Matt Wilson

Ok, that sounds great, and is reassuring. It was just something I noticed, so I thought I'd mention it.

I read through your entire set of posts this morning. I'm really enjoying seeing the progress, and there always something I can learn from reading about projects like this. Can't wait to hear how your engine runs once you get out started and dialed in. The brake and clutch pedals look as though they've been cut and welded back together, right at the elbow of each pedal. Am I seeing that correctly? If so, I hope the brake pedal welding was good. You obviously don't want that to let go during a hard panic stop. Not trying to alarm or criticize anyone in any way, but just bringing up my observation and a potential concern.

Sounds like the original poster got his situation addressed, but just for everyone's awareness, some ranges of year models used a chain and sprocket set that were 1/2" thick, while other year model ranges used 1" thick parts. I remember Vintage Power Wagons bringing this up to me when I ordered parts from them several years ago. And if I recall correctly, I believe the timing cover depth was also different to accommodate these different chain and sprocket thicknesses. VPW encouraged me to get the thicker parts, as they are more durable (makes sense), and that was fine for me, since that was what came off my engine to begin with.

Just so you're aware, many of the filter inserts/elements were cloth, rather than paper. So don't be surprised if you open up your filter housing and find an element that looks like it is encased in a sock.

I highly recommend thinking carefully about using a ridge reamer. I've had two experienced machinists from two different machine shops, 20 years apart, who told me not to use a ridge reamer, as those reamers will remove the only remaining unworn material that is square with the crankshaft, making it much more difficult to get the newly bored cylinders square to the crank. Also, it is difficult to avoid removing too much material, even if you watch closely and think you are stopping as soon as you have removed only the ridge. When I took one of my engines to one of those machinists, I was certain that I had been very careful and that the cylinders could be cleaned up by going no more than 0.020" oversize, but since I had used a ridge reamer, the machinst said he had to go 0.030" over. Not a huge deal, but I would rather have kept it to 0.020" in the interest of future rebuildability. And just as a matter of principal, I prefer not to waste material. I asked these machinists what to do if I need to remove the pistons and don't use a ridge reamer, and they both said I should have just pounded the pistons out, either through the top or through the bottom of the block. It would destroy them, but that's not a big deal, since they won't be reused anyway. The only downside is that I wouldn't have had any show pieces to hang on the wall.

Here's a photo of one of my bearing shells for a 25" engine (237/251/265 cid), with the oversize and other info stamped into the back. The characters are impression-stamped into the surface. There doesn't appear to be any raised material, but the characters are definitely stamped into the surface. I can catch them with my finger nails. These are new bearings (as of a few years ago), not NOS, that had Sealed Power on the boxes, and you can see F/m (I believe that's Federal Mogul) in the photo. I think Federal Mogul owns Sealed Power.

As was mentioned above, you'll need to figure out how to keep the sanding debris for getting into the oil passages, or figure how to get it out afterward. Maybe put a small piece of tape over the hole leading to the passage in each crankshaft journal, and sand around the tape.

As others have said, the Dodge/Chrysler/Plymouth/DeSoto flathead sixes have hardened exhaust valve seats from the factory, and they are very capable of handling modern, unleaded gas without any issue. They came that way starting in 1933 or 1934, and remained that way throughout all years that they were produced, which was well into the 1970's. So you don't need to worry about that.

Yes, I saw your post from the other day and I'm glad to be of help. I think nobody has talked about this because not very many rod bolts have cut threads. I think those went out in the early days, and it's probably one of those things that most people don't pay much attention to or know about. That's a good idea to ask about offset reaming. Good luck with getting your rods and bolts to play well together!

I dug out some rods and bolts and took some measurements this evening. The first photo shows a few rod bolts lined up side-by-side, with some dimensions and commentary for each one. You can see that the threaded section outer diameters don't differ greatly from bolt to bolt, and not as much as the bolts in your photo. The threaded section of the original 230 rod bolt (3rd from left) has an OD that is not consistent. It seems to be largest at the end of the bolt, then gets a little smaller heading toward the shank, and then gets larger again as we continue approaching the shank. I take that to mean that the bolt has been "necked down" due to yielding of the bolt in that region. Best not to use a bolt in that condition. You can see that my assessment of that bolt is that it has cut threads, whereas the other three appear to have rolled threads, since the threaded sections are larger in diameter than the adjacent shank section in each bolt. The next few photos show a couple of 230 rods and caps, focusing on the thickness of the wall between the bolt hole and the bearing saddle. One of these rods is an old rusty one that is not usable and has been hanging in my garage as wall art. The original-style bolt in my first photo was taken from this rod. I measured the thickness of that wall and then sanded away the rust from the bearing saddle (bolt hole wasn't rusty) and the measurement didn't change (reads about 0.015"). As you can see in the end view of that same rod, the wall at the opposite hole is a little thicker (I think it was about 0.030"). I also measured the cap from another 230 rod that has been preserved in a plastic bag with some oil (see photo). It shows about 0.006" wall thickness, which seems extremely thin, but this cap and its rod were running just fine in an engine I rebuilt over 20 years ago. I disassembled that engine for other reasons about 9 - 10 years ago. This cap and its rod were in service with the ARP bolt shown in the first photo. As long as there is no burr or other raised metal to interfere with the fit of the bearing within the rod, I suppose there won't be any issue with such a thin wall. I also measured the wall thickness of a 251 rod (not pictured) and it was about 0.012" at one hole (opposite hole's wall was thicker). Again, this is a rod that had been run that way, and I believe it was factory-original. Hopefully this is of some help. Let me know if you want more photos or measurements.

Here's a possibility. I wonder if the Dodge rod bolts have threads that are cut, while the Pontiac rod bolts have rolled threads. Rolled threads are formed by dies that displace (smash) the material into the shape of threads, without removing any material. This results in threads that have larger outside diameter than the adjacent shank section of the bolt. On the other hand, cut threads are just that - they are made by cutting material away to achieve the thread shape, so the threaded section diameter will not be any larger than the diameter of the adjacent shank. It's kind of hard to tell from your photo, but it looks like that might be the situation. If so, then accordingly, the Dodge rod might be made with smaller bolt holes to snugly fit its cut-thread bolts, but the Pontiac bolts, with their rolled threads are too large to fit. I have a couple of Dodge 230 flathead rods at home, along with their bolts, and I can tell you that the threads in those bolts have the appearance of being cut, which surprised me, since I have seen other Dodge flatheads that have the appearance of having rolled threads. I have no reason to think that those are not the original bolts, and perhaps they were early rods that used cut-thread bolts. I could take some measurements and photos of those rods and bolts some time in the next few days and we can see if they match the dimensions of your bolts. We can also see how thin my other rods are (the ones that used rolled-thread bolts) in the wall between the bolt holes and the bearing saddles. I remember them being pretty thin. We might find that you have room to ream out the bolt holes in your rods to accommodate the slightly larger Pontiac bolts, or some aftermarket bolts, such as those from ARP. From the strength and durability (fatigue) standpoint, the bolts containing rolled threads are very much preferred. I believe virtually every manufacturer uses those types of rod bolts nowadays and have for many, many decades. I remember seeing early rod bolts from other engine makes that used cut-thread bolts, but I think most everyone moved away from that type of design long ago.

Thanks, Jim! That's helpful.

Hi Jim, I see that you used Crower custom bushings for the connecting rods (small end) and 0.866 diameter wrist pins. Do you know the OD of the installed bushings? That would be the same as the ID of the rods. I'm looking to determine the wall thickness of the bushings after they were installed and honed to fit the pins. Are these bushings made completely of bronze, or are they steel-backed, as some bushings I've seen? Thanks.

Thanks, guys, I appreciate the inputs. The machine shop did not use a torque plate. One was not readily available at the time, and I didn't see it as necessary. As for digging too deep, I would agree if I was running OEM-style pistons and rings, but I will be running modern forged pistons and modern low-tension rings. The first person who told me that my rings would not tolerate my misshapen cylinders was Freewheeling Tony Smith. He works with these engines an awful lot (machine work, assembly, etc.), including the incorporation of upgrades to use modern parts like I'm doing. He really seems to know his stuff and has an excellent reputation in the Dodge/Chrysler flathead community. Since my last post, I also received word from someone who knows a Total Seal tech rep, and he conveyed my situation to him. The rep said the same thing - that the rings are not forgiving of this type of situation, and he recommended I immediately get the bores straightened. Of course, that will require I get new, larger pistons and rings. Sigh.... If I want to use modern rings, it seems that the old standard of several thousandths of taper or out of round being acceptable is no longer applicable. I've also read some things to indicate that torque plates are recommended (some say necessary) for low-tension rings. I don't know if that's really 100% true or not, but in any case, since I will be re-doing this aspect of the engine, I asked Freewheeling Tony if he has a torque plate for this engine. He said he doesn't, but would enjoy fabricating one and would rent it to me. I plan to go that route. With all the effort and money I've put into the rest of this engine, I figure I'll go the whole nine yards on this part of it too. It will be a couple of months or so before he has time to make it. That will work out ok, because it will be a couple of months before new pistons would arrive anyway.

You're right, I am leaning in a direction and yes, I've talked to 4 people. I question whether the two from JE Pistons were "experts," as one is a salesman (although he seems to be knowledgeable) and the other one is in tech support but changed his answer for no apparent reason, and neither person could give me a taper spec (seems like that would be basic available info). The other two I spoke to are machinists, but again, one gave me one answer and the other gave me the opposite answer. The one who directed me to re-do it all with new pistons, rings and overboring was the only guy to give me some technical reasons that sounded pretty solid. The others literally just said "it'll be fine" or "I wouldn't use them as is." I'm thinking that, as painful as it is (financially), I should lean toward the side of caution by buying new pistons, rings and having the cylinders bored more oversize so they will (hopefully) be straight and round. At this point, as you alluded to, I am kind of looking for confirmation that this is the right decision so that my wounds won't hurt as badly as I'm licking them. On the other hand, if someone has some really good reasons that I don't need to go that route, I'm still open to listening.