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 "1623" & "1714 (photos #1) "1769" (photo #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

 

[dibbons]

Per internet search valve specifications:

Mopar performance P4876397 Stainless Steel 1.88" diameter, 3/8" stem, 4.98" long

Milodon 45645-8 Stainless Steel 1.60" diameter, .371" stem, 5.010"/4.93" 0.250" valve tip length (use with either 7 or 10 degree locks)

I just found Mopar Factory Performance manual diagram on where to place the adjuster when measuring for pushrods which is usually described as 1 to 1 1/2 threads showing. Well, in this case, it explains it as 9/32 inch protruding from the body of the rocker.

 

[replicaracer43]

I agree, that is extremely poor work, I wouldn't have paid one dollar to a guy that sends out jacked up crap like that. That blue tip? That's burned up from just grinding excessively hard. Sorry work, 100%

 

[volaredon]

I've seen 4 valve heads never a 5 valve head. What's that used on

 

[teringer]

Check the valve length the last time I used those valves they made a change , and told me the valves only comes in a plus .100 length stem I ordered a few replacement valve and all were .100 plus so and the oringal I bought were std . length . just something else to check if they checked spring height. Sorry for the extra warning

 

[Killer6]

I've seen 4 valve heads never a 5 valve head. What's that used on

Ferrari, VW/Audi, others.....

 

[Killer6]

These are the notations the machine shop left on the cylinder head "1623" & "1714 (photos #1) "1769" (photo #2). Another view of the intake/exhaust valves installed (photo #3).

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1) Those exhaust seats are shot, the valves are sunk, the seats need fixed with new inserts.
2) It looks like they tried to "fix" the stem height on them by grinding them, as stated above, they just hacked 'em away on the wheel & burned the tips. They're ruined, the temper has left the building.
3) Don't get any pushrods until the valves/seats are fixed correctly.
4) Sorry You've got to deal with this, but Ya' do.

 

[toolmanmike]

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

 

[PRH]

As an example on how mix-n-matching brands can lead to tip height issues…….
Just noting the OAL for 1.60 ex valves:

5.020” Milodon
4.970” Manley
4.970” MP
5.006” SBI stock replacement
5.000” SI Port Flow
4.970” Ferrea 6000

 

[dibbons]

Update: i have two sets of factory adjustable 273 rocker arms/shafts both reconditioned with bushing inserts. One set is "virgin" so to speak (no signs of grinding for spring interference problems). The other set shows signs of some (not all) rockers having been ground down slightly to improve valve spring/retainer clearance problems by a previous owner.

When the virgin rocker set was installed, one rocker was definitely touching a valve spring. When the "modified/butchered"" set was installed, I was able to experiment by switching rocker arm locations on the shaft here and there until none of the rocker arms made contact with the springs. Of course, clearance is pretty tight all over, some with less clearance than others. And the funny thing is that some of the rockers with the most clearance have no evidence of grinding mods. It seems the original casting of the rockers was not an exact science.

So I called Mike at B3 Racing Engines who coincidentally has been following this thread. I asked if rocker shaft shims would help alleviate the small clearance between the new stock 340 valve springs and rocker arms? He advised against that, citing that may very well upset geometry. He suggested looking for springs with a smaller outside diameter.

To get an idea of the current geometry, I placed a little dab of Lubriplate white grease on the valve stem tips and tapped the valve with the rocker arms. Of course, this is just with the valve closed. The pattern looks to be this: the rocker arm tip contacts the valve just a hair back from the center of the rocker arm tip. On the valve, the contact point looks to be just a hair toward the engine centerline, but pretty close to the center of the tip. (valve lift apparently will be .441/.472). I don't see any big problem with geometry at the moment.

 

[replicaracer43]

That is absolutely NO indication of correct geometry!

 

[Killer6]

Update: i have two sets of factory adjustable 273 rocker arms/shafts both reconditioned with bushing inserts. One set is "virgin" so to speak (no signs of grinding for spring interference problems). The other set shows signs of some (not all) rockers having been ground down slightly to improve valve spring/retainer clearance problems by a previous owner.

When the virgin rocker set was installed, one rocker was definitely touching a valve spring. When the "modified/butchered"" set was installed, I was able to experiment by switching rocker arm locations on the shaft here and there until none of the rocker arms made contact with the springs. Of course, clearance is pretty tight all over, some with less clearance than others. And the funny thing is that some of the rockers with the most clearance have no evidence of grinding mods. It seems the original casting of the rockers was not an exact science.

So I called Mike at B3 Racing Engines who coincidentally has been following this thread. I asked if rocker shaft shims would help alleviate the small clearance between the new stock 340 valve springs and rocker arms? He advised against that, citing that may very well upset geometry. He suggested looking for springs with a smaller outside diameter.

To get an idea of the current geometry, I placed a little dab of Lubriplate white grease on the valve stem tips and tapped the valve with the rocker arms. Of course, this is just with the valve closed. The pattern looks to be this: the rocker arm tip contacts the valve just a hair back from the center of the rocker arm tip. On the valve, the contact point looks to be just a hair toward the engine centerline, but pretty close to the center of the tip. (valve lift apparently will be .441/.472). I don't see any big problem with geometry at the moment.

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Mopars locate the springs on the ID, You'll most likely need to machine the spring seats in the head to fit them, and change retainers as well. It won't hurt those rockers one bit to clearance them for those springs, but You still have an installed height issue, if You're not gonna fix the valve issue. Valves are listed in overall length, some exhaust valves have thicker margins than others, but the retainer groove to seat-face distance is the same....so just looking at listings isn't enough.