230 vs 251

[RMS]

i started reading the tm9 1804a manual and i noticed when flipping through that the 230 is a lot different to the 25. besides the major differences displacement, stroke head length...I noticed that the plugs were a different heat range with the 230 having auto light ar5s and the 251 AL ar7s ? the 230 a compression ratio of 6.7to1 and the 251 6.6to1 would this 0.1 less comp demand a higher heat range ?

I have only read a few pages but it seams that they either didn't include the info or the rods contain no manganese.

is the 230 mil spec block equipped with sodium filled exhaust valves or stelite seats ?

dose the 230 have a brass water distribution tube ?

[RMS]

ok finished reading tm9 and ord 9 -g741

it appears that the 230 may have stelite seats but they are only refereed to as "special alloy"


interesting to note

230 251
intake Head diameter 1 13/32 1 23/32

I couldn't read the exhaust head diameter in my cdn manual but my first thought is typo

with a 0.340 stem diameter for both intake and exhaust vs the 0.430 diamiter of the 251 exhaust valve I will assume that the 230 t249 did not receive sodium filled exhaust valves. I will also assume the t249 received steel guides and a steel water distribution tube. as the book mentions: "A hooked piece of heavy gage wire may be required if tube is badly corroded"

[carolinamv]

That's interesting info to know!

[LegionPiper]

Say Folks,
anyone have some detailed pictures of the 251 ?

I am pretty sure I have the 230 in my "Air Force Blue" M37.
However there's a T98 transmission in her, so I know that doesn't fit the picture.


I'd love to determine that my engine is definitively a 230.

[w30bob]

Legion,

Just find the T245 code on the side of the block behind the oil fill tube and you'll know you have a 230 and not a 251. You can also just look at the exhaust manifold.....the 230 dumps at the rear and the 251 dumps between the runners.



regards,
bob

[isaac_alaska]

You can also measure the head with a tape measure. It's nearly 3" difference, so pretty obvious. Fitting the 251 requires moving the front engine mount forward, as well as the radiator, and stretching the hood. At least in my power wagon. Never did it in an M37. Maybe it's easier.

[w30bob]

Isaac,

Yup.......but the hood isn't stretched on the M37. It would be kinda cool if someone listed ALL the differences between the 251 and 230 installations in M37s. I've looked around a bit from time to time and never found a place where ALL the differences are listed. Just sayin'............

regards,
bob

[just me]

Here are a few differences. LOL!
The block, head, rods, valves, pistons, oil pump. Oil pan, pickup tube, fan, transmission, front mounts, radiator mounts, valve springs, plugs, head bolts, distributor....

[w30bob]

Yeah, let me re-phrase that.............it would be nice if all the EXTERNAL differences between the 251 installation and the 230 installation were listed in one place.........so someone looking at an M37 could determine what engine is sitting between the fenders and if the rest of the install is correct. I, for one, have never seen a Canadian M37 in real life.......but have seen lots of folks who didn't really know what engine was in their M37. There was a guy on Ebay last week or so who swore the engine he was selling was the original 230 out of his M37. But even I knew it was a 251 (exhaust manifold, 6 blade fan, etc, etc).

Regards,
bob

[LegionPiper]

Awesome feedback guys !

I've been running through the TM9-1840A manual, comparing to my own engine.
However, to your point, I haven't found any manual to explain the 251 to compare, thus my curiosity.

Thanks guys, this helps me figure it out, particularly, DUH, the Engine Code Stamp.
I nearly fell on the floor laughing...

[RMS]

I did my best to note the differences



in the thread : l head mods keeping the info alive. I did a quick summery of the specs for the t249 and other long block Chrysler flatheads from north of the 49th.
http://www.g741.org/PHPBB/viewtopic.php ... info+alive
it would be great if someone could post some 230 t245 dyno sheets to go with the Ind 251 and Ind 265 sheets.

[LegionPiper]

Hi guys,

This is what I saw when I cleaned up the Plate beside the Filler Tube :
IND 5A236378 star ( The star is actually the symbol, a star )

( Mind you this is what I could make out with my old eyes )
Does this make sense ?

The Exhaust manifold exits via the rear, looks like a 230 !

[Kaegi]

there are 230s that have exhaust dump in the center as well. the sodium filled exhaust valves were found in some of the industrial engines and larger truck engines in both the short and long engines. but as far as I know no sodium filled valves in light trucks like WC/M37/PW. ALL Chrysler built flatheads have hardened valve seats after about 1933. there are 2 known versions of hardened valve seat I have never had to replace any in many 230 rebuild over the last 25 Plus years so never checked what the 230s have. whatever it is it handles the unleaded really well.

[w30bob]

Legion,

The engine you have is a 218 cu in Industrial Engine. You can look up the 5A code here;

http://www.t137.com/registry/help/other ... ngines.php

regards,
bob

[LegionPiper]

Wow,
Thanks Bob, now that's interesting.
Is this common for some M37s ? or would this have been done by someone along the way ?

Everything else around the Engine looks the way it's supposed to in the manual.
It's amazing it all fits.