Hydraulic Lifter question

Hi there, I installed and torqued the Rocker arm bolts in my 73 351 C. I did this when each cylinder was at TDC with the lifters being both at their lowest point. 15 of the 16 pushrods feel reasonably tight with no up and down movement or sideways. They sit right in the center of the rocker arm as was described. I checked preload on two and was within tolerances. However one pushrod seems rattley and not as tight as it should be. These are all brand new lifters. I am concerned about this, could this be normal? Maybe it will fill with oil or something after the engine starts? Any help is again appreciated!:huh:

ok i think i got what you need. when adjusting valves there is a sequence in which you adjust the valves. this information is from my 1971 motors book( good cheap investment tons of info )

turn crankshaft to the number 1 piston at tdc of compression stroke. with the piston in this position adjust the following valves to optain the clearances listed

no. 1 intake no. 4 exhaust

no. 1 exhaust no. 5 exhaust

no.2 exhaust no. 7 intake

no. 3 intake no. 8 intake

turn crankshaft to position no. 6 piston on tdc of the compression stroke

no. 2 intake no. 6 intake

no. 3 exhaust no. 6 exhaust

no. 4 intake no. 7 exhaust

no 5 intake no. 8 exhaust

you can also adjust the valves putting all the pistons one at a time at tdc but they have to be on the compression stroke. you might have a few that we not on compression. also make sure you are turning the engine over clockwise


valve lash .100 intake .200 exhaust

Putting each piston at TDC and then adjusting them there should get you straight. You should be able to just spin the pushrod, but no slack in them. If they are factory non adjustable pedestal monunt rockers, they should be torqued at 18-22 lbs/sq in.

It is quite easy to install a push rod upside down .

Putting each piston at TDC and then adjusting them there should get you straight. You should be able to just spin the pushrod, but no slack in them. If they are factory non adjustable pedestal monunt rockers, they should be torqued at 18-22 lbs/sq in.

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That is exactly what I did and yes, they are non-adjustable and 15 of the 16 are fine, tight but no play but this one renegade lifter that has the slack, I even took off the rocker arm again to make sure that it was seated properly and yes it seems fine.....

Please look for confirmation of the below suggestions:

Try swapping a rocker with a valve that is known good. If it fixes your problem, you have a bad rocker.

If this doesn't help, try swapping a push rod from one that is known good. If it fixes your problem, then you have a push rod length issue.

If the above suggestions don't work, then either your cam lobe is small, or your pedestal is tall.

+2 on you should be able to spin the push rods with your fingers. shouldn't take to much pressure to make them spin. the 351c did come with two different length push rods from the factory. when i built mine when i tore it apart it had one push rod with a odd length and the guy who rebuilt it before put shims to make up the difference.

Dilemma solved! I changed one of the new lifters from Summit I installed with the new cam and replaced it with an original from the car and guess what? It torqued fine and the pushrod is tight with NO rattling. I hope to start the engine tom orrow, if carb and intake install dont pose any problems!

Dilemma solved! I changed one of the new lifters from Summit I installed with the new cam and replaced it with an original from the car and guess what? It torqued fine and the pushrod is tight with NO rattling. I hope to start the engine tom orrow, if carb and intake install dont pose any problems!

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Good job, Shellbuyer. I know you're excited!

Not sure you would want to run with 1 old lifter?? The lifter is worn to the old cam and may cause the new cam lobe that it rides on to wear prematurely. I would probably get a hold of summit and get 1 new lifter. I know your probably itching to fire the motor but what 1 or 2 more days to save a cam lobe??? Just my thoughts. But good luck with it.

It is definitely not recommended to use an old lifter with a new cam.

The lifter is already "worn in" to the previous cam. You risk having a cam issue.

You might want to measure a couple of new lifters to compare with the "defective" one to see what you get. To prevent damage to the lifter during measuring, use feeler gages on the lifter surfaces, then subtract the feeler gage thicknesses to get a true measurement.

That is why you should always keep your old parts when rebuilding.

Great tech advise on this thread fellas!

What likely happened was whoever did the valve job did not get all the valve tip heights set equally, within .005". That causes all kinds of trouble with a nonadjustable valve train. I would go back through and check all of the lifters preload with a dial gauge on a magnetic stand so you know exactly what you have on each lifter. Lifter preload and valve train geometry is very important. If you get figures all over the place then your in a bad position