Another Pushrod chewed up

I have read the other post, but am still at a lost as to what could be causing this issue as I have done most everything stated.

Last year, the 2nd pull out I chewed off a pushrod on the #5 cylinder. I went through and grooved the lifters, changed lifter bushings as they were a little loose, and a few other little things. Made it back out at the end of the year for a couple passes. When I prime it, you need to move the lifter off of base circle just a little to get the oil to flow out the top of the jesel rocker. We switched to fuel injection this winter, so I put it on the dyno. We made 12 pulls that day and everything looked great. 1st pull of the year about 6 secs into run(according to datalogger), both pushrods on #4 cylinder are chewed off. Any Ideas on what I am missing. The only difference between dyno and real life is length of run, and I missed the gear a little. Dyno max rpm was 8500 (record to 8200) and on the track it turned to 8900. Any ideas on where to look for what is causing this issue?

Thanks
Mike

my build is no where as big as your but i did have problem with the pushrod top end rad. breaking. during the inspecsion i notice that all my intakes were starting to fracture at the top. running thru its cycle i notice that the intake would come with in a few thou. of the rocker trunion and did leave a witness mark on the rocker. i changed the pr to a shorter length and its been working. the geom. is off a little with the the valve stem center

Any bluing?

Just a thought. At engine speeds you mention, I'm sure valve spring pressure is astronomical! Is the pushrod (structure) up to the task?

Dave.

When I prime it, you need to move the lifter off of base circle just a little to get the oil to flow out the top of the jesel rocker.


shouldnt have to move it to get oil, this is the problem, ive seen it too many times


bushings installed wrong,or oil hole in wrong spot,


feel free to call me

815 712 8738-rich


if not fixed it will happen again

That is what I was thinking. If it is never flowing on base circle, it will not lubricate the pushrod tips and rocker cups. I should have known better.


Thanks
Mike

I started comparing the old Crane Ultra Pro lifters I had to the new Morel lifters I put in. I find out that the Cranes have the oiling hole higher on the body by around 1/8" or so. This could be why when I switched lifters I had to start taking the cam off base circle to get oil to the top. Expensive little oversite on my part. Will let you know anything else I find

Mike

here's my deal...

https://www.429-460.com/t13953-push-rods-chewed-up

Ace

I have read and re-read those posts. It is very informative and got me to looking at some things. That is why I started comparing the lifters. There had to be something different between the 2. It just sucks and is discouraging to have it happen so early in the season, especially after 12 dyno pulls and everything seemed fine. At this point in time I don't have the time to work on it. The kids are busy in everything, baseball, 4-h, etc, etc and I would rather watch/help them than work on it.

Mike

Mike just take drem tool and make a small channel from the oil band to the lifter hole and put the lifters back In and reprise the motor

I done that the last time I had it apart to try and get a little more oil up top. It is still chewing the pushrods off. I think I need to either make a groove up the lifter or down the bushing to get the oil to flow a little at base circle. I think it needs to send a little oil up top on base circle otherwise you will never lubricate/cool the pushrod tips because the only time the oil is flowing it is lifting the valves.

Mike

Have you run this block with these bushings before?X

I had new bushing put in a couple years ago. The original bushings had .040 holes, and the new ones are .125. They put the new holes in the same location as the original bushings. But I also changed lifters at that time as well. Since then I have made a total (not counting dyno time) of 5 passes w/o breaking. With the oil hole being in a different location on the lifter body , I need to make a way for the oil to get to it while the cam is on base circle. That is why I was thinking of cutting a groove from the oil hole down the bushing a little to allow the oil to flow at base circle. I also spoke to Jesel this morning to order a couple replacement rockers, and he told me to make sure that the pushrod tips are compatible with their tool steel cups.

Mike

Did your machine shop hone the bushings for the proper clearance? If its to tight this could be a problem as well. I know I had to do this for my stock block 514

Yes, I got the spec from Morel on the bushings and they honed them to the recommended spec. I don't have a dial bore gauge that small, but I do have some telescoping ones, and as far as I could tell they were with in the spec. That was why I had them changed in the first place, they were tapered towards the bottom and were way loose.

Well, I did put my engine back together. It had good oil at all times, when priming, coming out of rockers, between rockers & pushrods, everywhere.Before we pulled I even poured a bunch of oil over the top of the rockers just in case. Well guess what. Went to a pull this weekend and burnt 5 more pushrods off, within 5 seconds. I heard the engine change tone and shut it down. Went a whole 90ft and all this chaos. I am at a total loss. If anyone has any ideas I would like to hear them. Who knows maybe in a couple years I will try again. Just very frustrated right now.

Mike

Give BOSS429 a call. He's pretty sharp.

what brand and weight oil?

Do you pushrods have the correct oil holes?

Springs good? Possible float?

Mike,

I'm wondering if they have the 210* radius pushrod ends on them. If they are 180* radius, then they should probably be the 210* stuff. Next question, are the pushrods hitting the underside of the main body of the rocker at full lift? Then another question is, are the pusrods hitting the pushrod holes in the heads? Whenever the shaft mounted rockers are used, we always need to elongate the pushrod holes. Make sure the pushrod clears the head throughout it's entire lift travel/cycle.

Due to the intake rocker being canted over around the intake port and the angularity of the pushrod, if the angularity is too great, then use a lifter with an offset cup in the lifter body.

Hope this helps,
Charlie

The valve springs are brand new. This was the first pass on them. They should be more than capable 400 lbs on the seat and 1100lbs open pressure. The push rods are trend 7/16 double taper .165 wall with .210 ball ends. I have elongated the holes in the head, and I will check to see about the rockers clearing the pushrods.

What else did you change? Other than the bushings?

Do the lifters have the same diameter wheel as the ones you where using before? Same cam specifications? Same rocker ratios?

yes all that is the same. I have had 2 different sets of lifters in there now. 1 set of crane ultra-pro & a set of Morels. Modified both to get oil at all times during valve cycle. It used to work. I ran it for 1 whole season before this started, and now I just keeps getting worse. It is doing it almost instantly out of the hole on every pass. But I made 12 dyno pulls this past winter and no issues what so ever. Is it possible I need tool steel tip pushrods? I see Manton makes some adjusters & tips?.

Bushing have everything in the same positions? Oil holes, slots etc? same sizes?

Are the installed correctly or have they slipped or moved?

Oil restricters in the block?

You replaced the adjuster on the chewed up parts?

There is oil at all times in the valve cycle now, from base circle to max lift and back down. It wasn't this way originally, but it was this last time. The results were actually worse. It started happening at the #4 & #5 cylinders 1 valve at a time, now it is all over the place, and several at 1 time. This last time it was 2 in & ex, 3 in, 6 ex, & 7 in. That is what makes this such a pain. There is no reasoning for which cylinder it is happening on. I could see if it was always on the same cylinder, but it is not. However while typing this I realize they are all in a row. 3 on 1 side and 2 on the other, right in the middle of the cylinder head.