I finally got the motor back together Monday (Labor Day was a good day to labor). I fired her off last night for a heat cycle and to check for leaks since most everything was disconnected during this process. I ended up going with the Comp stainless roller rockers and bought new pushrods after checking many many different sizes. I want to make sure everything is just right given my previous problems.

When putting the valve train back together I set the cold lash to the lash settings on my cam card knowing this would be off when hot but wanted to get things in there and parts mated up before finalizing. I am little leery after my valve train drama, so I want to get a second opinion on the valve lash setting given the propensity for this motor to trash the valve train. The valve train was more loud than normal, but I realize it is looser than normal too. I am now read to warm her up and set the final valve lash, or should I drive it a day or so before doing this?

My cam card says to us .016 .018 valve lash. That is what I set it to cold. From reading this means that when warm, it is more like +.006 given that this is an iron block with aluminum heads. Is is best to warm the motor and then set valve lash or just set the cold lash to -.006? I have also read that with a normal ramp, you can go +.004 or -.008 on the lash. Given that my motor like to eat the valve train, should I decrease the hot lash to say .014 .016?

On another note, when reinstalling the intake, I noticed the bolts continue to move before hitting torque mark. In other words, the torque wrench hits 18#, then on all bolts. If I go back through threm, they will turn a little more before hitting 18#. I used ARP moly lube. Is this normal? Should I keep going through them until they stop moving at 18#? I really do not want leaks after having this thing all apart and all over the garage for the past 3 months. (kids, wives, and sleep really hinder project progress).

 

no idea about the valve lash, but having to re-tourque the intake bolts a hundred times is normal.
You set them in the torque order to your rating and when you have all of them done the intake will have dropped slightly which causes the bolts to get loose again
I have to do it about 4 times all round to get to a state where they don't turn anymore before reaching final torque. every V8 intake seems to be like that because of it's shape

 

Thx Kalli. Good to know. Since I have heat cycled it, I will go back through the intake bolts again and again.

Oh, I guess I should have said this is a solid roller lifter and roller rocker setup.

 

You need .018" hot. Since the engine runs hot (obvious, but I had to say it) that's when the lash needs to be correct. If you run .006" hot, you'll smoke your valves. Once you get used to it, you can do all 16 in under an hour.

 

I meant I read if you set the lash cold at .018, when it is hot it will be .018+.006 which is .024 due to heat expansion and oil thinning etc. So if you want to set the lash cold and want the hot lash to be .018, then you should set the cold lash to about .018-.006 which is .012. Is there any truth to that? If not, I will just bring it up to temp and burn my fingers .

The second part to my question is should I deviate from the factory lash specs to help my parts out?

 

Deviating will damage the valves and rockers, not help them.

 

urban, i've been out of the loop for awhile..... what happened to your motor this time? i remember trashing valvetrain before and you going to lash caps and such - did it happen AGAIN? what is your new setup? valve brand/series, lash or no lash caps, spring pressures, cam lift? I've heard the beehive springs are more stable and require less pressures than normal springs which could help your situation.

about your questions....

a) after heat cycles i would certainly recheck intake torque, but let it cool down before doing it because thats when you should have that spec (and if i remember its actually 15-18 for a 5/16 bolt)

b) i always thought as things got warm and expanded (valves and pushrods, but especially the exhaust valve) the gap closes not opens. .016-.018 seems like alot to me, most solid lift motors i've messed with (which were stock) always seemed to be in the .010-.012 range.

usually the exhaust needs another .002-.004 clearance than the intake. if they are too tight you'll burn a valve, but if they are too loose you'll be beating the sh*t out of your valvetrain and it will also be loud as all hell.

if your cam card is calling for .016-.018 i'd go .016 intake and .018 exhaust. let it get nice and hot, rip a cover off, and check where your at - then adjust accordingly.

 

77, I had a massive rocker failure (10 out of 16 failed in someway). It looks like the steel cap that the pushrod sits in failed on most everyone and the snap rings on the roller bearings failed on half of them. There was no excessive noise, so I assume the lash was right. I basically tore the motor apart, cleaned it out, and put new pushrods and stainless rockers in. The lash caps and valves did fine, but the rockers not so much. I did not personally set the lash the last time, but my friend who did it said it was .14 .16. The card calls for .16 .18, so that is where I started cold this time. It is louder than it was, so I guess the hot lash is more like .22 .24 right now. Hopefully this weekend I can set the hot lash. I wanted to get a second opinion on where the lash should be. It sounds like I need to follow the card directions.

 

i'd follow card directions as well. if anything goes wrong everyone will tell you: "why did you do it different from what the manufacturer is saying". not worth it ;-)

 

i'd run them a hair tighter than that - and i still thought the gap closes when it gets hot not opens.

btw, what kinda rockers did you have on there before?