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Ummmm.  I'm a little foggy on this right/wrong thing, but end up wrong a lot of the time.

 

Tom- can you be more descriptive of how the gaskets can be installed incorrectly?   Knowing that, I assume the correct way is simply not the wrong way as there are only two choices.

 

 

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21 minutes ago, Zimm63 said:

Ummmm.  I'm a little foggy on this right/wrong thing, but end up wrong a lot of the time.

 

Tom- can you be more descriptive of how the gaskets can be installed incorrectly?   Knowing that, I assume the correct way is simply not the wrong way as there are only two choices.

 

 

  When the intake gaskets are installed correctly the gasket completely surrounds the ports into the head . If you flip the gasket the voids/holes in the gasket will not align correctly with the ports. This can be inspected without removing the manifold, it can be seen by overhead inspection. I have seen this quite a few times also but when done it is pretty obvious in the way the engine responds.

Tom M

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Hey guys 

I just checked the flywheel and it looks to be in the correct location. I can see the alignment hole with the help of a small mirror and a light after pushing back the torque converter, thanks Tom for your instructions on that. The harmonic balancer looks ok too but I’m going to remove the fan belts tomorrow for a closer look.

 

Exhaust passages??? 

 

I was was hoping it would be one or the other so I can put this problem to rest.

 

Thanks, Joe Camisa 

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Hi guys, 

I took the day off to do more investigating on my car for this vibration problem. I confirmed the flywheel is in the correct position and the harmonic balancer is in good shape too. I ran the engine at various rpm’s to feel for vibration. Nothing really was present other than the running of a big V8. So I removed the rear axles and differential and took them to a rear end shop who “said these are fine, nothing wrong with them”. I put everything back together but was not able to road test because of weather. I’m going to try the plate under the carb to block off exhaust gases that was suggested earlier. This weekend I’ll take my drive shaft to another shop out of town for another opinion as this vibration was not as prominent prior to removing and rebuilding my driveshaft. 

 

Any thoughts or comments are appreciated. 

 

Thanks Joe Camisa 

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21 hours ago, joe c said:

Tom,

It's a 425 engine rebuilt in 1986 

 and transmission rebuilt 2018

both are original to the car.

 

thanks, Joe

  In my experience it is a well established pattern in `65 to find the 3:23 rear gear paired with a 425 equipped car. It is possible the 3:23 gear was the standard ratio with the 425, although I do not recall seeing any documentation to support same.

  Another possibility is that because Buick described the 425 option as a "high performance engine" the salesmen may have been encouraging the purchase of posi traction and a rear gear that would produce the desired result. No matter how it came about there seems to be a trend of finding the 3:23`s in `65 425 equipped cars. I`ve been tracking this for years as to obtain a reasonable pool of data because the 425 single 4 barrel equipped cars are few....but there seems to be a trend..

  Is your car also equipped with posi traction? If so, this is an option which would have been deliberately chosen so that may shed some light on the cause for any trend...

Tom Mooney

Edited by 1965rivgs (see edit history)
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Tom,

I don't believe I have a posi rear end, I can't find the markings to prove this. Although when I've tested this out on a stone driveway both wheels spin and also when reversing out of my garage one day the same thing happened with both wheels spin. On the hoist when both wheels are in the air they turn opposite not the same way.

 

The X in the circle is what I was looking for. I should have taken a look for that yesterday when the rear end was out but didn't think about it.

 

Thanks for the info,

 

Joe Camisa

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19 minutes ago, joe c said:

Tom,

I don't believe I have a posi rear end, I can't find the markings to prove this. Although when I've tested this out on a stone driveway both wheels spin and also when reversing out of my garage one day the same thing happened with both wheels spin. On the hoist when both wheels are in the air they turn opposite not the same way.

 

The X in the circle is what I was looking for. I should have taken a look for that yesterday when the rear end was out but didn't think about it.

 

Thanks for the info,

 

Joe Camisa

Joe,

  Some times if a posi has worn clutch plates the wheels will spin in different directions. Best way to tell is by inputing torque through the driveline when the tires are loaded as this will even apply worn clutch plates.

  Also, the filler plug on a posi rear will be a large square which protrudes from the plug. A non posi filler plug will be a recessed square which accepts the end of a 3/8ths extension.

  Curious if your car was built with a posi...

Tom Mooney

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24 minutes ago, joe c said:

Tom,

I don't believe I have a posi rear end, I can't find the markings to prove this. Although when I've tested this out on a stone driveway both wheels spin and also when reversing out of my garage one day the same thing happened with both wheels spin. On the hoist when both wheels are in the air they turn opposite not the same way.

 

The X in the circle is what I was looking for. I should have taken a look for that yesterday when the rear end was out but didn't think about it.

 

Thanks for the info,

 

Joe Camisa

If you want to be thorough about what the original gear ratio was when built clean off the bottom of the axle housing where the pumpkin installs and look for stampings. There are exceptions but generally one will find the ratio stamped in a "stacked" arrangement. For instance a "3" and underneath a "23"

 

Tom M

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Tom,

I’ve seen 3 with 70 stamped under the 3 

or stacked like you mentioned. I’ll take a better look to confirm these numbers. My brother in law who owned the car from 1970-81 said it has a posi rear end. Like you said if the clutch plates are worn that makes sense why both wheels spin on stones but not up in the air. Would worn clutch plates  cause vibration?

 

thanks Joe 

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1 hour ago, joe c said:

Ed, That’s the same stamping on my car too

so what exactly does this mean?

 

Joe

3.07 gear ratio. 

3 (whole number in the ratio ) on the top line;

07 ( decimal in the ratio ) on the bottom line,

 

A 3.23 rear end would have this stamping on it.

 

   3

  23

 

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Ed

I’m sure mine is stamped 3 stacked 70 just as you describe. 

i’m going to have to take a second look to be sure of the numbers  I’ll see if I have any pictures in my files. 

I’m still fighting with the vibration and can’t seem to figure out yet... very frustrating. 

 

Joe

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For the 9 3/8" rear end, there were some standard ratios and some optional ones.  3.07 and 3.23 were pretty standard - Tom Mooney elaborated on that.  The 1965 Gran Sport had a 3.42, and a trailer towing ratio of 3.91 was offered as an option.  There is some indication that a 4.45 gear was available but from what I've read, there's nothing in a parts manual with a part number.  No 3.70 ratio was offered.   The smaller A bodied cars with the 8.2" rear end had some other ratios like a 2.92 and a 3.73.  I'm doing this from memory so there's no guarantee of accuracy.  

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9 hours ago, telriv said:

Some one may have installed a Posi in the non posi carrier.

Good call Tom...I have a posi case here with a square fill plug that someone swiped the posi carrier from and installed a non posi carrier. I bought it for the 3:23 gears

Tom M

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Tom,

that makes sense that the stamping is generic. When I look up pictures these are the numbers I usually see in the pictures. That’s why I asked earlier about the common gear ratio being 307,308 I thought it was related somehow.  

 

Thanks, Joe 

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18 minutes ago, joe c said:

Tom,

that makes sense that the stamping is generic. When I look up pictures these are the numbers I usually see in the pictures. That’s why I asked earlier about the common gear ratio being 307,308 I thought it was related somehow.  

 

Thanks, Joe 

Here are some pics of a `65 GS stamp....there are quite a few light stampings in the housing including the ratio so sometimes its nearly impossible to make out the stampings, enjoy,

Tom Mooney

 

65 GS diff stamp 1.jpg

65 GS diff stamp 2.jpg

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Tom,

 

   Would you still have the Posi  fill plug from that rear & with the Posi tag??  It's a special thread which is a very fine thread & I haven't been able to find a replacement ANYWHERE.  I was at one of the last Riv. meets in P.A. about 10 years ago.  Someone I thought I knew & trusted said he had misplaced his & asked if I had one. Was told as soon as he found his he would return my plug.  Guess what, NEVER HAPPENED!!!!

   IF you do would you be willing to part with it & IF you do what would it take for you to part with it???  I am re-building a 4.45  Posi for my Riv. after I freshen up the engine & probably be taking it to 6K or beyond & IF I get it right I may have my Riv. in the 12's & MAYBE instead of pulling the left front an inch or so MAYBE pull both fronts.

 

Tom T.

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  • 3 weeks later...
On 12/19/2019 at 9:11 PM, telriv said:

Tom,

 

   Would you still have the Posi  fill plug from that rear & with the Posi tag??  It's a special thread which is a very fine thread & I haven't been able to find a replacement ANYWHERE.  I was at one of the last Riv. meets in P.A. about 10 years ago.  Someone I thought I knew & trusted said he had misplaced his & asked if I had one. Was told as soon as he found his he would return my plug.  Guess what, NEVER HAPPENED!!!!

   IF you do would you be willing to part with it & IF you do what would it take for you to part with it???  I am re-building a 4.45  Posi for my Riv. after I freshen up the engine & probably be taking it to 6K or beyond & IF I get it right I may have my Riv. in the 12's & MAYBE instead of pulling the left front an inch or so MAYBE pull both fronts.

 

Tom T.

Hi Tom,

  Just now saw this although it is stale...I am building a center section from misc parts I have accumulated to swap in and out depending on the situation.... as you are doing...actually planned to call you to see if you had a carrier for me? Lol...

Tom M

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  • 3 months later...

So I’m back at trying to solve my vibration problem I’m changing my rear axle bearings and seals today, don’t know if this will help but it’s cheap enough to try. On the hoist I used an electronic stethoscope and ran the car and listened... no unusual loud noise from each side of the axles or the center bearing mount just slightly louder on the 3 rd member near the pinion but not by much. I used a magnet and a clear cup I saw this on the internet..fill half with water and use this as a vibration detector...no vibration detected the water remained still while running the car through the gears. I’m still stumped where and why I’m getting this vibration. I’m going out tonight to bring the car home and road test after the bearing change so I’m hoping this makes a difference. This vibration is a there and not there kinda sound I’m not sure how to describe it but any thoughts from anyone. Thanks Joe

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Well after a road test the vibration seems to have eased a bit after changing the rear axle bearings but I can still feel it, now more relevant at 50 mph instead of 40 mph. Both bearings didn’t seem bad while changing them. I still believe this vibration is from the 3rd member bearings but not sure how to change them yet..

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