Guys,
Is there a rule of thumb for valve spring seat pressure and what would be considered the max for an engine that had a max. rpm of 8000rpm?
I'm trying to find some answers to a very worn out cam in a very short time frame.
Dave

Did you use new lifters? Is it a new cam or a reground nissan cam? I know there are a lot of problems with the L-series valve train if you don't use the right parts together things wear out quickly due to the difference in the metals.

80/90lbs seat pressure,240/260lbs nose(open)pressure will handle 8000rpm.sounds like to much pressure or not run in correctly or lack of lobe/lifter radius not right.

It's on an A series. It was a reground used cam and refaced lifters. (I donated the core )

I'm with bige on the run-in time. Or how it was run-in.

The followers were resurfaced for a new cam that would not have done 10 hours work and did not perform to expectations.
A new cam was fitted and the engine was run for around 20 minutes at 2000rpm followers were not resurfaced for the new cam.
This cam would not have done 500kms and is completely worn out. What is of note is that some of the lifters appear to have been machined much more than others, almost to the point of being concave and the worst of the worn lobes correspond with these ones.
I originally thought that I may have a worn valve spring issue but they appear to be fine, in fact I think they have too much- 110lb seat pressure.
Dave

Sheesh that's scary stuff....completely worn.

Any pictures?

Well if the followers were not flat (and surface finished) to start with then they certainly would affect the profile of the lobes. The fact that they are now concave would indicate that they had also been contacting more surface area of the lobes (as the lobes began to wear down) so the wear process was magnified and intensified.

Pics would be helpful.

It is not recommend to use old lifters, even if they had only been used for 10 hours previously. The 20-minute run in procedure matches them to the previous cam.

Okay, seat pressure exhaust 110/ 275 and inlet 100/270 so it appears to be way too high.Interesting - a so called expert set them up in that head....

Holy Crap,

So called expert needs to give you a whopping refund mate.

Sounds like sabotage!! Hahaha.

Good luck with getting it all back together.