1966 Mustang 289 Engine Rebuilt but now having Valvetrain issues!

QKPony89 · 02-08-2007

I am rebuilding a 289 from a 1966 Conv mustang. I used Edelbrock's ready to run alum heads and Edelbrocks pushrods which are 6.805 long (Stock) along with the performer cam/lifter kit (Not too radical)
Attempted to reuse the stock rockers and bottomed them out to the torque settings. When attempting to fire the engine I noticed that there was no compression. I ran a bore scope in the # 1 cylinder and it seems like the intake valve never closes. I am sure they are all doing the same thing. What am I missing? I thought I had the non adjusting rocker set up. The cam says it requires zero lash.... Am I missing something? Do I need to convert to an adjusting rocker nut like the ARP set up? Any help would be great!!!! Thanks In advance!

**stlwagon** · 02-08-2007

Welcome... I'm going to move your thread to the Classic Mustang forum for greater visibility.

QKPony89 · 02-08-2007

Thanks for the quick sort for exposure!

meangreen92 · 02-09-2007

Maybe the lifters were dry when you torqued the rockers.

QKPony89 · 02-09-2007

I'm thinking of purchasing the motorsport roller rockers and installing them as directed. I'm betting the stock rockers are the problem. Any other thoughts?

The Greek · 02-10-2007

There could be the possibility for the rocker arms hitting the top of the valve spring retainer when using the stock rail type rockers . This could become a real problem if the rails hit the valve spring keepers and result in a dropped valve. The easiest solution, I believe, would be to go to a set of roller rockers with (very important) guide plates that attach under the rocker studs. The purpose for the rail rockers was a design change in the early heads, the push rod holes in the early heads were slotted to keep the push rod in position. The slots were changed around 1966 to round holes and the rockers went to the rail design to keep the push rod and rocker in position without the use of guide plates or the previously mentioned slotted holes. Cheaper way to go for Ford. The valves had a higher tip to allow the rails to clear.---Chuck

1qwk67 · 02-10-2007

Was there a shoulder at the bottom of the rocker arm stud. Should have been if they are non adjustable. You should be ableto look at your old head stud bolts to compare. If not you have adjustable rockers. Also you need to make sure your push rods are not to long.

QKPony89 · 02-10-2007

I think you guys have convinced me.... I'm going to get the roller rockers now... I looked at the old heads and did not see any sholder. The stud does have a small taper but I'm betting that is just the transission between the shank and the thread cut on the stud and not the landing your talking about. Also understand on the guideplates. The Edelbrock heads come with 5/16" pushrod guide plates, so I think I am in good shape there.

I'll let you guys know how I make out... This is a great source for help!
Thanks again
John

QKPony89 · 02-11-2007

Sure enough, the roller rockers fixed the problem. Runs great! Just need to find tune the timing and I think I am all set.
Thanks again!
Oh and BTW chuck, you were right you could see rub marks on the tops of spring keepers so clearly using the stock rockers is not a good idea.
John