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By oldcarmark - 2 Weeks Ago
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I have a 292 in my 56. Engine could use rebuild. There is a good (supposed to be) 312 Crank and set of 8 Rods on Facebook Market Place. Supposed to have been salvaged from rebuilt Engine with bad Block. CDN $400 for Crank and CDN $240 for set of Rods. What is involved in using these Parts in a 292 Block? Worth while if rebuilding Engine anyway? Thanks
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By FORD DEARBORN - 2 Weeks Ago
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I did a 312 crank swap many years ago. Ground the mains of the 312 crank to std. 292 size and .010" (in my case) undersize for the rod end. The ECZ rods I had needed resizing so I purchased new 312 "Probe" rods from Mummert. The crank grinder had a narrow stone to allow preserving the oil slinger at the rear of the crank. With your project, one crank or the other will need to be ground, just make sure the 312 crank has enough metal for a successful grind. It will also be important to rebalance the rotating assembly. I bored my 292 block to stock 312 size and the pistons were replacement Silvolite for 312 engine thus there were no clearance problems due to the rods being shorter. Others will hopefully chime in but this was a very easy worthwhile modification. However, I already had a standard 312 crank in my stash. Maybe someone can provide some general numbers as to what this mod will do for HP and torque.
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By 55blacktie - 2 Weeks Ago
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I would say it depends on just what you want to do, what you can afford, and if you can find a competent person to do the machine work. I'm building a stroker 292 using Mummert's H-beam Stroker Rods, Autotec 3.825 pistons, B9AE 292 block, and 292 EC crankshaft with rod journals offset ground to 3.46 stroke.
I would be reluctant to use those ECZ rods as-is. Even if they have been reconditioned (resized with new rod bolts), they aren't the best rods to use for a performance application.
If you're looking to substantially increase performance, you can have the 312 crankshaft rod journals offset ground for 3.51 stroke, but you won't be able to use the ECZ rods.
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By Ted - 3 Weeks Ago
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The 312 crankshafts being installed in the 239, 256, 272, and 292 blocks requires that the main journals be ground to the 292 main sizes. My recommendation is to first install the main bearings in the block, measure the I.D., and then have the crankshaft ground to the desired oil clearance. The oil clearance for the mains being between 0.0020” and 0.0025” works for most street Y builds. Just arbitrarily grinding the crankshaft without first measuring the bearing I.D.’s can have the bearing clearance outside of specification due to the various manufacturing variances both in journal diameters, bearing thicknesses, and bore I.Ds.
Also required will be grinding the 312 crankshaft rear main seal surface down to the 292 size. The 312 rear seal surface is 2.750” while the 292 size is 2.625”. If wanting to retain the rear oil slinger on the 312 crankshaft, then a narrow grinding rock will be required. Not all shops will have that narrow rock but I have been both ways on the crankshaft rear oil seal slinger with no oil leaks using the neoprene seal and completely removing the rear oil seal slinger.
Using the ECZ or C1TE connecting rods will allow any 312 piston to be used. For bores less than 3.800”, the pin location in the 272 and 292 pistons are the same as the 312 pistons but there may be some clearance issues between the 312 counterweights and the bottom wrist pin boss of the piston depending upon who manufactured the pistons. Easily fixed if caught during pre-assembly and any balancing that is performed.
The longer EBU connecting rods in conjunction with the 3.44” stroke does create a rod/camshaft clearance issue. If desiring a longer factory rod such as in the case where the tops of the pistons are machined down accordingly or a custom piston is being used, then the C2AE rods can be used. These are the same length as the EBU rods. The C2AE rods have the shorter length rod bolts thus making those rods compatible with the 312 stroke. The longer connecting rods does require that the pistons have a shorter compression height (wrist pin location) than stock but if going the custom piston route to take advantage of some of the newer piston ring technology, then longer is better.
Offset grinding the rod journals to increase the stroke is another option but is another topic as it requires different connecting rods and pistons.
Here's the link to a past thread discussing how to order custom pistons.
http://forums.y-blocksforever.com/FindPost160000.aspx
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By Hoosier Hurricane - 3 Weeks Ago
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I have been using another method to put a 312 crank in a 292 block, and I'll mention it here for what it's worth. I align bore the 292 block to 312 size and fit 312 bearings by grinding the aligning notches for the bearing in the appropriate spots in the block and cap. I do not bore the rear seal area to 312 size, but leave it 292 size to used the 292 neoprene seal. I chuck the crank in the lathe and turn and polish the seal area to 292 size while retaining the oil slinger. I also turn the top of the slinger to 292 diameter to prevent any clearance issue in the block. Rod and piston fitment maintain the method outlined by Ted. I do this in my supercharged race engines so that I maintain the overlap between the main and rod journals. I have experienced crankshaft cracks and even breakage in that area. Another reason I do this is because I have equipment to do it this way myself.
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By 55blacktie - 2 Weeks Ago
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It seems like there is a lot of work involved in taking this route, and you still end up taking meat out of the main saddle bores, for which 312 blocks have been known to crack. Isn't that why 292 blocks are preferred for performance upgrades? Of course, 292 blocks are far more common (and cheaper).
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By Hoosier Hurricane - 2 Weeks Ago
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Blacktie, re-read my post. I use 292 blocks, not 312 blocks. I have had no cracked main webs in any of my converted 292s.
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By darrell - 2 Weeks Ago
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it would be just as easy to pick up a 312 block and in the end be just as cheap.
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By Joe-JDC - 2 Weeks Ago
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For what it's worth, if you are going to bore your block to 3.800/3.810", you will only be gaining 12 cubic inches by going to the 312 crankshaft and rod combination. That is a lot of cost for very little performance increase if any, depending on your compression, camshaft, carburetion, and exhaust system modifications. I would personally keep the 292 the way it is and just order new pistons with metric ring package and get you the horsepower difference and better mileage. JMO, Joe-JDC.
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By 55blacktie - 2 Weeks Ago
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Hoosier Hurricane, I read it correctly the first time. "I align bore the 292 block to 312 size." Isn't that exactly what Ford did to ECZ-A, B, C and B9AE 292 blocks to accommodate a 312 crank? Why, then would doing what you suggested be any less prone to cracking in the main web areas?
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By 55blacktie - 2 Weeks Ago
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Joe, I agree with you; however, finding +.060 pistons in my ECZ-A 292 block, I took it for granted that the crank would have to be ground as well, and the EBU rods would need to be reconditioned (resized/w ARP rod bolts). For those reasons, I decided to spring for Mummert's stroker rods and have the rod journals offset ground to increase the stroke. Watching John's video, "Building a Better 312" no doubt had something to do with it. Had I acquired a free, standard-bore, standard/standard B9AE block & EC crank before buying stroker rods, I might be going in a different direction.
Gas mileage? How many of us are using our Y-block-powered cars as their daily drivers? Considering the number of miles on Ted's Customline, he might be one of the few exceptions.
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By Hoosier Hurricane - 2 Weeks Ago
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Ford pretty much solved the cracking webs problem by reducing the torque from 130 ft.lbs to 90.
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By Ted - 2 Weeks Ago
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John. Thanks for reminding us that you are using bored main journal 292 blocks for your engines. That’s just one more way to use the 312 crankshaft in a 292 block. And while the blocks may be potentially weaker in the main web area as a result of boring the main journal holes larger, the crankshafts are indeed stronger with the larger mains.
It must be remembered that Ford went to reinforced mains in the blocks starting with the C1AE blocks and continued that practice with the C2AE blocks. Having never seen a C1AE block used for 312 production, I’m going to say that the 312’s used the B9AE block up until the C2AE blocks came out. Probably in an effort to streamline both costs and production, 312 production switched to the C2AE castings and discontinued the practice of having its own block. The earliest C2AE block used for a 312 that I have come across was dated May 1962. To date, I have not seen any cracking issues with the main webbing in any C2AE blocks used for 312 production.
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By 55blacktie - 2 Weeks Ago
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At what point does reduced journal overlap become a concern when stroking Y-block crankshafts by offset grinding the rod journals? It seems to be a common practice.
In addition to whatever horsepower gains that can be had, one must consider the increase in torque as well.
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By Joe-JDC - Last Week
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You can turn a stock crankshaft rod journal down to the Honda 1.880" size and keep the stock or near stock stroke. I have a 3.310" stroke Honda journal in my 303Y and use a Crower 6.400" connecting rod. So far it has made 463hp on the dyno at 7100 rpm. We have tested 4 different sets of heads and 2 camshafts and several different intake manifolds and carbs. The latest version is set up for the street and makes 437hp @ 6400 rpm. To try to stroke the crankshaft at the Honda journal size, you would uncover the oil passage and weaken the crankshaft too much to be reliable IMO. Going to the SBC 2.000" journal and stroking either the 292 or 312 crankshaft is an easy way to gain stroke and make torque. A perfect 312 crankshaft can be stroked to 3.600" or more in the hands of a savvy crankshaft grinder. Going to an undersize SBC bearing will allow even more stroke. Joe-JDC
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