Bob, I'm presently an engineer project manager in China [ 4 weeks to go and I'm out of here ] I'm trying to teach them quality control , "It would be easier to nail jelly to the ceiling" I ran those just numbers to demonstrate how easy the target is within your reach. 1hp / Cu In isn't too difficult to get[ or that efficient ] All you need to do is raise the rev range up to the 4500-6000 range. Now lets forget theory and look at reality This can be acheived by the "3 C's" [ cam, carbs, compression ] Most sixes are starved of air , but the Cyl heads are usually pretty good [ it is a tiny 1barrel carb and the end of the inlet manifold that is the culprit ] The engine only cares about cylinder pressure, so a poor breathing engine can be masked with a longer cam duration and a higher static compression ratio.[ it doesn't make it streetable though ] First suggestion is triple carbs [ Weber sidedrafts would be 1st choice , Weber 38 DCD downdrafts of an English Ford 2nd choice ] Then I would look at a "fat" hydraulic cam [ with the softest valve springs you can get away with ] Then plane the Head and use flat top pistons [ get the comp up to 12:1 plus ] While the head is off, consider larger valves [ from another brands OEM parts bin ] and back-cut them and "Throat" the head and do a competition "valve seat job" I would bother with porting at all. Most of the gains are in the valve job. The bottom end on these old slopers are bulletproof.[ I wouldn't bother balancing it either ] Back in the late 60's to early 70's the old Valiant sloper was a favorite in NZ for speedway [ there was a 241 Cu In limit ] These engines would be sitting at 6-6500RPM non stop for 14 laps on the 1/4 mile dirt track [ 6.5:1 diff ratios ] I cant recall any ever throwing a rod. They are tough [ overheating was every engines nightmare on the dirt ] Don't be afraid to rev it to 6500 [ the hydraulic cam is your limiting factor ] If you are gonna freshen it up, a new set of rod bolts wouldn't hurt.[ the donor engine has probably already done 100,000 miles ] In 1972 Chrysler Australia released a 265 "Hemi" with Headers [through mufflers] Triple Webers and a Hot Cam that produced 308HP from 265 Cu In [ this was a production car sold to the public ] The Aussie Hemi is just a marketing name only [ the combustion chamber is a wedge ] Carbs , Cam , and Compression all you need to get 1 hp / Cu In p.s Throating the head, is done on a "Serdi" machine, they use a special cutter tip to bore the throats and do a valve job in one cut [ Yellow Terra in Aussie were doing this on Holden engines ]
The dragster is packed away for the winter. The block and head are still at my friend's machine shop. Coming up on a year and only half done. As the pic shows, at least I'm almost done building the '40 Plymouth Pickup tow vehicle for the dragster (lol). Also been busy bending pipe for a 'glass Fiat street/strip altered. Expecting lots of pics and a good story from the last ANRA race. Good luck Old6. No broken parts this weekend.
Since the HA/GR forum is pretty quiet lately, I took the liberty of doing this: The chassis for my '40 Plymouth tow vehicle is pretty well done. The cab is in epoxy primer and I am now doing the minimal body work that it needs. For a Minnesota truck, the cab is very nice. Good news about the slant six for my HA/GRa. My friend with the automotive machine shop has actually started on the remaining work. The deck and the head have to be cut. The oversize valves need to be installed and a cut made into the valve pockets. I'll do the rest of the porting. I had a cam reground locally and purchased a "ported" oil pump with a hardened gear. This iteration will go together with stock bore and stock pistons and rods and is the next step in my learning process. If things go well it will gain displacement, compression, carburation and more porting after this coming season.
Bob, make sure you put a cam stop on that thing when you build it! Hopefully you will not have to go through the same thing I did. Robert
Bob.. Let me know if you plan to go to "The Rock" for some testing.. Im hoping to get out a few more times this year.. 'course I say that every year
Picked up my slantie block and head after only a year at the machine shop. It is looking real good. This isn't a race engine build but it got pretty involved anyhow. Turned crank, standard bore but honed for clearance, deck cut .100", ported oil galleries, new stock bore cheap cast pistons, reconditioned rods w/ARP bolts, ported oil pump with hardened gear, reground cam, Cloyes matched timing set, and so on.
The head is cut .050", oversize (but not very special) valves, new guides, pocket ported, 340 Mopar valve springs. I'll port match. With the block decked and the head milled I'll have to check for valve/piston clearance and pushrod length. Will probably change from the 2 Holley 1bbls to a pair of 2 throat BBD's. Hopefully the digger will be enough faster and durable to warrant the cost.
bob, make sure that you are not running too lean with the two BBD's after you put them on there. I think you will probably be running a little more compression than I am and I found out that I was running on the border line with two BBD's. I found an old Carter four bbl that I am trying to make work on mine. New problem is that it seems to run out of fuel in the top end of third gear. I really do not understand why the fuel pump would supply two two bbls and not be able to supply a four bbl??? Robert
Bob, Over the years Ive had the most fun (and satisfaction) with modest engine builds vs. full race engines. Im sure you will enjoy the added power of these sensible modifications. Skip Pipes
Got real tired of doing bodywork on the '40 Plymouth tow truck for the dragster so I started putting the better slantie together. It's like Gilda Radner said on Saturday Night Live, "It's always something". I started with a cast crank engine that was in very good shape. Had the crank turned 10-10. The block and head were baked and tumbled in stainless steel shot. I put the main bearing shells in the block and set the crank in place. It was "sticky" and didn't turn well. Finished assembling the mains and torqued the bolts. It turned over very hard even though it Plasticgauged at .0015". As you can see by the pic there is a very tight fit at the parting line (shiny spots. I filed a slight chamfer on the bearings and the block and caps at the parting line. Also used a scotchbright pad on the backs of the bearing shells and the block and caps. After that, the crank turned with an acceptable amount of force. Still, I'm concerned about the fit and will have the crank ground to provide .0025" clearance, which is the spec limit for a slantie. Looking for insight as to the cause of this problem and if you think .0025" is not enough, too much or just right. I'm thinking it is poorly manufactured bearings and possibly a little peening over of the block and caps parting line edge while in the shot tumbler.
Bobw -- Just for my small brain information bank can you tell me with the deck cut .100" and the FT pistons how far in the hole are they at TDC? What size ([email protected]) cam are you running? Those heads look real sweet. Hope to see it run again soon.
The '40 Plymmie tow truck is almost done. Darn project took way longer than anticipated. I must be slowing down in my old age. The short rides around the neighborhood indicate it should be a good, reliable truck. Got the slantie crank back with another half a thou polished off the mains. Won't be putting the new engine together until after this drag season. Since I'll have all winter the trans will get some attention too. Hope to be ready with tow truck, trailer and HA/GRa all set at the start of the 2012 season. Old28, I can't answer your clearance question yet, but I will. The cam is very mild with .465 gross lift. I need to start with a mild engine as they are easier to tune. With experience I'll hopefully be able to add more beans and go quicker.
Thanks, Bob, let me know when you start putting the motor together this winter. That is going to be one fine looking package with the truck/open trailer & HA/GRa heading down the road. Make sure you have good AC for the trip to Bakersfield, CA and the ANRA races in the future. It was 102deg at the race today and should be same Sunday.
hoffbug, Since the dragster is still apart, I took the Crosley to Brainerd this weekend for free drag racing courtesy of the Minnesota Street Rod Association. Were you there?
NO... Im not a MSRA member since everything I own right now is 1972 or newer.. The Crosley looks sweet though.. Im currently working on swapping out brakes and spindles on the Chevelle.. hope to hit the rock in October to test it out..
Even though it was in the mid-80's today, the rodding and racing season will be coming to a frigid end soon. So, I started preparing for next year. Got the slant 6 short block assembled and also put the valves and springs in the head today. This is an intermediate engine, not a high horsepower unit. I couldn't afford that right now. So, stock bore, cast pistons, mild reground cam and a tenth of an inch milled off the block. The head has oversize valves, 340 springs, pocket porting, new guides and a .070" cut on the mill. Compression ratio is still only 9.00:1. I didn't get to run the dragster the last two summers so I am really looking forward to next season. The car is going on a weight reduction program too. So is the driver. Tom, The Crosley went 11 flat. The problem is I have limited it to 5,000rpm so I end up feathering the throttle for the second 1/8th mile. For several weeks I was prepared to run the car (strip open every two weeks) but various problems (sick dog, I hurt my leg, wife having surgery) kept me away from the track. With the new red line of 6,000rpm I was expecting 10.60's. Then there's the trans brake I've never used...
bobw--More pictures of the engine rebuild if you have time. This weather is hard to figure out, a week ago it was 98 and today 68 and rain. Looks like it will be clear and nice for the ANRA & Eagle Field race this weekend. Your comment about Skips car is right on, it would be one of the quick cars out this way with the motor that in it. Got most of the welding done on the front suspension and the steering on Monday and need to make the aluminum pitman arm and the steering drag link and the car should be a steerable roller soon.
Found a source for OEM steel shim head gaskets. Should result in a half point higher compression ratio.
I got a bit burned out on the project in the background so on Thanksgiving I made the male guests dig the Hambster(a) out of the back storage garage and push it into my workshop/garage. Time for some revisions/improvements. Tom, I don't know what else the man might have. Dolmetsch on the main board led me to the gaskets. You can Google, Roblin's Garage (in Canada) and get in touch with him and see what he has.
The front end will be lowered 3". I made a well perforated front crossmember. It will be positioned back a bit from the existing crossmember in order to clear the tie rod. A new suicide mount will have a bit longer reach. The uncut '34 Ford wishbone which is only 3" above the floor at the ball end will be replaced with home made split bones.
Bob, looks like some nice changes in lowering the front. Let us see some pictures of the bones when you get them done. Do you have a extra set of the friction shocks that you would part with for the right price? I think I need something to make sure the front does not bounce from wheel to wheel.
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