buda rods

262 rods gas or diesel will work. Diesel ones are rifle drilled for better oiling. The rod journals need turned down to like 1.99 ish....I don't remember the exact spec. Good luck finding them.....guys don't like to give them up. I have a set I may sell....Diesel ones. It's definitely worth doing for some extra compression.

Stroke increases from 4.500" potentially up to 4.875".  I used custom built 4.500" bore pistons with a 2.700" compression distance and 61 cc Power Crater bowl with a .020" copper head gasket. Cranking compression was around 300 psi.

Dr, may i ask where you got a copper head gasket? I have been looking for one but can not find it. Thought about having one made bought the only shop around here that can make one wants way to much just for the set up fee!

Just wondering because I didn't know if they are a press fit, clamp fit or if the pistons have to be machined to have clips installed

Press fit I believe.

Pat, did you run the 201/226 pistons on them?

Re check your math in the original post, you'll be .2" down in the bore. Half of 4.85 is 2.425", 7.375" rod and 2.625" piston get you to 12.425" and you're dealing with a block deck height of 12.625.

I have a supply of Buda rods if you want some, I gave Butch here $50 for a bunch of them and "The Man" gave me a box of them trading favors and parts. So they're cheap.

I also have a set of Herculees rods that are 8" center to center with a 2" crankpin. About the same physical size as the Buda rods, straight cut cap and a much stronger rod. If you can make them work.

I also have a WD block here that I blasted clean, made sleeves to fit the original bores, line bored the mains, bored and honed the cylinders and decked the block. It comes with new coated 4.28" bore Sealed Power pistons and rings for a BBC. and new cam bearings installed. $750 for the complete package.

My plans for that block were to offset grind a WD45 crank, use the Herculees rods or weld a set of Buda rods and build about a 9 to 1 compression 280 cid engine for an old unstyled WC restoration project. I wanted something to run on pump gas for kids to play and pull eventually when they are old enough. Or use a 5.4 or 5.5 stroke crank with Farmall H rods..... just depends on what parts I have laying around, I've put some together for people here.

On the subject of the Buda rods, I had the idea for building a cheap engine to use John Deere 3010 pistons. They are abundant in the salvage yard here and they are 4" or 4.187" (4 3/16) bore. They are a 2.675" comp height and have roughly a 30 cc dish in them but I would have to measure for sure I was just guessing that was the approximate volume. With the Buda rods and just say you can get the crank ground at 4.85" stroke you get a pretty stout compression ratio of 15 to 1 and you can machine the piston tops off or cut a larger dish to get any ratio below that you want. The only issue you would have is to machine the tops of the Buda rods for the wrist pin, easy enough process with a milling machine. The John Deere sleeves would also work by turning them to fit the AC block or the AC 4 1/8 sleeves with a little boring would also work.

I've got a nice lathe and mill, so for me to use the Deere parts in one would only take me about a days work to machine the rods, make bushings, turn the sleeves and make everything ready to go together.
Just keep in mind that it only costs the difference on doing the crank work. Welding isn't all that expensive in the end. Use parts that are compatible with something else in the future should you want to bore larger or change something down the line.

I've got some more parts from this and that around also if you want to keep it cheap, other rods and pistons that work out

stroke shouldn't change with rod length,would have come from crank

o-k that's where you were getting it, how does the rod journal compare to a farmall 350, I have a 6inch stroke now pretty sure my rod joural is 2.25,running a 4.72 bore,and have 300 psi on compression,it takes battery power and custom starter

The Farmall rod can use a 2.29" or a 2.25" crankpin. There's 2 different bearings depending on the 152, 164 etc engines. The rod bores are the same. I usually go for the 2.29" crankpin as there wil be no difference in the physical size of the rod and it will allow you to turn the crank an undersize or if really messed up go to the 2.25" crankpin or undersize of that. The other reason being that it gives more material to work with if the crankshaft is ever changed to another rod or stroke, a guy could use the 6" stroke crank with the Farmall rod and go to a 6.25" stroke if needed with the billet rod for a matter of a few hundred bucks if ever changing combinations.

At 5.75" stroke the Farmall rod is tight to things. I have to do a lot of work to them to make them fit, countersink different cap screws, trim the profile, turn the cam, etc. A 6" stroke would take another .125" of clearance around things and it's possiable but it'll take some work to do. The cam is the problem, depending on how far you want to turn it down between the lobes, or notch it in places. There's one area on the rod that could be notched also to clear at 6" stroke.

The Farmall rod runs a 35* cap angle, the Buda is straight. So the bolts on the Buda rod will have clearance issues in other places than the Farmall rod..... But that Buda rod isn't long enough or strong enough for a 6" stroke. I really don't like to get the rod angles to poor, meaning the rod to stroke ratio in these engines. I like to see 1.4 or above but I'll go down to 1.33 which is a 8" rod on a 6" stroke when running billet rods. In the case of the Buda rod a 1.4 rod ratio would put a guy at a 5.25" stroke. Of course this is all applied to the low speed engines that run say 2100 RPM and less. If I'm going to rev one up, you need rods in it, good rods and good ratio, as the RPM increases the stress becomes exponential. Just last night I had about an hour long conversation with Gary Baker on similar subjects, he called me on a block filler question and we wound up off on various subjects.

I've got several engines right now and one of them is going to get a set of Buda rods on a 5.450 stroke, just because it works with the parts he already has and what needs to be done.....unless I go to an 8" rod and change pistons, do some boring, etc.

I get questions as to what rod will fit, what stroke, how much work is it going to be, etc. I made a tool and I'll have to post a picture of it on here and on YT so people understand it. It's a simple slug turned to fit tight in the main bore of a block, the slug has a 3/4" hole in the center. I took a piece of 3/4" shaft about 8" long and drilled and tapped the end of it for a 3/8" bolt. I turned a slug out to fit the rod bores of various rods and tapped the center for a 3/8" bolt. Then I took several pieces of 3/4" or 1" flat iron and drilled a hole in one end, moved half the stroke length in question and drilled another hole. Say a 6" stroke is 3" hole centers in my flat iron, or a 5.5" stroke is 2.75". I bolt the rod slug on the bar and the shaft to pilot of the center of the main. Now I have room and I can swing a rod around and check clearance for a given rod and stroke length, or when clearancing a block I can check things without having to use the crankshaft and bearings in a mess of grindings.... it lets me know what fits before trying something. All for an hour of time and various scrap pieces of material.

I like the Farmall rod much better than the Buda rod, it's stronger and gives you the ability to use other common off the shelf pistons in most instances. I just see to many cases where people spend a lot of money to use all the wrong parts and are unable to use things over in the future.


Edited by wi50 - 06 Feb 2014 at 10:23pm