Stock Pushrod Length for a 304

.050 will just about center up the plunger. No matter, preload will have a range. You need to determine where you are right now. Between .020 and .100 is ok. Less then .025 will be ok but not in the sweet spot.

Measure anyway you like. But you will need to know where the valve events are to check preload properly. I do one cylinder at a time removing the pr's after.


If you ever need to adjust/measure your valves or set lifter preload on an engine with adjustable valve train. This technique makes absolute sure the valve you are dealing with is on the right part of the lobe/heal.
Remember e.o.I.c. Exhaust open intake closed

on a given cylinder.

When the exhaust is just open about .150 (1/3) measure/adjust the intake valve.

When the Intake is almost closed about .15 from seated measure/adjust the exhaust.

If eoic is a bit involved. On a small hydraulic cam with less than 270* advertised duration placing the cylinder on tdc compression stroke is fine. Do both valves on that cylinder.
 
Last edited:
So I just picked up my new adjustable pushrod and it's too large!!!!
I am embarrassed to say that I am a mechanical engineer and couldn't read the g.d. Vernier calipers correctly!
So all those dims I gave out earlier are crap and are now:
stock pushrod - 8.788"
manley pushrod - 8.925"
got another adjustable pushrod on order crane cams part #7703-1, I bought a 7704-1. It should be in Friday.
Anyways I will loosen the 5 posts and removed 1 pushrod. I'll put in the adjustable and re-torque the posts. And I'll do that 8 times per side.
 
Robert kenney said:
shoot man I'da sent you one for half the price and it would have fit. :ciappa:
Click to expand...

I'll talk to Jeff about putting an adjustable pushrod in the online store along with the other tools.

Can you whip some out if he agrees? We'd need multiples of all four types/lengths. Or...do ya think one length in each end-type could do the job and be long enough for both engine deck heights?
 
The ones I make have enough range to handle both deck heights.

Why not just rent them to guys who don't buy ihon stuff and if you buy a cam/lifters etc from the store, you can use them for only shipping costs on the return trip?

I mean unless guys build engines regularly you would only need them once.
 
So I go back to machine shop guy who has my stock lifter, stock pushrod, schneider lifter and manley rod. The stock lifter and schneider lifters have different diameter pushrod cups. Machine shop guy said that will through off the geometry. He looks at the manley rod and it says 8.850 and decides to order the next size larger by 0.050". I then asked him to "Mike" the rod first. I measured it before and it wasn't 8.850 but around 8.770. He measures it w/his calibrated digital caliper and same dimension. The manley rod is actually 0.070" shorter than is written on the side of the rod!!!!!
Machine guys' math was correct but manley sent him a set of miss-marked rods. I measured the entire passenger bank and they all measured the same.
Manley didn't seem to think it was a big deal by the tone of his voice and willingness to take these back, check them and send me the correct ones (8.850").
I'm gonna run the truck this weekend and on Monday send back all 16 to be "checked" and have new ones sent out to me.
What a trip this has been. It has been since the week before memorial day that I've been picking at this (with all of you guys of course). So about 3 months later and now maybe we've got it figured out.
I'll still head to the speed shop to get that shorter adjustable rod for $24. I don't mind spending the extra bucks on it, at least I don't have to wait for the ups guy.
If the pushrods are 0.070" too short, what effect will that have on power? The valves won't open quite as far as they should?
 
Short or long push rods won't effect the lift of the valve unless:

if they are to short then what would be required to set the lifter plunger down into the lifter after the rocker assy in tightened. In that case it would make a bunch of racket due to excessive valve train clearance.

If they are to long they would have to be long enough to depress the lifter plunger sufficiently far to block the oil inlet hole in the side of the lifter or to bottom the plunger in the lifter body. Both would have running issues with the latter holding valves open and a no start condition..


A word on lifter push rod seats.. The lifter seat diameter is not always the same as the rod. The rod tip diameter rides on a somewhat narrow margin. The lifter is engineered to take the seating height and diameter in to account so there is only a negligible assembly difference if any.

I will take a couple of pictures of a lifter with only a few miles on it that should have witness marks on it showing the contact area I am speaking about.
 
So I have my new adjustable pushrod but haven't used it yet.
Manley swapped out my old rods for ones that are actually 0.077" longer than the ones that were in there. The machine shop recomended that increase (0.070"). The motor still makes a loud "ticking" noise constantly.
I removed my dui and checked the gear/shaft clearance and it was about 0.045". When I called performance distributors they said a max of 0.030" so they sent me shims and a new roll pin. I shimmed it down to 0.025" and the noise is still there.
I remembered taking the rocker shafts off and disassembling them. One rocker arm (boat style) I couldn't get off the shaft. I can rotate it 360 degrees but it wouldn't slide either way off the shaft. It would move a tiny little bit if I rotated and pulled/pushed but no dice getting it off the shaft. I couldn't feel any imperfections on the shaft.
I am still going to pull both assy's and check for rod length. But could a "tight" rocker arm cause a bunch of racket?
 
I personally feel that 0.030" endplay in that distributor shaft is too much, I'd go 0.015>0.020". All oem IH distributors (both cast iron and aluminum I set up at 0.015" when I build 'em. That is not the cause of the noise, but excessive endplay allows timing "wander" as the gear thrusts on it's helix.

A new boat rocker is a totally sloppy fit on it's companion new rocker shaft! The only point of contact between the rocker and the shaft are the two "pads" on either side of the oil slot in the bottom of the rocker stamping. That is the primary reason I do not like to use 'em. When the rocker assembly is on the bench (no pressure from the valve springs/cam/pushrod), they have tons of clearance, totally unlike a welded rocker system that uses a full-circle bushing with a precise clearance. That is why they used the separator springs on the five stand variation, to keep 'em kinda "lined up" so they don't rattle/slide sideways on the shaft when not fully loaded.

If the rocker will not literally fall off the shaft, then that is a major issue in itself. Most likely that rocker and it's point of contact on the shaft are toast, resulting in lack of lifter preload when in operation. Is that the cylinder/rocker/lifter that is ticking?
 
Thanks michael,
I will put my cut cover on and check for noise. I have my $8 stethoscope now. Before the longer pushrods, I had in some locations 0.010" clearance between the rockers and valve stems and some without using my feeler gauge. With the stethoscope I couldn't tell any difference in the amount of noise when I put it on the shaft in 8 locations near all the rockers on one bank.
I do have to check the pushrods for length so I am planning on possibly doing this over the weekend.
If I can move that rocker a little bit up or down the shaft and can't feel any ridge or imperfection can I deduce anything from that as far as it being toast? I won't be able to get it off and if I do happen to get it off the shaft and I can't pin point that it is making the ticking noise, does it make sense trying to put it on another place on the shaft? Do I just pull the trigger and buy another rocker assy from you guys for $200 if I can't get that rocker off the shaft?
I'll check for lash/clearance between the rocker and valve stems again. Then I'll use the adjustable pushrod and see if my pushrods are around 0.050" (schneider says 0.060" to 0.080" of preload I'm pretty sure) longer than what length takes up all the lash/clearance. .
the only thing I have done for replacement is the pushrods . I still have the same lifters,etc.
 
My advice...

Both rocker assemblies need to be totally disassembled and inspected for wear now. Replace any suspect rocker(s) and replace the shaft(s) if needed. You do not need to replace the entire "assembly", ya fix what's broke!

I truly feel that this has been an issue all along now that you have revealed that the one rocker won't come of the shaft, that is a total freak deal.

If one single rocker/shaft interface is kludged (and your descriptions says it is), then something caused that at some point in time...the only thing that can cause that is lack of lubrication at the point of rocker/shaft interface. The actual shaft oil hole at that single point could be blocked. But once both shaft assemblies are torn down, you May see evidence of fairly extreme wear at all rocker/shaft interface points, that is the typical failure mode of the boat rocker system.

You can remove the offending rocker....simply disassemble everything on either side of the suspect, then use an appropriate hammer to tap it off the shaft. I tear down used rocker assemblies all the time that must have some assistance from various "tapping" devices to make 'em move, especially the rocker stands themselves.

If you need some direct assistance in dealing with this latest development ya simply need to post some pics of the exact point of failure on the rocker and shaft so we can see what is going on.

Again...all these issue you have found (pushrod length, unknown lifter condition, crapped rocker/shaft, etc.) go directly to the point...the entire valve train is only "adjustable" by fudging installed valve stem height and pushrod length. Even a few thousandths of wear on a valve stem, rocker, or rocker shaft adds up quickly to a lifter with abnormal preload. The wrong pushrods have added to this.

At no point when the engine is either running or stationary should there be any "lash" in the valve train at all. Regarding any hydraulic lifter valve train, they run with no "valve clearance" whatsoever. If there is clearance, then that is point of noise. Instead of "lash", a hydraulic lifter system has preload!
 
Last edited:
Thanks again.
So how do I evaluate the rocker shaft/arms? Do you have values for the od of the shaft and id of the arms?
I will definitely take pix and post them. I'll try to do this this weekend.

I spun a cam bearing trying to start it for the 1st time and didn't have oil on the driver side (I'm pretty sure that's the side w/the tight arm). I ran the truck for a little while to see if oil would magically appear!!! That was a day before I started using this forum!!!! I probably did some damage that day and then compounded it by that 1st long highway trip. I wonder if I only ran 5 quarts when I took that 1st long highway trip that it put it over the edge?
I'm now running 7 quarts at your guys request and I've been "under the covers" several times. Each time I loosen the stands, before I button everything up I use my cut cover and check for oil at all the arms at idle.
So the drama continues....
 
I promise...if the problematic boat rocker will not literally fall off the shaft, then both the rocker and the shaft are toast! You will have no problem identifying the damage visually, no "spec" is needed! Those rockers are totally sloppy in fitment on the shaft, there is no bushing and no way to locate the rocker in any form of "accurate" relationship to the shaft until all the parts are bolted together on the cylinder head. At that point they simply kinda "float" in position with the oil film/cushion created through rocker shaft oiling at the two points of contact on the inside of the rocker arm, either side of the oil channel.

I have many boat rockers and boat rocker shafts, all exhibit extreme wear at the rocker/shaft interface resulting in non-usable parts. Every used part is cleaned and carefully inspected/graded, any part that is suspect goes into the scrap buckets to haul off for recycle. Good used parts then become part of the ihon inventory but attempting to use those rockers and shafts is a last ditch effort in my opinion. New rockers and new shafts are in stock, for the "boat-style" only.

What information I've developed regarding boat rockers begins in post #32 in this thread:

http://www.forums.IHPartsAmerica.co...I-4-sv-engine-non-oiling-rocker-assembly.html
 
Ok, so I'll be ordering some stuff then.
I guess it's moot to even tear the thing down and troubleshoot? Just get the new stuff and put 'em in. Do the pushrod lenght check once the new stuff is in?
I'm inclined to order all the arms, springs, spacers and a shaft.
What do you recommend?
I haven't been trying to save $ but rather eliminate future problems. I haven't had much success w/that though. I'd feel better w/mostly everything being new.
Do the shafts come w/plugs installed?
Do you "carb clean" the new pieces before you cover in oil and install? Do you use assy. Lube instead of motor oil?
Are all boat rockers the same from year to year? The new pushrods are 3/8 dia. Shafts but the balls are smaller (5/16 I think).
 
77ssii said:
ok, so I'll be ordering some stuff then.
I guess it's moot to even tear the thing down and troubleshoot? Just get the new stuff and put 'em in. Do the pushrod lenght check once the new stuff is in?
I'm inclined to order all the arms, springs, spacers and a shaft.
What do you recommend?
I haven't been trying to save $ but rather eliminate future problems. I haven't had much success w/that though. I'd feel better w/mostly everything being new.
Do the shafts come w/plugs installed?
Do you "carb clean" the new pieces before you cover in oil and install? Do you use assy. Lube instead of motor oil?
Are all boat rockers the same from year to year? The new pushrods are 3/8 dia. Shafts but the balls are smaller (5/16 I think).
Click to expand...

You will have to teardown your rocker assemblies and use the stands, spacers, springs, etc. From the current stuff. All you will need new are the shafts and rockers. Boat rockers and lifter pockets are all the same regarding the pushrod tips, ihc used two types of "ball" tips, either works in any lifter and boat rocker. There are intake rockers and exhaust rockers, they are not all the same pattern.

New shafts come already plugged and ready to install. I assemble the items using assembly lube on the rocker contact pads, then simply squirt engine oil all over the entire assembly once it's bolted in.

With boat rocker shafts, be sure to install the oil holes and the shaft with the holes facing down, they feed right into the channel stamped into each rocker arm at the point of contact.
 
Ok, just ordered a new shaft and 4 of each arms.
The store says they come w/springs but Jeff wasn't sure if they are currently available. I asked him for the springs as well and he said he would check and get back to me. Again, the more new pars the better (that mentality bites me sometimes). Hopefully they will be here by next weekend and then we'll have some fun. I'll make sure I put the oil holes down.
In the meantime, I'll keep coasting by local garages so they don't hear me coming!

The drive trane I have in the truck now didn't come out of that truck. I was gifted my first Scout back in college before I knew anything about them. The title said '80 so I told everyone I had a Dana 300 but it didn't and it wasn't. The truck had about 4 different colors under the paint and was well worn. It was the same drive trane though 304/727/Dana 20 w/the exception of 3:73s vs 3:54s(?).
Anyways, this truck I have now supposedly had 18k on it so when it came time to re-build everything I used the higher mileage stuff out of the "1980". The "1980" engine has 5 stand rocker assy. And the lower mileage correct motor has a 9 stand rocker assy. The line setting ticket says it was built in April '77.
Maybe after all this is done and I can get that noise to go away I'll spend some time tearing down the original motor and clean up the 9 stand assembly for future use. The arms on that 9 stand set-up don't have bushings and look the same as the 5 stand set-up I'm currently running I.e. Boat style. There are no springs but the spacers are there too. Is that normal for April '77?
 
Ok
got the new shaft, rocker arms and springs.
Put them in and decided to use my spankin' new adjustable pushrod.
Drivers' side bank:
2 intake I didn't do because of the air pump bracket
2e: 8.771"
4i: 8.783"
4e: 8.785"
6i: 8.770"
6e: 8.767"
8i: 8.785"
8e: 8.767"
the pushrods I am currently using measure roughly 8.865"
so my preload is:
2e: 0.094"
4i: 0.082"
4e: 0.080"
6i: 0.095"
6e: 0.098"
8i: 0.080"
8e: 0.098"
I ran it to check for oil at all the rockers and it seems like all the intake arms are full of oil and the exhaust aren't but they are oiling. I also noticed some oil coming from the bottoms of all the stands against the head.

picasa web albums - 10772221827797118... - driver rocker...

Best of all I think the ticking is still there!
I'll take it for a test ride tomorrow and see...
 
So from what I can figure, I have pre-load on all 8 even cyclinder's lifters.
I can now push the rockers down and collapse the lifters. When this first started back in May and I was using pushrods that where about 0.070" shorter than now when I removed the lifters I couldn't collapse them w/my body weight pushing down with a pushrod.
Now, with them in the motor, I can by pushing down on the pushrod side of the rockers....
I can fit a 0.005" feeler gauge between the valve stem and rocker arms on all of them.
Question 1:
could I have ruined all the lifters from running them @3000rpm for 1.5 hrs on the highway many times if they had lash or only 0.010-0.020" pre-load?
Question 2:
could I now have too much preload with the new rocker assy and now I'm collapsing the lifters beyond their sweet spot?

I ran the motor and now I hear a "clicking" noise from what sounds like all the lifters versus my good 'ol "ticking" noise I have/had (can't tell w/all the clicking)?

While using the adjustable pushrod, I could collapse the lifters by making it longer. I had to go back and use "feel" as to when the rod got just long enough to take away any up/down movement of the rod. I could then collapse the lifter by pushing on the pushrod.
I haven't driven the truck w/the new rocker assy. Just the new longer pushrods. Maybe 300 miles but w/some 1.5hr highway trips spinning 3k rpm.
Any thoughts would be greatly appreciated!
 
Q1) possible but I doubt you hurt them. Not all of them for sure. I have had to fix engines that had hydraulic cams in them but the owner thought he had a solid lifters and set them all to .022/.026 lash. Ran for thousends of miles till. He asked why his engine had so much valve noise when compared to other solid cams. After a breif inspection I set the lifter preload and it is still quiet today
q2) your posted measured lifter preload is perfect and very even across all of them.

You have touchced all of the bases. Rockers/lifter preload and verified good top end oiling... Only one thing left and you saved the worst for last...

You have a lifter gallery oil supply problem.
Rear cam bearing is first on my list.
Could be installed out of sorts, to far to the rear of the block, rotationaly indexed so holes don't line up, some debris blocking or partialy blocking holes.

Rear cam cover gasket installed wrong or the wrong one...

IH used two basic designs for the sv. In my opinion it makes not difference if you use the one with the two fingers or the open one. I've built enough of them to see both gasket styles on factory unopened sv's. All have been quiet and tick free.

I recommend having a helper start your engine while taking a video of it so we can hear how the noise developes and ends up.
 
Last edited:
You must log in or register to reply here.
Back
Top