Need help with best lifter preload solution!

[Cheromaniac]

JEEP 4.0 Notoriously noisy because of piston skirt slap , noisy sloppy timing chains and last but not least noisy rocker assembles!! [/b] Sorry for the Rant but I have never owned an Engine that from the factory was so noisy and rough idling.

Yeah, and that rough diamond of an engine seems to last forever (apart from the '00-'01 crackheads) with proper maintenance and normal use.

[Bike Guy]

Well push-rod lengths are all over the board. At first I thought that the Exhaust valves were roughly .014 longer than the intake, but it just didn't matter as you'll see by the lengths I came up with. It looks like the sizes I will be buying from Tread Pref. is 9.525 (I've listed as #1) and 9.550 (I've listed as #2) since they are sold in .025 increments. Probably 7- #1 & 5- #2 to get this to workout.

Cylinder 1 Ex = 9.515, In = 9.535 I will purchase 1- #1 P/R & 1- #2 P/R
Cylinder 2 Ex = 9.525, In = 9.525 I will purchase 2- #1 P/R
Cylinder 3 Ex = 9.520, In = 9.545 I will purchase 1- #1 & 1- #2
Cylinder 4 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2
Cylinder 5 Ex = 9.535?, In = 9.525? I will purchase 1- #1 & 1- #2
Cylinder 6 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2

Can't believe that there is a .030 between the short one and the longest one!
These lengths have .045 figured in for preload, but of coarse since I have to buy P/R's in .025 increments I'm going to end up with 4 having a .060 Preload, 2 with .050, 1 with .055 and the leftover 5 with .045. !!

If this was your valve issue would you fix it with push-rods like I'm describing or pull the head and have the valves done over again (on your dime) or dump the $750.00 to do the Hesco adj roller rockers-valve cover spacer & Thermostat housing spacer and would probably have to buy new push-rods (Shorter and just one length)?

It's hard to believe that I drove this to Moab and back (roughly 800 miles) with the stock 9.639 P/R's and it didn't do anything more then have a lifter clatter a dozen times or so when it wouldn't pump up. One of them (cyl #1 Exhaust ) had a preload of .169 , it is surprising it didn't the cam!!

I thing I'm going out and buying a Loto ticket!!

.

[SilverXJ]

Well, as I said you may need different pushrods with the roller rockers as well. And it all depends on how much you want to pay. The roller rockers are nice and make adjusting preload a breeze. I don't think the contribute much power but you will have a stiffer valve train and lower temps on the valves and head due to less friction. Which in theory can help prevent ping.

Before you jump to blame your valve job you have to consider the rocker pedestals, rockers, and the cam grind as well. You may want to see if you can get a precision straight edge (not a ruler) and sit it on top of the pedestals. I know a few of mine weren't even and I even used some of the Ford washers on them to get a couple even with each other. Now I have no idea how to measure the cam for different base circles and such. Now, if the valve job is an issue They would have to regrind the higher ones to match the lower ones. Which would seat the valves even higher in the combustion chamber, effecting flow. And I wouldn't say it is the machinist's fault right away. He may have just cleaned up the precision stock valve job.

If you want to save money do the pushrods and maybe the shims if necessary. You will be fine with that.

[amcinstaller]

you can check the cam with a dial indicator and just check each lobe for identical lift. in school we measured higher mileage (250-300,000 kms) chebby 350 cams, and the stockers were out by .002 from biggest to smallest iirc. nowhere close to all identical at any rate.

[SilverXJ]

Wouldn't it be possible to have a smaller or larger base circle effecting preload and still have the same amount of lift?

[amcinstaller]

yea, but i would think that you would do each rocker as per its own "situation" rather than by a set turn the nut x number of times then 3/4 turn more. but with the method i mentioned, the indicator would be zeroed on the base circle then the lift measured. we saw a difference in lift

[I6FAN]

Cylinder 1 Ex = 9.515, In = 9.535 I will purchase 1- #1 P/R & 1- #2 P/R
Cylinder 2 Ex = 9.525, In = 9.525 I will purchase 2- #1 P/R
Cylinder 3 Ex = 9.520, In = 9.545 I will purchase 1- #1 & 1- #2
Cylinder 4 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2
Cylinder 5 Ex = 9.535?, In = 9.525? I will purchase 1- #1 & 1- #2
Cylinder 6 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2

Something else to consider: Be sure to measure at the same lift location on the base circle of each lobe. Even though your in the zero lift range, most cams have a "lead-in". I think the best place to check is the point just after valve closing. You may want to research that, or someone here can corroborate.

[Bike Guy]

you can check the cam with a dial indicator and just check each lobe for identical lift. in school we measured higher mileage (250-300,000 kms) chebby 350 cams, and the stockers were out by .002 from biggest to smallest iirc. nowhere close to all identical at any rate.

This cam only has roughly 900 miles on it, I did check each cam lobe to make sure I hadn't flattened a lobe even thou the lifters looked like they were all spinning. Everything checked out dead nuts on.

Cylinder 1 Ex = 9.515, In = 9.535 I will purchase 1- #1 P/R & 1- #2 P/R
Cylinder 2 Ex = 9.525, In = 9.525 I will purchase 2- #1 P/R
Cylinder 3 Ex = 9.520, In = 9.545 I will purchase 1- #1 & 1- #2
Cylinder 4 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2
Cylinder 5 Ex = 9.535?, In = 9.525? I will purchase 1- #1 & 1- #2
Cylinder 6 Ex = 9.525, In = 9.535 I will purchase 1- #1 & 1- #2

Something else to consider: Be sure to measure at the same lift location on the base circle of each lobe. Even though your in the zero lift range, most cams have a "lead-in". I think the best place to check is the point just after valve closing. You may want to research that, or someone here can corroborate.

When I did my measurements, I checked to make sure that I was on the compression stroke at TDC of the cylinder I was testing (per Bennie).

Like I had said before, the only thing that is really bugging me about the P/R fix is that I will 4- lifters at a .060 preload.
But I really wonder just how accurate this is anyway since we have no way of knowing how much that preload # changes with expansion of the metals from 200 deg. heat. I'm going to give it a shot, I ordered the push-rods today and should have them early next week. I'll report in on how it runs when they come in and I have a chance to button it up.

Thank you all for your input!!
.

[dragginwagon406]

How did the pushrods work out?

I'm crosisng this bridge right now with my DD stroker. Stock cam and lifters, block decked .022" and head resurfaced and valves ground (exhaust replaced). I measure .058" between the pedastal and the bottom of the rocker at zero lash (I really wish I would have checked this measurement from the factory to see how far off it is).

Would you just buy .030" shorter pushrods and call it close enough?

[Bike Guy]

Sorry I hadn't done a follow up on this Thread.
The push rods worked out good, but If I had it to do over again I would go with one size of push rods that were close in the correct preload and drop the coin for the Hesco adj roller rockers-valve cover spacer & Thermostat housing spacer. Of course my problem of having up to a .030 discrepancy between my valve stem heights makes the Tread Perf. .025 increments not as accurate as I would like, since I do have a little bit of a noising valve train from some of my lighter preloads. Bennie had said that they like to run their builds at the upper end (.055 - .060) to prevent that.

Bottom line is, that it is running strong after having to throw some more fuel at it (47 PSI), strong enough that it never ran slower then 45MPH (at 4000 RPM or less) when pulling the passes (8000 + elevation) between Denver and Moab on our last trip there (May) and this is with our YJ pulling a 4x6 enclosed trailer full of offroad tires & camping gear weighing a combined weight of 6890#'s (I rolled it over a scale on the way home from Moab) .

To answer your question, it worked out. I would buy one of their adj. push-rod tools, to check your measurements before you order anything. I had found that trying other ways was not giving me a consistent measurement and doing it with their tool netted a precise result for each valve. All I know for sure is when you receive your Treads push rods, you'll wish you had a see thru head so that everyone could see the beauty of the workmanship Tread Performance puts into a push-rods.

Good luck with it, Randy

[SilverXJ]

I used Comp Cams adjustable push rod length checker. Part number 7704-1. Measures 8.8"-9.8" Each rotation = .050". I've used Smith Brothers push rods twice and they are very nice pieces and fast service. They also offer restrictor push rods down to .020". Really, if you are use to seeing the stock push rods any after market push rod would be beautiful. The stock ones just aren't that nice.