I finally pulled the head to fix an external coolant leak. The previous owner removed the exhaust brake, but I'm not sure if the removed the H.D. exhaust springs, or left them in. What's the best way to identify them - thickness, height?

If they are the H.D springs, should I leve them in even though I dont have the exhaust brake. What are the pros and cons?

 

Best way to ID them is to remove one and compare to a stock valve spring. Thickness is not a good ID. Height on the other hand is. The 60#er is taller. By all means leave it be. A stiffer valve spring will prevent a valve from slapping a piston during high rpm ~3500+.

 

The problem is that I don't have a stock one to compare it to.

 

If the PO took the time to install 60# valve springs for an exhaust brake, he most likely only did the 6 exhaust springs, not both exhaust and intake springs. If it concerned you, you could remove both springs on one cylinder with that cylinder at TDC. Compare them side by side. 'Some' 60# valve springs have a white stripe painted on them. Before pulling anything, clean them off and look for paint. The old stock springs have paint, but it probly will be blue and or faded. The 60's would still be bright, somewhat.

Now looking for paint isn't the best indicator, because I bought a new cylinder head and all the exhaust springs had a white stripe down the side. But when I compared them to my 60#ers they were much shorter. Although the stripe wasn't the same as the Cummins 60#ers, more like a quality control swipe of paint etc.

 

I've stripped the head down in prepartion of having it milled/trued. The exhaust springs do have a white stripe, and are considerably taller than the intake springs. Maybe the machine shop that's going to so the work will measure the spring force, too. I think I'll have a 3-angle valve job done since it's apart and I'll be doing some mild porting.

 

The best way to identify the heavier springs is to put one side by side with the "stock" spings....the 60#'ers have a chubby/barrel like center wereas the stock units are basically just a tad narrower and the coils are the same from top to bottom.

pb...

 

The exhaust springs are somewhat barrel shapped and about 5/8" taller than the intake springs.

 

Sounds like what I said. Here is a link to a pic of stock vs. 60# valve spring: http://www.turbodieselregister.com/u...=18626&width=0

 

Wouldn't a heavy duty spring be considerably harder to compress than a stock intake spring? Put one on a bathroom scale and see how much weight it takes to compress it say halfway down. A 2x4 stuck under something would be a considerable aid in this if you don't have the right equipment.

Edwin

 

now there's a free and tool!!!

 

I've done this with a hydraulic press and a scale, a little more control this way.

 

Are the valve springs measured like suspension springs: 60lb springs compress 1" with 60 lbs of force applied?

Here's a pic of my springs, the tall one is the exhaust, the shorter is the intake:

 

Do the 60lb springs accelerate wear of the cam lobes?

Also, the valves won't hit the pistons at high RPM with weak springs, they bounce on the valve seat when they slam closed causing a momentary pressure loss in the cylinder. Also the valve seat will start to erode necessitating a valve job.

 

That's my concern...

My exhaust seats do look more worn than the intake, though I would kind of expect that.

 

Make sure the exhaust valves have not receeded any. Compare them on their seats with the intakes and make sure they are about the same. I'm not sure if Cummins uses Stellite hardened exhaust seats or not, but if they do, forget about this post.