Thursday, January 19, 2012

January Updates

Long hours and late nights are the order of the day here at the speed shop this time of year. If you have noticed a "longer than normal" spacing between posts, that is the reason. Besides a couple of Panhead engines in for complete rebuilds, I have five sets of Knuckle heads here for valve jobs, with two of them getting big intake valves and porting. Oh, and don't forget the Big Twin Flathead top end. Then of course there are the normal dozen+ sets of modern heads in various stages of being ported. And then there is another biggie: an S&S 113 being turned into 126 cubic inch for drag race use only. All but the porting on the modern heads tends to be quite "time intensive." I had better stop there. I am beginning to scare myself.

The drag race motor, despite being based on a fairly modern design, is the kind of project that I can sink my teeth into. For one thing, its not the type of engine I build very often. Add to that, its somewhat challenging from a porting prospective. The standard S&S SuperStock heads, while providing more flow than a stock Evo head, have some serious limitations in their "as manufactured" state. Hopefully, with some heli-arc and grinding bench time, I will be able to remedy that somewhat.

Stock S&S intake port sports a very low floor along with an "interesting" vane protruding from it. My guess is that the design was influenced by the need to fit an air cleaner below wide fatbob tanks.

The first step in the process of attempting to make these into "racing" heads is to remove the guides and seats, followed by a generous build up of the floor in order to provide a good short side shape.

note: The welding in the picture above shows evidence of the approximately 15 years since I have had access to a tig welder. Now that one resides in my shop, I expect the welds to start looking more professional with a little more on the job training.

The chambers were also treated to some added material so that when done, 30 degree domed pistons will provide enough compression ratio for the motor to be run of E98 racing fuel (E98 is a commercially available mixture of 98% ethanol which is carefully controlled to maintain consistency). I will try to give updates on this project as it proceeds.


Mark said...

Hi Lee, can you show a pic. of the welding on the chamber? was wondering how much of the chamber your leaving as S&S made it. I had to put my Knucklehead projects off to the side for now, as I have alot of work to do also, my son and I are working on his 103" shovel trying to have it ready for vinage raceing.

pat said...

looking good lee!

St. Lee said...

Hi Mark, The welding on the Evo style head really doesn't cross over very well on a Shovel due to its really deep and small diameter chamber (comparatively). Or did I misunderstand and you are not asking about welding the chambers on the Shovel?

Anyway, I have already decked and shaped the chambers on the S&S heads, so without "before" pics, the after pics wouldn't tell you much. The idea is to fill in the sides of the chamber to make it a tight "bathtub shape" and then open it up around the valves just enough that the flow is not hurt, and then machine for the piston domes.

If you still think pictures might help you, shoot me an email and I will send you one.

Mark said...

Lee, I was thinking on the chamber shape on the 113" your doing, but I see your doing bath tubs, I'm working on a 113" S&S my self, I too have thought about taking out that giude fin in the ports. I was going to weld up the chambers on the Shovle and make hemi tubs but that will have to wait till next winter as we are running out of time for that, but I was maybe thinking welding up the port floor 3/8.

St. Lee said...

On this set of S&S heads we are shooting for very high compression ratios, so I added a bunch of material. They will also get 30 degree dome pistons with the heads machined for them.

On the Shovel you may want to add more than 3/8 of an inch to the floor, if possible. Really hard to get in there to weld with a tig though. You may have to get someone who can wire feed aluminum to get all the way up to the seat.