico, so perhaps "blueprinting" a Mopar is too much to ask. I asked the machine shop to install the new 340 factory style springs with dampers at installed height of 1.650". However, when I picked up the cylinder heads with valves/springs already installed they just told me all the final installed height measurements are not the same. No effort made to use shims to even things out for me.

I built my first small block 50 years ago, but an not familiar with shimming the valve springs. I notice some shims for sale on this forum called '31 VS! 303 which I assume fit a factory unmodified spring seat. Don't know how thick the shims are or if they come in various thicknesses.

Can anyone suggest a thread here that explains what one needs to know in a situation like mine? Or perhaps a video? Thank you. (Cylinder heads are 915 with 1.88 intake valves). Valves, retainers, springs, locks are all new stuff.

There will be small variations in stem height from the factory, those 340HP springs definitely need shimmed to correct height, they are a decent spring rate but short. They only have ~75# load on the seat factory installed ht., pretty light, & just like stiff suspension springs/T-bars...they lose load quicker in extension. Yes, they make various thickness shims, accurate measuring takes patience or a spring ht. Mic which can be had fairly reasonable these days. Do it.

 

[Oldmanmopar]

Take the heads to a shop and have them redone correctly. Mopars have rocker shafts and all the stem heights should be the same. Sure you could use adjustable rockers but that would be just a bandaid . Cutting the valve stems could result int the rocker arm hitting some of the valve spring retainers. Sorry for the bad news but the shop you used Fudged your heads up. Go have seats installed and buy new valves. Don't use that machine shop to do it.

Aske to see their head machine. They don't have one . If they did all your valve stem heights would be the same . They did them with a manual cutter

Could you imagine that shop doing 4 0r 5 valve heads with fixed rockers

3rd pic is our head shop manual machine, 4 and 5 is our digital machine. 5 valve heads need a special fixture 6and 7. Shop puts out at times 20 -30 heads a week. we do all the new 2022 and 2023 Ram heads for dodge dealers. The seats are falling out of the 4500 and 5500 comercial diesels.

 

[RustyRatRod]

Take the heads to a shop and have them redone correctly. Mopars have rocker shafts and all the stem heights should be the same. Sure you could use adjustable rockers but that would be just a bandaid . Cutting the valve stems could result int the rocker arm hitting some of the valve spring retainers. Sorry for the bad news but the shop you used Fudged your heads up. Go have seats installed and buy new valves. Don't use that machine shop to do it.

Aske to see their head machine. They don't have one . If they did all your valve stem heights would be the same . They did them with a manual cutter

Could you imagine that shop doing 4 0r 5 valve heads with fixed rockers

3rd pic is our head shop manual machine, 4 and 5 is our digital machine. 5 valve heads need a special fixture 6and 7. Shop puts out at times 20 -30 heads a week. we do all the new 2022 and 2023 Ram heads for dodge dealers. The seats are falling out of the 4500 and 5500 comercial diesels.

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Heck yeah yall got some nice stuff, Steve.

 

[dibbons]

Sure you could use adjustable rockers but that would be just a bandaid . Cutting the valve stems could result int the rocker arm hitting some of the valve spring retainers. Sorry for the bad news but the shop you used Fudged your heads up. Go have seats installed and buy new valves. Don't use that machine shop to do it.

Maybe you missed it in post above, I am using new valves (photo #2) and 1965 274 iron ductile adjustable rocker arms (photo #3). I just noticed the exhaust valves have different spring installed heights than the intakes. The machine noted measurements of spring installed height of one intake and two exhaust as follows : In 1.623 and ex 1.174 & 1.769.
It seems the grooves for the locks are manufactured in a different location on the exhaust stem and the intake stem and/or the tips have been been ground down on the exhaust valves (I see a blue coloration on the tip of one exhaust valve and I see what appears to be slight wear marks on two edges of the exhaust valve tips: see photo #1).

 

[dibbons]

My task this morning was supposed to measure for new pushrods. But now I'm not sure if I was mailed the correct adjustable pushrods from Smith Bros. to measure what I need. It looks to me like the cup end of the adjustable pushrods they sent are just a tweak smaller than the factory 273 pushrods which I know fit into the factory adjustable rocker arms correctly.

 

[dibbons]

These are the notations the machine shop left on the cylinder head (photos #1 & #2). Another view of the intake/exhaust valves installed (photo #3).

 

[PRH]

When replacing factory retainers, locks, and valves(especially valves that have a different style lock groove), the installed height and tip heights can often end up pretty far from factory dimensions.
Performance type valves will often also have margin thicknesses that can differ from factory pieces, adding to installed/tip height variances.

 

[Oldmanmopar]

They would never leave my sons shop like that. Even the deck surface would not pass. They must have primitive tooling