How much clearance for HS 1.7 roller rockers?
03-22-2007, 07:15 AM
#1
How much clearance for HS 1.7 roller rockers? I've searched through over 200 threads and still can't find an answer. I am putting together my new engine right now. Got one of the heads on and I am checking the clearances on the harland rockers. The front one on the #1 cylinder has VERY minimal clearance between the back side where the pushrod is, and it may even be hitting the head. I can't even get a piece of paper between the head and the back of the rocker. I have roughly about .007" clearance on all the others tho. So it looks like I am going to have to break out the dremmel for that front one at least. Should I make more clearance for the others as well tho? It is a very tight fit in there. Exactly how much clearance should I have though? Should I massage the head to fit the rockers, or take material out of the rockers to fit the head? This really sucks! 
03-22-2007, 08:10 AM
#2
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i just took a hand file and knocked the sharp inside edge off the heads. it was more than enough to increase clearance significantly.
i found the inside edge of the valve cover gasket surface was pretty sharp, and consequently it filed off easily. in minutes i probably increased the clearance on the closest rocker to about 1mm
i found the inside edge of the valve cover gasket surface was pretty sharp, and consequently it filed off easily. in minutes i probably increased the clearance on the closest rocker to about 1mm
03-22-2007, 09:05 AM
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I've ran into that problem before twice myself...on my old setup (LS6 heads), I had to grind an area around #2 and #7 just to make sure they had enough clearance.
On the new 5.3s I put on a couple weeks ago, I ground a spot for each rocker with a Dremel tool. Figured since I had the heads off the car, I'd go ahead and do it and be sure they had enough clearance.
So far so good...nothing bad has happened...
On the new 5.3s I put on a couple weeks ago, I ground a spot for each rocker with a Dremel tool. Figured since I had the heads off the car, I'd go ahead and do it and be sure they had enough clearance.
So far so good...nothing bad has happened...
03-22-2007, 09:42 AM
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Originally Posted by ChevyChad
Thanks guys. I'll try smoothing out the casting flash first and see how it goes from there. I guess if this is the biggest issue on the build, I'll be happy.
Good luck on the build!
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03-22-2007, 11:25 AM
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Originally Posted by vettenuts
I assume you are taking material off the head and not the rocker.
03-22-2007, 11:25 AM
#9
Originally Posted by vettenuts
I assume you are taking material off the head and not the rocker.
03-22-2007, 01:01 PM
#12
Originally Posted by heavymetals
Why not just get a pair of 1/2 " spacers from JEG'S and quit screwing around? 
I ended up doing that after grinding the crap out of the valve covers.
I ended up doing that after grinding the crap out of the valve covers.
03-22-2007, 01:07 PM
#13
There is a special bit that you can get that will widen the pushrod hole so it doesn't rub or hit the side of the hole.
The geometry may change with different rockers and the rocker may sit lower on the pushrod end, ergo, it may hit the hole.
I had this problem also, and it wasn't a pushrod length problem.
Come to think of it I have run into all of them!
The geometry may change with different rockers and the rocker may sit lower on the pushrod end, ergo, it may hit the hole.
I had this problem also, and it wasn't a pushrod length problem.
Come to think of it I have run into all of them!
03-22-2007, 01:36 PM
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My main interference was between the rocker (area around PR seat on the rocker) and the valve cover rail...other than that, they were fine.
Last edited by marv; 03-22-2007 at 02:47 PM.
03-22-2007, 02:00 PM
#16
Originally Posted by ChevyChad
Patriot had already elongated the pushrod holes before they shipped them out to me. My problem is not with the pushrods interfering with the heads, it is with the rockers themselves about to hit the head.
I would recheck the geometry.
Are you sure you ain't missing a shim/plate underneath the rocker fulcrum point?
Something sounds amiss........
03-22-2007, 05:42 PM
#18
There are only two things that set that distance.
Valve height and fulcrum height.
Obviously, the angle of the pushrod end to fulcrum also, but given your rocker arms are fixed, that isn't going to change.
Are you sure the valve stems are the same length as stock?
What a drag, welcome to mod hell.
Valve height and fulcrum height.
Obviously, the angle of the pushrod end to fulcrum also, but given your rocker arms are fixed, that isn't going to change.
Are you sure the valve stems are the same length as stock?
What a drag, welcome to mod hell.
