Pushrod Help

[Zacks 85GN]

We are finally getting the motor together and started checking the pushrod length today. We are running an ATR 309G cam Kit with T/A Performance 1.6 roller rockers (T&D), and the roller lifters are Speed Pro's. We have taken the measurements with an adjustable pushrod gage. Do we need to add .030" to the measurements we got for the proper pushrod length? The speed pro lifters have a pretty good spring under the plunger and held the pushrod up really good.

Too bad ATR went under, we did not get the pushrods for our kit as we took too long get this motor together.

Our numbers are:

#1 ex 8.180" #2 ex 8.098"
#1 in 8.184" #2 in 8.158"

#3 ex 8.159" #4 in 8.143"
#3 in 8.170" #4 ex 8.121"

#5 in 8.177" #6 in 8.148"
#5 ex 8.1635" #6 in 8.135"

Kinda of all over the place.

Thanks,
Jim

 

[Lee Thompson]

looks good

Looks like an 8.200 will work. Lifter have about .200 travel in them.
I believe my son has a used set of Comp chrome moly--8.200 or 8.220.

 

[Zacks 85GN]

Thanks Lee, long time no see, sure miss the Bristol events. Hope your car is running good, I have been away from Buicks for a while. Zack is about to get out of college and has a good part time job so he has started back up on our project again. Zack went ahead and ordered a new set of pushrods today, thanks for the offer. Hope your son is doing well.

Jim

 

[NCTURBOS]

So.... When is the final countdown Jim?? We're ready to see that car out and about again!!


K.

 

[jwillettgn]

Well Zack has decided to go with a T400 so that will slow us down again. There will be alot of little things we will need as well and you know how long it takes to get those rounded up. We have the intercooler that came with the Turbo Motion V2 kit but Zack wants a front mount. It is time to start selling off what we can't use now to raise some funds. We do have a good 200R4 (BQ I think) and good D5 converter we need to move. Now that Zack has a better job this summer we hope it comes together faster.

Jim

 

[Jerryl]

We are finally getting the motor together and started checking the pushrod length today. We are running an ATR 309G cam Kit with T/A Performance 1.6 roller rockers (T&D), and the roller lifters are Speed Pro's. We have taken the measurements with an adjustable pushrod gage. Do we need to add .030" to the measurements we got for the proper pushrod length?
Our numbers are:

#2 ex 8.098"
#1 in 8.184"
Kinda of all over the place.

I am no expert but looks like between the highest and lowest, you have a 0.086 "gap". This means that you may get too much preload on some and not enough on others.

Let's take the median between these 2 numbers = 8.141 Pushrod length for 0.030 preload = 8.171.

That leaves you with
8.171 - 8.184 = -0.013 preload on the #1 Int
and
8.171 - 8.098 = 0.073 preload on #2Exh

I struggled with this EXACT same issue and ended up with adjustable pushrods. Some may argue that adjustables are "not worth the chance" but no one can argue there are plenty of success stories out there.

These are low RPM motors, much like Harleys and adjustables have been used in Harley motors for decades.
I was able to get EACH valve at 0.035 - 0.040 preload with a dial indicator. 2K miles later, No issues, and, I sleep good at night knowing the lifters will not bounce of the lobe, bottom out, or flatten the lobe.

PS:
The shim under the rocker shaft technique is for the birds!

 

[NCTURBOS]

They have adjustable roller rocker arms, so they will be fine with the 8.200".


K.

 

[Jerryl]

They have adjustable roller rocker arms, so they will be fine with the 8.200".
K.

Like I said, I am NO expert! :tongue:
(Boy do I feel dumb!)

 

[HellOnWheels]

My experience. Roller cam and Harlan Sharp roller rockers (1.65) and I run BB Chevy INTAKE push rods for both intake and exhaust. Several thousand miles and no prob.


Good luck,
HOW

 

[WSLN 6]

I have a set of pretty much new (no run time) chromoly 8.225 pushrods if ya need em.

 

[jwillettgn]

Thanks guy's, but Zack went ahead and ordered a new set the other day. It will be unreal if this thing even runs at all after all the BS we have gone through. NCTURBOS is the only one on the board who has ever seen the car ever run and drive and that was 6 years ago.

Jim