engine swap auto vs. standard

[jpambca]

Hi:
The engine in my '66 230SL has seen better days. I've been offered a used engine from another 230SL in apparently good condition but it comes from a car with an automatic transmission whereas my car has a 4spd standard.  Can this engine be swapped over without nasty and arduous modifications? 
Many thanks.
J

[ja17]

Hello,

Are you trying to keep it standard shift or converting to auto?

[jpambca]

I want to keep it standard.  I've looked at the engine presently in my car and the numbers indicate it is for a 250SL.  It has "250" stamped on it, and the engine serial indicates "129" as apposed to "127" which is the indicator for the 2.3L engine.  I'm thinking that switching back to a 127 is a matter of dropping it in, perhaps changing motor mounts.  Any thoughts?

Many thanks for the assistance.
J

[merrill]

What is wrong with the motor?
Metric can rebuild for about 6K.

If it is not too far gone they may buy it for re sale....

[stickandrudderman]

There are quite a few differences between the installations. Nothing a competent person couldn't deal with but my guess is if you need to ask the question you probably shouldn't get involved. It'll be a lot simpler to simply o/haul your existing engine or find another good 129  one (with manual trans) to change it for.

[ja17]

Hello Jp,

You cannot switch the flywheels on the M127 engine and the M 129 engine. They have different crankshafts and balancing. Even the flywheel bolt diameter is different on these two engine  types.  You would have to find a standard flywheel and bolts from an M127 engine in order to use the M127 engine.

[Benz Dr.]

Hello Jp,

You cannot switch the flywheels on the M127 engine and the M 129 engine. They have different crankshafts and balancing. Even the flywheel bolt diameter is different on these two engine  types.  You would have to find a standard flywheel and bolts from an M127 engine in order to use the M127 engine.

 That's odd, because I have a 230SL here with a 280SL flywheel on it. Everything seems to work so I'm not sure what to think. I noticed this during a recent rebuild and saw that they used a 280SL pressure plate and throw out bearing. If it's not supposed to work, it does on this set up. I would expect it to vibrate but it doesn't and it hasn't been ballanced that I can see.
So, I believe you and everything but this car doesn't.

 Just a note on auto to standard trans conversions:
 It's far more difficult to change a standard over to an auto than it is to change an auto over to a standard. If you want an auto trans car, buy it that way. 

[ja17]

Hello Dan,

Most interesting Dan.........Aren't all M127 (230SL engine) flywheels counter balanced?  Also all 280SL M130 engines are balanced?  It should not work unless someone has done some serious modification on the flywheel ?

 Bolt heads on the M127 are 17mm and the heads on the M130 are 19mm.  In addition the bolt diameters are different.  I don't believe Mercedes went to the balanced flywheel until the seven main bearing engine of the 250SLs and 280SLs

Jp, just remove one flywheel bolt on each engine and check the diameters.

[Benz Dr.]

Joe,
that's what I thought but that what's on this engine. Everything seems to be work so maybe there was some modification done. I should have looked at it more closely when I had it apart.

 I had a 230SL flywheel on my 250SE engine before I changed it over to a 280SL flywheel and it didn't vibrate at all. Six cylinder in-line engines have a tendancy self ballance so maybe that factors into this in some way.

[stickandrudderman]

I've had to change flywheels twice in the last 12 months.
The first was because a car had a counter-balanced weight flywheel when it shouldn't have had, and you should have seen that engine trying to climb out of the car!
The second was due to a clicking noise caused by a cracked flex plate.
For the first one I simply machined off the counter weight and, since the engine was in bits, had the whole crank/flywheel/clutch/damper assembly balanced as a unit by these excellent people:
http://www.vibrationfree.co.uk/
The second left me in a bit of a quandry; I could simply order a new flywheel to part number at £350 but I had no guarentee that the engine or crank in the car were the original items. I was therefore concerned that if I ordered the "correct" part it wouldn't actually fit when it arrived. I decided that I would be better of finding a second hand flywheel that matched the failed one.
The combinations of hole size and counterbalance were then revealed with two different bolt hole sizes being found on both types of flywheel. I couldn't find a satisfactory flywheel without the counterbalance so I asked the same people above to modify and balance a counterbalanced one to suit my requirements.
A little long winded but it was the only way I could guarantee results.

[ja17]

Yes, I have also used a M127 flywheel on a M130 engine, but like yourself had to have the counter balance  machined off to balance the flywheel. I then had the bolt holes in the M127 flywheel bored to fit the larger crankshaft bolts of the M130 crankshaft. Everything worked fine after this.

However I do not understand how a M127 engine can use a M130 flywheel  unless special bolts are made and a counterbalance is added to the flywheel?

[stickandrudderman]

I think the OP has enough information now!

[jpambca]

Thank you to all that responded.  I appreciate the help. 
If I consider the cost of the used M127 engine, plus shipping, plus the time and cost to find an M127 standard transmission flywheel, plus bolts, I might as well spend a few extra bucks and rebuild the M130 that is currently installed in my 230SL.

Thanks again.

[perry113]

I thought the 230SL crank and flywheel were all counter balanced together, meaning that if I wanted to convert my 230SL Automatic to a 4 speed manual it would require that I pull the crank on the engine and have it counter balanced to the 4 speed flywheel.

I didn't believe however, this was the case for the 250 and 280SL series.

[ja17]

Hello Perry,
You are mostly correct. However it is possible to match balance the new flywheel up to the old one without removing the crankshaft. In other words, the machine shop, matches the counterbalancing of original flywheel to the new one. In this way the total balanced assembly remains unchanged.