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6.2 / np465 question

R

rustywagoneersdotcom

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Good Afternoon, Folks.

New here, first post, first thread, etc.
The 700 in my diesel Sub laid down again, and I am fed up. Pulled apart an 84 light 3/4ton (9.5 14b - 4.10's)
Swapped axles, 2 inch lift, 36's and swapped in the 465 / 208 combo. (light duty, family hauler camping type rig, not psycho rock crawler).

Anyone else find after doing similar that the diesel shakes the cr@p out of the 465 (lots of gear noise at idle, quiet on the road)
If so, what did you do about it? Change idle speed? Dual-Mass Flywheel? Nothing?

any info appreciated.
I would have thrown this in the diesel section but I have 4 kids and NO money...

peace
Dave
 
i did not notice any gear chatter - did almost the exact same swap into my blazer - 6.2/465/205/14bff/d44. sorry. is your flywheel new? did you have a flexplate which was balanced to your engine previously? how's your harmonic balancer? i don't know why that would happen at idle - perhaps if it's coming off of idle you have u-joint problems? can you further define this:

Anyone else find after doing similar that the diesel shakes the cr@p out of the 465 (lots of gear noise at idle, quiet on the road)
Click to expand...

maybe that will help.
 
Noisy at idle could just be a bad throw-out bearing...

Rene
 
new T/O brg (full clutch set) completely silent with clutch pedal depressed.

gas 350 flywheel, balanced to match the flexplate which came off the 6.2 / 700 combo. changed ring gear to 6.2 ring gear (after finding out the hard way that 6.2's use a 10-pitch /139 tooth ring gear versus the gasser 12-14 pitch / 168 tooth...

when i say 'shakes the crap out of the 465' i mean, it is like the countergear is bouncing back and forth as the truck idles in neutral. imagine the input gear rotating faster each time a cylinder fires (positive pulse) and slowing at the next compression stroke (negative pulse)

there is no vibration, no shaking that you can feel as the engine runs, it is just a LOT more noise out of this 465 now than when it was in the gas pickup which was disassembled.

thanks for the input so far, any more also appreciated.
peace
Dave
 
hmmmm...

I was under the assumption no other flywheel ,gas or diesel,would bolt up to a 6.2???....thats what I've read anyway!..I thought only a 6.2 or perhaps a 6.5 one would fit...I have no clue whether the diesels are internally or externally balanced..I know the 400 sb and 454 are externally balanced,and will shake like a hula dancer with the wrong flywheel (or harmonic balancer) on them!..

I don't know about your vibration problem,but I do have a friend with an 87 C30 ramp truck I drive sometimes--it has a SM465/6.2,and I don't notice it vibrating that much--more than a gas motor would,but not enough to be annoying or make you think there is something wrong with it.. perhaps your bellhousing is misaligned a bit,causing run out in the mainshaft?..:crazy:
 
And definitely use their own specific flywheel...

Rene
 
no shaking at all, perfectly smooth.. flywheel has same bolt pattern as SBC and BBC at crank flange, gas and 6.2 use same diameter pilot bushing, etc etc etc. this flywheel was balanced to this engine, and the ring gear was changed to the 6.2

it is 100 percent externally balanced.

the problem is that the 465 is noisy at idle, in neutral. if the trans had been noisy in the gas truck i would say it was the trans, but then again, i wouldn;t have stuffed it in this one...

say you have the label specified 800 rpm (or whatever rpm) idle... the engine, measured by the minute, is indeed making 800 revolutions... but the instantaneous velocity will spike 'up' at each firing impulse. this trans acts just like the countergear is being tossed forward at each impulse and as everything rotates the countergear is using up the backlash in the teeth, 'rattling' from drive side to coast side of the input gear teeth...

anyway... it appears that no one using this combo has experienced this condition so far...

thanks for the input, folks.

peace
Dave
 
My SM 465 had roughly 300,000 miles behind a 350 before I swapped in a 6.2 and bolted it up, and it acted no different and was not noisier in any way. That SM 465 after spending 3 years behind my 6.2 is now in Colby's truck behind yet another 6.2 and I'm sure Colby will chime in on whether or not it is noisy behind his. I don't think it is.

The 'velocity spikes' you mention are much stronger with a diesel, however even at 600 rpm I'd say those spikes are so close together that they shouldn't be noticeable. 600 rpm = 10 revs per second = 40 spikes per second (4 cylinders fire per revolution)

Rene
 
once again, thanks for the input... i was afraid no one else would have had theirs act like this... i guess i will change it to 85-140 and make sure i have a spare in stock, just in case this thing is indeed grinding itself apart...

peace
Dave
 
At this point I'd be suspecting a bearing, if the old oil is silvery looking there probably isn't much point in using a thicker oil...

Are you running 90W now?

Rene
 
The input bearing is a common item to replace on a SM465. That said, I have never 'needed' to change one. I run 85W140 oil in mine with the 6.2L. I've never found a 465 to be exactly what I would call quiet though.

The correct 6.2L flywheel weighs at least 50% more than a 350 flywheel. I wonder if there enough weight there to properly dampen the velocity spikes.
 
u2slow said:
The input bearing is a common item to replace on a SM465. That said, I have never 'needed' to change one. I run 85W140 oil in mine with the 6.2L. I've never found a 465 to be exactly what I would call quiet though.

The correct 6.2L flywheel weighs at least 50% more than a 350 flywheel. I wonder if there enough weight there to properly dampen the velocity spikes.
Click to expand...

Well the SM465 is a rock crusher trans so that means it has straight cut gears so you always here at the very least a definative whirr from it. It is easiest to hear it at idle, at least for me.

The engine I have in my truck now is 305 from an auto Firebird and all that was done was swap the flywheel from the junk 350 to the 305. But I would be sceptical that you can use a gas fly wheel with a diesel. I think the fly wheel is your problem.
 
Only first and reverse are straight cut, the rest are helical...

Rene
 
tRustyK5 said:
Only first and reverse are straight cut, the rest are helical...

Rene
Click to expand...

Wait, I thought they were all straight cut? :dunno:
 
Not the greatest view, but you can see it here.

SM465_exploded_bw.gif


Rene
 
Better view...

4x4sm465.jpg



And, it looks like it's just reverse that is straight cut...

Rene
 
thanks folks. I could definitely see a heavier 'wheel being a lot of help.

i will have to try to find a REAL 6.2 flywheel, instead of my homemade one..

85-140 is a fair amount quieter... the stuff that i topped off with 90 wt may have been slightly thinner, judging by the rate at which it came out of the gearbox. BUT no shiny, flaky, silver, etc, so i think all is (relatively) well.

peace
Dave
 
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