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Topic: Are these too long? (Read 509 times)
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Tiamat
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Posts: 148
BigBlockDart.Com
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Need some advice here guys and gals Are these pushrods too long? Pics taken at TDC#1 firing, zero lash, with no preload to the hyd lifter as I have checking springs on There is about a credit card thickness gap between the top of the cup and the bottom of the rocker No adjuster threads showing
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NYrr496
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I'm sitting here trying to imagine if it matters how the rocker tip rolling across the valve is affected by pushrod length on a shaft rocker.
Maybe only by a LITTLE. Like .050- .075.
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It takes a Mopar to catch a Mopar.
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68_Val_Sedan
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I would say definitly ... pushrods need to be shorter ... the 1st thread on the adjuster should be visible below the rocker ... and even with preload I do not think the 1st thread will be visible ...
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67 dart 270 resto mod in progress ...
68 chrysler 300 wish it was my daily driver ...
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Tiamat
Full Member
 
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Posts: 148
BigBlockDart.Com
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I'm sitting here trying to imagine if it matters how the rocker tip rolling across the valve is affected by pushrod length on a shaft rocker.
Maybe only by a LITTLE. Like .050- .075.
I don't think it makes any to difference to where the tip goes, its the adjusters breaking I'm worried about.
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NYrr496
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Yeah, wow.. I didn't even look at that. You're right. The ball shouldn't be disappearing into the rocker body like that.
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It takes a Mopar to catch a Mopar.
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Tiamat
Full Member
 
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Posts: 148
BigBlockDart.Com
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I would say definitly ... pushrods need to be shorter ... the 1st thread on the adjuster should be visible below the rocker ... and even with preload I do not think the 1st thread will be visible ...
Bummer  Thats what I was thinking too Thanks for your input guys
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moparteacher
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Have you considered placing shims under the shafts?
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Moparteacher
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Tiamat
Full Member
 
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Posts: 148
BigBlockDart.Com
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No I haven't considered shims, but in this case I think I have the wrong size rods  They are about 0.250 too long which would put them into solid lifter territory Looks like I ordered the wrong ones  Everybody grab a hammer and have a go 
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NYrr496
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No I haven't considered shims, but in this case I think I have the wrong size rods  They are about 0.250 too long which would put them into solid lifter territory Looks like I ordered the wrong ones  Everybody grab a hammer and have a go  Don't feel too bad. For some reason when I built my last engine with a roller cam, I used Comp lifters and ordered Crane pushrods. Apparently, Crane and Comp use a different height lifter, so they were painfully wrong. Live and learn.
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It takes a Mopar to catch a Mopar.
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ksdartguy
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I would say shim the shaft and run it. If the roller looks good on the valve tip now, a shim will only help. Ive run shims with hydraulics many times and works great.
Too short of pushrod is where you get into geometry probs. 3 or 4 threads and the pushrod gets in a tight angle at full lift. My $.02
Rick
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69 Swinger,3.54 Dana, 400/499, Stealth heads, Crower 262/266d, .686/.696L roller,11 to 1, 950 Bigs, E85 carb. Best so far, 10.82 @ 124mph through the mufflers.
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Tiamat
Full Member
 
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Posts: 148
BigBlockDart.Com
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If I were to shim it I would change the geometry wouldn't it? At present the rollers run perfectly on the valve tips
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ksdartguy
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If I were to shim it I would change the geometry wouldn't it? At present the rollers run perfectly on the valve tips
A shim would give you close to a thread out the bottom. Since you have it mocked up, try a shim and roll it through a watch the action. I thiink youll be fine, but try it and see. You can get some thin material at a hardware store to mock it up with.
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69 Swinger,3.54 Dana, 400/499, Stealth heads, Crower 262/266d, .686/.696L roller,11 to 1, 950 Bigs, E85 carb. Best so far, 10.82 @ 124mph through the mufflers.
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Thin White Duke
Full Member
 
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Posts: 423
BigBlockDart.Com
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Just do it easy and get shorter pushrods. Keep your geometry spot on. You'd have to shim the crap out of it to get it right.
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68_Val_Sedan
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Just do it easy and get shorter pushrods. Keep your geometry spot on. You'd have to shim the crap out of it to get it right.
 New pushrods are the way to go here ..
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67 dart 270 resto mod in progress ...
68 chrysler 300 wish it was my daily driver ...
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Tiamat
Full Member
 
Online
Posts: 148
BigBlockDart.Com
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Ordered them this morning. If the geometry wasn't spot on I'd give it some tweaking But in this case it was just poor parts choice ![\/][](http://www.bigblockdart.com/Smileys/classic/finger020.gif) Its great to have a panel of experts to run things past, my thanks to you all
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cudacain
Jr. Member

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Posts: 78
BigBlockDart.Com
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 I am going thru the same thing with a set of crane golds and hydralic lifters. My 440 and eddy heads running a split duration crane cam 292/298 dur. 528/539 lift with crane push rods. I ran into the same thing and I am going to get differant pushrods as soon as I figure out what length I need. I guess I am going to have to purchase an adjustable pushrod checking tool to get the length. Problem is I have ball and cup and seems like crane sells bal and ball checkers, any one can tell me the proper length for this combo or where I can get a ball and cup checker would be helpful. Good luck with your pushrods.
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Tiamat
Full Member
 
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Posts: 148
BigBlockDart.Com
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If you can't find an adjustable pushrod with a ball-cup you could buy a pair of rocker arm adjusters that have cups and use a ball-ball adjustable pushrod But I wouldn't take my advice, I started this thread 
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NYrr496
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You can make a checker out of ANY pushrod. Cut it in half, tap the inside of the two halves with like a 10-32 or whatever fits correctly and add a short section of threaded rod. Of course, cut a little of the pushrod out. if you add nuts, you can lock it on the correct length for checking and measuring. Don't use this tool with your actual valvesprings, though. Only checking springs.
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It takes a Mopar to catch a Mopar.
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beeprace
Jr. Member

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Posts: 67
Small Block A Body Baby
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Set your preload, 1/3 to 1/2 turn on your hyd lifters, then take your shafts/rockers off, do not move the adjusters. Measure the distance from the rocker arm to the end of the ball on the adjuster. It should be .280 plus or minus .030. Once you get the prementioned measurement deduct the amout it takes to get the perfect lenght push rod from your current pushrod and order what you need.
Valvetrain geometry is very important for a performance or race motor. Many parts failure issues can all lead back to pushrod length.
My 2 cents.
Beep Beep Out
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