230/251 Cam Specs...

[maineSS]

This shows the effect of better breathing. I may run another set of sims with the Late OEM with dual and individual runner carburetion, and the Asche 380 with IR carburetion. Dual carbs will give you more torque at higher rpms for taller gearing or tires, but higher Rpm's with a flathead mean markedly increased fuel consumption. Ideally, more torque at 1800-2000 rpm with an overdrive high gear would keep your low gears and allow 50-55 mph top end.

The sims provided much more data than shown here. Things like Volumetric Efficiency, Intake/Exhaust Flow pressure, CFM and velocity, Cylinder & Port temp, Piston "G" load, Heat rejected to coolant, etc. Unfortunately, I couldn't get the report to fit on a floppy in JPG mode, and I don't know if the attachment restrictions would allow it if I used a CD. Perhaps Gordon can reccomend a solution- I'll post it if it can fit, because it makes engine mods much easier when you know where the problems are.

[pwdave]

cams

where would a body go about finding a late model 230 cam, and be sure it's a late model? my truck is a 58, the last passenger car was 61, what was the last 230 truck? and can they still be had with new lifters? what I'm looking at, is the need for about 20-25 more hp. I have a 55 230 to start with. I have a 37 desoto that has the head shaved, although I don't know how much yet. I have a 2x1 tattersfield and will install cast headers and a two into one exaust to get back to a single exaust. this is all brand new to me, if it was a 440or a big block of some kind it would be a walk in the park!! I know that flatties and overheads require different things to make to make them do the required work. I'm not looking to hodrod my truck but a little more power wouldn't hurt either. while it's apart, has anyone done any port work on these little motors or would a simple port match do the trick? I'm fishing now, I have no clue what they like. well I'll leave it for now but will keep up with whats going on. thanks, Dave.

[maineSS]

About the only way you could be sure about the cam would be to have it measured, and compare the measurements to known specs. I don't know if the cams have a casting number that would distinguish them. I've heard two different stories about when the Late cam was introduced, one was that it was early on, as the Early cam came from the 218 engine, the other was that it came in the mid 50's.

The big tradeoff in flathead buildups is flow vs compression- more of one kills the other. The OEM 8:1 head was redesigned for better flow, it does have a casting number, and was introduced in late 1958. People have gone as high as 9.5:1 with this head with 93 octane. I'm going to stay at 8:1, so I can run 87 without problems. Increasing intake/exhaust flow with moderate CR increases seems to be the way to reliable flathead power- most seem to stay in the 8's for CR. There's a lot of sideways flow under the valves, an undercut style intake valve seems to do better than a tulip shape. Your ports need to stay small for velocity, don't go hogging them out, the valves are your main restriction along with the transfer area between the valves and the cylinder. Splitting the exhaust 1-2-3 and 4-5-6 into duals or a properly sized single helps also, along with a better breathing intake.

[Jason Mills]

it's interesting to see that the peak torque does not change much.. any ideas as to how to get more torque out of the flathead?

I think I would rather a torque monster, than a horsepower queen...

[pwdave]

MaineSS, do you or someone else in the know have an idea how many different grinds chrysler used? if the trucks were different from the cars, pick-ups different from the heavier trucks? if there is a number to use for lift on the exaust and intake it would be easy to asertain which one was the one. two v-blocks and a dial indicator would give total lift. if there was only two to chose from, it's a simple deal. but if there is a different duration event it could get a bit more drawn out but still doable. I don't have any way to check lobe sep. or center line. didn't the old motor books give cam spec's? if so all we need now is someone with about twenty five or thirty of them lying about to dig thru. simple huh? I'm pretty sure the 37 desoto 201 engine is going to have the small cam, I can pull that and get some info, it wont be exact due to wear but will still be very close. talk later, Dave.

[maineSS]

PWdave- the cam in your Desoto may not physically fit the 230 due to possible journal size or location differences, and likely wouldn't help Hp/torque. Your best bet would be to get an M37 or late model PW cam. Delta Cam in Tacoma, WA offers a cam spec service for $10- that's where I had mine done. The specs you see in the old Motors manuals that I posted earlier were done differently- Delta tried various ways to duplicate the specs I sent them, but couldn't. I had mine done at .050, I'll post the Late OEM, Asche 380, and 400M specs. I haven't been able to find if Chrysler used different cams for the trucks, event though truck engines were built on a different production line and received upgrades for severe service the car engines did not. The grinder that does Asche's cams and VPW both say they've never seen any differences in the ones they've measured. As far as getting more peak torque, the cam basically controls where that will happen, you need to increase compression and flow to get more power out of an engine.

[pwdave]

Dear Maine, it would seem that the best route to take on one of these engines would be a carfully done valve job, fit the pistons correctly, w/ good rings, set the clearences right and just use good practice to set it up. maybe advance the cam two degrees to help on the bottom? two rejetted carbs, and a well thought out exaust system would make a really nice set-up. what about head? you mentioned earlier that there was some differences in some of the heads. are there flow problems related to valve shrouding? if that could be the case we could open the c-chamber a bit around the valves to help flow. I guess I need a book on flatheads, maybe my little pea brain will soak-up something. Dave.

[maineSS]

Here's a link to the late model 1958-59 head: http://www.powerwagonadvertiser.com/...ate+model+head . Post #14 in this link shows an earlier head: http://www.powerwagonadvertiser.com/...ate+model+head . The casting # is 1676337.

The valve job and work done just below the valve seats is over 50% of the gains realized from porting- you can gain a lot or lose a lot depending on your understanding of the flow through this area. Most of the flathead work I've read has been done for Fords, but a lot applies to the Dodge. The Briggs & Stratton lawnmower engine is a smaller cousin of the Dodge, and some pretty radical work has been done on them. The best intake valve shape appears to be a "nailhead" undercut type like the Manley "Street/Race Flo" type. The British "RimFlo" developed for the "A" series might be even better for the sideways flow under the valves, but someone like Manley would have to make them up in the correct stem length, as they're too short. People supposedly have used Chevy valves with adjustable lifters in the Dodge 230 (they're slightly longer), so the Race Flo might be an option. This shows pics of the stock vs Manley and Rimflo valves- http://www.powerwagonadvertiser.com/...=Rimflo=valves .

[pwdave]

heads

Went out to the old truck this morning to compare the pictures of the high compression head and the low compression head with the head on the factory NEW replacement engine in the truck I bought. the cast date on the block and the head are both 55. the head is the high compression head with the good combustion chamber!! I was exploring a site last night that said there were two verisons of the 230 in 1955, one several hp more than the other with different cr's. so when the engine was replaced in this truck they optioned the better engine. this should mean that the cam is the better cam also. looks like I have fared well on this one! this engines ID pad is blank so it is a factory replacment sometime around 55or56. looks like a set of cast iron manifolds and I will be on my way to what I've been looking for. maybe some valves from something, who knows?? Dave.

[maineSS]

Is the casting number on the head 1676337- that's the best head, it came in late 1958. There are several different heads for the 230, all of which spanned the engine's service life. If the engine was rated for truck service, it should have T137 stamped on a pad (down near the oil fill tube on the left side of the block, if I recall correctly). The 230 was used in car, truck, industrial, and agricultural service, the truck, ag, and industrial versions got better parts.

[pwdave]

Just got back in from the shop, I just finished blasting the head and cleaning it up. no doubt, it's the 8to1 head, but to my surprise there is NO casting no. on the head!! I double checked the head on my truck and the no. is where it's supposed to be. on this head below a large P where the no. is supposed to be there is a spot ground flat by hand and a hand stamped no. 1554674. ever hear of this? next I'll get the engine out of the truck and torn down to check the cam and parts for wear&tear. btw this is the one w/no numbers on the block other than casting dates. this little motor shows no wear at the top of the cylinders so it may be an easy build. all cast dates on engine are in 1955. Dave.

[pwdave]

I forgot to ask about big combustion chamber low compression combos, were there any? or are all big combustion chamber heads the good heads? squish area looks better than the other head. Dave.

[maineSS]

I'll look at my head chart and see if that number comes up. The main difference in the 8:1 head is the shape of the transfer slot- it's shorter and deeper than the others. There's a HUGE tolerance stack in these engines- about 1/4" if everything's on the high end, so you need to measure & machine everything if you're trying for a specific compression ratio. I've heard the truck,ag, and industrial engines may have a very thin sleeve in the cylinders the car engines didn't get, this allowed the block to last longer before reboring. I've also heard that later truck blocks were better metal, and didn't have a sleeve. Don't know which is correct.

[pwdave]

cam & no.s

got some more info this morning, the cam is a small one .312 in. .339ex. I have found some new numbers on the block. these were on top of the id pad in 1/8" hand stamped (again). they are H 11 G 3, if the head is on the block you can't see these numbers. there is a large E stamped next to the no. one cylinder if that means anything(on top, next to the hole!) all these numbers may not be anything more than inspector stamps, or assembly codes, at this date it's unlikely we will ever know for sure. I took the lift no.s at the valve w/ a 1" dial indicator beginning on comp. stroke w/ both lifters loose (Turn w/ fingers) so they should be close enough to tell which cam is in it. this could be a combine engine, or a pump, or welder engine. I got to thinking,(something I'm not good at) it has a splash proof dist. but no vaccum advance, I wouldn't think that these would be in a truck engine. shouldn't it have the advance on it? Dave.

[pwdave]

PS to the last post, what are you calling the transfer slot in the combustion chamber? Dave.