Cr8crshr's Motor Problems found, We think?

69a100

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Disscecting his motor to figure out where his knock was comming from we discovered that 2 of his Con rod side clearences when out to lunch. The book calls for .07-.019", his #1&2 were speced out at .028" and #7-8 rods came out to .021". The middle set were in tolerance. I'm sure this is where the knock was comming from, what do you motorheads think? It's a sad commentary to the fails that were built into this motor as it has some very good componets that are in the motor.
What would need to be done to salvage this motor, a new set of rods & bearings or what? :blob1:
 

cr8crshr

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Thanks Bro for getting this started. To piggy back on it....The motor when it was built by the Builder:angryfire: I contracted with, the invoice shows the he had to replace the #1 Rod as per his explanation..."It Was Cracked." He procured a single Rod for a 383 and the part numbers were run the last time I had this thing apart, and it is a correct rod for a 383 BB. Now I am sure back in the day that Ma Mopar wasn't the most thorough of motor builders and things were not as spot on as they are today. Technology finally caught up with itself and tolerances are much more finite now. That being said...this replacement Rod when I last had the motor apart didn't look the same as the others which are the originals to this motor. But here is the thing that baffles me!!! It works even though it is not original to the other 7 Rods. Is it possible that in replacing this one with the so called broken/cracked one, that too much milling was done to it at the crank end so that now I have this excessive side clearance issue with the #1/2 Rods. And #7/8 was news to me until today. I have a complete matching set of Rods for a 383 BB that I could swap out with the Pistons that are already in place. They are the Speed Pro 2315F/.30 over. As it stands right now I basically have 2, 383 BB's I am working with. The first is the one that is the problem child and the 2nd is the Short Block I picked up a few weeks ago. I have swapped out the heads to the second, Cam, Lifters, and Push Rids as well. All the exterior Motor parts, Intake, Fuel Pump, etc. is being swapped to the 2nd Motor. Connecting Rod Clearances and Crank Shaft End Play have been measured and check according to the FSM, and spec'd out to be within limits. I am using the FSM as my base line because I am not trying to build a race motor but more of a stock re-build with a little attitude. So far the feeling I have is that the 2nd Motor is going to be OK and come through for me. If not then it is on me because I am doing it all myself with the help of Brother Jon. In addition I also have a bare 440BB but that is for another time and usage. The first 383 BB Motor is salvageable and will be put together in a stock configuration. I will either sell it as a re-builder unit or for scrap but would like to see someone that can use a very good Block for something. Me...I would build a Stroker but I am getting at the point that after the new Motor is in and the car is either running or not, I am done with the Hobby and will liquidate all my parts and the 66 Ply Sat....cr8crshr/Tuck
 

dryheat

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Those numbers don't seem too horrible to me ... especially since the #1 rod was replaced. I don't think sightly larger side clearance would be the cause of the knocking. Have you plasti-gauged the rod bearings?
 

lewtot184

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i seriously doubt side clearance causes knocking. keep looking. i believe excessive side clearance can bleed oil (through off). pistons with straight pins will be noisey when cold. excessive bearing clearance can be noisey and cause the engine to run rough. keep looking.
 

69a100

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I can grab either #1 or 2 rod and wiggle it back and forth and it clanks against the other rod.
Dryheat- I don't see how you can say that they are not that excessive? For cryin out loud, the #1-2 rods are anywhere from .09"-.021" out of Mfgr specs seems like it's a problem to me, they put tolerances there for a reason. Yes, we gauged the bearings, they're fine.
 

Supershafts

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I have a motor purposely built using a totally different rod for a length and width i wanted.

I can literally just about put a pencil between the rods, i am beyond your .021 side clearance and can say that is not your noise problem trust me.

The only kinda issue a narrower rod presents is increased oiling off the crank (which i argue since even if the rod side clearance was tighter the same oil volume is going thru and out either a .130 side clearance or a .010 side clearance), which in turn i would address with better windage, scavenging and more pump. My motor makes no noise.

I didn't see the other thread, but what crank is being used and exactly when does the knock appear and it is constant thruout a rpm or not ?
 

cr8crshr

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Stock 383 BB Crank @ 20 under sized. Correct Crank and Rod Bearings. Knock appears each time the engine is fired up. Don't even mention the Valve Train, Rockers, and Lifters as that is not where the knocking is coming from. The first Motor is haunted at best because no matter how many times I tear it down, re-check the components and re-install, I am still getting a knock. The Pistons in the 1st BB do not have any indication of Valve/Piston Slap and only have slight ware from running the Motor. I have checked and re-checked the Crank/Flex Plate Bolts, and the Flex Plate to Torque Converter Bolts and with the exception of 1 stripped out Flex Plate to Converter Bolt...found that yesterday during inspection and will repair that or replace the Torque Converter...every thing matches up. Like I said in my earlier post, the 2nd Motor is coming along nicely and I have a good feeling about it. Just after all the set backs and let downs with the 1st BB, and the $$$$ I have put into it, I just hate to see it go to waste is all. Granted it ran but not correctly and the knocking was constant. I am off to do some more work on it so I will update later and grab some pics...More to follow....cr8crshr/Tuck
 

lewtot184

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the first BB strokers using BB chevy rods ran all day long.....thats not it
this is correct. i've put 470's together with .070+" side clearance with no issues. i have a 440 with about .040" side clearance; pistons are noisey cold, straight pins, but no rod side clearance noise. loose fuel pumps are noisey.
 

69a100

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i have a 440 with about .040" side clearance; pistons are noisey cold, straight pins, but no rod side clearance noise.

What do you mean by pistons noisey, is it because of the large clearance or something else? Otherwise then I have to say and assume that excessive side clearence can cause a rod knock and that everything else is a contradiction.
 

lewtot184

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What do you mean by pistons noisey, is it because of the large clearance or something else? Otherwise then I have to say and assume that excessive side clearence can cause a rod knock and that everything else is a contradiction.
a piston, especially a high performance piston, with the pin centered in the piston will "rock" (knocking sound) when cold. when the piston warms up and expands it stabilizes in the bore and is quiet. this is why almost all OEM pistons use an off set pin to reduce noise. if your hearts set on it go ahead and change the rods out and report back.
 

cr8crshr

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The more I get into this the more I am beginning to believe that the first motor is possessed....:DMAGE:
 

Supershafts

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I had a sb that made a lower end noise, sounded like a rod, woulda swore it was a rod had you heard it, removed bearings in every rod, nothing perfect clearnace, not even a slight scratch from micro dirt, replaced them anyway.
Made the noise still...
pulled the mains, replaced all bearings even though they have no signs of nothing.

Still made the same noise.................

Went out of the shop cold, made a 1/2 mile pass on both stages (150/200).

Nothing flew out, noise didn't change, i come back to the shop on both stages and my buddy said well there ain't nothing wrong with it, just leave the radio on.

Well i did that and Ignored it for a year as best i could ignore it.

Only thing that bothered me was the oil psi, it wouldn't get over 65 psi, at 4k, or over 6k rpm, 65 psi was the max..

After a year of listening to this sob lower end noise i couldn't ignore it anymore and ripped it out, made many passes on 2stgs, never hi-cupped or anything.

Ripped the motor out, pulled it all apart, checked pistons and bores and rods, wrist pins and crank and mains....

NOTHING, now my temper flared and things started getting tossed and hit with a hammer, smacked the crank right on the snout with a 32oz BP hammer.
then i heard the crank hit the floor (eagle forged) pissed off it fell over i turned to see that only the TOP half of the crank fell over...

The bottom half with a exceptionally perfect crack was still standing there, right on the trust main.

It could be put back together and you couldn't see the crack, this explained the noise and the oil psi issues clearly now.

Eagle demanded the crank be returned for them to figure out what happened, i had wanted to keep it for another shop front counter look at this shit item, but they really wanted it back, so away it went.

But the new crank i hit it first before putting it in, didn't fall over and the motor stopped making noise.
It was amazing that it came out in one piece and needed my temper to hit it to find the crack, i was about to put it back together after having blowing off some steam, had i never hit the crank with that hammer i may never have found that
 

69a100

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Ripped the motor out, pulled it all apart, checked pistons and bores and rods, wrist pins and crank and mains....

NOTHING, now my temper flared and things started getting tossed and hit with a hammer, smacked the crank right on the snout with a 32oz BP hammer.
then i heard the crank hit the floor (eagle forged) pissed off it fell over i turned to see that only the TOP half of the crank fell over...

The bottom half with a exceptionally perfect crack was still standing there, right on the trust main.

It could be put back together and you couldn't see the crack, this explained the noise and the oil psi issues clearly now.

Eagle demanded the crank be returned for them to figure out what happened, i had wanted to keep it for another shop front counter look at this shit item, but they really wanted it back, so away it went.

But the new crank i hit it first before putting it in, didn't fall over and the motor stopped making noise.
It was amazing that it came out in one piece and needed my temper to hit it to find the crack, i was about to put it back together after having blowing off some steam, had i never hit the crank with that hammer i may never have found that

Sooo, what are you saying, there was a hairline crack in your crank? I can see that being a problem but how would that cause a knock? Weird story.
 

Supershafts

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He's saying his motor is possessed, i just showed him and you thru true events that this motor went thru, that a crank made a knock noise just like that of a worn rod bearing and even upon disassembly and lifting the crank out didn't show it was cracked.

It's showing that it isn't always something that is common and easily found, it's also showing how a noise may sound like, and be exactly like what you think it is and doesn't need to be it at all.
.
It made noise since day one, but the crank was in one piece upon assembly and 1 piece upon disassembly, it was in 1 piece upon 3 other in vehicle inspections over the course of more than a year, if not for the hammer it would have been put back together and still making the noise.

The noise was the 2 halves of the crank moving ever so slightly, the crank was split straight thru between the thrust main, it was so straight you would have thought it was machined.

Only thing changed was the crank, no more noise.
 

cr8crshr

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69a100...You know that just might be the cause if you think about what I initially had with the crank issue and #1 piston skirt and then with the crank swap to the one know. The only running time on that motor is after I did the crank swap and the subsequent removals and re-builds. Might have to check it later today...See ya in a few...Bro
 

coloradodave

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Supershafts: Great story. I've filed that one in the way back of my brain. Never know when it might come in handy. Thanks for the info.
 

Supershafts

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I'll tell you guys what though, that crank made driving that very annoying, even though i did have some fun here and there i was always listening to it and staring at the oil psi and always wondering when that noise was gonna turn into the break i couldn't find and figure out and leave me stranded or worse in a world of shit from the bottom end coming thru the pan and putting oil under me at a high speed.

For more than a year i lived with that damn thing, though i will say this, after many discussions with Eagle back and fourth and me swearing the crank did this the minute i got it in and hit the pavement in front of the shop, they did send me another at no cost other than shipping.

Though i'll say this, i really did hit the new crank with a hammer before i put that one in.

Noises can be a sob to deal with, and live with
 

Cranky

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One thing that excessive rod side clearance can do is let the small end rub the piston but does that make a knocking sound. Possible, but the side clearance would have to be a lot. What's your crank end play like? If the thrust bearing clearance is excessive, then you might hear a low knocking sound. Piston pin clearance can be excessive too. What does the knock sound like?
 
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