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maineSSS

Higher Performance 230 Rebuild

64 posts in this topic

Hi all- I've owned a '49 Power Wagon for a number of years that I've been working on, and am getting squared away for an engine rebuild & upgrade.

I've used both the Ball & Ball and Fish M-2 carburetors, and will be trying out a triple CVK 40 (Harley carb) setup on the rebuilt engine. I also will be using a '59 head for the 230.

I made up some clear head chambers from casting resin so I could observe flow when I do flow testing on a junk block. I'm going to be looking at valve shape and seat angles very closely, as that doesn't seem to have been done before. I have a friend who is a professional head porter, and will be asking him what I can do with port shape to improve breathing- the flathead's big weak point. I'll be looking at keeping velocity up, as this is a street-oriented build.

I'm wondering if anyone has done CV (constant velocity) carbs on a 230 before- the Harley carb is CV, and has been used quite successfully on Samurai's, as it will run upside-down. I heard that the Ramcharger group campaigned a sidedraft 230 back in the 60's, anyone have any info on it? (I suspect it probably used SU's).

Another thing I'm thinking of is a lighter piston- is there a modern piston that will substitute for the stock 4-ring monster? Less weight would certainly help 60 yr old parts at higher rpm...

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with the nearly 5 inch stroke of the 230, piston weight is not nearly the concern as piston travel, and it's associated friction loses, trying to build for mouch over 3800 Rpm is self defeating.

I believe a couple of SU's off a similar sized engine like a Healy 3000, or 4 L Jag, would be a nice set up and easy to accomplish, plus they have adjustable jets so tuning for mixture is pretty easy also.

matching the ports to the gaskets is doable upping compression will get you some good snap also.

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There is another thread on hopping up the flathead that has a picture and description of a newly made custom piston.

The poster used rods from a shorter stroke motor, which are longer. This put the pin higher and gave better rod angularity. The pistons are 100 grams lighter than stock and considerably shorter, more like a modern piston.

The old rules on piston speed and acceleration don't hold as much water as they used to. Today's pistons and rings will stand more stress than the old type and then there is synthetic oil.

In your case you might use 217 rods with custom pistons and get a performance and longevity boost even if you never revved it higher than a stocker.

There is also the possibility of putting a 250 or 265 six into your Power Wagon, they were standard equipment in Korean War era military Power Wagons.

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ID: 4   Posted (edited) · Report post

Re: the long stroke of the 230. It is considered a long stroke engine because the stroke is greater than the bore but how does it compare to some modern, short stroke motors?

Dodge 230 = 4 5/8

Chev 454 = 4

Cadillac 500 = 4.304

Pontiac 455 = 4 7/32

Olds 455 = 4 1/4

Slant 6 225 = 4 1/8

So the stroke is long but not crazy long compared to some well thought of, more modern motors.

With modern light weight pistons and a careful balance job 4500 or 5000 RPM should be within reach. Maybe not the kind of motor you want for a Power Wagon but not out of the question.

Edited by Rusty O'Toole

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Comparing apples to oranges. Comparing a Mopar 230 to a Chevy 454.

If the 230 had the same bore to stroke ratio as the 454, the bore would be 4.91, and the total displacement would be 526 ci. If only that could be done huh? The block would be about 3-1/2 feet long!

Maybe its more like apples to pineapples:)

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Exactly. Comparing "short stroke" to "long stroke" motors is comparing apples to oranges. Can you tell the difference?

Some so called short stroke engines of large displacement actually have quite a long stroke.

The longest "short stroke" on the list is the Cadillac at 4.304. No one would be shocked at a hopped up Caddy revving 5000 RPM. The Dodge at 4.625 should be able to do the same, if it had light weight pistons, modern rings and a good balance job.

Whether this is advisable or not, especially in a workhorse like a Power Wagon, I can't say.

The point is, if you want to invest in more modern, light weight, pistons the potential for higher revs is there.

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Cross drilling the rod jounals would help in the oiling for safe higher revs...hudsonator{?} did this to his 23" and improved the oil pressure via milling of the pump top and could hit 5000rpm all day and touch 6000rpm in short bursts on a tractor. I, myself, wouldn't need to hit 6000rpm but the possible hitting of 5000rpm and having longivity of your crank does sound nice...heck, a solid 4500rpm would be great at any point. The limiting factor with these 6's is the low revs and the prone crank failure if one takes the revs higher without modding the oiling system.

The one thing I saw with that build that I don't exactly agree with is the addition of a groove on the rod and crank bearings for added oil flow{I could be thinking of another build too, been researching afew of these lately}...I feel this would take away from the bearing surface area which to me would be a no-no.

Talk was the possible use of slant 6 offset pistons but no one could figure out the mild offset those pistons have so that's in limbo at the moment.

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One thing I've noticed with these builds is the use of flathead pistons since theres no o/h valves and to mill the head upwards of .060 to .080 to raise the compression...but this can hurt the air flow while doing it by lowering the pocket over the valve area. I wonder if a slightly domed piston could do the same effect while leaving a nice open pocket over the valves for good flow...the valves are raised over this block so relieving isn't needed like with the ford version because of they're low valve pockets.

I want to use the shorter skirted type of pistons to aid in even less weight and sidewall friction as opposed to the keithblack type of aluminum long slugs that are out there.

I have a McColluch supercharger and would love to use that on my 265 but I've got no support from them{paxton} so far as to how to repulley mine to be used for low rpms and still get full boost..a turbo set up would be the same problem..need higher flow to get higher turbine revs to get full boost. Naturally aspirated is an easier way to go, but one of these days someone has to break this barrier for the good of all!

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...There is also the possibility of putting a 250 or 265 six into your Power Wagon' date=' they were standard equipment in Korean War era military Power Wagons.[/quote']

With these 25" motors, they have the larger rod journals at 2.125" as I recall...one could offset grind that back to the 23" block's 2" size and have a slight added throw...is it worth it for the small amount of added cubes...that's going to be your call whether it's a "get everything I can build" or "well, that's not worth the machining but I'll do everything else"....as I recall those rod bolts{23" too?} have T bolts for the rod caps to keep the width down so to attempt to increase the crank throw would require checking the block clearance and getting some good new rod bolts{ARP?}.

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Would be interesting to do a flow test on the engine pictured below. I was told this engine was used in a circle track racer back in the day. Seems to me that the relieved section would cut the compression ratio down a lot and compression ratio is what makes horsepower in these engines.

relieved.jpg

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ID: 11   Posted (edited) · Report post

I see that the piston question interests a lot of people. What I'm looking for is less stress on the rotating assembly and faster revving, but not necessarily higher revs. The most critical load on the rods is tensile- the stretch at the top of the stroke when the piston wants to continue upward as the rod is starting down. A lighter piston pays off bigtime at this moment. As far as rpm's go, I've found that much over 2200 leads to noticeably increased fuel consumption- I can watch the gas gauge drop. Presently, with lockout front hubs, radial tires, and the Fish carb, I get around 12-13 mpg at 35-40 mph in 4th- which seems to be better than most PW's. Switching to radials from bias-ply gave me 2 mpg! The truck weighs 5400 lbs empty and has 5:83 diff gearing.

My big problem is the low gearing and lack of torque at 2000 rpm- I want to run a Laycock OD, and not have to double-clutch downshift for hills. The early 230 cam torque peaks at 1300, the later cam at 1600, but I'd like to get a grind for 1800- but engine breathing has to improve to support that. I think it can be done, but some internal development will have take place in port & valve flow, bolt-ons alone won't do it. As far as turbo/supercharging is concerned, Turbos back up a lot of heat in the exhaust manifold- you'll likely end up with a cracked block, as the casting is thin around the valves. Supercharging would require a lot of special bracket/pulley work, I'm hoping to get what I want thru natural aspiration.

I made up a manifold for a Harley carb, along with an aircleaner base, it will be a tight fit at cylinders 1&2, as this is the closest the engine compartment is to the engine. I used hydraulic cylinder tube, as it had enough wall thickness to machine a 2 deg taper from carb to engine block, but it's not cheap- $80 for 24"! Fortunately, I can get 3 manifold lengths, and have enough leftover to chuck up in the lathe.

Since the Harley carb is a motorcycle carb, it will flood bigtime if subjected to car fuel pump pressures. The Samurai folks use low-pressure regulators and return lines which often need lots of fiddling, so I've decided to try replacing the inlet needle jet with one that will accept a Q-jet offroad needle (more machine work). I think this will work better once I get it scienced out.

Does anyone make a torque plate for the 230? Didn't see anything on BHJ's site- bummer! Cylinder honing with a torque plate makes a difference in engine breakin/longevity- well worth doing.

I have pics- what are the requirements for images?

Edited by maineSSS

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One thing not to lose sight of is it is a Power Wagon. Unless you are prepared to throw lots of money at is you will always have poorer fuel economy. One of the fellas that cruises with us has taken his PW and put it on a newer dodge chassis with a 5.9 Cummins. Now you are talking torq and he gets better then 22 MPG. US. There are many options for you. Will give it to you for trying to keep the Flatty. Makes heads turn when ever the hood is open.

As for fitting a reground 25" crank in a 23" engine. Will that work even tho there is a 2" difference in the blocks?

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A)I see that the piston question interests a lot of people. What I'm looking for is less stress on the rotating assembly and faster revving, but not necessarily higher revs. The most critical load on the rods is tensile- the stretch at the top of the stroke when the piston wants to continue upward as the rod is starting down. A lighter piston pays off bigtime at this moment.

B)The truck weighs 5400 lbs empty and has 5:83 diff gearing.

C)My big problem is the low gearing and lack of torque at 2000 rpm- I want to run a Laycock OD, and not have to double-clutch downshift for hills. The early 230 cam torque peaks at 1300, the later cam at 1600, but I'd like to get a grind for 1800-

D)As far as turbo/supercharging is concerned, Turbos back up a lot of heat in the exhaust manifold- you'll likely end up with a cracked block, as the casting is thin around the valves. Supercharging would require a lot of special bracket/pulley work, I'm hoping to get what I want thru natural aspiration.

E)I have pics- what are the requirements for images?

A) I agree, this is the reason why I like the idea of the modern short pistons.

B) Wow, she's a brickhouse!{lol}

C) I'd suggest an RV cam regrind and have them try and recurve the torqu to your needs...Edgy and a few others should be able to help you with that.

D) I agree there also, while either of those would be neat, there's alot of work to be done to make them work...someday though!....

E) "IMG coded" pics are taken here but I think you upload from your PC too...I use my photobucket account{free}.

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Would be interesting to do a flow test on the engine pictured below. I was told this engine was used in a circle track racer back in the day. Seems to me that the relieved section would cut the compression ratio down a lot and compression ratio is what makes horsepower in these engines.

relieved.jpg

This is an interesting sight...a flathead with relief in the block...cool. This set up would support my thoughts of a slightly domed piston to recoupe the loss of area from relieving instead of head milling...theoretically speaking, to add an equal mass to the top of the piston that you would have removed from the block would/should equal unchanged compression...to add to that further should raise compression without any head milling or flow impedement.

To be able to CC the top of the block, if one could seal off the top area of the piston hole and have the valves closed, you could attain a starting level for measuring, now remove any material and then reCC to see what's gone - now add this amount to the piston top to "equal" the compression.

A large clear acrylic tube could be used for the piston and maybe the same thing for one cylinder{at a time}...mark the starting level on the tube with a fine mark....I'm not a rocket scientist so this whole theory could be mute...

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"I have a McColluch supercharger and would love to use that on my 265 but I've got no support from them{paxton} so far as to how to repulley mine to be used for low rpms and still get full boost."

John Erb in Denver is the man. He goes way back with the McCulloch blower and will be glad to rebuild yours for full boost at low RPMs and advise on pulley ratios.

He is also a piston designer, I think he works for Ross pistons? so he could advise on pistons too.

Speaking of offset pistons.. practically all engines since 1910 have had cylinders offset to the crankshaft (Ford flatheads are this way) or offset piston pins. OHV Chrysler engines use the offset piston pins, by .060 I believe. The purpose is to control piston slap by not having the piston "rock" from one side to the other at TDC.

An old hop up trick is to reverse the pistons. This cuts friction but increases piston slap noise.

Does anyone know if the flathead Chrysler products have offset cylinders or offset wrist pins? In any case it should not stop you from using the slant six pistons, if noise is not a big worry.

On the subject of stroking the big Chrysler six. The biggest version, the 265 with 4 3/4 stroke, is about as far as you can go with this. The rods come so close to the block that they had to use headless rod bolts to stop them hitting.

Now that I think of it if you ground the journals smaller and used smaller rods it might just be possible. But now we are talking about a 5" stroke which is getting out there.

The 265 with stock crank and bored 1/8 over gives you 283 cu in which is about as far as I would want to go. If that wasn't good enough I would be looking at a straight eight or possibly a V8.

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Maine SS can you tell us about your experience of the Fish carb? I have been intrigued by them for years, have read everything I can find and even bought Brown's manual. Would love to hear from someone who has used one and knows what's what.

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A)"I have a McColluch supercharger and would love to use that on my 265 but I've got no support from them{paxton} so far as to how to repulley mine to be used for low rpms and still get full boost."

John Erb in Denver is the man.

B)...using the slant six pistons' date=' if noise is not a big worry.

C)...4 3/4 stroke, is about as far as you can go with this. The rods come so close to the block that they had to use headless rod bolts to stop them hitting.

D)...bored 1/8 over gives you 283 cu in which is about as far as I would want to go. [/quote']

A) I hear ya, I've tried 3 emails to paxton to ask them if they could get back to they're roots with a set up for a mopar flathead, like the kaiser had, except with a fixed pulley....nothing.:mad: It'd be a simple manner of respinning the blower faster than a V8 set up because of the lower rpms required for a flathead...question is what are the correct pulleys?:confused:

B) Aren't those listed as an offset piston...in another forum where they concetrate on inlines it was asked what said offset was...no-one seems to know due to lack of available specs. I think it was a slant 6 .060 over piston that would work for the 265....?

C) Yup, stock they have T bolts for clearance issues but another guy who's done well with 23" motors seems to be planning a 25" 265ci with 25" 231ci{?} longer rods and a high pinned piston for a larger than stock displacement. Still in the planning stage....{Hud 1 or Hudson...dad and son}

D) "1/8 overbore"...wouldn't that loose the sleave...I've heard the blocks are soft enough to require sleaves and that .060 was the max overbore with a sleave. I've seen the sleaves in my 265 and heard the 23" motors are the same, but, I haven't cracked open my 201ci motor yet to tell.

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I love the look and sound of the old flatties but I honestly believe it's a trade off for performance. These things just have too many design strikes against them to consider them a viable performance motor. You can take a $300 decent running 318, slap on a set of headers with a cam, aluminum intake, and a Holley and produce way more power than if you spent thousands on a flathead six. And even that 318 is 40 year technology. So my personal thought is that you pick one; nostalgic coolness or high performance.

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ID: 24   Posted (edited) · Report post

I think the majority of the folks here working the flathead is keeping more in line to what would have been done when these cars were in the beginning period and what little heyday they did enjoy...the WOW factor of seeing/hearing a dressed up and modified flattie usually will catch an eye faster than a V transplant..except maybe if old style hemi..that is always a eye catcher whatever it is in..

so while it will not be a 1/4 miler or a hole shot king of any short..but yeah...it will be peppy and different..while I have no desire to pep one up..I do not slam those who are. if they just keep in mind what the limits are and if the trade off on some mods are going to shorten the life of the car overall..I mean why go straight to the max bore of the block and the max shave of ahead when .030 will clean it up or .010 will save the head..leaving you plenty of margin for future builds/maintenance actions..what you looking at by doing this..maybe a whole max of 9-11 CI and a engine block that is now beyond normal service limits..

Edited by Tim Adams

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Well said, tim. OTE=Tim Adams;305644]I think the majority of the folks here working the flathead is keeping more in line to what would have been done when these cars were in the beginning period and what little heyday they did enjoy...the WOW factor of seeing/hearing a dressed up and modified flattie usually will catch an eye faster than a V transplant..except maybe if old style hemi..that is always a eye catcher whatever it is in..

so while it will not be a 1/4 miler or a hole shot king of any short..but yeah...it will be peppy and different..while I have no desire to pep one up..I do not slam those who are. if they just keep in mind what the limits are and if the trade off on some mods are going to shorten the life of the car overall..I mean why go straight to the max bore of the block and the max shave of ahead when .030 will clean it up or .010 will save the head..leaving you plenty of margin for future builds/maintenance actions..what you looking at by doing this..maybe a whole max of 9-11 CI and a engine block that is now beyond normal service limits..

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