Crappy head work
Thread Starter
|
Lead Driver
Joined: Mar 2008
Posts: 7,165
Likes: 375
From: Near Los Angeles
Crappy head work
I think that with hp work the motto has to be: Trust but verify.
I had a shop install isky v.springs, p&p the head, deck it, install sbc oversize valves, hardened seats, guides, etc. Since day one it has sounded diesel-ly. I just thought it normal for a highly modded 300.
But finally it got to be too much, and I broke down the head. The shop did not even use the Isky hole saw to lower the area where the spring sits so that proper installed height could be acheived! The spring was too short, creating too much seat psi, forcing the p.rod into the lifters, so the lifter could not compensate by pumping up and keeping the p.rod securely pressed against the rocker. Things were slapping.
What did I do? I took out the inside spring, measured the psi at installed height. I now had 118 psi at the seat, instead of 150 psi. Minimum for a hp 300 is about 110. 150 psi at the seat for a little hydraulic cam...wow!
Now it runs so smooth and quiet that I laugh when I pull up to a light. I'm still wondering how to deal with machine shop.
I had a shop install isky v.springs, p&p the head, deck it, install sbc oversize valves, hardened seats, guides, etc. Since day one it has sounded diesel-ly. I just thought it normal for a highly modded 300.
But finally it got to be too much, and I broke down the head. The shop did not even use the Isky hole saw to lower the area where the spring sits so that proper installed height could be acheived! The spring was too short, creating too much seat psi, forcing the p.rod into the lifters, so the lifter could not compensate by pumping up and keeping the p.rod securely pressed against the rocker. Things were slapping.
What did I do? I took out the inside spring, measured the psi at installed height. I now had 118 psi at the seat, instead of 150 psi. Minimum for a hp 300 is about 110. 150 psi at the seat for a little hydraulic cam...wow!
Now it runs so smooth and quiet that I laugh when I pull up to a light. I'm still wondering how to deal with machine shop.
Post Fiend
Joined: Jan 2006
Posts: 5,037
Likes: 9
From: Kasson, Minnesota
Man that sucks that a machine shop did that crappy of work. Best thing you can do is go back and tell them what you told us and see what they say. Probably won't matter, but at least you can let them know they suck. Good to hear you got em working better though.
Elder User
Joined: Apr 2003
Posts: 502
Likes: 0
Yeah, machinists can be funny. And of course, the stupid-uhh, its not a 350, jam it together.
I had a friend get a built 514, it blew up a few times, not from crappy parts, but from idiots not checking tolerances. Yet every blow tie came out perfect.
A very good reason I will be spending more money for something done right, even if shipping is killer. I actually talked to a local machinist regarding some head work, and his reply was: We don't, I drive a Honda. I walked out shaking my head.
I had a friend get a built 514, it blew up a few times, not from crappy parts, but from idiots not checking tolerances. Yet every blow tie came out perfect.
A very good reason I will be spending more money for something done right, even if shipping is killer. I actually talked to a local machinist regarding some head work, and his reply was: We don't, I drive a Honda. I walked out shaking my head.
Last edited by Thunderjet4x4; Mar 6, 2011 at 07:34 PM. Reason: add
Thread
Thread Starter
Forum
Replies
Last Post
F-250 restorer
Ford Inline Six, 200, 250, 4.9L / 300
6
Jan 15, 2011 03:06 PM
