Who is running Pedastal Mount Roller Rockers?

[forkliftfixr]

Anyone running the pedastal mount roller rockers? What size shims did you end up using?

 

[OnyxCobra]

I am, and none. I'm pretty sure if you buy the correct length pushrods you don't need shims.

 

[forkliftfixr]

The problem I am running into is this.... GT40 heads, had them reworked with a 3 angle valve job and brand new Crane valve springs. When he did the heads he set everything up for the cam I am running and set the seat pressure on the valves, he had to shim the springs to get it correct. Competition Cams stock length pushrods and Crane 1.6 roller rockers. Heads are on, everything was set according to how Crane said to set up the rockers. Buttoned up the top end and went to fire it up.... Gave a couple of pops so I figured I could be 180 off on the timing. Pulled #1 plug and had my daughter bump the starter, I can not feel any type of compression whatsoever. I know the heads are torqed correctly, brand new head gaskets, brand new head bolts. The only thing I can think of is that there is the possibility that that the rockers are holding the valves open? Nothing was done to the bottom end at all, just the head swap. Unless someone has another idea I am leaning twords the rocker theory.

I am going to pull everything apart Monday and loosen the rockers to see if I get compression that way, if I dont then I guess I will have to pull the heads and try and figure out why the head gaskets wouldnt be sealing.

I am open to suggestions on things to check

 

[OnyxCobra]

did you install the rockers yourself?

 

[forkliftfixr]

yes, I installed the rollers myself

 

[OnyxCobra]

Well when you torqued them down did you notice the rockers pushing the valves open?

 

[forkliftfixr]

No I didnt, that is what has me confused at this no compression thing. I guess I am just shooting in the dark at the moment trying to figure the most obvious problem first, and the simplest to check.

 

[OnyxCobra]

try feeling for compression while turning the engine over by hand. You have more control over it that way.

 

[forkliftfixr]

believe me......... Tried it that way first! Got tired of turning and watched almost a complete rotation of the belt, then had my daughter bump the starter. I am going to throw a compression guage on it just to make sure though.

 

[OnyxCobra]

weird, don't know why you wouldn't have compression, did you check any other cylinders?

 

[LAFENATU]

Becareful when you torque them down...

Don't torque as much as the "stock" rockers...the fulcrums the pedestal mount sit on are not as strong....you'll crush it.

What rockers are they???

The Crane "cobra" 1.7's??

 

[forkliftfixr]

I just went and checked #1 and #2 so I had one from opposite banks..... NEITHER cylinder is showing compression on the guage. It has to be the rockers holding the valves open, I would be concerned if it was only on one bank as a possible head gasket problem, but with two different banks showing 0 in the compression guage....... Im really leaning twords the rockers now.

 

[OnyxCobra]

So your pushrods are too long?

 

[forkliftfixr]

They are the FRPP 1.6 roller rockers, pretty sure they are made by Crane though.

 

[forkliftfixr]

ONYX, I dont understand how the pushrods could be too long...... They are the stock length. Im currious if the shims will make up the difference if they are too long. I might have to buy a pushrod length checker I guess..... Unfortunately I dont have one. When I bought the rolers I asked the guy at FORD if I needed new pushrods, he did some punching on the computer and said "nope stock ones will work" so thats what I went by.

 

[94Pro-5.0]

i dont think i had stock length pushrods with my GT40's. i had them converted to stud mount though, but my pushrods were 6.5" cranes

 

[OnyxCobra]

What size pushrods are you running? Nobody can tell you over the phone what size pushrods you need to run in your engine, you need to measure to find the correct length. every time you change your heads, cam, or a valvetrain component you should measure to make sure the pushrods are the correct length.

 

[forkliftfixr]

They are Competition Cams PN# 7826-16 5/16 Dia and 6.250" long

 

[Mr. OAM]

I have Harland Sharp roller rockers on my wife's 331 with GT-40X heads. With the head torqued on the block I mounted a rocker and measured between the adjuster seat in the rocker and the seat in the lifter with the cam turned to the "closed" position on that lobe, and the adjuster turned to 2 threads protruding below the rocker, per HS tech. I used an inside micrometer to measure the distance and had custom pushrods made up and shipped for $100.

If your pushrods are not obscenely too lonog you would think that the hydraulic aspect of them would compensate for not being perfect.


Steve

 

[forkliftfixr]

Well everyone was right, the valves were being held open by the rockers so the pushrods are too long. Interestingly enough I also found one broken pedastal (the spacer under the rocker that bolts to the head) And it definately was not torqed too tight. FRPP is sending me another one no questions asked. I ordered the shim kit from FRPP also, after taking some measurements the shims will take up the extra height of the pushrods and everything should be correct then.