57 rocker arm covers

[Ames]

Hey ya'll, I'm trying to get my bird as far as original as possible. I had a conversation with an engine guy that said my engine may be a 292 instead of the 312 (that I was told was in it) because of the rocker arm cover style. The covers are not the "Thunderbird" labeled aluminum one, instead they are chromed steel. I've noticed through research that the same style covers came with a decal that says "Special". My question to you guys is; what makes the 312 "Special"? And, should I get the decal and put them on the covers I have versus purchasing the Aluminum ones. I have no pictures of the engine way back, the car belonged to my Father-in-law, who purchased it close to brand new from a dealer in Buffalo NY, but he is 89 and not in great health and I hate to get him fired up trying to remember back then. I know the car came off the assembly line in December of 1956 and it is the 1957 model. (according to the ID plate) So, what do ya think.

 

[Dale Leonard]

The only way that you can tell if it is a 312 is to pull the pan and look at the main bearing caps. There is a designation on the cap that says it is a 312. Also you can remove the dust cover on the flywheel and take a flashlight and look at the crankshaft behind the flywheel. Slowly turn the engine and look for a flat spot with a raised round flat spot in the middle of it. That is a 312 crankshaft. The 312 is a weaker engine than the 292 and the 57 292 is the most desirable of the 292's. If you pull the valve cover look for the designation on the head. If it is ECZ-G then it is a 1.92 intake valve and it flows more in stock configuration that the 1.94 chevy head. You can use a 312 crankshaft in a 292 and turn it into a 322 cu. in. motor and it is way stronger that the 312. Hope this helps. Im in the process of restoring a 1955 third that has a 312 with two 4 barrels on it.

 

[jack-in-sac]

Hey ya'll, I'm trying to get my bird as far as original as possible. I had a conversation with an engine guy that said my engine may be a 292 instead of the 312 (that I was told was in it) because of the rocker arm cover style. The covers are not the "Thunderbird" labeled aluminum one, instead they are chromed steel. I've noticed through research that the same style covers came with a decal that says "Special". My question to you guys is; what makes the 312 "Special"? And, should I get the decal and put them on the covers I have versus purchasing the Aluminum ones. I have no pictures of the engine way back, the car belonged to my Father-in-law, who purchased it close to brand new from a dealer in Buffalo NY, but he is 89 and not in great health and I hate to get him fired up trying to remember back then. I know the car came off the assembly line in December of 1956 and it is the 1957 model. (according to the ID plate) So, what do ya think.

The valve covers make no difference. The finned aluminum valve covers were part of a ford dress-up kit that had the finned aluminum valve covers, chromed oil filler cap and chromed air cleaner top. If you look at the data plate on the passenger side firewall a 292 will begin with a C. If it is a 312 it will begin with either a D,E, of F. Aft this time the engine could have been changed but most likely the original engine would have been rebuilt. The rear oil seal on the 312 is different than the 292. The 312 rear main seal usually leaks on a 312, not so much on a 292. The chromed steel covers are usually after market reproductions as Ford never provided chrome valve covers for this car. The two choices were black with the decal or the dress-up kit with finned aluminum valve covers. The factory aluminum valve covers always have the Thunderbird logo painted. Is their a reason you care whether it is a 292 or a 312? They look the same and I don't think anyone is likely to know the difference in an exterior inspection of the engine. If the engine was replaced by a passenger car engine it would have had the crankcase ventilation on the drivers side of the block and the valley cover on passenger cars is not vented. The Thunderbirds originally had a road draft tube that exits the valley cover at the rear and may or may not have been replaced by a pcv valve which was not original.
good luck, J.

 

[Ames]

The only way that you can tell if it is a 312 is to pull the pan and look at the main bearing caps. There is a designation on the cap that says it is a 312. Also you can remove the dust cover on the flywheel and take a flashlight and look at the crankshaft behind the flywheel. Slowly turn the engine and look for a flat spot with a raised round flat spot in the middle of it. That is a 312 crankshaft. The 312 is a weaker engine than the 292 and the 57 292 is the most desirable of the 292's. If you pull the valve cover look for the designation on the head. If it is ECZ-G then it is a 1.92 intake valve and it flows more in stock configuration that the 1.94 chevy head. You can use a 312 crankshaft in a 292 and turn it into a 322 cu. in. motor and it is way stronger that the 312. Hope this helps. Im in the process of restoring a 1955 third that has a 312 with two 4 barrels on it.

Good information, I am going to copy this info and put it in my shop manual. Good luck with your 55.

 

[Ames]

The valve covers make no difference. The finned aluminum valve covers were part of a ford dress-up kit that had the finned aluminum valve covers, chromed oil filler cap and chromed air cleaner top. If you look at the data plate on the passenger side firewall a 292 will begin with a C. If it is a 312 it will begin with either a D,E, of F. Aft this time the engine could have been changed but most likely the original engine would have been rebuilt. The rear oil seal on the 312 is different than the 292. The 312 rear main seal usually leaks on a 312, not so much on a 292. The chromed steel covers are usually after market reproductions as Ford never provided chrome valve covers for this car. The two choices were black with the decal or the dress-up kit with finned aluminum valve covers. The factory aluminum valve covers always have the Thunderbird logo painted. Is their a reason you care whether it is a 292 or a 312? They look the same and I don't think anyone is likely to know the difference in an exterior inspection of the engine. If the engine was replaced by a passenger car engine it would have had the crankcase ventilation on the drivers side of the block and the valley cover on passenger cars is not vented. The Thunderbirds originally had a road draft tube that exits the valley cover at the rear and may or may not have been replaced by a pcv valve which was not original.
good luck, J.

Thanks Jack, if the leak is any indication, then its definitely the 312. I appreciate your response, just like all of the responses here, they help me get smarter about this car. I just want to make sure I don't put something on this car that does not belong or is incorrect, your info was helpful.

 

[Dale Leonard]

Thanks Jack, if the leak is any indication, then its definitely the 312. I appreciate your response, just like all of the responses here, they help me get smarter about this car. I just want to make sure I don't put something on this car that does not belong or is incorrect, your info was helpful.

You cannot depend on the oil leak to indicate that your engine is a 312. Early 292's had rope seals also and all 312's had rope seals. As I stated earlier in this post there are only two ways to tell if you have a 312. I will find out the designation on the rod cap and post it here as soon as I find it. The other is the button on the crankshaft. I also will try to find out what year Ford went to the neoprene seals in the 292.

 

[Dale Leonard]

Information on the 312 main bearing caps.
ECZ is cast into the 312 main bearing caps
All others are 292 EBU main bearing caps
The 312 has a round button cast on the outside diameter of the crankshaft flange behind the flywheel.
Only two ways to identify the 312 from a 292 other than by checking the diameter of the crankshaft with a set of mic's
292 and 312 blocks are identical and was used for both. The block numbers are identical except for the A, B or C as to what plant they came from. C = Cleveland ect:

 

[Sierra977]

Dale, after reading your first two sentences, I read the rest in Karol Miller's voice.

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[doug7740]

I thought I would attach the following two articles, one will help you identify if your engine is a 292 or a 312. I know that you said that you have a 1957 Thunderbird, but the other article that I found informative is from the November/December 2000 Early Bird magazine and explains the differences in the three versions of aluminum valve covers used on the 1955 Thunderbird engines.

doug7740
1955 Thunderbird Blue

 

[Tater Salad]

I thought I would attach the following two articles, one will help you identify if your engine is a 292 or a 312. I know that you said that you have a 1957 Thunderbird, but the other article that I found informative is from the November/December 2000 Early Bird magazine and explains the differences in the three versions of aluminum valve covers used on the 1955 Thunderbird engines.

doug7740
1955 Thunderbird Blue

Thanks for the valve cover article Doug, I was unaware of the 3 versions

 

[Ames]

Good stuff guys, I appreciate the information. I called my father- in-law and he was happy to talk about his old bird. Back in the early 60's he had the covers chromed at a place in Hamburg NY. He thinks they were black with a decal but couldn't be sure. My motor guys assured me that the motor is a 312 because of the machining and rebuilding they went through. As always, thanks for all the conversation and information.