PK I am building a Tri Y design header for a Willys 134L I have the first section of the primary's completed. They look like this: Due to space restrictions they have to pass the Oil pump/frame and Steering shaft in a straight line. I have the next section mocked up where they all make a 90 and work towards being stacked properly to enter the first Y collectors. It looks like this: I was planning on taking two of the tubes #3  up over the transmission cross member and using that to balance the lenght of the tubes. While the other 2) #1 and #2 run pretty straight back passing just under the cross member. I had that pretty much figured out. Then I got to thinking about a TRI Y calculator I used on line that said the tubes for my engine and rpm range should be 1.09"ID x 56" long. Well that where I have the problem My tubes are 1.375" ID If I figure the volume of the tubes that means they need to be roughly 35" long to have the same volume as the Calculator says. Now I know lots of Tri Y's primary's are no where near the length a calculator would say they should be. BUT my tubes were going to end up about 50" long. Should I rework and try to shorten my overall tube length? I have to find away to lengthen one of the tubes almost 5.5" So you can see what I am working on here's a Chassis shot. And one with the Cast Aluminum intake I made from a 1500cc MG intake Should I work towards the same volume as the calculator suggested or will having longer Primary's work as well? My first build so I am way out of my skill set here. Any help greatly appreciated.
First off, Really Cool Build and motor. This is the stuff I love to see, so much more interesting then stuffing a SBC in there. 2nd, You are worrying about volume and equal length tubes on a Willy's flathead. That is a bit like Bill Gates wasting time to bend over and pick up a nickle. The flow restrictions are inside the block at the ports. I would concentrate more on packaging, clearances, and the looks of the header then having equal lengths and volumes. There is going to be very little to gain from the extra work.
The normal pairing on a four cylinder is 1&4/2&3. That way each cylinder of a pair is firing 360* from the other. Your pairings may give your exhaust a nice beat. Sometimes packaging gets in the way of optimum.
Seconed what FM stated.. "Picking the Fly shit out of the Pepper". Looks and packaging are the important considerations.
Hey Silverton Nothing wrong with your skillset, looks like the hardest part is done, looks good to me. Neat intake too!
Hey, Mark; Nice Sewing Machine mill. . Slick trick on the Al MG intake. On the Tri-Y, check the pairing #'s. Off the top of my head, I can't tell you the correct length vs volume.Need to do some math for the mill's intended usage, because it can & does matter, if you want real good results. Anything will work, but... What some folks forget or don't know on header length(s)/inside dia/configuration is that what you are after is the proper usage of the various harmonics that result from your available choices. Which usually ends up in a compromise, or two. &, btw, the intake both affects & gets effected by the exhaust & it's own length/ID. I'll either post a link here to a discussion(the subject-mills are very OT, but the subject-matter is not) on that, or send it in a PM, when I have a few minutes later today. You can then follow-up w/some more research. It is a very interesting subject. Marcus...
Just a little up date I have to top section of the primarys welded (waiting on the main flange weld until I have the rest of the top section welded up. as I can move the whole setup about 3/4" closer or farther away from the frame. I might need that for the steering shaft) The 4 in line flange is also welded and honed flat ready for Gasket. I just took this photo before that. The second or lower section where the tubes change from 4 in line running front to back to 4 across running from side to side and paired up #1 & #4 and #2 & #3 ready to go into the first pair of 2 into 1 collectors was a week long puzzle. I have them if I am am measuring everything correctly within .75" of each other and its not going to get any closer then that.
OK the hard work is done. I had to compromise on the length of tube #3 I just could not find a way to get it any closer that would end up working with all the variable. I still need to finish welding tube #3 and then attaching the 4 in line flange to the top of the bottom section. Followed by attaching the little Cone Engineering 2 in to 1 collectors to the ends of the Primary's Then its on to the Secondary's and the Tail Pipe. This Winter after I have got the jeep running and while I am working on the aluminum hard top I plan on building I'll send the Primary and secondary sections off to Jet Hot and have them Coated. I am thinking the Polished Silver finish will look nice between the Gray Engine and the Pacific Blue Inner Fenders.
That header is a thing of beauty! Why not have a local shop do your coating? Russ Meeks' Finish Line Coatings in Milwaukie does very nice work, and I'd also bet he would give you some compliments on your fab work too. I like the "Titanium" color he uses, that is what I plan on using on both my roadster and Nova. http://finishlinecoatings.com
I see you did the Saginaw steering box swap, but I can't see how you connected it. My son picked up a 1948 with that box on it already, but it was way too slow of a ratio...so we lengthened the pitman arm, and then we used the special Jeep tie rod end with a spare tapered hole in it so we could connect the steering main link at the Rt side "inner" tie rod hole, to also help speed it up. We could not find any web help on that swap.
F&J sent you a conversation. I do not have my Column connected as yet since the Tub is not on the Chassis yet. I am going through the left motor mount I have a short stub shaft with a Borgenson joint that includes a vibration dampener in it then a shaft that will pass through a Heim bearing and then a second U joint and on up to my Ididit Classic Hot Rod column (looks very much like the stock column) I'll have to anchor the column to the floor with some sort of mounting flange. Something else to make LOL.
The welding and grinding etc. is done on the Primary's it works it fits its close enough. I am moving on to the Secondary's a simple 45 away from the Primary collectors and a short section of 1.75" OD tubing then a 45 back to the tail pipe collector. It will go fast now. The job the Jeep will go about 65-70mph but thats more then fine.
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