need some help ..again

[yannick47]

my mopars driving me insane / the best help i can get is from people whos 10,000 miles away lol anyws moving onto my next problem

my car vibrates around 3000 rpm on 3rd,2nd gear .dosent vibrate on idel (maybe a slight shake on the steering)
i think its the transmission thats vibrating(4 speed)
if i put my hand on the gear i can feel the vibration...
what could cause this?wronge flywheel?

the engine dated coded 73 so first i though i had a cast crank(the dampner which came with it was quite big)but my mech said its steel and ended up buying a dampener from summit for an internally balanced crank

how do i know if i got a cast and steel crank?if it all i got the wrong dampner on shouldnt the engine vibrate/shake a bit at idle?
the engines very straight while idling..no vibration
is there a way we can know?

if i rev it i can feel a slight vibration around 1500 rpm but goes away if i just move upto 1800

any help is much appreciated

 

[RustyRatRod]

Sounds like a balance problem of some sort. Here is how you tell cast vs steel. Cast cranks have a pencil thin parting line, like on the left, while forged cranks have a very wide parting like on the right, or sometimes none at all. You MIGHT be able to tell looking at the flywheel flange, but most likely you'll have to drop the oil pan to be sure.

 

[trimmer]

You must have both a harmonic balance and a flywheel that matches your particular crank. Morpar Performance manual has instructions how to drill a steel crank flywheel to match a cast crank. If either of these three items do not match it will vibrate like crazy and ruin your engine. Hope this helps.

 

[yannick47]

right so i need to pull the engine out again as i cant pull the oil pan atherwise....how do i know the diffrence between the flywheels...i did sme googling and found that cast cranks flywheels have 3 holes drilled onto them yeah?

and if the balancer was wrong would the engine have some vibration at idle??

 

[WP29440SE]

if that crank had the thick balancer on it originally, it needs to go back on there. from everything ive read , almost all 73 and up 440s are cast crank and externally balanced. if you still have that balancer, put it back on or get you one you can try before you pull the engine again, thats what i would do.

 

[yannick47]

yea thats what i wanted to do...but how do i make out if it works or not ??trying revving it up again and see if somethings wronge?and i got the pushrod thing sorted runs all good no noise ...just an update

if that crank had the thick balancer on it originally, it needs to go back on there. from everything ive read , almost all 73 and up 440s are cast crank and externally balanced. if you still have that balancer, put it back on or get you one you can try before you pull the engine again, thats what i would do.

 

[RustyRatRod]

If you get it right, trust me, you'll know it. lol

 

[yannick47]

man i hope so....here the thing the engine dosent vibrate(visually) even if i rev it up but if i sit inside the car i can feel it vibrate? maybe flywheel?i just noticed the passenger side headers touches the tortion bar:angryfire:

If you get it right, trust me, you'll know it. lol

 

[trimmer]

I just cracked open my M.P. manual and it says, "The1972 and 1973, 440-4 Bbl. high performance engine uses a different crank, PN-3671283. The standard 440 (1973) uses PN-3671242 crank. Both of these cranks are forged and differ from the 1971, 440 crank primarily in the balance weights that are required because of the lighter pistons used in the 1972-1973 engines. The cast crank was introduced in the 440 in 1974 PN-3751889".

 

[WP29440SE]

If you get it right, trust me, you'll know it. lol

exactly

man i hope so....here the thing the engine dosent vibrate(visually) even if i rev it up but if i sit inside the car i can feel it vibrate? maybe flywheel?i just noticed the passenger side headers touches the tortion bar:angryfire:

if the flywheel and the balancer are not matched to the crank , it is going to vibrate, and more often than not, it wont be visual. you arent going to notice it much at idle until you get the RPMS up. this is when it is going to do damage. if the crank is indeed a cast unit, it needs the proper balancer first regardless of what you are doing with the flywheel. if the header is hitting the torsion bar , you have other issues with engine alignment at the mounts, or the wrong headers. you will also get a vibration and/or rattles from the contact. you need to rule out the header contact as the problem, either with a hammer or dropping the header out of the way, or situating the engine so there is no contact. regardless, if that crank originally came with a cast balancer, it HAS to go back on, or you need to get one specifically for a cast crank. if you go putting a steel crank balancer on a cast crank, you are asking for engine failure.

- - - Updated - - -

The cast crank was introduced in the 440 in 1974 PN-3751889".

FWIW .... the cast crank i just pulled out of a 73 passenger car 440 is in fact a 3751889. but again , these are mopars , so anything is possible lol . it could have been a fluke. of course now i cant find where i read that 73 and up were cast

 

[trimmer]

Yes Super77se, I have also found that to be the case in some of my own engines I have personally torn down. I just quoted what is printed in my Mopar Engines manual (Part No. P4452790). I also understand that it has to do something with the actual production date of the engine in question as to day and month of the actual engine assembled at the factory. Not much surprises me when we are dealing with these vintage cars.

 

[RustyRatRod]

man i hope so....here the thing the engine dosent vibrate(visually) even if i rev it up but if i sit inside the car i can feel it vibrate? maybe flywheel?i just noticed the passenger side headers touches the tortion bar:angryfire:

Whatever you do, don't let it overwhelm you. It's just a material thing. If you get too much, step back and drink you a big glass of iced tea and relax a while. Knock it off one little chip at a time. You'll get it.

 

[coloradodave]

Rusty: Nice comparison picture of cast verses forged crank. Should help a lot of guys. Thanks for that.

 

[RustyRatRod]

Rusty: Nice comparison picture of cast verses forged crank. Should help a lot of guys. Thanks for that.

You betchya. I keep that one on file for just such occasions. ;)

 

[yannick47]

can ni use part number http://www.summitracing.com/parts/pfs-90013

it shows it can be used with both types of cranks

 

[RustyRatRod]

Yeah.

 

[Sharp929]

I guess, from reading thru this post and then going back and reading the original post. I have some questions.
1) Does it vibrate in 2nd gear at all RPMs?
2) Does it vibrate in 3rd gear at all RPMs?
3) Does it vibrate in 4th gear at all RPMs?
4) Does it start vibrating at a certain MPH, and then continue at anything past that?
5) If it does start vibrating at a certain MPH, what happens if you push the clutch in and move the engine thru different RPM ranges, while in the vibrating zone?

 

[yannick47]

I guess, from reading thru this post and then going back and reading the original post. I have some questions.
1) Does it vibrate in 2nd gear at all RPMs?
2) Does it vibrate in 3rd gear at all RPMs?
3) Does it vibrate in 4th gear at all RPMs?
4) Does it start vibrating at a certain MPH, and then continue at anything past that?
5) If it does start vibrating at a certain MPH, what happens if you push the clutch in and move the engine thru different RPM ranges, while in the vibrating zone?

no on all 4 gears vibration starts around 3000 rpms ....if i cruise around 2000...25000 there no vibration at all.if i press the clutch in the vibration goes away
i pulled the oil pan and found out i have a cast crank and i ran a balancer for internal engine around 300 miles now
hopefully there nothing wrong with bearings,engine etc
anyone wants a 73 roadrunner?:angryfire:

 

[RustyRatRod]

What about sitting still with the trans in neutral or the clutch depressed? When you run it up to 3K does it vibrate then?

 

[yannick47]

yes if its in neutral ,clutch not pressed in it vibrates at 3k

What about sitting still with the trans in neutral or the clutch depressed? When you run it up to 3K does it vibrate then?