1cm
 

merc 4"?

https://i.imgur.com/7kMwuuY.jpg

https://i.imgur.com/KAR4Trt.jpg

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Well it for sure has Mercury heads but has Ford three bolt carb so it's a toss up!:cool:

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Sorry Beater, but I'm not sure why there are continued efforts to ID cranks (and blocks) by evaluating bolted on bits, and by looking at the outsides.

Even as beautifully and evenly crusty as this one is... The internals may have been done fifty years ago.

Might it be a long throw crank? Yeah, but the type of cylinder heads will never (or any bolted on component) be definitive evidence.

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Pickups didn't come with the 255 even if its a Mercury pickup. I have one 1CM head on one of my 51 Mercury cars but the other one has 8CM heads on both sides. The stroke length & piston pin location is the only difference between a basic Ford 239 and a basic Mercury 255. The Mercury 1CM head may compare to an 8RT truck engine head as far as compression ratio is concerned.

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Pretty much the same response here as over on the HAMB. Only way to know for sure is to pull a head and measure the stroke.

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Seems to be some betting going on here lately, so my money is on a stock Ford 3 3/4" stroke. Back in the day, there were a lot of folks who thought Mercury heads were superior to Ford heads because the Merc's had a higher HP rating from the factory.

They were wrong.

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im sorry guys, i should have given more info. this is in a 51 mercury M6 truck. truck was my grandfathers. 20,000 original miles. the truck has never left the farm, and has never had any work dont to the engine. that is fact , not guessing. purrs like a kitten. so im tossing around the idea of useing the engine in a rod. i expected to see 8BA on the heads. im not about to pull a head to find out for sure however

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thats how she came from the factory. still has the factory rad hoses and clamps aswell lol

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Pull it from your grandfathers truck with 20,000 miles for a hot rod? April fool right?

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Since it is a Mercury M6, Does it have Canadian 1CM heads on both sides? Canada always did things a fair bit different than the US cousin prior to the buy out by Ford Dearborn. The reason I ask, is that both of my 1951 Mercury cars were early 1951 manufactured in December 1950 at the same plant in Saint Louis, MO. One has never been apart and it has 8CM heads. The other had an overhaul by one of my uncles back in the late 50s and I think the 1CM head was the replacement part for a cracked head. I can't confirm it since none of the folks involved are currently living but I've always wondered why it only had one 1CM head. When the 1952 engines came out, they changed to EAC 255 heads to increase the compression a bit just like they did with the EAB Ford 239 higher compression heads. Trucks in the USA seem to have mostly 8RT heads in 1952 & 53 and possibly much earlier for the most part.

Another question would be to any late 1951 Mercury owners out there about whether they have 1CM heads on both sides or not? I am just wanting to confirm whether they were used in 1951 production or whether they were just replacement heads. Ford may have changed a mounting location such as the oil filter canister or something of that nature as well.

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Beater can we get some more pictures of the truck sounds pretty exciting to me and i’ll bet some other fellows to

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My '51 Mercury was built March 13, 1951, at the St. Louis plant. It has the late '51 transmission and 8CM heads.

Ken

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I’ve seen quite a few 1cm heads on the east coast that are suppose to be factory mercury heads. (So I’ve been told) My mercury engine came with eac heads 4” crank from an unknown pickup from a old paving company. (Still stock bore)
I’ve seen 8cm heads on ford cars and ford trucks up here. Who knows about rebuilds

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1cm heads on both sides yes. i know its never been touched.

no its not an april fools joke, the truck sits and does nothing. once or twice a year i run it up and move it around just to keep it from going any farther down hill. im very torn on useing it for something else allrighty, but however. costs a lots to build one

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There were Merc trucks in Canada that came with the 255. I had understood it was only '52's, but possible that also in '51. Only in M5 and M6 "big" trucks.

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It's your truck to do with as you please. Sounds like it is really a good one!

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After finding that the truck is an M6, I am revising my bet. (I originally thought it was a pickup.)

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hard to say what to do with it. it sits and does nothing

https://i.imgur.com/NMS0DiX.jpg?1

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Since I have a Canadian 1950 Mercury and not a Monarch (yet) 1949 and 50 Canadian Mercury in both the Mercury and Monarch flavors had heads with C8CM with Made In Canuckastan casted directly below. In 1951 our heads had C1CM and the same casted comment below made in Canuck
American 1949-50 had 8CM and 1951 1CM and I suppose I have an American 1951 core in my hoard as it has 1CM on the heads.
My transmission also being a Canadian Borg Warner with OD has the same part number as the American parts manual BUT has a C in front of the part or casting number.
The additional C in the model and part number indicates Canadian or perhaps Complicated:D
Oh and our trucks also had 8RT heads, both in Ford and Mercury trucks. I have seen a number of them over the years as well. Who the heck knows about the Mercury and 255 but anything is possible? My father used to have a 1952 Mercury M7 3 ton and it is unknown to me what it had under the hood because he sold it over 40 years ago. In the owners manual I was surprised with the engine options! The flathead V8 of course, a 317.5 Lincoln engine and this was the same year it was offered in Lincoln replacing the 337 flathead and to my surprise a Diesel engine as well, possibly a Detroit??
I will dig around and see if I still have the manual which would be hard to find now being a Canadian Mercury truck.

One thing is for sure is the Meteors in the same time period and up to 1954 had the 255 in them quite often. I had a 1954 Meteor and it had the 255.

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Does it follow that these engines with the !CM heads will probably have a 1CM cam fitted?
Phil NZ

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i actually have a 51 merc M7 with the 317 in it

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Back to the original question... merc 4-in? Since you say you run it up, that means it's not stuck. So, pull a plug, and measure the stroke. I think it might have been Ron that posted long ago, regarding using a large zip tie (or other flexible 'something', like a cable.) I'll let others elaborate. Should be able to tell if it's 3.75 or 4.00

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Not a betting man, but I'm hoping the zip tie says it's a 255. That truck that it's in is already a hotrod. Put a license plate on it (or not) and run it into town on a Saturday night. What could possibly go wrong?

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Put a ramp bed on it and haul your hot rod!:cool:

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I don't think an accurate measure can be taken with the heads on. The tie strap is generally used to find TDC on #1 cylinder. The crankshaft counterweight measurement across the cheek is a good way other wise pull a head and measure from TDC to BDC.

The F6 we had back in the day had a 239 CID engine but it wasn't made in Canada either. The F7 & F8 Big Jobs all either had the Lincoln 337 till 1952 then they had the 279 CID or 317 CID big Y-blocks in F7/F8 or F700/F800 respectively till 1956.

Ford of Canada always did things differently so the larger F5 & F6 Ford trucks may have also had the 255 available to them. This is not common in the US. All the F1 through F6 Ford trucks I've worked on had 239 CID engines with 8RT heads.

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Since this is said to be an original truck with an untouched engine, the combination of 1CM heads and a three-bolt carburetor has always bothered me. How about this scenario? The trucks had lower compression heads (8RT) than the cars (8BA). Maybe they ran out of 8RT heads and substituted 1CM units. The concurrent year Mercury's had a larger chamber because of the longer stroke. Everything turns out as it should, and the line keeps running.

Unfortunately, that would make it a 239.:( I think you going to have to measure it to satisfy all of the inquiring minds out there.

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Can you see any casting marks on the block? Like "C1BA"...if so, good chance it has a 4" crank.

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That's odd, because I thought the 317 Lincoln Y-Block didn't come out until 1952 ? It was the 337 Flathead V8 before that.

Sal

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A friends parents bought a new 52 F-2, he was still using it in the 70's and I ask him about the Mercury heads. He said they were on it when it was new and they were to lower compression for trucks. But it was a USA build.

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it could be a 52. it is the big OHV engine crammed in there

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i live in the land of mercury trucks. you are the first one ive ever heard say that the trucks didnt come with the 3 bolt 97. i have about 400 trucks lined up, and there is exactly 1 truck in the yard, mercury or ford, that doesnt have the 3 bolt carb on it

https://i.imgur.com/4zKJzvN.jpg

https://i.imgur.com/QSzCk61.jpg

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yes dont forget we are talking about M6 not F6 things happened different at ford of canada allright

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Wow all those trucks! Not only was the 255 optional, but the M series 6 cyl 254" was in the mix. Newc

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For US production, it was '52 when trucks got the 279 and 317 OHV engines. I would think it odd that Canadian production would have them earlier, but some states/provinces titled vehicles by year of 1st sale, not by model year.

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As far as I know (which I will admit is limited), the Canadian trucks came from the same plant whether they were Ford or Mercury at Walkerville at least till the Oakville plant was built later.

I think what Tubman was trying to get across is that Mercury engines generally used the 4-stud Holley 885 type carb so they had a different manifold and air filter. Ford US didn't put a 3-stud model 94 on a Mercury engine for the 8BA era. They generally always used the Holley 885 to the best of my knowledge. I can't say about Canada for any certainty but it does make a person think about what they were doing there.

Mercury heads would have been comparable to truck heads for compression but they aren't the same. They are close but not the same. Trucks pulling heavy loads had to have lower compression and gearing for the engine to survive. Mercury heads were not as low a compression as truck heads but not far from it. They lowered the compression due to the increase in cubic inch displacement to keep the overall compression about the same as the 239 CID engines. This would lower the possibility of detonation under extreme loads. This is why I question the use of 1CM heads or any Mercury heads on a truck for that matter.

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I have a '50 C8BA block that had the C8CM heads on both sides, a four bolt intake, and a Merc crank and had never been bored.
My best guess is that they were short a proper Merc block and just put all the Merc guts in to satisfy the Merc it was to be matched to as the basic block was used for both Ford and Mercs. The block came out of a Merc.

So who knows for sure what happened on the assembly line back in the day...

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The 8BA in my 52 Vic had Merc heads & cam. It ran quite well . When i rebuilt it, found out it had domed pistons. I think those pistons may have helped improve performance...?

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I guess it depends on how high the crown of the dome is. All the Ford made 8BA pistons were domed originally. The Mercury and Ford pistons only differ by the piston pin location since they have the same con rods. The French made SUMB engines are the only exception to that rule that I'm aware of since they made a shorter con rod for their 255 CID engines.

There have been all sorts of aftermarket 8BA type pistons over the years depending on application and manufacturer. Some have a cone shape dome instead of a radius shaped dome and some were made on a different radius.

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My Mercury engine still has a lot of the original green paint ECM heads 4” crank and it came with a 3 bolt manifold and a strange tower on the 3 speed that the shifter came forward up over the back of the engine.

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Cab Over Engine (COE) trucks had a different shift tower arrangement. Maybe that's why it has the strange shape.

Another thing I wanted to mention on post 38 is that all the 8BA era blocks were basically the same. Ford Dearborn used the same casting till sometime in 1951 when they added a 1BA casting mark in the lifter valley. This designated two things. The 1BA blocks had the rotator type valves and the crankshaft had a larger bore in the back end to accept the automatic transmission torque converter.

I would not be surprised if a Canadian C8BA block had Mercury heads if it was truly an OEM Mercury 255 build but it's easy to replace the heads too. Some of the Canadian truck engines I've seen had the tan color paint but I don't know how far that went. Ford Dearborn even changed colors several times in the 8BA era depending on whether it was a Ford, Mercury, or a truck.

With Canada's separate Ford and Mercury dealer system it made for a lot of interesting differences from their US counterparts. It likely makes it hard to get parts for some of the semi-orphan models like the Comet and the Monarch cars since there were no US counterparts.