push rod? crane rockers .040 gasket
08-04-2006, 08:20 PM
#1
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push rod? crane rockers .040 gasket Hey fellas, just wanted to double check and make sure that my push rod lengths are correct or my set-up. I will be running a 228R .588 lift cam with crane 1.7 gold quicklift rockers on ls6 heads with a .040 commetic gasket. I would assume that 7.350's would be about the right length for this combo but, I just wanted to see what you guys think. Thanks.
08-04-2006, 10:46 PM
#2
No. The crane rockers on a stock setup are 7.250, with the gaskets, etc. you may be looking shorter. Currently, I am running Dart heads and Crane 1.7's with the GM 6.0 MLS gasket, I ended up with 7.150 pushrods to get the right wipe pattern and the correct preload on the Morel lifters (running 0.040 on these lifters). The 7.250's might still work with your setup if you have sotck lifters, but check the wipe pattern and make sure.
Did you get the Crane rocker kit? It comes with the Crane 7.250 pushrods.
Did you get the Crane rocker kit? It comes with the Crane 7.250 pushrods.
08-04-2006, 11:29 PM
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I bought the kit used but the pushrods are trick flow 7.350s. I was under the impression that the rods that came with the kit were 7.4's. I guess I'll just have to measure once everything is in place. I will call crane tomorrow as well.
08-05-2006, 07:21 AM
#4
I have the original kit, the PR's are 7.250. Best bet would be to measure. One interesting thing if the heads are off the car, I actually set the wipe pattern on the workbench by measuring the distance between the top of the adjusting nut to the top of the stud. I found there was a range in adjustment nut heights that produced the best wipe pattern. I used this information to help with pushrod selection and ended up with the 7.150 PR's, but the Morel lifters require a lot less preload.
08-05-2006, 12:27 PM
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The heads are off of the car, I will use the method use just stated. That's a good idea. I'll probably end up using adjustables in the end just to be sure though. Just doing some quick math, You used morrel lifters and ended up with a 7.150 PR. If I'm not mistaken, the preload on the morrels is somewhere between .005-.008 and the stockers are around .090. So therefore, the 7.250s would be correct for unmilled heads and a stock .053 head gasket with the carne 1.7s. Subtract the .013 difference in gasket size and that should put me at 7.237 PRs respectively. I guess that if my measurements are off, I can always shim the stud. Please let me know if I'm on the right course or not. I have never built a pushrod engine before, so I'm poppin my cherry here and want to do it right the first time around.
08-05-2006, 06:29 PM
#7
Just to clarify, the Morels are set at 0.030 - 0.050".
You have to use checking springs to do this.
On the bench, I used a dial indicator and set it on the valve retainer adjusting so it read my total lift. The I installed the Crane studs and guide plate (I didn't loctite them at this time, just snugged them up). Put on the rocker and an adjusting nut (no jam nut) and use a Sharpie to coat the valve stem. Them I screwed down the adjusting nut and moved the rocker through its motion to open and close the valve by hand. You have to sort of pull up at the fulcrum so it doesn't slide around, but you will figure that out. I used a depth gauge (on my vernier) to measure the distance between the top of the adjusting nut and the top of the stud. I found that between 0.275 and 0.290" depth I got a nice narrow wipe pattern on the valve. Let me know if this still doesn't make sense, its kind of hard to explain.
OK, found some photo's I took. Hope they help.
This is the setup and the depth is shown that you measure.
Here is an other view. It is hard to move the rocker by hand and not have it wiggle so the wipe patterns get a little wider then they will on the car.
Here are two wipe patterns with different measured depths. You want to be in the middle or slightly to the intake side of the valve.
You have to use checking springs to do this.
On the bench, I used a dial indicator and set it on the valve retainer adjusting so it read my total lift. The I installed the Crane studs and guide plate (I didn't loctite them at this time, just snugged them up). Put on the rocker and an adjusting nut (no jam nut) and use a Sharpie to coat the valve stem. Them I screwed down the adjusting nut and moved the rocker through its motion to open and close the valve by hand. You have to sort of pull up at the fulcrum so it doesn't slide around, but you will figure that out. I used a depth gauge (on my vernier) to measure the distance between the top of the adjusting nut and the top of the stud. I found that between 0.275 and 0.290" depth I got a nice narrow wipe pattern on the valve. Let me know if this still doesn't make sense, its kind of hard to explain.
OK, found some photo's I took. Hope they help.
This is the setup and the depth is shown that you measure.
Here is an other view. It is hard to move the rocker by hand and not have it wiggle so the wipe patterns get a little wider then they will on the car.
Here are two wipe patterns with different measured depths. You want to be in the middle or slightly to the intake side of the valve.
Last edited by vettenuts; 08-05-2006 at 06:37 PM.
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08-05-2006, 10:15 PM
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Awesome, I understand now. I'm a machinist so I can get a grip on these kinda things quickly. Thanks so much for your help! Next bit of free time I get, I'm going to try it. I would be lost without this site. Thanks again!
