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Rytari
03-26-2009, 14:08
i have 62 diesel in my 83 caprice, its orginally equpped with diesel but the size of the engine in been cahnged during the years...

now im been thinking some gears... i have good memory in my mind about my 6,2 blazer mpg when changing 3.08 gears to 4.56 ones... maybe some 6-7 mpg change in consuption...

now wondering if i can do the same for my caprice...

i have od trans so the 4th gear is 0.70 ratio... but what could be the caprice orginal rear gear ratio.. where to find it...

correct me if im wrong but some 1800 rpm would be what 6.2 likes... now i dont have that much... gear calculator says that at 1800rpm@55mph needs some 4:1 gears...?? does anybody have some experience about the issue...
convert2diesel
03-26-2009, 19:03
Typically this vintage of Chevy came with the 2.73 or 2.93 gears, especially if it was a diesel from the factory. 3.23 gears were used alot in the trailer towing package but never have never seen a diesel with the towing option. If the 5.7 was ordered, the manual states no more then 1,000 lbs.

The Buick I converted started out life with 3.23 gears but when I tow with it, I use only 3rd gear. The 3.23 gears make it hard to maintain 60 MPH (noise more then the ability). Have since gone with the 2.93 but they are a little to tall when in 4th (1,650 at 60 MPH). There are a bunch of options available for these diffs from the aftermarket, but if you are using 15 in. tires, I wouldn't go higher the 3.23 or 3.43 with the 200.

Bill
Rytari
03-27-2009, 10:17
i made some tests with gear calculator...

28" is approx size of my tires...

at 60 mph 4th gear calculator says following.

3.73:1 1800 rpm

3.42 1664 rpm

3.23 1567 rpm

3.08 1494 rpm

2.73 1324rpm

but i have to drive mostly 50-55 mph (tax thing :) )so it wll be lower rpm... now driving 50 at 4th is hard play for the trans... im wondering if 373 is too much for it.. but w/3.23 only 1300 rpm@50mph sound still little low for me and 3.42 gives only 50 rpm more at 50mph... but im not sure if i have calculated my tire size correct.. and converter increases some 200 rpm i think?
convert2diesel
03-27-2009, 13:29
Two questions:

1. How did you manage to marry a 6.2 to a 200r4? Was not aware of any 200s that had the chevy bolt pattern. All the ones I have seen are the BOC (Buick, Olds, Cadillac) pattern.

2. What rpm convertor are you using? See if the following works better (or for that matter , actually loads). Allows you to convert tire size as well as do rpm calculations.

Bill
Rytari
03-28-2009, 07:19
i havnt done the conversion... its some previous owners work.. if i had done myself i would used 700 instead on the 200 but anyway.. i think the TC is the orinal one used behind 5.7 dx thats been this caprices original engine and also lockout in it works with and uses the orginal system.

some 200r4:s only chevy pattern... or bop pattern, but most ones i have seen are having both patterns like my trans.

i use 4lo.com converter, mostly desingned for 4x4 calculations but using 1:1ratio for transfercase it can be used for calculating normal gearing etc...



http://www.4lo.com/calc/gearratio.htm


my tires are
235/75-15 winter
275/60-15 summer

those are approx 28" dia.
Rytari
04-01-2009, 14:14
now i am ebay victim.. i found and bought a 3.23 gears (and auburn locker) to my rear... it will take some weeks to come but in that time it will be nice spring and snow hopefully melted so i can go under my wagon and make some noises there...

i hope it helps...
odgs455
01-27-2010, 09:18
Hi, I just discovered your discussion on 6.2d caprice... Great !!
I need a lot of help as I'm thinking on replacing the 5.7d by a 6.2d on my 1982 Oldsmobile custom cruiser.
Can you send me some pictures of the engine bay, and all the details of what you've done, to make it work ??
Thanks
Olivier
convert2diesel
01-27-2010, 14:03
Hi, I just discovered your discussion on 6.2d caprice... Great !!
I need a lot of help as I'm thinking on replacing the 5.7d by a 6.2d on my 1982 Oldsmobile custom cruiser.
Can you send me some pictures of the engine bay, and all the details of what you've done, to make it work ??
Thanks
Olivier

Oliver:

Did a conversion on my 91 Buick Roadmaster. Your conversion should be similar as we share the same chassis (78-96). Would be more inclined to use a 700R4 as opposed to the 200 unless you pour a bunch of money into the 200. The nice thing about this chassis is that it was available with both the Chevy and the Olds engines (depending on year) so retro fitting the chevy mounts and things is just a process of finding the right donor car.

You can find some pictures of my conversion at:

http://gmlongroof.4umer.com/lrom-f24/hybrid-longroof-locomotive-t272.htm

and

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=27921

Did a complete write up on another forum but it suffered a crash late last year and the thread was lost.

Bill