I just put a new cam and lifters in my 68 firebird 350.
Question about setting the pushrods. I imagine is would be best to adjus/set the rockers them while I have everything open. I was thinking it would be best to set each pushrod/rocker when the cam lobe at the very top of its rotation, where the rocker arm pushes the valve all the way down. If I set it at this point with no slack wont that be the best way to set them or am I wrong here, maybe they should be set when they are at their lowest point, lifter all the way down.
Please provide some guidance. This is my first cam/lifter job. I do NOT want to screw it up. I prefer to set it all before I put the intake manifold back on.
If things aren't stock, you need to be careful and do it correctly. First you need locknuts. You can google and find a procedure for rotating the crank a certain way and adjusting certain rockers. I do it the hard but simple way.
Find TDC for cyl 1. Mark the balancer at 3 additional 90 deg spots. Since both valves are closed when the particular piston fires, you can adjust the intake and exhaust for that piston. First adjust cyl#1 valves. Then rotate the crank to the next 90 deg spot and adjust the #8 cylinder, 90 more degrees and adjust #4, etc. Firing order is 18436572.
To adjust the lifter, back off the nut until the pushrod is loose and can wiggle up and down. Wiggle the rod up and down as you tighten the nut until you have just removed the slop. Then give it 1/8 to 1/4 more turn and lock it. I use polylocks with the setscrew. That 1/8 to 1/4 rotation is enough to lock the set screw as you turn the nut and setscrew at the same time.
Bob's right, if the heads have been shaved and/or the block decked, head gaskets not same thickness as original, valve seats reground, different rockers and/or pushrods, any of these or a combination of these, the factory procedure of torquing the nuts to 20 lbs does NOT apply anymore. You need to go with an adjustable set-up and do like Bob says.
Yes 20 pounds torque on the ball retaining nut, no other adjustments. Make sure you use assembly lube on the cam and lifters. The rods and rockers should go back in their original positions with the top of the rod mating to the same rocker it was mated to before you disassembled. Use a good quality break-in oil and follow proper break in procedure. Flat tappet camshafts need proper oil and break in. Many new cam failures have been attributed to oil and break in. I'm not entirely convinced there wasn't a bad batch of cams produced as well but nevertheless you need a good oil for break-in. Most important, keep everything clean. Just my opinion I'm not an expert.
Oh yeah, a tip on keeping your rocker covers from leaking and still be able to remove when needed. I glued the gasket to the cover, gasket cement or rtv silicon, then with the head side of the gasket clean installed on clean heads and lightly tightened the rocker cover bolts. After the glue dried, about 24 hours, I removed the covers and spread a light, thin layer of silicon onto the bottom of the gasket and let it air dry for another day. Now one can install the cover and the sealant does not stick to the head upon removal. I had to remove my covers five times trying to adjust the the rockers on a full roller valve train. Finally I sent the lifters back and got a new set, adjusted them once. Still no leaks from the covers.
X2 Also helps to prime the oil system and get pressure and oil to the top of the engine before firing up. Also set the timing as quickly as you can when you first fire up and break in the cam. It helps to have another set of hands when trying to do this on the first fire up.
Thank you all. I am so stoked to get the help on this. What is the procedure to prime the oil system, start it with the distributor wires removed so it wont fire? If so how long do you recommend to crank it over to fully prime everything? I added a bottle of COMP CAMS 159 12 OZ ENGINE BREAK-IN ZINC ZDDP OIL ADDITIVE LUBE to the oil and lathered the cam and bottom of the lifters with break in lube.
Since I have your ear: I bought a HEI distributor and a new old stock points distributor before this work because I thought to was the ignition system causing the carb to pop when giving it gas then I thought it was the timing chain so new gears and chain but I was wrong obviously, it was a rounded cam lobe. What are your thoughts on HEI vs a points ignition? If I keep the points ignition I am installing a point eliminator kit from Accel part#2010 which I bought already and I also have ab Accel Super Stack performance Coil part#8140. I also bought new 8.5mm Spark Plug Wires for the points ignition.
One more thing: since I don't have locking rocker arm nuts on my rockers should I buy them or are the stock nuts ok? 7/16 locking rock arm nuts I think for $17 better safe than sorry correct? And are they 7/16?
I have an old distributor that I modified that I use to spin the oil pump drive using a 1/2" drill. The factory rocker arm nuts that you torque down on the bottle neck studs are different at the bottom than regular type locking nuts. So you can't just use any nut and torque it down. Most of the time a HEI distributor is a tight squeeze against the firewall on a first gen. There is nothing wrong with the factory points distributor on a car but just like every other parts produced today the quality of points can be a cap shoot. I have done electronic conversion on factory distributors that also worked fine. Remember if you are upgrading to electronic ignition to have a full 12v to power the coil.
On the distributor I cut all the teeth off the distributor gear and cut the top plate off the shift and welded on a piece of steel to extend the shift so I can attach to my drill. I'll try and get pictures today. Those locking nuts won't work unless you have 7/16" diameter rocker studs. I would also be cautious on the offshore parts. I have seen quite a few poly locks that cracked and split right in half.
If you're doing the stock rocker nuts with 20 ft-lbs, I would check it carefully. Wiggle the push rod up and down while you snug up the nut to make sure you are slightly compressing the lifter and all the wiggle is gone with the nut snug.
I found a full set of newer pushrods and those locking nuts at a car show swap meet this weekend. $10
I also bought a MSD ignition box that came with a MSD blaster 2 coil attached. I can set it up for points I guess or HEI but after taking with a lot of people I am convinced HEI is the way to go. My old wires for my points system wont work with the HEI ignition correct? What wires do you recommend if I need to change them.
Also Do I need new spark plugs? If so which do you recommend?
Looking for ward to that pic of the modified distributor big chief, I am definitely doing that to my old distributor. Its original, do you think its a mistake to destroy it? Its already beat up, I had to chizzle off the base to get it out
I used Mr. Gasket poly-locks on several Pontiac engines, with bottleneck studs, street and race. I tried some of the sbc 3/8 nuts but found that there was always one or 2 in a set that would back off.
I BOUGHT SOM4E LOCKING ROCKER ARM BOLTS WITH THE ALLEN KEY LOCKS. wHEN i GO TO TORQUE THEM DOWN i CANT GET THEM TO TPORQUE TO THE 20LBS WITHOUT COMPRESSING ALL CYCLINDERS.
THESE ARE THE LOCKING NUTS i BOUGHT: Pioneer # S1010 SBC 262-400 Chevy 3/8" Stud Poly Locks/Rocker Arms Nuts http://www.ebay.com/itm/Pioneer-S1010-SBC-262-400-Chevy-3-8-Stud-Poly-Locks-Rocker-Arms-Nuts-/161595009928?hash=item259fd02b88:g:C6MAAOSwqu9U2NjE&vxp=mtr
Guys i dont want ti hijack this thread but how about adjusting rockers when you have polylocks, cam and lifters and stock length p/rods . The cam was changed out about 1000 miles ago. I have just replaced the heads that came with 1.5 roller rockers, new valves and double springs and bought new hardened p/rods
Could i adjust to 20lb also or is it not that easy ?
To adjust turn over till the lifter is on the base of the cam "where the cam lobe has no ramp" start tightening the poly lock to take up all the slack. Tighten slowly till you can barely spin the pushrod with the tips of your finger. Then go 1/2 turn on the poly lock. With the wrench holding poly lock tighten down the set screw.
You've changed the heads, and the rockers from stock to roller. Check the pushrod lengths. The roller tip must stay away from the edge of the valve stem, a short pushrod will have the roller near one edge and a long pushrod will have the tip near the opposite edge. Not a big deal with stock rockers but with roller one wants the rollers to be as close to the center of the top of the valve stem as possible.
Jeff, I missed a page of posts. I'm not an expert, but my advice is, if you are using stock stamped steel rockers use the stock rocker nuts. Unless you've made big changes from stock that is all you need. Adjusting to 20 pounds torque sets the preload on a stock engine, You could reset then after you get the engine running by backing off the nut until the lifters clatter then tightening until quiet, but that is a rather messy job even with a rocker cover with the top cut off. You said you changed the cam on your stock engine, you didn't re-valve with longer or shorter valves, or make any other large swings from stock, what you had before you disassembled will work now. You could put in BBC screw-in rocker studs and use a polylock, but I wouldn't Just my opinion, I'm not an expert. I use a piece of 1/8 rod with one end flattened to fit the oil pump and hand drill to pre-oil. Keep it running until oil comes out all the pushrods and you maintain good pressure.
Also sometimes when priming the system you have to roll the engine 90* ,after getting oil through the rockers, to get oil through the rest of them. Might even have to turn it a couple of times for the right passages to line up.
