Crank Thrusting Foreward Issues

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T56MaxTorq said:
Well I built my 318 turbo Magnum from the oil pan up but I noticed an issue the other day. I have a trigger wheel installed on my balancer and when I give it a little rev, the balancer and bolt all move foreward about .020" to .035"

I noticed this first when I was putting on the custom 36-1 trigger wheel. But the bolt wasn't torqued just yet. I torqued the bolt and it didn't happen anymore. I've had a lot of issues with this wheel setup and have had it on and off many many times and finally got it right and bolt torqued. But I don't recall if it was ever ran hard with the bolt only snugged down, not torqued. The thrusting hasn't affected the crank sensor...yet. I always put that crowbar on and thrust the crank when torquing that main cap. Any ideas??

Thanks fellas
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Thrust bearing,crank will be shot too.
 
Thanks for all the advice guys, much appreciated. I'm gonna have to take the pan off and check it out. I built the transmission so I understand the fundamentals of the pump and converter. I can't say for sure if the converter came out of the pumps' slots or not and was forced in, nor do I remember having to pull the converter fwd to start the flexplate to converter bolts, but I have a feeling the install was uneventful. Next time I will have to document everything thouroughly. I'm no stranger to a mopar engine build, this is my third, I can't see why i wouldn't have checked the crank end play after torquing the caps down. I have all the tools. It was about 2 years ago. I won't be able to take the pan off for a while but I will follow up to report the diagnosis. Thanks again fellas!
 
T56MaxTorq said:
Thanks for all the advice guys, much appreciated. I'm gonna have to take the pan off and check it out. I built the transmission so I understand the fundamentals of the pump and converter. I can't say for sure if the converter came out of the pumps' slots or not and was forced in, nor do I remember having to pull the converter fwd to start the flexplate to converter bolts, but I have a feeling the install was uneventful. Next time I will have to document everything thouroughly. I'm no stranger to a mopar engine build, this is my third, I can't see why i wouldn't have checked the crank end play after torquing the caps down. I have all the tools. It was about 2 years ago. I won't be able to take the pan off for a while but I will follow up to report the diagnosis. Thanks again fellas!
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Can you even get the pan off in the car? I must have missed the application somewhere in the thread.

If you catch it quick enough, you can clean it up, polish the crank and drop bearings in it and go. Doubt it killed the crank, unless it has been out for a while or the crank was jacked up from the gitgo.
 
yellow rose said:
Can you even get the pan off in the car? I must have missed the application somewhere in the thread.

If you catch it quick enough, you can clean it up, polish the crank and drop bearings in it and go. Doubt it killed the crank, unless it has been out for a while or the crank was jacked up from the gitgo.
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Yeah I would probably have to at least hoist the engine up a couple inches to remove the pan, if I'm lucky. I built a custom baffled pan for it that shrouds the pickup screen so it's a little stupid getting the pan on/off. I want to check out #3 bearing and go from there. I honestly don't think I could have let that amount of end play slide during the build. I want to say i even measured using my dial indicator and it was within limits. I hate to toot my own horn but I've been building aircraft turbine engines and propellers for the past 11 years so I have a decent amount of attention to detail. But who knows...stranger things have happened Lol. I do think I whacked the balancer a few times to persuade it to go on straight but it was only a 1 lb plastic dead-blow. Live and learn, hopefully it's not too bad and I find a smoking gun.
 
Are they stock bolts on your main caps........or arp studs and nuts?
 
In 1978, I had a low $ fixer upper rebuild on my 383.
By 1980 I had noticed about 1/4 inch forward thrust when blipping the throttle from idle.
You could actually feel it whump forward onto the #3 thrust face.
At about the same time, the mains had worn so you could feel/hear
the crank whip and throb at lower rpm in hot weather. Put in all new mains while in the car one Sunday afternoon.
Crank throb was gone, but only half the crank walk.
Lived with that until I did a full proper rebuild in 1986, and there was a pretty good worn spot on the forged crank to weld up, but smooth as glass.If it's an automatic trans, and you have floating piston pins, fret not.
But it's new, check it out.
Much cheaper before something breaks.
 
Darthomas said:
In 1978, I had a low $ fixer upper rebuild on my 383.
By 1980 I had noticed about 1/4 inch forward thrust when blipping the throttle from idle.
You could actually feel it whump forward onto the #3 thrust face.
At about the same time, the mains had worn so you could feel/hear
the crank whip and throb at lower rpm in hot weather. Put in all new mains while in the car one Sunday afternoon.
Crank throb was gone, but only half the crank walk.
Lived with that until I did a full proper rebuild in 1986, and there was a pretty good worn spot on the forged crank to weld up, but smooth as glass.If it's an automatic trans, and you have floating piston pins, fret not.
But it's new, check it out.
Much cheaper before something breaks.
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Fret not?
it needs to be checked out A.S.P.
 
This is a good insurance policy. J.Rob

Thrustfix.jpg
 
They're oem bolts. I only installed arp rod bolts.

J.rob, I believe I installed fully grooved main bearings for oiling.

I can't imagine I missed this much end play. Something had to have broken loose in there under boost. Unfortunately, It'll be a while til I can tear it open
 
T56MaxTorq said:
They're oem bolts. I only installed arp rod bolts.

J.rob, I believe I installed fully grooved main bearings for oiling.

I can't imagine I missed this much end play. Something had to have broken loose in there under boost. Unfortunately, It'll be a while til I can tear it open
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I was referring to the drill bit, illustrating what I do to ensure pressurized oiling to the rear thrust surface. J.Rob
 
Just a thought: Erratic rough running sometimes indicates a broken crank under a main bearing....
 
RAMM said:
I was referring to the drill bit, illustrating what I do to ensure pressurized oiling to the rear thrust surface. J.Rob
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Ooh, ooh, ooh, that is the coolest idea I have seen in a loooooong time.
 
Wow didn't notice the drill bit, that's a great idea!

Engine runs very well. Timing is rock solid. Crank doesn't blow out of the pan at 13 psi. Just wants to thrust forward.
 
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Here's an old 440 crank #3 main. Top is toward engine front, bottom is rear.
Think it had "some" play?

WastedThrust.jpg
 
I ask about the arp main studs because they pushed my main cap out on #3 and cause basicly 0 clearance. 0 clearance translates into burned up thrust on #3 bearing.(not the issue for you)
Nice drill bit, didn't catch that at first either!
It's almost like the thrust bearing didn't get installed, or didn't come in the kit.....?
Were all just guessing, waiting for you to pull the pan off.
 
The timing chain (double roller) was surprisingly tight after 4 years of the crank walking. But it was only a quarter inch for a little while, maybe 3 years at 1/8".
 
Ironmike said:
I love this idea. Especially with a stck car. I think I might steal it from ya. I'm assuming through the the bearing and the rear saddle surface.....I'm thinking a teeny tiny hole is all you need. What size bit?
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Be my guest, this is why I shared it. Steve Dulcich had this problem with a 318 and I suggested this as a fix. He called me up and he published this fix and some pics I took in an issue of EngineMasters Mag. It works so well I do it on almost all engines with a #3 main thrust--even Fords. Use a small bit, I think I used a 1/16" the first time and then moved to a 1/32" but it is scary , you don't want to break a bit in that awkward position. J.Rob
 
Cool idea RAMM - but I'd be panicking with the small bit too...lol.
 
Interesting on the extra hole to the thrust faces and the wear problem ever ocurring in the first place...... It would not be obvious to me that oiling to the thrust faces would ever be a problem if the main bearing itself was getting adequate oil. RAMM, was this a solution for manual 318 that was seeing hard service, or what?
 
I'm wondering if it possible this might "starve" #3 main .........
Just a thought.
 
Ironmike said:
I'm wondering if it possible this might "starve" #3 main .........
Just a thought.
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I think i would want to do all the other oil mod that keep the oil at the crank, before i did this one..........and i would only do it on the back side.....IF i had a clutch car.
Still like the idea.

To the Op. I would be looking at the bearing surface on that #3 bearing. maybe some trash got in the oil hole feeding that bearing and you're about to spin a bearing as well as have to much end play!
 
Ironmike said:
I'm wondering if it possible this might "starve" #3 main .........
Just a thought.
Click to expand...
I would not worry over it with such a small hole as is being recommended. Remember, #2 and #4 mains oil feeds also have feed oil up through the cam to the heads, and that extra oil flow to each head does not starve those mains particularly.
 
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