TBird engine

[Habusailor]

Was the 312 TBird engine a good solid engine? How did it perform stock?


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[Charlie Stephens]

I drove a '57 T-Bird for years. It was a heavy car. I was happy. If I remember correctly they had a 190 hp version with a 2 bbl, a 245 hp version with a 4 bbl and one that probably put out 275 hp with a supercharger that never had hp released by Ford. They also had dual quad version and I don't remember the hp. These are the numbers I remember from almost 50 years ago so GOOGLE if you want the real numbers. The engine was heavy and solid. It was also a big engine so I wouldn't recommend it for your AVATAR if that is what you are thinking.

Charlie Stephens

[40 Deluxe]

For me, yes it was a solid engine IF the oil was changed regularly. Between the oils of the day and inefficient crankcase ventilation, sludge would form and block the narrow passages to the rocker arms, causing premature wear. They lasted as well as other engines of the era. And 312's held their own in NASCAR and other racing series. In stock form, power and fuel mileage were like most cars of their day.

[dmsfrr]

As 40 Delux mentioned, like all Y-block engines they can develop clogged oil passages to the rocker arms if they weren't maintained well... non-detergent oil and infrequent oil changes.
The 312's can have a tendency to leak oil from the rear main a bit more often than the 239 thru 292.
They do perform well in stock form, but as Charlie said they are heavy, esp. when compared to newer engines.
Horsepower chart: http://www.portholeauthority.com/thu...ch/engine.html

Should we assume you're looking at one to buy?
Is the engine from a 'full sized' car with T-Bird labeled valve covers, or actually from a '55 / '57 Thunderbird (there are several noticeable differences) or is it even a 312???
Look for the Letter Prefix of the (6015) casting number on the block. photo 1, see this link...
http://ford-y-block.com/Block%20identification.htm

Is it really a 312?
Some sellers can be 'confused' about what they have...
photo 2, only 312's have this dot at the rear of the crankshaft.
http://ford-y-block.com/identify312.htm

What are you hoping to do with it?
Depending on how complete it is, what it's actually from and what you'd like to put it in, the number & size of challenges will vary.

After all these years it could easily need a rebuild. That cost may be more than you expect.

If you can attach photos it could be helpful.

[Pete]

Originally Posted by Habusailor

Was the 312 TBird engine a good solid engine? How did it perform stock?


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It was a reliable engine if you didn't abuse it too much. With the addition of 3 Stromberg 48's it had a very noticeable better kick in the pants but still wouldn't keep up with a stock Corvette. The cranks had a reputation of breaking at around 60K miles. Many kept running with cracks though. Shortly after the 57 312 engines came out the factory issued a bulletin to their dealers that they expected in excess of 3% of the 312 camshafts (EDB) to fail within 200 miles. (which they did)

[paul2748]

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All the Y Blocks, not just the 312's, had the 6015 cast into the block. This is Ford's group number for all engine blocks.

[miker98038]

The other problem, in addition to those mentioned above, was bad specs’s for the main caps. Way too high, and resulted in cracked blocks in the main web.

I bought a cheaply rebuilt 312 that ran fine. But on doing a full rebuild, the crank didn’t pass the mag check. Don’t know how long it ran, but it did.

Best gasket has pretty much solved the rear seal problem with a neoprene rear main gasket. They had some silicone (I think) ones that were orange colored. Those failed in under 500 miles. The one in my car failed in 100 miles. The new black ones are better, but installation in critical. Ted Eaton at http://www.eatonbalancing.com has some excellent articles, and one on the rear seal.

Lots of guys prefer to put the 312 crank in a 292 block by turning the mains down. A good crank grinder will put a better fillet on the throws than Ford did. I’ve done that, works nice.

You can offset grind either crank, the 312 in my 32 is 340 cid. Rono over at yblocksforever has a mid 30’s coupe with a 471 supercharger on it. Tight, but can be done.

[dmsfrr]

Originally Posted by miker98038

The other problem, in addition to those mentioned above, was bad specs’s for the main caps. Way too high, and resulted in cracked blocks in the main web.
...

Some things that can go wrong...

http://ford-y-block.com/assemblyerrors.htm

http://ford-y-block.com/troubleareas.htm

[slumlord44]

I've been running Y Blocks since 1963 when I started with a '58 Ford with a 292. Traded it for my '57 T Bird that I still have today. Never found a small block Chevy that I coldn't beat or at least keep up with. They have there quirks but are tough and powerful if built right and well maintained. Have beat a few big block musule cars with a mildly hopped up dual quad 312. The 292 in the '58 would beat most 265 and 283 Cheveys. It was stock with a 4 barrel and dual exhausts and a 3 speed full syncro 3 speed and 3.89 rear end.