273 ci V8 in ‘52 Dodge Coronet w/GyroMatic

[Retrorudy]

Can a 273 cubic inch LA Chrysler Marine Engine (Mine  has a ‘67 block) bolt up to a 1952 Dodge Coronet GyroMatic transmission without adapter being necessary? What flywheel is required (can the 230 6 cylinder flywheel bolt to the 273 crank?).  I know most will say get rid of Gyro, put in a T5 or modern auto tranny, but the Gyro works perfectly and I want the running gear to remain stock, no mods to car other than engine swap. The 273 is only rated at 195 hp at around 4K rpm so I think it will work well without overstressing the drivetrain with everyday driving. Not planning to drive it like a muscle car.

[Retrorudy]

Also, I already have the 273 Chrysler Marine in my garage, and not looking to go buy another engine like a Poly or the like.

[kencombs]

Flywheel won't bolt to the crankshaft and the clutch housing won't mate to the block.  Sorry.  The 273 is a good engine and IMO, would be worth adding a newer trans.

 

 

[Retrorudy]

I suspected the modern bell housing patterns were not a match, and same for flywheel, but needed confirmation. Hate to start modding the whole drivetrain with tranny and mod to driveshaft, new tranny mount, linkages, etc. Thanks for quick response. If anyone knows of adapters to do what I want, lemmee know...

[Los_Control]

1 hour ago, Retrorudy said:

Also, I already have the 273 Chrysler Marine in my garage, and not looking to go buy another engine like a Poly or the like.

Just curious, I have no clue, seems I read that some marine engines actually run backwards compared to a automotive engine. Then there may be a issue with distributor, cam vacuum etc.

I guess it depends on the boat manufacturer and the out drive it was connected to?

 

I just assume you already know this and checked into it, if not you may have a bigger surprise then just bell housing coming.

[kencombs]

1 hour ago, Los_Control said:

Just curious, I have no clue, seems I read that some marine engines actually run backwards compared to a automotive engine. Then there may be a issue with distributor, cam vacuum etc.

I guess it depends on the boat manufacturer and the out drive it was connected to?

 

I just assume you already know this and checked into it, if not you may have a bigger surprise then just bell housing coming.

Usually the only reverse rotation engines would be one of a pair in a dual engined inboard boat.  They do that to counter torque/prop steer.  Some even used gear drive cams rather than chain, but I've never heard of one of those after the LA engines came into use.

[Los_Control]

Thanks kencombs for explanation.

I was particularly  thinking of a thread in another forum where a guy was putting a chevy 4 cyl marine engine into a model T ford.

Dual 4 or 6 cyl may be more popular combo for the average joe boat.

A Mexican drug cartel leader, may want dual 273 mopar engines .... Just not a impossible combo.

 

If I was parting out a dual engines boat, I wanted one of the engines for self, which engine would I sell first?

I just thought it worth mentioning, most boats would have single engine and a non issue then I suspect.

Even then, is the marine engine like a stationary industrial engine? No vacuum advance, governed carb and sometimes a cam to match the use of a stationary engine?

 

Just thinking that a marine engine is fine, it just may not be a drop in plug & play engine. If a guy is aware of what they have, could be very minor changes.

[greg g]

Rule of thumb for most Marine conversion of Chrysler engines, starter on left rear (flywheel end) rclockwise on right side counter clockwise. Or that's what I read some where.

[Retrorudy]

I had thought about this and had not checked, but when I bought the 273 my friend said it was from a single-engine boat so for now I am assuming standard Left Hand rotation like automotive engines. I also have a pair of 350 Chevy 80’s vintage marine engines complete with marine trannies and reduction gears. They came from a large cabin cruiser and are a left and a right hand rotation. They look identical so the guy who pulled them marked them “L” and “R”. Putting 12 volts to starters is a quick way to determine rotation. If plug wires were on both 350’s a quick comparison should indicate one is reverse of the other, and firing order that matches auto applications is standard Left.

Yes, cams are reversed grind on reverse engines, and therefore firing order and maybe distributor gear pitch angle since it would spin reverse to match cam distributor drive gear, but I would have to look at that. I have often wondered if reverse engines also have reversed cranks or if the standard cranks can just spin in reverse - anyone know for sure? It’s off-topic but just wondering...

Edited March 15, 2020 by Retrorudy
Typo

[Retrorudy]

To Kencombs: so in follow up to my original question, are there any V8’s that ARE a bolt-up swap to the GyroMatic, including Bellhousing and flywheel? Perhaps  a 241 or 270 Dodge or Plymouth Poly? Or did these engines also use a different tranny flange pattern? Engine mounts are of little concern, as I said, keeping original drivetrain is the thought. If there is an adapter for 273 to Gyro, that might do. Then there is the 12 volt conversion to think about...

[Doug&Deb]

The 12 volt conversion could be a problem. The gyromatic doesn’t like that or electronic ignition. If you can make it work you are correct that it will handle the power. The early Hemis used the same trans with no issues. Good luck and keep us posted.

[Retrorudy]

Ok, thanks. Will give this a lot of thought before moving forward. So again to last question: Dodge or Plymouth Poly or small Hemi’s will bolt up to the ‘52 Gyro with no modification? 

[kencombs]

5 hours ago, Retrorudy said:

Ok, thanks. Will give this a lot of thought before moving forward. So again to last question: Dodge or Plymouth Poly or small Hemi’s will bolt up to the ‘52 Gyro with no modification? 

I think the answer to that is:  Yes, with the v8 clutch/coupling housing.

[Retrorudy]

Thank you Kencombs, and all the others for your time and info.

Rudy

[dpollo]

A 241/270 would be the easiest to adapt if you have the bell housing for that engine,  BUT  I got to the mockup stage with a 241  standard with overdrive

into a 52 Plymouth and the starter will not clear the steering box  .   I used a 273 with a 3 speed all synchro in a 57 pickup with great success.  The column shift was a challenge  .  I used the lever selector (at the steering column ) from an early 50s Chevrolet.

[Retrorudy]

Thanks, dpollo, I am learning that best way is remain stock and soup up the 6, or do entire engine and tranny swap. How do I resolve modern ‘67 273 starter and ignition negative ground 12 volt vs. ‘52 Dodge positive ground 6 volt system?

Edited March 18, 2020 by Retrorudy
Corrected typos

[dpollo]

convert the entire car to 12 volt negative ground if you must.    6 volt wiring is heavier gauge so most wires can be retained.

The ammeter connections must be reversed and voltage must be limited for the fuel gauge ans other items such as the wipers and heater motors.

Horns and all light bulbs must be changed to 12 Volt units.   It is not a conversion I would recommend except when a more modern engine is installed.

[Doug&Deb]

If you keep the stock drivetrain the 12 volt conversion will cause problems with the gyromatic. I’m sure it can be done but I’m not sure how.

[Retrorudy]

Yes, I thought about the solenoid for electro-hydraulic shifting getting burned out quickly since its a 6-volt coil. The tranny speed governor is a switch, as are the lockdown and high-limit, which should have not problem handling 12 volts at their contacts. I see complete kits online for ‘49 to ‘52 Dodge 6 to 12 volt conversion with all components required, but none include a shift solenoid. I guess these are intended for manual tranny cars only, or one is left to their own ingenuity to solve Gyro concerns...thanks for the reply. Just a thought but perhaps earlier vacuum operated solenoid from 40’s Chrysler products Fluid Drive would work, but then a vacuum sequence system needs to be transplanted as well. Will keep thinking-thoughts cost me nothing.

[greg g]

Perhaps wiring in a ballast resistor to drop voltage might protect the elec hydro circuit.  Should drop input to 7 to 8 volts. And only be energized when shifting is happening sieving heat creation concerns.

Edited March 19, 2020 by greg g

[Retrorudy]

Yes, except the kits reverse the electrical system to more modern negative ground typically, so polarity would be reversed at solenoid and therefore solenoid action reversed ( power would retract it rather than extend it) which would not allow it to operate the hydraulic vale to cause upshifting. Will keep thinking...

[Dartgame]

The early dodge plymouth small V8's (1950's ) are supposed to share the same bell housing bolt pattern as the LA v8 (273-360 series). If I remember correctly the difference is with the flywheel spacing, the two series dont interchange. I'll check my info and let you know what chrysler says about that.

[Retrorudy]

So the Poly 241 & 270 Powerflite transmissions will mate with a 273 LA if a correction is made to flywheel spacing  (if possible), but NOT to the 230 ci 6 cyl Bellhousing. So really not a solution if the goal is to keep the Gyro and stock drivetrain. I am confused by the fact that early Chrysler and Desoto BIG hemi’s used a fluid drive tranny per another member’s post. I guess the early hemi’s had a different Bellhousing pattern that matched the 6 cyl pattern, or a different bellhousing was used with Fluid Drive on bigger Chrysler & Desoto engines.

Geez, looking like “leaving well enough alone” would be best advice, unless I want to hire a machinist to build my own LA to GyroMatic adapter set, or go full out and put in a torqueflite. Of course the latter choice would allow for full conversion to 12 volts which allows modern bulbs, radio, battery, one-wire alternator, etc. but then it is no longer the “ old car”...

[Dartgame]

I checked my interchange info and the 277-301-318 (1956 and up) series does use the same bell pattern. No info on the flywheel. My thought was to use a gyromatic bell housing  & flywheel from that v8 series if such an animal exists and mate it together...not sure if this kind of thing exists. I dont know much about the gyromatic trans. The bell housing pattern on the early series hemi's are supposed to be the same as the LA motors.

Edited March 19, 2020 by Dartgame

[Retrorudy]

Oh, ok thanks. Then although early big hemi’s may have used Fluid Drive or Fluid Torque it must have been a different bellhousing mated to the same M6 tranny, clutch and fluid coupling or torque converter. Hemi/Poly/A series/LA series history aside, consensus is that a gyro and an LA do not mate without some sort of machine work to adapt the two together, and then maybe a separate 12 volt electrical system to run the LA on, while leaving the rest of the car 6 volt so that all accessories AND the Gyro electrical controls can be left stock. I think do-able, unique, intriguing, but to most people I doubt it is worth it. In my personal case it is almost becoming a conquest...a bug in my brain that needs to be worked out. Stay tuned. Maybe when it gets warm out I will begin “playing”...