Valve lash & pre load

[Ralph Cali]

So I have a date coded 72 440 block stroked out to 522 by a professional engine builder and extremely happy with the results.
Its got a mild cam something like a 440 sixpack cam and its basically a street car - no racing.
It has edelbrock alum heads performer RPM.
See the attached photo for the drivetrain.
It has a hydraulic flat tappet cam and puts out between 480 & 500 HP

Looking to understand how to set the valve lash & preload

From what I can understand its zero lash and 1/2 turn preload, it sounds like a mechanical cam at this point with only about 3000 miles on it. So I would like to check it but do not have any knowledge here.

Any advise would be helpful.

Thanks Ralph

 

[lewtot184]

it would set preload at .060" to start out. that would be 1 1/2 turns in from zero lash.

 

[sputnik 440]

You will end up with about 1 1/2 turns...agreed. I would plan on setting them with a warmed up engine. Drive it for 20 minutes and check the setting again. I usually fined one or two that need to be reset. If you had the valve train worked on, I'd check them again after a couple hundred miles. Funny that those hydraulic lifters want to settle in and new pushrods and lifters want to do the same. This might sound like overkill, but with a new valve train I think it is worth the extra time.

 

[lewtot184]

factory magnum/6pak cams hd long closing ramps that kept the valve train quiet. modern aftermarket camshafts don't have those long ramps and they can produce a little clatter.

 

[Garys1969RR]

As I understand it, to get to zero lash, you set the cyl you are adjusting to TDC on the firing stroke. That way both valves are closed and the lifter is on the base circle of the cam.Then you back the adjuster off until the plunger is at the top of it's travel. I think you know this when the pushrods can be spun with your fingers. Getting to zero pre load seems to be the hardest part. From there you just turn the adjuster in the desired number of turns. Apparently a half turn gets you .020 of pre load. So if that's all your doing, it prob isn't enough. Try the 1 1/2 turns suggested.

 

[Garys1969RR]

I think it's easier to set valve lash with a solid lifter cam, then you don't have to determine where zero pre load is. I just did mine today, since I just upgraded my 440 with some Eddy Perf RPM heads and Crane Gold Roller Rockers.

 

[dieseldazzle]

I use EOIC method. Been dosing it that way for years on everything from Subaru engine making 80 horsepower to single turbo 331 ford making 960 horsepower. Can't go wrong imho

 

[Ralph Cali]

Thanks to all

Appreciate it

Ralph

 

[miller]

Yesterday I killed some time, researching hydraulic tappets. The few that made 'em, and what was out there these days, plus several sites talking about them. Everyone of them agreed on one thing (for what it's worth)...
Pre-load range were all given .020 - .060. Of course, depends on the tappets used, since a few give different settings.

Just me, I guess, but I've always gone for in the middle of the range.

 

[IQ52]

Some cams and lifters just aren't designed to be quiet. Most of the recommendations here will get you close. It is important to know what lifters you really have. These for instance want almost no preload.

http://www.compcams.com/Instructions/Files/COMP4-115.pdf

 

[lewtot184]

Some cams and lifters just aren't designed to be quiet. Most of the recommendations here will get you close. It is important to know what lifters you really have. These for instance want almost no preload.

http://www.compcams.com/Instructions/Files/COMP4-115.pdf

this is why i measure plunger travel first and then make a preload decision.

 

[moper]

It's most critical to get the manufacturer's recommendation. Better it be to spec and noisy than quiet.