Flathead Rods PistonsFLATHEADSRODS PISTONSEvery time Ive looked at a Flathead Ford connecting rod Ive thought the same thing how can something that spindly be that strong Truth isthat the flathead connecting rod is very strong as Fords engineers were a heady lot. Forged from a nickelvanadium steel alloy, they were certainly more than adequate for the horsepower and RPM ratings they were designed for. Now, howz about we start doubling or tripling horsepower and multiply the RPM rating 3. Howdo they hold up at this point and beyond The answer I have found is quite well thank you. Welding Cracked Aluminum Cylinder Heads' title='Welding Cracked Aluminum Cylinder Heads' />Having used nothing but stock rods myself in allmy race engines and, approached 6. RPM at times, I can honestly say that Ford Engineers knew what they were doing when designing theseconnecting rods. As in most engineering applications, a Factor of Safety is considered bridges are usually rated at a portion of their actual strength. Im assuming that Fords Flathead connecting rodshad a factor of safety somewheres around 1 2 to 1, hence they will hold up under much heavier use than they were rated for. Now, of course this is an assumption and although I have found it to be true in my experience, Ill add the disclaimer here that this assumption only holds true under the best of conditions. In other words, things have gotta beright. If they arent then youll have plenty of pieces to pick up. In over 2. 0 years of wringing out flatheads on the race track, Ive only lost two and both were due to rod failure. Its led me to this simpleformula Fatigued rod 6. RPM Schrapnel. Both were well used engines and both were turned up to their limit. The rod type did not matter as one had a set of 8. BA insert type rods while the other had 2. Afloaters. Rods stretch. Barney Navarro told me that theyre like rubber bands in the engine and can stretch as much as 0. This cyclic stretching and contracting causes fatigue after so many cycles and the material deteriorates which is why many good racers of the flathead era changed out their rods often. Ok, so what did manyracers do with themOpen Monday Saturday 8am8pm Pacific time Search by Keyword or Item no. There are persistent rumors that the main ingredient in JB Weld is magic. This twopart epoxy that you would normally find on a shelf next to your basic 5. First of all, you have to start with a good rod. For strokers the 2. A and 9. 1A floater rods are the only two that will do, earlier floater rods fit but dont have the additional strengthening flange material so Iwouldnt recommend them for anything but stock applications. Ive often read that the 2. A was superior in strength but in comparing the two, I can see only a difference in the big end boss and have used both. For the standard stroke Merc. Ford cranks 2. 1. A floater is preferred although the 8. BA works fine on the later two oil hole cranks and clevite inserts are still available which makes them attractive. The rods must be perfect in alignment, pin fit they can be re bushed and large end fit as well. Many of these rods came with additional material on the small end pin boss that wasnt turned off these naturally are a bit heavier but again preferred for additional strength in say a blower application. My father recalls going out to B M Speedshop in Rochester where they had their assemblies balanced and watching shop workers check rods for roundness on the big end, often tossing them back until they found 8 perfect ones. Cliff Kotary has told me the same of his selection process. You have to start with a good one, preferably new if you can find it, or at least one that has been reconditioned as new. Racers of the era started here, with good rods and then worked with them. Some were cruder than others. Bob Cain once told that he looked all day for a set of rods for fellow racer Gordy Wood and finally came up with a full set of new ones which he took over to Gordys one day. A place to talk about howto, techniques, troubleshooting, welding processes, welders, plasma cutters or other metalworking tools. Wood promptly took a piece of re rod and welded the chunks to the beam to strengthen them. If I knew he was gonna do that Id have gotten him a set of used rods. Bob related. Dick Nolte once showed me a set of rods that had been gusseted with thin plate on the beams, much in the same manner that Ardun Guru Cotton Werksman had often done. My first thought as I was bouncing them in my hand was man, these are heavy. Welding Cracked Aluminum Cylinder Heads' title='Welding Cracked Aluminum Cylinder Heads' />They were, one of the few advantages a flathead has over say anotherengine of that era is their light rods and with this procedure, that advantage is gone. Not to mention the additional stresses induced to the metal from welding, which now requires straightening and stress relief, again another problem from the relief process is that the rods bolt threads which are integral with the rod itself may be weakened. I knowmany used this procedure but I question just how much they really gained, maybe someone with experience can comment. Most of the guys Ivetalked with simply had the rods properly sized and magnafluxed to ensure integrity and then balanced with the assembly. Bob Hayslett related apoor mans magnfluxing trick to me once, using a light Mystery oil on the rod, wiping them down and then covering them with flour. The oil would seep out of any cracks thereby exposing the rod as scrap. My process in using rods includes magnafluxing first, sizing and then polishing of the beams to remove any edges or flashing that may cause a stress riser and encourage cracking, then shotpeening to further enhance surface tension and strength. Then after fitting I send them for balancing with the assembly. There are other options of course. Back in the day Howard Johannsen reportedly offered aluminum rods, Ive never seen a set but Id lay a bet that they were race only and considered expendable. Todaythere are many options as Cunningham, Crower, Scat and Eagle all make an H beam severe duty rod for the flathead. I contacted both Cunningham and. Crower years ago to inquire about their rods as many Left Coast drag racers I had talked with recommended them for their high quality which Idont doubt. The prices at that time were 1. Ive stuck with the stockers. The Scat and Eagle rods are a cheaper alternative pricing in at around 3. Buick insert bearing which is readily available, and they are rugged. Theyre also heavy and may require extra work at the balancer. I only know of one fellow who has used them and his experience at Bonneville left them picking up pieces so I cant really say from experience how theycompare. My latest thought is to continue to use what Henrys boys created and work with them, maybe even check out freezing cryogenics them to make them even tougher than they already are. OK, just a little on fitting them and well move on. Insert 8. BAs are a breeze so long as they are sized properly, snap in the bearings and check clearances, 0. Floaters, as discussed briefly in the crankshaft page, are a bit trickier as you have to check for clearances with a good micrometer to be accurate, measure the rod end ID, then subtract out the crankshaft rod throw diameter, then subtract the bearing thickness X2 and then divide by two remember, theyre floaters and thats the clearance. Again, 0. 0. 02 0. Bearing adjustments on floaters is still doneemploying the tried and true hammer whacking method. Wiley Plus Hack Acct Solutions Staffing here. I use a rubber mallet and a good piece of oak wood to make the adjustments, place the rod on the bearing with plenty of Permatex Super Slick STP works good too, torque to spec. Ft. Lbs and then I want to see that rod be able to drop to the bench. It takes time and a lot of scotchbrite to make itwork but in the end, that is the way it has to be.