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1K views 9 replies 5 participants last post by  idoxlr8 
#1 ·
Pulled these lifters from a buddies Pontiac. Motor has approx 200 miles since build. Broken in with good oil and zddp additive. Run at varying RPM for 30 minutes. I have never seen a cam take so much off the bottom of a lifter. Cam is lobe doesn't show much damage other than chipping the sides of the lobes. I would have expected it to be completely rounded off to have removed that much material from the lifter.
Anybody ever seen this before? Know what the cause could be?:confused:

The motor is a stroked 496 Pontiac with Edelbrock RPM heads and a pretty big Hydraulic Flat tappet cam.


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#3 ·
Ouch .... that is by far the worst one I have seen yet :( Now he has all that metal to clean out of the engine :( The cam has to be done with for sure. Wonder if the spring combination on the heads is wrong, or something else in a bind in the valve train ? Edelbrocks heads usually do not come with a lot of valve spring though. Just looked at Edelbrocks site and it looks like they are good for .575 lift. How big was his cam ? Also, its hard to tell for sure but it looks like the springs are double springs. They have 130lbs seat pressure, thats a pretty good spring. Did he take the inners out for break in time ? Almost every cam manufacturer I know of tells you to remove the inner springs during break in.

Those are the types of questions I would be asking.
 
#4 ·
Ouch....I feel bad for your buddy. That's some serious wear! I recently broke-in my cam and so far so good. Lets see...good oil and additive, never let it idle, removed inner spring, EOIC valve adjustment, changed oil after break-in and continued to add supplement to oil. Goodluck!
 
#5 ·
Bill,

The cam lobe is worn but I have seen worse lobes(completely rounded). This one is no where close to that. Can the lifter/cam machine that much metal off of the bottom of the lifter? I am wondering if he got a couple of wrong lifters for this cam, they all came with the kit.
He does have Harland Sharp roller rockers, the springs that came with the cam kit where checked/set/installed on the heads. The springs a singles with just a flat dampner inside. He also checked valve to piston clearance in the build up.

I have never seen a lifter loose 1/8th of an inch before and am trying to figure out what happened to cause it.

Thanks
 
#6 ·
Tony,
Post some details and part numbers of the cam and springs. Pontiacs normally use a very short valve spring, if something else was used it might be coil binding at full lift ? It is very possible for the cam to wear that much off the bottom of the lifter :(
 
#7 ·
Bill,
Sorry for the Delay, It took him a few days to get back out to his shop (garage).

The cam that he had installed is a Lunati Voodoo cam grind number VD-PV8-276,
specs are .504I/.527E lift,
233I/241E duration @.050.
He did not change the springs out from the Edelbrock ones (Don't know why he has the Lunati ones for this cam).

Next question is how do the Edelbrock springs compare to the Lunati ones for this cam? (Lunati spring p/n 73949LUN, Spring Type:
Dual w/damper, Outside Diameter: 1.440 in.
Seat Load: 120 lbs @ 1.650 in.
Open Load: 265 lbs @ 1.250 in.
Coil Bind: 0.950 in.
Spring Rate: 363 lbs/in.)

Bigger Question:
He wants to switch to this Comp Cam HydRoller: XR288HR
.520I/.540E lift
236I/242E duration @ .050
And it calls for these springs
p/n: 995-16
O.D. of Outer Dia. 1, 1.437
I.D. of Outer Dia. 2, 1.073
I.D. of Outer Dia. 3, .697
Seat Load 115 @ 1.700
Open Load 336@ 1.150
Coil Bind 1.020
Rate (Lbs./In.) 402

Will the Edelbrock springs work or should he change them out?

Thanks for your patience and help!:beers:
 
#9 ·
Tony,
The Edelbrock springs appear to be a little more spring than the Lunati ones, but the main thing is the fact that they are a double spring and the inners should have been removed for breakin. As far as switching to the hydraulic roller goes, what you really need to do is pull the heads and have the spring setup checked before you order anything. You really need to know exactly what the existing spring pressures and installed hgts are first. Hydraulic rollers are a lot more forgiving than a flat tappet cam. You can generally run more closed and open pressures. The lifters are heavier so they usually need more pressure to keep them following the camshaft properly.

The Edelbrock springs might be ok, but what you really need to do is take the heads apart and check them. Also check for retainer to guide clearance etc.

By the way, I dont think you will be able to use the Comp Springs without changing something. Maybe just retainers or locks with more installed hgt, but once again you just have to check them :)
 
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