clutch/flywheel issue

[BETTER motorsports]

Good day,

I am doing an engine swap for a customer and have run into a snag, the car is a 1965 230SL manual transmission, he got an engine from a 280 sedan, automatic, everything was going fine until the flywheel. The flywheel bolts are different, the ones in the 280 are bigger. Here is the question, is this related to automatic vs. manual or year related? Wondering if a 250SL or 280SL manual flywheel would have the bigger bolts or am I chasing my tail?

I could have my machinist drill the 230 flywheel to take the larger bolts but thought I would enquire about the interchange first.

Thanks,
Sean.

[Benz Dr.]

 A 230SL flywheel is different from a 250 or 280 and they won't interchange. Whatever you have planned, don't do it! You need to find a 250 or 280 flywheel.

[ja17]

The flywheel on the 230SL is counter-balanced (notice the large mass on it's backside). The flywheel on the 280 engines is balanced. You will have a huge and imbalance which will destroy the engine. The attachment bolts and their holes in the 280 flywheel are larger. Find a flywheel from a standard 280 engine and you will be in business. You will need the bolts from the standard 280 engine also.

Years back, I converted a counter-balanced 230 flywheel to work in a 280 engine for a rally car. I took the counterbalanced 230 flywheel to a automotive performance shop. They machined off the counterbalance and balanced the flywheel. The bolt holes were then enlarged to fit the standard 280 flywheel bolts. The 280 engine was then able to accept the newly machined and balanced 230 flywheel. The engine was raced for years, it frequently saw 6500 rpms, worked good no problems. However it would be easiest  to find a 280 flywheel in the first place. Most flywheels from the 250 series (except for the very early sedans) are balanced and will work without modification also.

[BETTER motorsports]

Awesome, thanks for the response, exactly what I was looking for!

[ja17]

Metric Motors, in Ca. probably has some good used 280  flywheels laying around. Be sure to get the bolts for the standard flywheel since the automatic flywheels, takes shorter bolts.