1.7 RR install question...I think something is wrong.....

ram360 · Jun 15, 2004

I have Gt 40p heads, 1.7 pedestal mount crane rockers, and stock pushrods. I started w/ the #1 cyl at TDC and torqued the two rockers for that cyl to 20 ft lbs. Once I was done I was able to move the rocker arm roller tip off the valve head. I have no tool to measure how much it's moving but in any case It still moves after it's torqued. Is this normal or should there be no movement in the roller rocker arm once it's torqued. I know the stock rockers didn't do that, but are 1.7 rr's are different? Thanks.

bmorrisj · Jun 15, 2004

you may need to get a shim kit.... http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=2668&prmenbr=361

DropTopR · Jun 16, 2004

It shouldn't move off of the valve. Maybe some back and forth, but not completely off. You might need different length push rods too. Not for sure on the P heads.

Michael Yount · Jun 16, 2004

Which TDC were you at - overlap or firing? There are 2 tdc's for each rotation of the cam. If you were at overlap, then both valves were open when you were trying to install the rockers. Are you certain both valves were closed?

davs5.0 · Jun 16, 2004

http://www.cranecams.com/pdf/453e.pdf Check the instructions from Crane. You'll need Adobe reader to view. You might have used the wrong timing events like Micheal said.

ram360 · Jun 16, 2004

DropTopR said:
It shouldn't move off of the valve. Maybe some back and forth, but not completely off. You might need different length push rods too. Not for sure on the P heads.

but wouldn't that just move the rocker arm farther up causing it to be to have even more play in it?

Michael Yount said:
Which TDC were you at - overlap or firing? There are 2 tdc's for each rotation of the cam. If you were at overlap, then both valves were open when you were trying to install the rockers. Are you certain both valves were closed?

I took the dist cap off and had the rotor pointing to #1. Or is the rotor going to fire the #1 cyl. twice in one rotation of the cam? I'm kinda confused?

ram360 · Jun 16, 2004

davs5.0 said:
http://www.cranecams.com/pdf/453e.pdf Check the instructions from Crane. You'll need Adobe reader to view. You might have used the wrong timing events like Micheal said.

yep, that's the instructions I was following (or at least trying to follow) I'm no expert but I just seems the reason I have that play in the rockers is because the pushrods are too short that's why I can move the rocker tip slightly off the valve w/ the rocker torqued down

ram360 · Jun 19, 2004

Does it sound like I need longer pushrods? How would I go about figuring what length I'll need? I mean they only need to be slightly longer. What would you guys reccomend? Will I be able to pick up the pushrods at a parts store or are they a special order thing? I know I can find the stock ones but I never asked about longer ones. Then I could use the shim kit bmorris reccomended to fine tune everything. Thanks!

85GTlover · Jun 19, 2004

www.autozone.com has massive amounts of technical info.......might help,might not, but a great site regardless.

Michael Yount · Jun 19, 2004

If you found tdc for #1 by comparing with the distributor - that's the correct way; distributor rotates once for every 2 crank rotations. If you have gap even with the rocker tightened, the pushrods are too short. I'd go through the proper installation procedure again, torque them all properly, and measure the gap on the rocker/valve end (hold the other end of the rocker against the pushrod). Take the biggest measurement, and add .01-.02" to it, add that sum to your current pushrod length, and that will be your new pushrod length. Remember you can shim the rockers up if they're a little long, but if you get them too short - well, you know what happens if they're too short. If you're only off a little, or if it's just a few pushrods, you may be able to carefully remove some material from the bottom of the rocker fulcrum -- essentially lowering the rocker. Just be careful if you go that route, and I wouldn't try to remove more than .01 or .02 that way. Crane will quickly make and ship pushrods in any length you want - for a fee of course.

Mean88 · Jun 19, 2004

I am running the exact same setup you are, crane 1.7s on gt40 p heads. The stock pushrods are the right length. Just make sure the rockers are as tight as you can get them so they dont move side to side. Good Luck
Ted

Michael Yount · Jun 19, 2004

One variable that's often difficult to determine is whether the heads or block have been cut or not by a previous owner. If stock pushrods are used, that change is usually easily resolved with rocker shims. Also, if the cam has been replaced, it's possible that a slightly different base circle dimension is present - that can also make the stock pushrods unworkable. If different valves have been put in the heads, that too can make the stock pushrods the incorrect length. So sometimes, it's difficult to know if one set up is 'exactly' like another even though head type and rocker ratio are the same.

ram360 · Jun 20, 2004

Michael Yount said:
If you found tdc for #1 by comparing with the distributor - that's the correct way; distributor rotates once for every 2 crank rotations. If you have gap even with the rocker tightened, the pushrods are too short. I'd go through the proper installation procedure again, torque them all properly, and measure the gap on the rocker/valve end (hold the other end of the rocker against the pushrod). Take the biggest measurement, and add .01-.02" to it, add that sum to your current pushrod length, and that will be your new pushrod length. Remember you can shim the rockers up if they're a little long, but if you get them too short - well, you know what happens if they're too short. If you're only off a little, or if it's just a few pushrods, you may be able to carefully remove some material from the bottom of the rocker fulcrum -- essentially lowering the rocker. Just be careful if you go that route, and I wouldn't try to remove more than .01 or .02 that way. Crane will quickly make and ship pushrods in any length you want - for a fee of course.

Thanks mike. I'll go the longer pushrod route (I just wouldn't be comfortable modifying the rocker fulcrum.....never had too much luck w/ that kind of stuff). The new rods should fix everything, now that I know how to measure for them

Mean88 said:
I am running the exact same setup you are, crane 1.7s on gt40 p heads. The stock pushrods are the right length. Just make sure the rockers are as tight as you can get them so they dont move side to side. Good Luck
Ted

Yep, I even triple checked everything and my rods are just too short. Like michael said there are alot of variables. I did have my heads milled and larger valves were installed, and I'm also using a b cam so my setup may be slightly different than yours in the end.

Michael Yount · Jun 20, 2004

Here's the thing that bothers me - if you had the heads milled, then the pushrods should be too long, not too short.

1.7 RR install question...I think something is wrong.....

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