Just got back from the local machinist,and as usual,he's changed my mind.Was planning a solid cam,and now have decided to stay with a hydraulic. Also he recommended break in with 85 lb springs and some different moly lube than Comp supplies with their cams along with the 1.50 rockers. He's an old timer that used to run at the local track,and I believe he's forgotten more about engine building than I will ever know.

Also mentioned staying with the 1.50 rockers as a safety net against valve spring breakage.He's run at the track a 400 smallblock turning 9200 rpms and in the 10's. I think I'll follow his lead.

 

need more info , what lube, which cam you going with ??

 

Please don't take this as an insult.... but you aren't adjusting the rockers using the "twist between the fingers" method are you?

I have repaired many engines that were blown due to this method of rocker adjustment.

 

The cam I decided to go with is Comp's XE-294 flat tappet hydraulic. I looked at solids and more guys than not told me the "newer hydraulics" are as strong as the solids,and there's no need to lash them.I'm also going with 1.60 roller rockers and moly pushrods with the .080 thick wall to try to eliminate breakage.Not sure of the break in lube,I think I saw a can of some ARP lube on his bench.He did check my springs and showed me over 340lbs/in. at my expected .560 lift. Not a problem he said,but the rockers will have to be rollers.

The "method" I use, and have for over twenty years is the twist the pushrod while tightening the adjuster nut method.Once the tension begins(you can tell)I tighten the adjuster nut 1/2 turn.This 406 is running fairly stiff springs and I do tend to wind it up once in a while,so I'm not surprized at a few broken parts now and again.

 

"The "method" I use, and have for over twenty years is the twist the pushrod while tightening the adjuster nut method.Once the tension begins(you can tell)I tighten the adjuster nut 1/2 turn."
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Well... okay then. You do realize that once the tension begins, you are already past zero lash? Once the plunger starts to move, you are already past zero lash. Thrown a lot of pistons with holes in the top, broken valves, and bent pushrods in the trash bin because of this method. Best of luck with it. You're a better man than I.

 

I hate to say it, but I would get some second opinions. I'm just a skeptical person. I don't agree with you statement about expecting hots rods to break and bend parts. There are really only two ways to hurt the valve train. Improper clearances and Valve float. Clearances includes valve adjustment and coil bind. Valve float is caused by to much weight for the existing springs as a function of rpm.

Many years ago racers used low ratio rocker arms. But as valve lift grew the cut off point came when they didn't have enough rod base to cam clearance. So if you can't make the cam any bigger you had to run higher ratio rockers. Small blocks that spin 9000 rpm often use valve lifts in the .800 inch range + or - .050. Your not going to reliably do that with less than 1.7 ratio rockers


I ran H-flat cams to 7000+ rpm for years and the worst problem I ever had was an occasional worn tip on the push rods just around the center hole. I also never did the lightweight breakin spring trick and I ran 125-130# spring seat pressures. Just 20 minutes at 2500 and I never have had a flat cam.

Just one word of advice - throw away the spring caps and rotators shown in your motor picture! They are big heavy junk that add to cam train failure. Clear back in the 70's when I was rebuilding my first motors that was the first thing you threw away and replaced with lighter Chromoly retainers. It's the best $50 bucks that you spend on the valve train. Lighter is better and the spring caps defeat the oil cooling of the springs.

 

The springs shown here are junkyard parts the machinist put on just for cam break in.I'll be putting on the AFR springs after break in.I still need to check the geometry out and order the correct length pushrods.In fact the tax refund hasn't arrived yet,so I haven't even baught the cam or rockers....... .Any last words of advice?All I'm looking for is 6500 rpms give or take a few,and rock solid reliability.Last cam was close,but the pushrod thing got me started.

 

Use the best chain that you can afford. I use the Crane billet sets, I've been so impressed with it. I ran the same timing set on three different cams and the chain was still so tight that it was hard to install.

My new motor got one also. I used to run torrington barings between the block and cam gear. This last setup was a bronze shim.

Soak the H-flat lifters in oil for a day before installing them. I would also pump un the plunger a few times on each while they are submerged to get any air bubbles out. When your adding oil to the motor before running a primmer don't add the last quart. Just before you fire the motor take the last quart and fill every rocker arm all the way around and they snug on the valve covers.

You have to do the 20 minutes. If your motor starts to get hot because it's new and stiff. Shut it down and let it cool off, just keep track of the total minutes at 2500 rpm. I had a dragster motor once without a cooling system and we could only run it about 1-2 minutes at a time before shut off