Sealed Power HT817R Lifter Question

[zarfnober]

I have a set of these from the way back machine, is anyone using these on a street car? Specs show adjusting cold to zero lash, and when warmed up, .001 - .002 lash, and if noticeable ticking, turn down only until noise disappears. These are "anti-pump", but can these be adjusted like regular hydraulic lifters? New TB30 cam going into rebuild, and I really don't want to be re-adjusting lifters. Thanks!

Rocco
65 Turbo EFI Corsa

[vairmech]

Those may be a bit noisy no matter what adjustment you use if they are the fast leakdown also.
It sounds like they are using the tiny lash as the "anti" pump up feature. You can do the same with any lifter but then again I'll say that all of that is not needed because I run a full turn down and rev to 7000 rpm and my lifters don't pump up. I run anywhere from 90 to 115# spring pressure.

[zarfnober]

email sent Ken

[66vairguy]

Those may be a bit noisy no matter what adjustment you use if they are the fast leakdown also.
It sounds like they are using the tiny lash as the "anti" pump up feature. You can do the same with any lifter but then again I'll say that all of that is not needed because I run a full turn down and rev to 7000 rpm and my lifters don't pump up. I run anywhere from 90 to 115# spring pressure.

Agree with Ken. At one time the lifter "pump up" problem was blamed on the hydraulic lifter design. The "fast bleed down" lifter design was meant to allow the lifter to quickly reset after pumping up. These lifters tended to be noisy on startup and sometimes at low RPM. When younger I bought into this well meaning misinformation about hydraulic lifters and read about the noise issue with the "racing" fast bleed down lifters.

Lifters pumped up when the valve spring tension was not adequate to close the valve at high RPM (called valve float) due to valve train inertia. The lifter simply did it's job and extended to fill the gap, then it took awhile to bleed back down and the valve would not close for awhile - hence the fast bleed down design. Eventually light weight valve train components, refined cam profiles, and stronger valve springs solved the issue.

Of course higher valve spring tension can be a problem during camshaft brake in. Back in the 60's Pontiac shipped their High Output V8's with a box of high tension springs in the TRUNK. The engine was equipped with a lower tension valve spring for engine break-in.There was a BIG cardboard tag attached to the dash board that warned not to exceed a low RPM (I forgot the number) until the breaking mileage was completed. Then you had to go to the dealer to get the high tension valve springs installed. Of course these engines only went to racers, but to be legal for racing they had to be available to any buyer - hence the tag and instructions to return to the dealer.

At one time a performance car magazine had an article about installing a flat tappet hot cam and lifters from a well known manufacture with high tension valve springs in a big block Chevy engine. They used break in lube and did the adjustments properly. Upon startup the engine ran fine for a few minutes then started to run rougher. Upon examination a couple cam lobes were "wiped out", severe wear! Well ---- the article pointed the finger at the cam manufacture's lousy product. The next month the article reappeared with a humble apology to the cam manufacturer. Seems the magazine guys did not read the instructions to BREAK-IN THE CAM AND LIFTERS WITH LOW TENSION VALVE SPRINGS AND NOT EXCEED A SPECIFIED RPM. They repeated the process with low tension valve springs and then after cam break-in they installed the higher tension valve springs and went racing without issue.