Eagle 4" 8BA Crank?

[leon bee]

Since we been discussing Asian parts and tools: I saw these cranks for sale, less money than I would have figured. By the time you bought a decent Mercury crankshaft and had it ground, might be about the same money. These have been discussed here before, I haven't found the relevant posts yet, though. For example, GaryGosfast, I remember he liked the Eagle or the Scat one or the other, but not both of em. Any thoughts from anyone?

Also, do these go okay with original 8BA rods? Just wondering, not spending any money yet. Thanks!

[Tim Ayers]

Curious, what's the price of one of these? Grinding a good. old crank ain't that much.

[Jockeyshift41]

$581 on Ebay

[Ronnieroadster]

Original crankshafts made by Ford are superior in quality to any scat or eagle crankshaft made in china. Typical job shops that use off shore chinese parts are not a place I would spend my money or use there choice of parts as guide to what quality truly is. A good merc crankshaft including grinding would cost at the most what a cheap quality import crankshaft is going to cost.
Ronnieroadster

[Black Fifty]

Deleted.

[GOSFAST]

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Originally Posted by Ronnieroadster

Original crankshafts made by Ford are superior in quality to any scat or eagle crankshaft made in china. Typical job shops that use off shore chinese parts are not a place I would spend my money or use there choice of parts as guide to what quality truly is. A good merc crankshaft including grinding would cost at the most what a cheap quality import crankshaft is going to cost.
Ronnieroadster

Hi Ron, the problem using only OEM Merc cranks is there aren't enough "decent" ones around to meet the demand and the work (labor) to make certain a shaft is usable normally outweighs the price of an aftermarket piece.

I'll give you an example of the general procedure here for "prepping" an OEM 4.000" crank. First it gets magged, then the 4 clean-out holes get drilled and tapped (3/8" NPT), and next (generally) gets turned to an undersize.

By the time you purchase a used Merc crank (we get an average $300.00 for a "mint" Merc shaft) and then do all the above labor it's a no-brainer to go with a new off-shore piece! Plus you have the option of using the 2.000" rod journals w/o any add'l machining!

In short, you pay $200.00/$300.00 for the OEM piece, you mag it, drill/tap the plugs, machine it to whatever u/s and usually find it'll cost more than new! We get $525.00/$550.00 for the Eagles (depending on any shipping we see) and also now have the choice of the strokes!

We are able to balance most Eagle Flathead cranks with a bob-weight between 1500 & 1550 grams in under 1 hour! Also never had to "fill" a single one so far to get it balanced!

Thanks, Gary in N.Y.

P.S. The above info is looking at it from a business standpoint, we move enough Eagle shafts to keep a good inventory on hand, and we save the incoming frgt by buying in numbers! We now avoid ALL Scat shafts here any longer, had too many issues getting them balanced w/o adding some heavy-metal. This is based not only on the Flathead ones but on the Chev's as well!

[Bored&Stroked]

It kind of comes down to stroke and rod-choices for me. If you're just going with a 4.00" stroke and running standard 49-53 rods, I'd rather have a performance regrind on a stock Merc crank than an aftermarket one. I would find one that is STD or .010 - then have it checked out and performance reground from there. I'm not inclined to buy a crank that is already .020 and worn . . . then have to go to .030 or more on the regrind.

Now, if you're going to a 4 1/8" stroker, then things start to change - depending on what rods you're wanting to run. To get to that stroke on a Merc crank, we have of offset grind it and either run the early 221 cubic inch 91A or 21A rods and full-floater rod bearings. Or, you buy a new set of SCAT H-beam rods with the 2" journals. You start investing quite a bit of money on rod work, floater bearings or new H-Beam rods - it starts adding up quick.

Also, one has to make sure that the Merc crankshaft you start with will actually give you a 4.125 stroke after offset grinding . . . I try to start with a STD stroke crank to ensure I reach the 4.125 stroke - such that I have the correct resulting compression height for standard off-the-shelf Ross pistons. Otherwise, if the stroke comes up a bit "short", I have to order custom pistons with the compression height (pin location) to match my newly offset ground crankshaft.

In the end, I'd still rather have a 4 1/8" stroked Merc crankshaft at this stroke level - and I'd probably run H-Beam rods as they really don't end up costing any more than reworked 21A rods and cadmium silver full-floater bearings (if you can find them).

One you get over 4 1/8" stroke - say 4.250" and you're not building a Bonneville or true race motor, then you pretty much are reliant upon SCAT or EAGLE to supply you a cast stroker at a price you can afford.

If you're building real race motors with 4.250 strokes or more - with high horsepower levels, then you're stepping up to a true billet custom crank, lower end girdles, etc. - and you're talking $3000 or more (these days) just for the crank - and God only knows how long it will take to get one . . .

[Ol' Ron]

B&S, I have to agree with you on all of the above, However I was told by a crank grinder that he could make a 4 1/8 stroke cranl out of one that was .020 under and even more if you wanted a 4 1/8 that was .010/.020 under. Then you'd have yo find floaters that were undersize or "H" beam wit undersize bearings. I never did the Math here but i suppose it possible to save a good Merc crank for something useful. I have one that;s .030 under that i was thinking of turning to 1.998 to save. BUT??

[Pete]

Quote[Once you get over 4 1/8" stroke - say 4.250" and you're not building a Bonneville or true race motor, then you pretty much are reliant upon SCAT or EAGLE to supply you a cast stroker at a price you can afford.]Quote

Not necessarily. People seem to forget about the welded strokers. You can still get one made. People also seem to have forgotten that Ford made quite a few CAST STEEL Merc cranks. (prefered for welding)
A welded crank will last as long as a billet in a street engine.

[Tim Ayers]

A tad off topic, but has anyone ever worked with a French 4" crank? I have an NOS one that I've been saving for my next motor.

[40 Deluxe]

Originally Posted by Pete

Quote[Once you get over 4 1/8" stroke - say 4.250" and you're not building a Bonneville or true race motor, then you pretty much are reliant upon SCAT or EAGLE to supply you a cast stroker at a price you can afford.]Quote

Not necessarily. People seem to forget about the welded strokers. You can still get one made. People also seem to have forgotten that Ford made quite a few CAST STEEL Merc cranks. (prefered for welding)
A welded crank will last as long as a billet in a street engine.

Hi Pete, I have a question: I have a couple Merc 4" cranks. How do I tell if they are cast steel or not?


Thanks, Allan

[Zeke3]

I don't have any desire to build an engine like you all have been describing, but I love to read about it. Amazing.

[tubman]

I was of the opinion that only some '32 cranks were steel. I will be interested in where this iron/steel discussion goes,

[Bored&Stroked]

Originally Posted by Pete

Quote[Once you get over 4 1/8" stroke - say 4.250" and you're not building a Bonneville or true race motor, then you pretty much are reliant upon SCAT or EAGLE to supply you a cast stroker at a price you can afford.]Quote

Not necessarily. People seem to forget about the welded strokers. You can still get one made. People also seem to have forgotten that Ford made quite a few CAST STEEL Merc cranks. (prefered for welding)
A welded crank will last as long as a billet in a street engine.

I agree Pete . . . with one caveat - "price you can afford".

Having a crankshaft shop create a welded stroker will be a lot more money than a $600 Eagle 4.250 stroker. This is a semi-educated guess

I'm sure the prices vary all over the board, but I think the last price I heard (20 years ago) was over $100 per journal. Just for shits and giggles, I will ask Fowler what they charge these days - they have one of those cool journal welding machines (they use it a lot on big Diesel cranks with spun bearings).

I've never had a 'Cast Steel' Merc crank (that I know of) - what is the best way to positively identify one???

[Bored&Stroked]

Originally Posted by Ol' Ron

B&S, I have to agree with you on all of the above, However I was told by a crank grinder that he could make a 4 1/8 stroke cranl out of one that was .020 under and even more if you wanted a 4 1/8 that was .010/.020 under. Then you'd have yo find floaters that were undersize or "H" beam wit undersize bearings. I never did the Math here but i suppose it possible to save a good Merc crank for something useful. I have one that;s .030 under that i was thinking of turning to 1.998 to save. BUT??

Given the stock rod-journal size of the Merc Crank is 2.138, in theory you can just make it with a .020 undersize crank - if it has no wear. In my experience it always seemed like that was pushing it - that anything under .010 was kind of a crap shoot.

[Ol' Ron]

had a Ford 3 3/4 crank that broke inspected at he bullard foundry lab abd it had a catavation errosion brake, from excessive oil pressure. It was also made fron perlitic iron. Not a merc crank but they spark the same??

[Pete]

Originally Posted by Bored&Stroked

I agree Pete . . . with one caveat - "price you can afford".

Having a crankshaft shop create a welded stroker will be a lot more money than a $600 Eagle 4.250 stroker. This is a semi-educated guess

I'm sure the prices vary all over the board, but I think the last price I heard (20 years ago) was over $100 per journal. Just for shits and giggles, I will ask Fowler what they charge these days - they have one of those cool journal welding machines (they use it a lot on big Diesel cranks with spun bearings).

I've never had a 'Cast Steel' Merc crank (that I know of) - what is the best way to positively identify one???

The cost for a welded 4.5 stroke crank would vary quite a bit due to who you knew, whether they were interested and bunch of other stuff.
It would end up somewhere between a SCAT/Eagle and a billet.
One thing for SURE. It would last a whole lot longer than a SCAT/Eagle.
4.5" welded cranks lasted for at least 20 runs in the old days of top fuel.
Scat cranks would only last 100 feet on the first run.

The easiest way to identify a steel crank is the spark test. There are very subtle differences in looks also, so unless you have compared the 2 examples side by side, it is difficult. ONE THING FOR SURE IS, ALL OF THE STEEL CRANKS I HAVE HAD, HAD "1CM" cast in one of the big counterweights.
I have seen plenty of cast iron ones with "1CM" also, so that is not a positive identifier.

[Pete]

Originally Posted by Ol' Ron

had a Ford 3 3/4 crank that broke inspected at he bullard foundry lab abd it had a catavation errosion brake, from excessive oil pressure. It was also made fron perlitic iron. Not a merc crank but they spark the same??

No, Ron, the sparks are quite different from cast iron to steel.
Iron is dark red with no sparkles.
Steel is yellow with sparkles.
This is for the flathead cranks only. Sparks will vary widely with different steel alloys.

[tubman]

"Pete" - Would it be possible to post a couple of side by side pictures of a steel vs. an iron crank? I have a pristine 1CM crankshaft and would hate to "waste" it on a street engine if it is something special.

[Pete]

Originally Posted by tubman

"Pete" - Would it be possible to post a couple of side by side pictures of a steel vs. an iron crank? I have a pristine 1CM crankshaft and would hate to "waste" it on a street engine if it is something special.

I don't have any pics of that.
I haven't used OEM cranks for many years.

The spark test is more reliable.
Take a die grinder with a 1 inch diameter stone in it and see what the sparks look like. Bear down so the sparks are bright. A cut off wheel might produce brighter sparks. Try that also.

[Brian]

I dunno; I built a stroker with a genuine Merc crankshaft that was definitely made of steel. Apparent when drilling the counterweights during the balancing process; iron does not have swarf that comes off in long continuous strips.
I always use steel forged cams in all my builds. They are readily apparent to the eye as they are fully machined, however, I have noticed that if you suspend one and tap it with a metallic object, it'll ring, clear as a bell. The later cast cams won't; just a dull 'thud'.
Pretty hard to 'suspend' any flathead crank whilst giving it a 'ring' test, but I'm pretty sure the acoustics will differ from a cast crank.

[frnkeore]

I'm a aircraft machinist, that had my own machine shop (still have it but, I'm retired now), up until the time I retired, in 2007, I new the Mil Specs for that time period.

You do not, weld any thing that goes on a aircraft, unless it's had FAA approvals, heat treat and a lengthy inspection that includes X-ray, that went with it. Extremely costly! And you sure didn't use dissimilar metals in the weld, as I would assume you would have to do with a cast iron crank (high nickle). You can weld cast by heating the whole crank, block or head to it's critical temp, weld it with cast rod and anneal it after, also expensive, if you can find someone that will do it.

Then after you do all that, you will have to have it ground. The cheapest I found that was $250.

I'm NO fan of China, for sure but, I would buy a Eagle crank first, for over a 4 1/8 stroke.

[JWL]

Oh yes, the old mythical STEEL Merc cranks. I have never seen one. More folklore. If they were made they did not follow the original Ford material specifications. All the 1 CM cranks had the torque converter counterbore and that is the only difference.

[Pete]

Originally Posted by JWL

Oh yes, the old mythical STEEL Merc cranks. I have never seen one. More folklore. If they were made they did not follow the original Ford material specifications. All the 1 CM cranks had the torque converter counterbore and that is the only difference.

Ah yes, the "guru" has spoken. We all realize, John, that if you didn't see it, it never happened.....LOL

[tubman]

"Pete" - I see you are in Washington state. The only other person who has seen one is "Brian", from New Zealand. Perhaps these are Canadian made?

[flatheadmurre]

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Don´t think it´s location related...it´s more time related...
All i´ve seen is late with the big rear bore to take the automatic transmission.
And they are cast in the same process as the Y-block cranks so thinking in the transition period to Y-block they where made.
We all know ford did reuse and use what was available..
I have a NOS EAB crank here that is steel...in the ford box!

[tubman]

Originally Posted by flatheadmurre

Don´t think it´s location related...it´s more time related..........

I have a NOS EAB crank here that is steel...in the ford box!

Now that I have never heard of. Where was that crank made? Since you're in Sweden, maybe it is "location related".

[Pete]

Originally Posted by tubman

"Pete" - I see you are in Washington state. The only other person who has seen one is "Brian", from New Zealand. Perhaps these are Canadian made?

I have heard from several people that they might be but don't have any info on that.

I had 4 of them over the years. In the 50's I had a friend that worked in the tear down area of the local authorized Ford rebuild plant. He would check all cranks that came through the shop and save me any steel ones. He went through hundreds. There were not many.

Another way to tell if it is steel is when you weld on them. I used to turn the OD of the crank down .750 and then weld plates on the counterweight sides to balance them. It made a VERY noticeable difference in how quick the engine would spool up.

[40 Deluxe]

Originally Posted by tubman

Now that I have never heard of. Where was that crank made? Since you're in Sweden, maybe it is "location related".

Hey! Maybe he picked it up in Minnesota, ya?

[tubman]

Or Canada, eh?

[flatheadmurre]

I have no idee what plant that crank came originally from...but sold here in sweden as a replacement back in the days.

[FL&WVMIKE]

These Chinese sourced cranks are used extensively in small/big block Fords, Chevys, Dodges, etc. The come in cast as well as Forged alloys. They, as well as the connecting rods have proven themselves. They've been around since the 90's, and people are making big horsepower with them. I have a 4340 SCAT crank for my 363 (302) Ford that will make around 600 hp off the bottle, with another 200+ added with nitrous, and close to 8k rpm.

What you run into with the foreign cranks is not strength. Issues that generally need addressed, are balance and journal sizing. Journals can run on the large side, and not provide enough bearing clearance in some cranks. Another issue is balance. Balance is more prevalent in the cheaper cast cranks. Some can take a little extra work on the balance machine.

But, as for the core crank, they are generally pretty good stuff. On most, the journals will be just fine. Most will also have no issues on the balance machine. It's just something that needs checked.

Connecting rods tend to be plenty strong, but need to have their big ends checked by a machine shop before use... which should be the case with any connecting rod. Many will not be within spec.

NOTHING wrong with the Chinese cranks/rods... but use your due diligence, and double check the machine work. It sometimes needs a little attention.

Good Luck

[Brian]

"Pete" - I see you are in Washington state. The only other person who has seen one is "Brian", from New Zealand. Perhaps these are Canadian made?



The one I used I bought off of eBay. I no longer have the sellers spiel, but it was something along the lines of he was a racer and this crank was one of two built by some legendary flathead guru. It was a beautiful [if you can call a crankshaft beautiful] thing. Had a bluish tinge to it...I think it had been nitrided. It had been installed in an 8BA block, because I got the steel main bearing caps with it. This crankshaft now resides in my mates [kiwitony] 284 powered 37 pickup. But that crankshaft is definitely steel. About the only other detail I can recall about it is that it had a big recess in the flywheel end, dunno if all Merc cranks have that.

[rotorwrench]

The 1CM crank was the one made for automatic transmission use. It likely carried through to the end of production of flathead parts. Ford may have outsourced some in the years following 1953 for replacement parts. Canadian Mercury's had the Y-block in 54 but they may have produced some cranks. It likely would have had a C on it somewhere though.

[Ol' Ron]

Most of the "Y" block cranks were Shelll molded. Some of the Ford 53 cranks were also shell molded. The look like a forged crank and are made from Marninsite iron with Magnesium and cast iron. Thes cranks don't have the brakaway area like the cast crank which as a group of four.A sad note the Ford industral rebuilding plant on Patterson NY didn't rebuld Mecury engines and when a 4" crank was found in a block it was scraped. The did the rebuilding for Sears and others. Boy that waz along time ago
Gramps

[Brian]

I also built a French flathead with a steel crank. It was however, 3 3/4 stroke. Are the French 4" stroke cranks steel?

[Tim Ayers]

Originally Posted by Brian

I also built a French flathead with a steel crank. It was however, 3 3/4 stroke. Are the French 4" stroke cranks steel?

You have me wondering now if they are. It’s in the garage so I’ll check

[philipswanson]

I would just as soon run the stock 8BA crank. Never could understand why anyone stroked a flathead anyway, when they lacked RPM, not torque. Nice 8BA cranks are all over the place too. I must have at least 6 of them and all std. Usually the blocks were cracked and scrapped and cranks saved. I ran an 8CM crank in one of them and never noticed any difference in power.

[frnkeore]

All other things equal, cubic inches, create more HP and torque. That's why Ford went from 221 to 239 to 255. That's why the V8 60 didn't last long, either. Only the Midgets kept that engine in the public eye.

If you put a 4" crank, in a 239 engine, you should have a noticeable power increase if a good valve job goes with it. Other wise there is some other issue with the engine.

[FL&WVMIKE]

Airflow is what dictates maximum potential horsepower. You could bore/stroke a flathead out to 500ci, and it wouldn't turn over 1200 rpm before it was maxed out in the breathing department. Only thing it would be good for is a tractor. Horsepower requires airflow. Once the airflow path is maxed out, it's simply maxed out.

We'll ignore the 500ci reference, as it was only to make a point. When an engine has limited airflow, adding more displacement doesn't make that much more peak horsepower. It's main effect is lowering the rpm where peak horsepower is made. It also tends to add torque.

If you have an airflow limited engine making 200 hp at 5000 rpm, and then add stroke... It will likely still make 200 hp, but do so at let's say 4500 rpm, while adding more average power below that peak.

[Ol' Ron]

Mike is right, it takes air to make hP. However I have a "stock'280 ci engine in my truck. It has astock valves and ports. Milled EAB heads.eab cam, 2gc carb and a dist by richard. The compression is close to 9:1 and the torque is increadable. I have a 3spwith OD and a Spicer 44 3.74 rear. The drivability is fantastic. Yes those 4" cranks sure do work. Gramps

[flatjack9]

For a street driven engine, torque is king.

[KiWinUS]

I’m with FlatJack. Having driven many stroker flatheads some built by me some by others. There’s no comparison. Strokers rule.

[Pete]

Originally Posted by FL&WVMIKE

Airflow is what dictates maximum potential horsepower. You could bore/stroke a flathead out to 500ci, and it wouldn't turn over 1200 rpm before it was maxed out in the breathing department. Only thing it would be good for is a tractor. Horsepower requires airflow. Once the airflow path is maxed out, it's simply maxed out.

We'll ignore the 500ci reference, as it was only to make a point. When an engine has limited airflow, adding more displacement doesn't make that much more peak horsepower. It's main effect is lowering the rpm where peak horsepower is made. It also tends to add torque.

If you have an airflow limited engine making 200 hp at 5000 rpm, and then add stroke... It will likely still make 200 hp, but do so at let's say 4500 rpm, while adding more average power below that peak.

Don't forget, there are 2 MAIN things that alter the RESULTS of the maximum flow through a given port and that is pressure and the composition of what is flowing......

[leon bee]

So Ford 8BA rods would be okay with one?

[Ol' Ron]

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I think we all like to consider say, 91 oct fuel and a normally aspirated Carb or EFI. The amount of fuel and air necessary to make 200 HP is beyond comprehension. Especially when you consider the fact that AIR is only 20% oxygen . The rest just goes along for the ride. I'm sure it can be done, but it eludes me.

[Krylon32]

I'm no FH guru like you guys but when I put the Roadrunner blower with 2 94's on the 276 motor in my one of my deuce roadsters it came alive. More air definitely helps. I would do it again with my French FH but to my knowledge Joe's not doing anymore.