DP #24 Engine failure....

[Adger Smith]

When you loose a rod bearing the extra clearance between the crank and whats left of the bearing and rod start acting like a slide hammer and all the damage you have is the results. This slide hammer effect snaps pins and pops the pin bosses out of pistons. It can also snap rod bolts. hummm 8,000 rpm = 133.3333 times a second that the slide hammer hits. Looks to me like you simply lost a bearing.. show us a picture of what is left of the bearing.. that might be all we need to see.

I didn't see any spun bearings in the pics on the site the link goes to?

Are there more pics?

[Chris "drooze" Wertman]

Originally Posted by LSP

I didn't see any spun bearings in the pics on the site the link goes to?

Are there more pics?

The only potentially spun bearing was #3, the #4 rod is sitting in its place in the pics (the Z'd rod)

All the rest of the journals are as clean as can be.

The engine drank garbage, and its hard to tell on the bearings (to me) what was caused by that and when.

Ive got another "issue" now that well isnt a product of anthing other than incorrect information. Note to self, when something "smells" bad spend the time to dig a little deeper not matter what everyone says (not everyone here) but it could have been a "misunderstanding", and a typo on Mopars part, or a change a bulletin wasnt recieved on.....and well.....a difference in early or late/other DP motors ? wont know till I talk to Stanton tommorow........no "good" solution that isnt really a "hack" in the time I have to make it to Houston. 1 chance....1 very small chance.....

Oh well...itll be "right" in the end just not by tommorow.

[CrateCamaro]

Super Stock GT with a 426 Hemi if its legal. Problem solved. Or start measuring for one of those oil retention diapers.

[Ed Wright]

I keep seeing coments about Scat rods. There is nothing wrong with them. I have used them for years, they came with ARP 2000 bolts. Never had to re-size one or correct the balance on a new one right out of the box. Never one single failure. Machining has always been dead nuts. I can't say that for Eagle and some others. Putting Manley rods in that one sure isn't going to cure anything. Valve to piston contact had nothing to do with that failure, nor did the rods.

[Chris "drooze" Wertman]

Originally Posted by Ed Wright

I keep seeing coments about Scat rods. There is nothing wrong with them. I have used them for years, they came with ARP 2000 bolts. Never had to re-size one or correct the balance on a new one right out of the box. Never one single failure. Machining has always been dead nuts. I can't say that for Eagle and some others. Putting Manley rods in that one sure isn't going to cure anything. Valve to piston contact had nothing to do with that failure, nor did the rods.

I will agree....I dont know about the rods coming out of round. I have not seen that in person, These do not have the ARP2000 bolts even just the base 8740's

I am shocked at the fact the rods held and didnt break, for a budget engine I will definatley consider them.

I will say the machining is like you said "dead nuts" on myself and others were suprised at a 300$ set of rods would be this accurate.

One of the "issues" with the Scat rod it it requires the crank to be reground and journals widened to work.

The manley does not.

In addition the manley well....its a good rod, and good for 1000 hp in this series thats been proven in many other engines. I do know well never make that kind of power, but I cannot see a Scat rod (not the one we have) doing that.

We got the real "bargain basement" of the scat rods. Most everyone sells good, better best and bargain....we got bargain.

Im not bashing scat or dont mean to, the choice by whoever it was that this particular scat rod was chosen, and we were not given a choice ? Well that is were the real issue lies.

And the bolts, we were led to believe the bolts were different and the 2000 series...they are not.

Your right also we thanks to the help here have come to the conclustion netiher the rods or the PTV contact caused our failure, but rather the bolts if they didnt played a role. of the ones I personally took out 2 (1 on each journal) took another 20+ lbs of torque to get to their "stretch" and suggested torque range of 63 lbs.... yes 63 lbs...

Having to take a stock crank and have it machined JUST to run these rods....when I can take a set of Manleys and they will run on the stock 2.125 journal and are better, have much better bolts and the same bearings HN, HXN, and more undersizes are available ? Well it makes sense to me anyway.

K1 is getting an H beam approved, that may be an option down the road, but isnt now, and when it will ? At least 6 weeks away according to Tom over at K1

Chris

[Rich Biebel]

It is a basic engine....really nothing out of the ordinary. Bore/stroke/crank pins/rod length/piston and rod weights.......all similar to hundreds or thousands of engines........The design/sizing/parts are not unusual.....The heads are a bit different than a wedge or a porcupine like a BB Chev or a Cleveland Ford.......but nothing really out of the ordinary in the bottom end.

So, the diagnosis is simply that an overly agressive burnout led to an rpm that caused the rod bolts to break???..........

What exactly was the problem with the first engine? I don;t recall hearing any details of that one....

And what about the valve issue where the heads were pulled and fixed by the Pro Stock engine builder. Had some sort of dragging valve issue and hit a piston ???.......

Personally I don' t see anything all that unusal in the bottom end.

Shouldn't be all that hard to make one stay alive........


P.S. I have an SFI diaper on my dragster......Makes me feel a lot safer at 170.........I also have 2 sets of brakes and a parachute.........

If you ever oiled your tires up from a blown engine you'll be wishing you had a diaper......

I did lose and engine in low gear and was fine, then a little voice in my head said go over on the grass so you don't slop up the racetrack.......not a good idea....came within inches of tagging the guardrail......

Grass next to the racing surface was another bad idea......luckily I did not hit anything......

[Chris "drooze" Wertman]

Originally Posted by Rich Biebel

So, the diagnosis is simply that an overly agressive burnout led to an rpm that caused the rod bolts to break???..........

What exactly was the problem with the first engine? I don;t recall hearing any details of that one....

And what about the valve issue where the heads were pulled and fixed by the Pro Stock engine builder. Had some sort of dragging valve issue and hit a piston ???..........

#1 Pretty much......with really crap bolts I may add, ARP lists them for STREET use....

#2 Well it was several problems that were a combination of people faults, ours included to some degree, but Ma Mopar well she took care of it in stellar order for us , even having me up to Stantons to see the motor Dynod, dissasembled, inspected, checked and re-assembled....as well as some other work they were nice enough to include. Thats all that matters on that one to us.

#3 That was MY issue, there was a binding on one of the rocker collar retainer shims against a rocker shaft stand. Or a very good possiblity of a lock condition between the keeper and the rocker Clearance was a bit tight (on a NORMAL engine its only about .060 there on a DP about .040 , and on ours with the moly retainers we "tried" well it was a possiblity. Changed retainer, changed shim clearances and it hasnt resurfaced, even the head guy agreed it was probably a "combination" issue with those 2 items.

I like the thought of a diaper, saftey equiptment dosent scare me in the least, Ive landed on my head on a motorcycle several times at odd angles between 70-100 mph and walked away (ok not always walked away) but something to be said for saftey gear....

AND on our car the clearance around the engine would be fine with it.

The only thing that worries me is oil temp...thats it.....but till I use one I wont know I guess.....I like the "Pan" idea better because well....a)it looks trick b)its got an airgap and a place to but my hotplate pan warmer c)Im used to it, and I cant pull the pan without pulling the motor, so it would just fasten on then and I could put a trapdoor in the bottom. Just me being me I guess...

[mtkawboy]

Hang in there, its been forgotten by now but there was a very large learning curve to keeping 428 Cobrajets alive in stock & especially SS for years.

[Chris "drooze" Wertman]

Originally Posted by mtkawboy

Hang in there, its been forgotten by now but there was a very large learning curve to keeping 428 Cobrajets alive in stock & especially SS for years.

Im going to "cross post" this to 2 threads related...

What yall think about these mains ?