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-   -   Push Rod length/T&D Install Lash (http://www.viperalley.com/forum/viper-discussions-gen-i/57943-push-rod-length-t.html)

BAD68GTO August 25th, 2007 11:42 AM

Push Rod length/T&D Install Lash
 
Adding a set of used MOPAR Blue T&D 1.7 to my Viper and wanted to check the push rod length as I installed the rockers. I was told by the seller that these were not regular T&D's, but rather these were made to use with stock push rod height and I wanted to check the geometry before adding the rockers. I do not have a push rod length checker myself, but I have changed roller rockers and adjusted mechanical cams and such, dealt with stud girdles on my GTO and the like. Do I buy or borrow a push rod lengh checked? If i buy, any special one I should or should not purchase? Is there a place online where it will give me instructions on how to the length checker it since I do not want to guess? I have built motors, even honed them with a drill (ghetto builder but never had a problem!), cut my seats and valves myself, but never did this before (sounds kind of weird I know). I have an arrow rebuilt motor, so I assume they are standard MOPAR push rods, so anyhow want to get the motor healthier to take a little more RPM and HP now that it will breathe better. Regarding adjustments on the Viper's valves on my 708, is it no lash and then 1/2 turn lash on these cars? TY for advice. Gary

Greg Good August 25th, 2007 04:06 PM

The checker you need is a Comp cam 7702-1.

I don't know what valves are in your heads, but if they are stock length just bolt the rocker stand down with no shims, put on a rocker, set the adjuster out one turn, and check the gap with the 7702-1 checker. Comp sells pushrods in .050" length incremments, so what you want is a pushrod length that will put the adjuster out no more than 2 turns when the preload is set.

Also, use a 3/8" diameter psuhrod. They'll drop in with no clearance issues.

FE065 August 25th, 2007 09:55 PM

I recently read an in depth article on this somewhere...

Seems like I remember them recommending checking all the pushrod lengths on an engine and not measuring just one to order all the pushrods based on that one measurement.

True?

Jack B August 25th, 2007 10:18 PM

Quote:

Originally Posted by Greg Good Cylinder Heads (Post 897336)
The checker you need is a Comp cam 7702-1.

I don't know what valves are in your heads, but if they are stock length just bolt the rocker stand down with no shims, put on a rocker, set the adjuster out one turn, and check the gap with the 7702-1 checker. Comp sells pushrods in .050" length incremments, so what you want is a pushrod length that will put the adjuster out no more than 2 turns when the preload is set.

Also, use a 3/8" diameter psuhrod. They'll drop in with no clearance issues.

Why are you ignoring the geometry?

Greg Good August 25th, 2007 10:37 PM

Quote:

Originally Posted by Jack B (Post 897431)
Why are you ignoring the geometry?


I wasn't. If he has stock length valves he needs to bolt the stands down with no shims. They will still sit too high. If he has longer aftermarket valves then he needs to check the geometry and shim if necessary before checking for pushrod length. I was waiting for him to respond about which valves he had before going further.

Greg Good August 26th, 2007 12:37 AM

Quote:

Originally Posted by FE065 (Post 897427)
I recently read an in depth article on this somewhere...

Seems like I remember them recommending checking all the pushrod lengths on an engine and not measuring just one to order all the pushrods based on that one measurement.

True?


About the only time you'll have to do that is when the head guy doesn't get the stem protrusion the same on every valve. A valve tip that sits high will need a shorter pushrod, and vice versa.

plumcrazy August 26th, 2007 05:16 AM

let us know what length pushrods ya need, i might have a set for ya. they have about 250 miles on them

FE065 August 26th, 2007 08:10 AM

Quote:

Originally Posted by Greg Good Cylinder Heads (Post 897454)
About the only time you'll have to do that is when the head guy doesn't get the stem protrusion the same on every valve. A valve tip that sits high will need a shorter pushrod, and vice versa.

What have you found then with this type of thing on OE heads? Many of the T&Ds are going on unmodified heads.

Does the factory valve placement in the head get stem protrusion good enough to just measure one pushrod length and go from there?

RedSrt007 August 26th, 2007 11:18 AM

I have the Jesels, and went 1.25 turns preload. I have stock heads, no valvejobs done and I still had a variance in height of push rods.

Greg Good August 26th, 2007 12:42 PM

If it's an unmolested factory head then yes you can check one and order your pushrods because the valve tips are all the same height. If the heads have been worked on you need to lay a straight edge on the valve tips to see how far off they are and then decide if each one should be individually checked.

The geometry of the T&D rockers with stock length valves always has the rocker trunnion a bit too high. I've had to machine as much as .125" off the rocker bosses to get them correct. That's why we always put longer valves in ported Viper heads. It gets the rocker geometry right and increases the installed height so we can run a better valve spring.

BAD68GTO August 26th, 2007 02:54 PM

My motor was rebuilt by Arrow, so I suspect they might have done a valve job or at least lapped them. I have 33K miles on car and 15K on Arrow engine. I ordered comp cam part as instructed, and valve covers ar still on the car now. From what I was told, the T7D's I have are not normal T&D's, they are made to work on stock push rod length and were not sold by T&D, but rather MOPAR performance years ago. I have 20 rockers and 40 bolts, but no stands or the like included with the goods I purchased. is there something else I should have received? Excuse my ignorance, I never had my valve covers off before and do know know how they are set up on a Viper.

As for preload, what should I run on these lifters-1.25 like Red? TY, Gary

TT R/T August 26th, 2007 04:21 PM

as soon as you have the pushrod length checker, all of your questions will be answered on their own. As for pre-load, the hydraulic lifters are quite forgiving. 0 pre-load is noisy but works just fine. too much pre-load and the valves don't close. long story short: 1 to 1.5 turns should do it. assuming you are correctly finding 0-lash. if the car runs like sh*t, you didn't adjust correctly so go start from scratch.

JD

viper spray August 26th, 2007 07:39 PM

The blue Mopar perf. T&Ds are exactly the same as the regular T&Ds , except for the color , like the posts above say , make sure that they are correct. The heads from the factory are not all the same .

BAD68GTO August 26th, 2007 10:18 PM

It appears I am missing the part where the T&D rockers screw into-that long piece that screws into the head. I've contacted the member I bought them off of and he thinks he might not have it. Anyone have an extra one laying around to sell me if the seller doesn't have it? Thanks

Greg Good August 26th, 2007 10:39 PM

Those are called "stands", and I have seen two versions of those T&D stands so far. There are a few floating around that are .050" ( IIRC ) thicker than the normal T&D rocker stand. I don't know if they were sold by Dodge or T&D because they both came to me on heads that had been run, and I had no way of finding out where they came from. No part numbers on them either that I saw.

If you have an Arrow rebuild then it has stock factory valves in it. Do not shim the stands. Bolt them down directly. The rocker geometry will not be perfect, but it'll run. Nothing you can do to fix it except to pull the heads and put longer valves in or cut the rocker stands down.

dun4791 January 28th, 2008 10:27 PM

Quote:

Originally Posted by Greg Good Cylinder Heads (Post 897767)
Those are called "stands", and I have seen two versions of those T&D stands so far. There are a few floating around that are .050" ( IIRC ) thicker than the normal T&D rocker stand. I don't know if they were sold by Dodge or T&D because they both came to me on heads that had been run, and I had no way of finding out where they came from. No part numbers on them either that I saw.

If you have an Arrow rebuild then it has stock factory valves in it. Do not shim the stands. Bolt them down directly. The rocker geometry will not be perfect, but it'll run. Nothing you can do to fix it except to pull the heads and put longer valves in or cut the rocker stands down.

I know this is an old thread, but wondering how the install went?

Also, Greg, If the T&D geometry isnt perfect and the trunnion is too high, would a better choice for stock heads/ cam be the Harland Sharps, or do they have a less than acceptable reputation?

Greg Good January 28th, 2008 10:43 PM

No, I'd still use the T&D's. The geometry isn't perfect with stock length valves, but it's not out of the ballpark. The rigidity gives them the nod.

I know, lots of guys run the Harlands, but it's like this; if you ask a priest if you can cuss, he's always going to tell you "No".

BAD68GTO January 28th, 2008 11:02 PM

Oh, this thread is still going :-) While I think the stock push rods might have worked, the correct length with the push rod checker (Thanks Greg Good for the tip!) was a bit longer. My friend joe Dell shipped me up a whole used set of very slightly longer Comp Cams rods for me to use (speaking of which, I never sent him his money!).

Anyhow, thanks to the Alley mebers like Greg Good and Joe Dell I am all square and thanks to Kenny Katowick (SunRaKat) for helping me along the way with upgrades, advice or just being there. This almost sounds like a group hug time, but seriously I got a lot of help with 5 years being on the Alley from different folks. Gary


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