Flathead 218 and 230 numbers - conversion

[49plymouthdotcom]

Anyone know if all of these 230 crankshafts work in a 218/230 conversion? Also looking for flywheel numbers. I searched the forum, haven't seen any part numbers mentioned for crank and flywheel.

[Plymouthy Adams]

yu will need the longer rods to go with the 230 crank..else..bolt in..only thing to be aware of is the bolt number on the rear for those using standard tranny, Hy-drive and Fluid Drive applications...

[james curl]

All of the fluiddrives and Hydrives used an eight hole crank, while the standard dry clutch used a four hole crank, However, a four bolt flywheel will fit the eight bolt flange. It will take a bit of effort to find the only place the four bolt flywheel will bolt to the eight bolt crank. I painted a line on the crankshaft and the flywheel 180 degrees apart and numbered them 1 & 2 so that I could return the flywheel to the correct location after removing it.

[greg g]

my 56 Plymouth 230 used 6 fasteners for the flywheel. So I guess more is better in most cases.

[Bodacious]

yu will need the longer rods to go with the 230 crank..

Actually the 230 rods are shorter than the 218 rods, not longer.

[Plymouthy Adams]

sometimes I type before I think we worked that out a long time ago with the rods with olddaddy..misquoted my own self even after writting these measurements down in my repair manual.

230 rod is 7 13/16

218 rod is 7 15/16

measurements are ctr to ctr

[Bodacious]

sometimes I type before I think we worked that out a long time ago with the rods with olddaddy..misquoted my own self even after writting these measurements down in my repair manual.

230 rod is 7 13/16

218 rod is 7 15/16

measurements are ctr to ctr

Happens to the best of us! And the 201 rods are longer yet. Some day I'm going sit down and figure out some pistons of a more modern, lighter design that could be used with one of these rods to get to zero deck w/o cutting the block. I did this on a SBC stroker I built by using a 3.80" crank and using pistons with a CH for a 3.75" stroke.

[Plymouthy Adams]

Mother Mopar has always gone about CI in another means as compared to Chevy and its many different crank throws. Mopar has always believed in the RB design...that is casting the block with a longer bore..(RB=raised block to those who are not familar) they did this over a long period of time...to even include the more recent engines, 2.2 to 2.5 4 cyl. 3.3 to 3.8 V6 of course we all know the 383/440 story..

[Bodacious]

Mother Mopar has always gone about CI in another means as compared to Chevy and its many different crank throws. Mopar has always believed in the RB design...that is casting the block with a longer bore..(RB=raised block to those who are not familar) they did this over a long period of time...to even include the more recent engines, 2.2 to 2.5 4 cyl. 3.3 to 3.8 V6 of course we all know the 383/440 story..

Same thing with the small blocks. 273s, 318s and 340s all have the same stroke. They finally did increase it in the 360, but it has a smaller bore than the 340.

Also, before aftermarket cranks were as cheap and plentiful as they are now, the hot ticket for 340 racers used to be to swap in a crank from a 318 poly engine, believe it or not. They used stronger cranks (steel or maybe even forged steel, I don't remember now) and were a bolt-in into the 340.

[Plymouthy Adams]

some of the truck 318's in the 70's have forged steel cranks..I have ne of these block assemblies in the garage..been saving it for years..I may one day build a nice 318 from a bevy of 318 parts from 67 to pre magnum..look to the 4WD trucks for this crank application...I have a couple 360's here, one being S code built in the special engine cell at Mopar...police interceptor engine..I have a couple big blocks but still have preference for the small blocks

[B-Watson]

Mother Mopar has always gone about CI in another means as compared to Chevy and its many different crank throws. Mopar has always believed in the RB design...that is casting the block with a longer bore..(RB=raised block to those who are not familar) they did this over a long period of time...to even include the more recent engines, 2.2 to 2.5 4 cyl. 3.3 to 3.8 V6 of course we all know the 383/440 story..

The raised block scheme lengthens the stroke of the engine. Chrysler did that with the first generation hemis - Dodge, DeSoto and Chrysler. All three had different deck heights in both standard and raised versions plus the three had different bore centres. Thus nothing interchanged between the three and the trio were replaced with the B block (1958) and the raised B or RB block (1959).

Bill

Vancouver, BC

[Plymouthy Adams]

I think you just confirmed exaclty what I just said...been doing it over long period of time...recent engines still getting the RB treatment...and I quoted the 383/440 story the point being cubic inch increase by NOT changing the throw of the crank..

In the Mopar engine book you will find data on the early hemi's for Dodge, DeSoto and Chrysler..the data is in error...little fuzzy math involved...and in some case..conflicting bore and stroke data from other periodicals of the era..

[blueskies]

Anyone know if all of these 230 crankshafts work in a 218/230 conversion? Also looking for flywheel numbers. I searched the forum, haven't seen any part numbers mentioned for crank and flywheel.

I did this conversion with my '50 Plymouth 218. I bought a NOS crank from Vintage Power Wagons, along with a NOS 230 flywheel. The rods I used were reconditioned used 230 rods. I also used my original '50 218 bellhousing.

The 218 block and 230 block are the same.

The 230 flywheel is different than the 218, as it has a 3/16" recess in the face that mates to the crank. This is because the 230 crank flange is 3/16" thicker than the 218. The recess in the flywheel positions the teeth on the ring gear for the starter in the same place for either setup. If you use the 218 flywheel, the starter will not fully engauge the ring gear.

Also, there are differences in the flywheels, my original 218 flywheel was drilled for both the 9 1/4" car and 10" truck clutch, but the 230 flywheel that I bought was only drilled for the 10" truck clutch. I had it drilled to fit the smaller clutch at a local machine shop.

Pete

[Don Coatney]

I had it drilled to fit the smaller clutch at a local machine shop.

Pete

Pete;

Did you ever resolve your vibration issues?

[blueskies]

Pete;

Did you ever resolve your vibration issues?

Nope... but I'm sure it's not the flywheel. The vibes are not there unless the car is rolling at speeds of 50mph and up.

I have only driven my car three or four times this summer, just no time to crawl under and pull the driveline again. Pathetic, I know...

Once we settle into school with the kids and our routine gets back to normal, I'm going to pull the driveline and sent it off to be checked for balance.

Pete