Burnt Push rods

Looking for some direction on a problem I'm having. My KB BAE fat head 4 motor keeps eating push rods. I replaced valve springs and this amplified my problem. I ran external oil lines to the heads, relocated the rocker stands to acomidate the external lines and welded the ends of the rocker shafts. The last straw was at my last race, I ordered all new IRC push rods and adjusters. used high temp high pressure grease to fill the push rod cups. plus used Lucas on all tips and rollers. On the warm up it burnt #3 intake push rod and adjuster. Put a new push rod in and adjuster and made a 330 ft pass. Brought it back to find all 8 intake push rods destroyed. I brought it home and drove the oil pump with an electric drill, have very good oil flow at all rocker arm tips. Am I using the wrong brand push rods or is there something I'm overlooking. The regimine of lube I use worked in my prevous combination with pretty good results. I need your help. Thanks In advance!

 

I use peanut butter..this is a detroit diesel torx compound, I put it in the cups and use torco on the tips also I use manton push rods and have never had a problem..good luck Dave Lowe

 

We had the same problem, but not that bad. We took the adjusters out of the rockers and ground a small flat spot on the very end. That let some grease stay in the pushrod cups ! End of problem !

 

my experiance w/burnt pushrods, i have found these causes

to much spring psi
incorrect pushrod lengths
to tight of valve lash
not lubing cups before first start up
oil not being warm enough
wrong rocker geometry

take your pick im sure there is more.......hope this helps

 

I have used IRC pushrods for years and I can't say enough good things about Mike and Walt Austin and how they have taken care of me over the years. We also have burnt a few pushrods over the years. For us the fix was the PSI modification to the intake rockers. This way the oil actually comes out through the adjuster ball. Another part of the PSI mods is to grind a groove around #4 cam journal so the oil goes to the heads constantlynot just when the hole in the cam aligns with the hole in the cam bearing. Another fix is to ensure the passage from the cam to the rockers is clear. Also clearance the bolts in the rocker stands so the oil can get past them and all the way to the end rockers. I always grease the cups with an extreme pressure grease before I start the car when the motor is cold. Another thing is to set the valve lash at the hot setting all the time this leaves some space for oiling when they are cold. They only oil during the time when there is clearance between the adjuster and the valve head. A motor runs best when it has all eight cylinders working and getting the pushrods to live can be a real pain.

 

As with most folks on this board we have all burned a few cups and rods I switched to manton tool steel adjusters with the hole and a set of pushrods with tool steel cups. We went all year without a single failure they where pricey but Im sold on them,
Gary

 

whosyrdady,

We used to have those same problems, but since we opened up the oil groove on the camshaft itself for the past couple saesons we havent had a problem. We put it in the lathe and open it up to about 90 thou wide. Now we get lots of oil up there and no problems. Just make sure not to cut any deeper than the original groove.

Another thing we do for the first warmup of every day is take one bolt out of the intake rocker shaft and with the squeeze bottle cram oil in there till it pours out the intake rockers. We found that helps too, only need to do it first warm up, or if you take the stands off between rounds for any reason.

Went to the Manton adjusters this year too, they seem a whole heck of a lot harder and don't seem to burn quite as easy as the others we have used.

Good luck!

 

Your problems will go away if you do what Dave Germain says. We almost burned our car to the ground at Phoenix a few years ago after tossing number two intake pushrod off in low gear. I don't want that to happen again.

Along with what he said I recommend going to the next larger size push rod cups and adjusters. It spreads the load and reduces PSI pressure.

Lastly, there have been a lot of discussions on oil here lately. Make sure you are using one of the oils recommended by the guys who race hard. I like Valvoline 70wt nitro oil with Pyroil additive. Oils with SJ and later ratings where the zinc and phosphates are pulled back will give you grief. Rule of thumb...if your oil can be purchased over the counter, don't use it.

I like the grease from Lubrication Engineers. It's tough to find but works very well as a prelube.

 

where can this peanut butter compound be bought at,thanks!

 

Grease around the cup just keeps the oil from getting in where it should be!!

 

make sure to lap in the cups- just use lapping compuond and the push rod end in a drill--high spots in the cup are both common and a killer!

 

Detroit Diesel #2 Compound is what you're looking for. It costs about 38 dollars for a can of it, and your friendly local Detroit Diesel dealers can get it for you. It's also great for head studs and nuts. Don't use it on main or rod bolts, as you'll close up the clearances and make a mess of things.
Henry

 

Update

Bob; that's an old thought, but when you think about it, it simply doesn't work. Dave Crower talked us into putting the adjuster ball in the drill press while moving the pushrod cup by hand using lapping compound. The finish and fit were brilliant, meaning there was NO place for the oil to be !!! This was in the 80's with the Donovan when 240 lbs. spring pressure was a lot.
One of my Aussies just sends the adjusters out for "Nitrite" finish and problem gone.

 

Bob- you are smarter than me- but if the ball rides on high spots it causes friction= heat = death
We used to go thru push rods on the warm up and on burn outs, but we use rifle drilled adjusters at present and with grease added when we set the valves we have never lost another push rod---just our experience--

 

I have also experienced burnt out push rod tips or broken tips through out the season on the intake only with my Veney combination and what I experienced was that it all dependent on weather or not I had a clean run on the car weather I had problems or not. I could make a hard run and even hit 10,000 rpm but as long as the motor was happy I would not experience problems. I have tried the Manton tips but had better susses with a tip I bought from Roger Way Racing not sure the make.
I have tried Bob’s suggestion of lapping in the Manton tips on 2 particular pushrod tips that I burnt out on a previous run and next run those 2 tips burnt out again. I then went to the tips that RWR supplied me and Smith Brother push rods the problem went away. I have compared the Manton push rods to the Smith Brothers push rods and also had better success with the Smith Brothers push rods. But over all through out the season it seam that if I was on a very rough track or peddled it at all I would be looking for burt out push rods or broken tips at the next tear down.
The last 2 season’s I would start with all Manton tips and pushrods on the intake as I thought they were the best and would only change these out as I had problems with the tips but by the time the end of the last two season came around I ended up back with the push rod tips from RWR and back to the push rods from Smith Brothers on all the intakes but still running the Maton's tips and push rods on the exhaust.
I did not think that the manufacture type would make such a difference but I guess it is what every makes your combination happy.
Roger maybe you can comment on who the manufacturer is on those tips that you supplied me not the Manton ones.
Greg Sereda TAD699

 

Whosyourdady: on your 4s check to see if the pushrod is hitting the rocker at full lift. You will see a witness mark on the rocker. If so, you can clearance the rocker with a die grinder so it will not side load the pushrod.

Opening up the restrictor by 10% or so often solves lesser blackening problems.

Then again what do I know, been chasing #2and #4 exhaust and can't seem to shake it.

 

Mike canter...thank you so much, I have learned alot by reading all your post, you have taught me alot of things, you go very deep into subjects...Thank you again. also like Mike said call terry manton he will help you find the problem, he did for us. thanks Dave Lowe

 

Why fix it?

It helps with keeping the crew in shape...

After warming up for first round you have to quickly fix the burnt push rod end or ends for first round...

What fun..

 

peanut butter

buy peanut butter at any Detroit Deisel parts counter. Western country racing