Author Topic: 3.27 rear end  (Read 34729 times)

winston

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3.27 rear end
« on: February 01, 2012, 22:22:56 »
Does , any one have or know of a 3.27 for sale ? Thanks , Paul

Jordan

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Marcus
66 230SL  Euro 4 speed

Benz Dr.

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Re: 3.27 rear end
« Reply #2 on: February 02, 2012, 03:28:23 »
Humm.... I just sold one for less.

I'm not sure where he figures your trans will wear out any faster in high gear. ??? On a standard trans, the power goes straight through with no gearing involved. Not sure on an auto but I suspect that statement may be bogus. :D
 
330 pounds seems a bit heavy. Maybe they really are that heavy but I never would have thought so.

 You will probably need rear discs, pads, axle boot, seals and maybe bushings. The E brake cables will definately have to be changed to 113 units, LT & RT, because they're only used on disc brake 113's. If you are changing from drum brakes you should also get a brake force regulator. The car could spin out of control during brakng in wet or slippery conditions.
 So, with all those parts and purchase price, you could be looking at well over $2,500.00 before you're done.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

winston

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Re: 3.27 rear end
« Reply #3 on: February 02, 2012, 14:17:15 »
Thanks , Jordan and Doc. Everybody talks about the pros of changing to a 3.27 , but are there any cons ?
Paul

Benz Dr.

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Re: 3.27 rear end
« Reply #4 on: February 02, 2012, 15:30:01 »
Speedometer error and slower 0 to 60 times. Speedometer can be changed to reflect higher axle ratio but the taller ratio is what you have.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

twistedtree

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Re: 3.27 rear end
« Reply #5 on: February 02, 2012, 18:10:23 »
Other down-sides would be:

- A lot of work to make the swap

- Deviation from original configuration and parts

You get to decide how much they all mater to you.
Peter Hayden
1964 MB 230SL
1970 MB 280SL
2011 BMW 550xi

Iconic

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Re: 3.27 rear end
« Reply #6 on: February 02, 2012, 18:32:17 »
Additional cons:
Car accelerates slower in each gear.
Engine not allowed to rev freely at highway speed as it was originally designed (unless of course you drive faster than you would have with the original rear end).  :D
These engines love to rev high, and when you let them do that for a little while, regularly, they run much better.
1970 280 SL Automatic, USA version, Grey-Blue (906G/906G), Blue leather (245)
1968 SS396 Camaro Convertible (owned since 1977 -- my first car :D)
1984 Porsche Euro Carrera coupe, LSD, SlateBlueMet/Blue
1998 BMW M-Rdstr Estoril Blue
1970 280 SL Automatic, Anthracite Grey-173G, Red Interior-132 - sold

hank sound

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Re: 3.27 rear end
« Reply #7 on: February 05, 2012, 03:03:08 »
 ::)   I look at it this way: one person's con could easily be another person's pro --------- and the reverse of that, as well.     I live in the land of freeways (Los Angeles) and my average speed (to keep up with most traffic) is 70-75 MPH, so a 3.27 RE ratio really would work for me.    And further, if there's traffic, why would I care about how long it takes to get to 60??     If I lived in the hills or mountains, that would certainly be a horse of a different color.

Cheers, Hank

ja17

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Re: 3.27 rear end
« Reply #8 on: February 05, 2012, 05:28:06 »
Hello,

The high rpms do not bother me.  However I do know a lot of owners who have switched to the 3.27 and I do not know of anyone who was sorry for doing so.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
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1965 220SE Finback

66andBlue

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Re: 3.27 rear end
« Reply #9 on: February 05, 2012, 17:45:26 »
... These engines love to rev high, and when you let them do that for a little while, regularly, they run much better. ...
A con, why?  You can always drive in 3rd gear to the red line if you want!
Alfred
1964 230SL manual 4-speed 568H signal red
1966 230SL automatic 334G light blue (sold)
1968 280SL automatic (now 904G midnight blue)

Iconic

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Re: 3.27 rear end
« Reply #10 on: February 05, 2012, 20:14:10 »
OK, Alfred, agreed, you can always run in 3rd at high revs if you want.
But, the acceleration is still slower in every gear.
Hey, he asked for cons, that is a valid one.  ;)
Oh yea, by the way, a big con would be the expense and hassle of doing this (if your stock set up is functioning correctly).
And, as already mentioned, it is a deviation from original.
1970 280 SL Automatic, USA version, Grey-Blue (906G/906G), Blue leather (245)
1968 SS396 Camaro Convertible (owned since 1977 -- my first car :D)
1984 Porsche Euro Carrera coupe, LSD, SlateBlueMet/Blue
1998 BMW M-Rdstr Estoril Blue
1970 280 SL Automatic, Anthracite Grey-173G, Red Interior-132 - sold

pagoden

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Re: 3.27 rear end
« Reply #11 on: February 08, 2012, 18:49:57 »
I'm comfortable with the revs, too, but wanted to be able to get all the way through a largish intersection without having to shift while still somewhere in it.  I started with a 4.08 in mine, as many of us do.  A little math showed me that, starting from that ratio, the original ratios for european 113s -- 3.92 and 3.69 -- would only drop my revs by about 5% and 10%, respectively.  The same calculation for the 3.27 yields very close to a 20% result.  I drove smaller, higher-winding engines back in my youth and so don't miss the comfort that 2,000 rpm cruising gives to guys with the much more common V8 history, and the five and ten per cent gains didn't seem worth the time, expense and effort, so when I discovered that there was such a thing as a 3.46 ratio, I guessed that it would be the best to get me where I want to be ... and it sure is.  3.46 represents a 15% reduction in revs from the 4.08, which feels about right to my metallic partner and me.  Yes, we do spend a lot of time in 3rd and below, just as we spend most of our time either in traffic or on the rolling, snakey blacktop where I'm not nearly skilled (or crazy) enough to have much need for fourth.  When it does come time for five or six hundred miles of cruise to PUB, for instance, we're still around 4,000 and happy, eating up the miles. The pipes come into a really nice resonance around 3800-3900, too, don't they.     ;~)

Downside:  I was diligent and fortunate to find a nice 3.46 axle, Joe went through it and installed it beautifully, and it's great.  BUT... I lost the 'Differential Vent Vomit' lottery.  Some significant minority of swaps will not tolerate the removal of the external circulating tube without blowing all their lubricant out though the vent at the top of the center differential ring gear housing.  That large U-shaped tube conflicts with the understructure of 113s, where there's less room than under the donor sedans.  Removal is easy and neat.  Most axles tolerate the U-tube-ectomy but those that do not make for a messy surprise and a serious risk to the health of the axle.  It can be altered sufficiently to clear the understructure but that is much better done prior to installation, and it's tricky trying to predict just where and how to tweak it when it's out and clear of the car where it's most easily got at.  Altogether an inconvenient situation, one which I cannot seem to solve myself nor have I gained any effective enlightenment from those much more experienced in such matters, several of whom I've polled thus far.  Most unsatisfactory.     ;~(

I continue in surprise and disappointment that this august body tolerates our inability to diagnose, predict and prevent these occurrences.                                  Is a puzzlement.  [Yul Brynner, King and I, 19...54?  ah, i dunno]

Happy motoring all,
Denny  

1968/69 280SL, just+100k mi, manual 4, 3.46, both tops, 717/904

awolff280sl

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Re: 3.27 rear end
« Reply #12 on: February 08, 2012, 23:01:21 »
Have a look at this thread re: diff vent seepage   http://www.sl113.org/forums/index.php?topic=9633.msg64934#msg64934

I was able to cure the seepage without cutting the frame by using a flexible hose
Andy   Sarasota, FL
'69 280SL 4speed
'06 Mitsubishi Evo

pagoden

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Re: 3.27 rear end
« Reply #13 on: February 11, 2012, 07:25:05 »
Thanks, Andy, for a solid contribution to the situation.
Mine was more than "seeping"; it nearly emptied the axle in the first 5-600 miles.
I hope we can get to the bottom of it, make all of our installations routine instead of about three out of four.  I've taken my rant on that topic over to the thread/link (with the excellent photos) you provided in your post above.

Winston - Best fortune with your swap, and especially, may it be one of the dry ones!

Denny
 
1968/69 280SL, just+100k mi, manual 4, 3.46, both tops, 717/904

awolff280sl

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Re: 3.27 rear end
« Reply #14 on: February 11, 2012, 20:04:52 »
oil can leak out under either end of the rubber boot if the ring clamps aren't tight enough
Andy   Sarasota, FL
'69 280SL 4speed
'06 Mitsubishi Evo

hank sound

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Re: 3.27 rear end
« Reply #15 on: February 12, 2012, 00:12:37 »
Hey all,

As for this "other than the steel cooling tube" option, I'm now looking for additional approaches.     I was directed to a local speed shop, where their focus is all manner of hose issues in high performance and racing applications for cars, boats and planes.   These guys understand oil & gas, heat & pressure, and they deal in rubber & braided SS.   What fun !!!

I'll post my findings very soon - but honestly - - I think I hit pay dirt !! :):)

BTW - we've got two threads that seem as though they should be married :)

Cheers, Hank   

hank sound

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Re: 3.27 rear end
« Reply #16 on: February 12, 2012, 01:03:09 »
And in that other thread (which seems to be dancing in lock step to this one), Benz Dr. (Dan C.) made some interesting points.    Seems to me, that in our desire to "lubricate", we may be over filling to a fault.

What thinks ya??

Hank


jeblack123

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Re: 3.27 rear end
« Reply #17 on: February 12, 2012, 13:20:11 »
Good morning all,

As I am preparing to change the rear end on my 68 Euro 280 SL Automatic from 3.92 to 3.27, I have read with great interest this and other threads that are providing a wealth of information, including the pro's and con's of the conversion. Is there anyone who has changed and regretted the swithch even to the point of reinstalling the  original rear end?

Thanks,

James

hank sound

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Re: 3.27 rear end
« Reply #18 on: February 12, 2012, 17:31:20 »
 :D

Not according to Joe, in post #8 (above).    With 100% certainty in the validity of my decision, I pulled the trigger - and so my 3.27 will be delivered this Tuesday (can't wait - like when I was a kid at Christmas !!)

Cheers, Hank

hank sound

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Re: 3.27 rear end
« Reply #19 on: February 13, 2012, 01:43:05 »
Hi all,
I'm throwing this one out - - because this simple issue, "simply" blows my mind !!      OK, to my knowledge, "seems that" no one with a stock differential, has been whining about leaking, overly hot diffs or anything else.   But for some (one or more reasons) some of our tribe are experiencing issues after changing from their stock unit, to (let's say - that which I'm about to do) a 3.27 from a donor 280SE/SEL 4.5 car.   I'm not an engineer.   But I'm curious beyond sanity, to find out why things happen - like, why these "seeping", "leaking" & "overly hot, weeping" issues seem to take place after some rear end change-over modifications - but not in all............ Hmmmmm  

This shouldn't even begin to approach the level of "rocket science engineering" - and should be reduced to a simple question - with a simple answer.     What is it:  the viscosity? - -  type or brand of rear end lube used (assuming we don't overfill)?        Auto and Air racers have dealt with these issues for decades and have proven their worth.    I believe the answer to this question/concept - has already been answered - - and shown, albiet, in a place and at a time, with which we are not familiar.  

This one intrigues me!!!    Hey - - I got metal tubes, I got rubber hoses and braided stainless steel "stuff" as well.   I'm on it !! :):)

Be well, Hank
« Last Edit: February 13, 2012, 02:45:13 by hank sound »

Leester

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Re: 3.27 rear end
« Reply #20 on: February 13, 2012, 19:16:01 »
I've been following the discussion on both threads with interest as I bought Brad's (Badali) 4.5 rear a few months back. At the moment getting the engine finished and into the car is a higher priority for me, but down the road the "new" rear is going in. I have to agree that there has to be a reason (maybe multiple) for the problem. Seems like Benz Dr may have hit upon it. Possibly what is needed is a repositioned metal tube (to work its cooling magic) rather than a non-metal tube that doesn't provide the cooling effect. I also agree that the lube used may have an effect and for those who don't have the problem - can you let the rest of us know what you guys are using. Ensuring that diff isn't overfilled, regardless of anything else, sounds like a key factor as well.
Lee Backus
1963 220SE Cabriolet
1970 280SL (reassembling - hopefully soon)
1978 450SL (disassembled for paint)
1985 500SEC

awolff280sl

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Re: 3.27 rear end
« Reply #21 on: February 13, 2012, 20:12:30 »
using Redline 75W90 GL-5
after prolonged high speed driving, infrared thermometer reading 125degF on the diff in 70degF ambient temp
no vent seepage
Andy   Sarasota, FL
'69 280SL 4speed
'06 Mitsubishi Evo

ashley

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Re: 3.27 rear end
« Reply #22 on: February 17, 2012, 00:57:04 »
My 3:27 diff comes tomorrow and I can't wait to do this swap. Actually I can't wait to drive the car after the swap, the doing part I'm not looking forward to....It seems prudent to just do a flexible cooling tube before as opposed to once its in the car if it turns out to be a leaker. I will be doing this at a friends well provisioned shop with a lift, we hope to do it over a weekend and not have it tieing up the lift come Monday.  So heres my question, does anyone have a list of the unusual or MB specific tools that maybe required? I dread getting it half way apart and not have the correct tool to finish the job. I read in an old post about someone buying a MB tool for this job (to use once) and loaning it to other members, and another guy who just fabricated one that worked fine. Any tool tips would be appeciated.

Thanks,

Benz Dr.

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Re: 3.27 rear end
« Reply #23 on: February 17, 2012, 16:32:26 »
You will need 113 E brake cables - the 108 cables are too long. You will also need to remove the calipers, rotors and all of the E brake parts to take the old cables off.

I'm doing a conversion right now and found that the end of the E brake cable was seized in the brake caliper carrier. We had to heat to red hot before it would come out so be prepared for such an adventure. I provided a new set of E brakes and springs because everything was either broken, missing, or rusted.
 
We also found that the boot, pinion seal, and axle seals were worn so those will be replaced as well. If you don't have the jig to install the trailing arm bushings leave them alone. The doughnuts at the end of the arms are easily replaced.

If you want to use the non split boot you will have to seperate the right axle tube. This isn't that easy to do but I've found that it comes apart better by knocking the shaft towards the rear. Inspect the bushings and if they're worn it's a good idea to replace them.

I have a MB tool that's used to check the bushing carriers. If they're straight, the tool will slide through the two bushings without binding. If it's not straight, and few are, we heat the axle and pull it back into alignment.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC

BaronYoungman

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Re: 3.27 rear end
« Reply #24 on: February 17, 2012, 17:24:35 »
I know this mercedes shop by me (the one that helped me with my 3.27 swap) has a complete already set up rear end: new seal, rebuilt brakes, swapped spring, and new parking brake cables ready to be put in sitting at the shop.  I believe they did it for a customer repainted and all, and the customer punked out if you have questions they can help... email me for their number.
Bob
Bob "Baron" Youngman
1971 280 SL silver  1 car 0 boxes
1983 500sec Wheeler Dealer AMG w AMG coupe
1965 220se coupe restomod
1988 560sec  Japan "Yakuza Car"