galianoken

[Ken Kucille]

I've put in a Comp Cam in a 1965- 656 block and I'm having a hell of a time setting up the hydraulic lifter setting. To make it run somewhat properly, the valve lash setting now is only 1/16th down on the nut. If I try to set the lifter at the usual 3/4- 1 full turn, the valves are open and the engine obviously will not start. The cam specs are as follows:
Comp Cam # 48-000-5
Adv. is 275 int/exh
Dur.@.050 is 224 int/exh
lube sep-110.0
valve lift .526/.526
Is this the way they(Comp Cam) want me to set the lash or is this the wrong cam? Is there something wrong with my brand new hydraulic lifters? I did pre-load before firing her up.

 

[409newby]

I start mine with zero lash, then 1 full turn but some only need 1/2 turn

 

[mpris]

That number is just a core number isn't it? Did you have it ground to your specifications? When you say you preloaded before firing it up, exactly what method did you use to do that. If you really have hydraulic lifters, they should bleed down after you turn down the adjusting nut. They may open the valve as you adjust them down, but should bleed down to allow the valve to close.

Poocho

 

[Don Jacks]

For years now on hydraulics that I'm going to "rev',I will set them up at zero lash plus 1/4 turn.Have you checked your valvetrain geoimetry? It sounds like your pushrod length may be incorrect[too long].

 

[MRHP]

That's how I set them up too Don.

 

[Ken Kucille]

I've tried going down more than the 1/16th, but the engine starts to falter due to valves not closing. No I did not custom grind, this cam from Comp came off their shelf. I preloaded by pumping them up with oil on the bench before installing. I will have to check the push rods for the geometry. I thought that I had the right ones(intake /exhaust) in the correct holes. Even with the 1/16 turn down, the engine starts to" pop" around 2500.

 

[MRHP]

Is the valve train noisy?

 

[mpris]

Pumping up the lifters prior to installation is not recommended by any of the cam suppliers that I know of. This can lead to problems on initial cranking and trying to adjust the preload of the lifters properly.

From Comp Cams:
"It is not necessary to “pre-pump” hydraulic lifters full of engine oil prior to installation and valve
adjustment. It is actually undesirable to do so as the “pumped up” lifters will cause the valves
to open during the adjustment process, rather than positioning the lifter plunger in its operating
position as it is supposed to do. “Pre-soaking” hydraulic lifters in a bath of engine oil is a good
idea but not mandatory. Doing so ensures that the lifters are adequately lubricated on their outer
surfaces prior to installation. It may also result in a quieter engine start up as the oil in the bath
may displace some air from the lifter’s plunger reservoir. "
From Crane Cams:
"To adjust preload on hydraulic lifter camshafts with adjustable rocker arms, turn the engine in the normal direction of rotation until the exhaust lifter starts to move up, then adjust the intake valve to zero lash with no preload, then 1/2 to 1 turn more. Turn the engine over again until the intake opens completely and then is almost all the way back down. Now, set the exhaust valve to zero lash, then 1/2 to 1 turn more. Continue the above procedure for each cylinder until all valves are adjusted to the same amount of preload. This procedure will give you the correct lifter preload for any hydraulic lifter cam with adjustable rocker arms."
Did you get the entire kit from Comp. The cam, lifters, and springs? Are the springs set at the proper height and did you check for coil bind on the springs?
Poocho

 

[Ken Kucille]

With the lifters set at 1/16 down, there is no noise from the lifters or tappets. I will try what the Comp Cam article recommended. I will also check for push rod lengths, although I don't think that is the problem. Is there any chance that the lifters are in a loaded up state and not hydrauling as they should? Ken

 

[mpris]

If your push rods are correct, I would adjust the valves as above in the Crane article. Adjust to zero preload (where you can spin the push rod easily with your fingers) and go 1/2 turn more on all of the lifters. Let the engine set for an hour (lets the lifters bleed down if they were pumped to the top). Remove the coil wire and turn the engine over and see if you have good compression. If you do, put the coil wire back on and try to crank it. If the engine is running and you try to turn the adjusting screw down, you will probably get a miss on that cylinder until the lifter conforms to the adjustment. Hydraulic lifters only pump up on a running engine when the valve springs lose control of the rotating valve assembly, allowing the lifter to lose contact with the cam lobe. I feel sure if you give the lifters enough time after the above adjustment, they will bleed down and work corectly.

Poocho