Valve height install ?
 

I am doing the springs on my 500 efi's, and am using comp 929-16 springs. Can someone tell me the proper valve install height? Thanks in advance....Rick

I used the Comp 929's on my carbed HP500 the specs were:

Installed height 150 lbs. @ 1.880"
Open 434 lbs. @ 1.230"
Rate 437 lbs.
Coil Bind @ 1.180"

Hope this helps!

Dave

919,
I might be wrong, but I dont think the 929 springs will go on the 500 heads without some machining. The small inner spring will hit the valve guide step, unless the heads have been machined for double springs already. Are you using Comps retainers with them ?

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Yes i got the part #'s off another thread.... comp. 929-16, comp. 741-16 retainers and locks, 612-16 keppers, and 505-16 seals...... i never read anything about machining, is this going to be necessary?

It was also my understanding that the 929's could be used as a replacement spring when servicing the HP500EFI heads. I was unaware of any machine work necessary to install them.

That was my understading also Bubble, i hope it's not the case.....

919,
I am at home answering this so I cant be certain, the 929 springs measure .754 id so they might be ok. Just make sure that the both the inner and the outer spring sit on the same surface on the head. If the inner spring hits the step on the head where the valve guide is, it will not work. Also, I am fairly sure you need to use Comp's retainers but ..... without a stock retainer to look at and measure on the spring tester, I cannot say for sure. I have a set of stock 500 springs and retainers at the shop, and probably the correct Comp retainer too, but they are not doing me any good sitting here at home :( Make sure that both the inner and outer spring fit thier respective steps on the retainer correctly. Also, if you are not using a Comp retainer, you should measure installed hgt then check the spring pressure with the retainer you plan on using. Comp Cams loves to list parts in thier catalog as direct replacements but I have found that about 75% of the time it is not as easy as that :(

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

I have the comp 929 with the comp cams matching retainers and keepers with no problems.They set up at Installed height 155 lbs. @ 1.880" 120 plus hours

Thanks Bill, job was done today, i used all new comp components. Everything went well. Thanks for all the replies.

I hope you freshened up your roller lifters while it was apart. GM makes a new (and supposedly stronger) roller lifter for these motors now. They are advertised for use in the 572 motors, but have identical dimentions as the standard 502 lifters. Word has it that the standard 502 lifters are breaking the shaft for the roller at about 200 hours with the spring pressures that we're using with the 929 comp cams springs. I only know of one guy who lost a motor due to the lifter breaking....but I hear there are more.

Also did you notice that Mercury removes the small tensioning spring on the valve seal for the exhuast valves. This will allow a little more oil for lube and cooling.

I did notice it and did the same thing. I had no broken springs, it appeared that they may have been changed once already. Without being able to be sure, or know when and if they were done, i did them again......