Lightened Crankshaft advantages/disadvantages?

[2.216VTurbo]

Hey Alan, do Masi cranks fit a regular common block??

I really like the full counter weights, even if they weigh more.

2.4 crank is looks almost fully counter weighted but they probably don't fit common blocks??

Thanks
Randy

So get this, there were FOUR different FORGED cranks available on an 89 Masi TC(any wonder why Chysler 'lost money' on each one?)


1) Early build non common block 8V

2) Late build (after June 88, also got suspension upgrades and at least a dozen other changes that I know of) common block 8V

3) Early build non common block 16V

4) Late build common block 16V(also got those running change updates)

All forged, even in the autos, so yes, common block Masi 8V or 16V cranks will fit in a standard common block. That crank is HEAVY Randy but once it's turning it is very smooth. I discovered back in 96 when I bought my first whole Masi TC in San Francisco area that you CANNOT stall a motor with that crank in it. Go ahead and let the clutch out first before applying gas, it wont stall.

[johnl]

Almost as a matter of physics, there is a conflict between accelerating a rotating assembly and running it at very high rotational speeds. Weight is good once you're spinning but it's bad in getting there

[Reaper1]

The Masi crank weighs 53# (verified on 2 different scales now). If you need the engine to transition from one rpm range to another very quickly (think motorcycle), then a light crank is for you. NVH might go up (the only reason I can come up with as to why the Masi crank weighs so much...to reduce NVH). They can even work well in drag racing, but your launch method will certainly have to change, and possibly your shifting strategy as well.

[4 l-bodies]

Hey Alan, do Masi cranks fit a regular common block??

I really like the full counter weights, even if they weigh more.

2.4 crank is looks almost fully counter weighted but they probably don't fit common blocks??

Thanks
Randy

Randy,
The Masi cranks are nice, BUT they use a unique rod bearing width journal size. In the past, very difficult if not impossible to locate NOS rod bearings. Because of this, most Masi owners install a steel TII/TIII/TIV crank and use their Masi crank and rods as paperweights. I think Rick D has found a rod bearing from a different application that works with the Casar (masi rods).
Todd

[GLHS60]

I appreciate the input guys, anyone have any pics of a Masi DOHC crank??

Thanks
Randy

[4 l-bodies]

I appreciate the input guys, anyone have any pics of a Masi DOHC crank??

Thanks
Randy

See attachments
Todd

[tryingbe]

Thanks for the pictures, Todd!

[RattFink]

Are the non common block Masi 8v cranks heavier than normal? Do the 8v cranks have different rod bearings? I am curious because I recently bought a T2 8v engine from an 89 Masi TC. It is a non common block with an 87 casting date on the block. It does have a forged crank.

[tryingbe]

Masi 8v is just a standard 88 TII block with the TII forged crank and rods with cast pistons. Nothing really special about it.

[Reaper1]

I figured I'd chime in on the Masi rod bearings as I have a little bit of recent experience with them. The journal diameter is the same as any other 2.2/2.5, but it's narrower. Also, the big end of the Casar rods has a larger diameter than the other rods. What this means is the bearing shell itself is thicker, but its width is narrower. I bet that if it were possible to get a rod that had the same big end diameter, but narrowed that bearings would become a bit easier to source.

[GLHS60]

Good info!!

Do the Masi cranks have deep rolled radius, or negative fillets like the regular 2.2/2.5 cranks??

Thanks
Randy

[2.216VTurbo]

I figured I'd chime in on the Masi rod bearings as I have a little bit of recent experience with them. The journal diameter is the same as any other 2.2/2.5, but it's narrower. Also, the big end of the Casar rods has a larger diameter than the other rods. What this means is the bearing shell itself is thicker, but its width is narrower. I bet that if it were possible to get a rod that had the same big end diameter, but narrowed that bearings would become a bit easier to source.

If I were a part number guy, I'd tell you guys the Renault bearing that accomplishes this. Yes, it has to be narrowed about .050 but it solves the NS1 problem... I've had a few sets made but it was years ago.

[83rampage]

I had about 6.5 lbs taken out of the non-common-block-converted-to-common-block forged 2l IMSA crank Im going to run(someday) in the 9500RPM Masi Motor. The project is nowhere near ready (tho I do have a bunch of the parts,still need rods/pistons made) and I waited A YEAR for that shop to finish modding that crank. One of the reasons was that they do all of DCR's cranks. About once a month I would go in to 'check on the progress' and there were always a half dozen cranks that said DCR on them. It's a well respected shop in Santa Fe Springs, CA. Surprisingly primitive in there but if they have the tooling and the knowhow, good parts can be built I suppose. Before visiting the shop a few times I never knew that cranks are 'trued up' on a jig with a hammer and a brass punch. Looks really brutal but they just hit the thing, turn it over in the jig by hand and read the measurements on the dial indicator.

So I finally went to check out this motor. The crank in question doesn't look anything at all like yours, and it is NOT a DCR crank.

I don't have pictures but it is basically the counterweight cut so that it is only a wedge shape (triangle) is left as wide as the crank journal at the base and extends to a point from there about as far as the counterweight used to be.

Very hard to explain but the counterweight has been 80% machined off. Not knife edged like your crank. Never seen anything like it. Not sure how long it would last, but I'm not going to be the test mule.