OK. The race motor. Built in the late 40s I am told. Jahns cast pistons, model A rods. . Ran short tracks on alcohol. .410 down at TDC. Big bump from the stock. But still .110 down from my GMC. 25 Olds head, intake for two Winfield down drafts. 3.8125 bore. Leaves about .185 between cylinders for gasket seal. My '26 Dodge engine which is + .125 bore and my 368 Lincoln which is +.060 both have about .625 between cylinder walls. that's about a 9 7/8 compression ratio on the race 28 Chevy.
Six Ball, are you going to use insert bearings? Bumping the compression that high will pound the babbitt pretty quickly!
Neither of my engines have this step in them. Seems as though that would make installing new rings a real pain. Maybe someone got carried away with a ridge reamer on yours? Rings are pretty far down from the deck.
Mac, Yes I'd use Model A rods with inserts. I'd probably buy a new set rather than having old ones cut. If Rich's engine was racing with a 3.8125 bore mine might work at 3.81125. I don't know if I could turn down the pistons a little without screwing them up. I would go full pressure and counter weight the crank. My friend is looking for his extra set of weights. I was looking at the Venolia pistons Patrick sells and they look the same as mine but they don't have the nipple on top just a shiny spot. I don't know if it is supposed to be there or be removed. The pistons were on rods with new bearings when I got them. I can not find a compression height for them.
That nipple is for turning the piston. It would not be there if the domes had been finished. Cut them off.
Thanks, Maybe I'll wait until I see if they can be made a little smaller. I might also need to make them a little shorter. I thought they might be some weird turbulence thing. I probably should keep looking and use this set to build another 270.
Not sure what a period correct multi-carb intake would have looked like in the late 20's or early 30's, but this is what I drew up today with Solidworks while it was raining. This will be easy to cast with no problem. Thanks to Six Ball for sending me a stock intake a while back so I could dimension everything. I have no idea what the carb spacing needs to be, but it can be easily moved farther apart if needed and the carb risers can be made taller if that is desired as well.
It seems aftermarket intakes in that era tended to be cast. This is for a flathead Ford four, but you get the idea: Multy Aldrich ran a dual downdrafts on his RAJO head, and since the RAJO is the Rich Man's Chevy Head, it might be worth emulation as well.
I could also do a later 50's style McGurk box plenum intake with the elbow runners that bolt to the underside of the plenum. Endless possibilities!
Herb, Rich, and you other smart guys, could a block be bored even farther and have a steel sleeve instead of cast installed that is thinner then .125. Would the rings seat? Just thinkin'.
Ford and others have used steel sleeves. The thing I don't like about boring it bigger is thaat the cylinders are what holds the crankcase to the deck surface. Most fast Bonneville bangers, and some slow ones, will eventually fail by pulling the deck off the block. Mine did and I am told it's not that rare. Montana Dodge boys did a good one. The one fast Chevy four I remember had extra bolts to clamp the top and bottom together. The stock arrangement is pretty poor.
I saw the Montana Boys mess, it was ugly! I think they purposely bored through the water jackets and then sleeve it. I know you've tried just about everything possible and a few things impossible, that's why I asked. Thanks.
Scott that intake sure looks better than the rusted out one I sent to you. That would be great with a pair of Zenith 28s but the bases would need to be rotated 90 degrees. I'm sure that is doable.
That's what I was thinking. This is a pretty neat engine and the possibilities with intake are endless.
I was looking at a side draft carb for an early skid steer with a Wisconsin V4. Too expensive and I couldn't find two. I'll keep looking.
I was thinking of a side draft also and maybe even a mechanical fuel injection intake for the hardcore Bonneville guys or other racers.
Side draft would be cool, SU or Stromberg variable venturi carbs would be simple upgrade. SU would be a good lookin carb for this ! Is there any relations between this car and the Spurgin and geovanni car? http://blog.hemmings.com/index.php/...barbeque-stove-bolt-special-heads-to-auction/
I don't mean the are related or brother or any thing like that. I just find it puzzling both ran a Hot small chevy banger, with a Ford "C" crank, Jahn pistons and two horisontal carbs on a three port olds head. There migth be a connection at least in spirit or looking up to the S&G car, or he was a fan like us
I know you weren't referring a familiar relation, I was just short on time, so went with "No connection." Quite frankly as rare it is now to hop up a Chevy, back than they had a long history of being modified and were one of the most common off brand engines to hop up in the 30s. I have a couple Mid 30s Modified roadster programs and a number of entries were Chevy & listed performance heads I was unaware of. It is possible the Hill RPU was somewhat inspired by the S-G roadster but as likely to have been an engine Jim Hill's dad had experience with. I will scan the article on Doug Shaw's Chevy 4 in the morning as another example from that era. Sidedraft carbs were used as they offered the clearest run down the intake ports and seemed to give the best engine response. This is why Rufi famously eliminated the intake altogether and bolted the carbs directly to the head. Yes, I am around 11 hrs ahead, it is currently 12:44am.
This is the intake that came with the Olds head on my 28 Chevy. It's steel and pretty heavy for a race car. I know it's upside down for the picture. The yellow stuff is my take on mechanical FI. Throttle bodies are available cheap. Sealed ball bearings on the shaft. Many sizes on different cars and bikes. You might cast up the rest of it.
Thanks Rich, I think this will give a lot of guys some different options to toy around with. I also wouldn't be opposed to casting some one off intakes either. This is a pretty simple engine and design, so it wouldn't be hard to create several different patterns.
That's a great pic! What size TB's are they.That setup is still mechanical FI with the TB's being used as basic air valves, correct.
They are off of a 4.6 SOHC Ford engine and are about 2.550 Diameter. But there are several sizes and types. Yes I am just using them as air valves. You can see where I put the Hilborn fuel nozzles in the above pic. Here is yet another I did using Suzuki 750 TBs.
I know this is a little fare out, but since the cylinder walls becomes to thin when bored our for modern pistons, and there is so few pistons in the rigth size, could this be a possible idea. I've been eyeballing a block cracked from being left outside with only water in the block. But we can't agree on a price. I've been juggling the ideer of cutting of the block right above the little lip up to the deck, and only leave the front and water pump in. And then go for Diesel pistons out of a Perkins , they are avalible as what we call a "hole"-kit. Pistons, rings, wrist pins and a wet sleeve and make a new water jacket around the sleeves. Then a crank from a tractor motor, with that is drilled for pressure. Because if I go for the sleeves engine I can move the bore spacing a little, and I only need to care for the distance between the three mains, and the overall length. Because pistons with so big a grown hight, I've only ever seen a Diesel and they bring the added bonus of a turbulens chamber or plenum that will help the mixing in the chamber, and they often comes with relief cut in them for valves. And I'd I do it like that I can run long studs to the bottom of the block and all the way up, and use them to hold a sleeve support inside the water jacket. I'm a good enough welder to make it work, but I can do the machine work to back it up. But that's what friends are for, right? ☺ We cross that bridge when I get to it.
Rich, I have been meaning to tell you for quite a while that you have a great amount of ingenuity, and it shows up very well in your projects you have shown on here!
One thing to consider about the diesel pistons is that they are typically much heavier than pistons in a gas engine. So you may end up having to put them on a diet with some machining and lightening modifications.
That intake could run either up or down depending on what Winfield carbs you were running. Rufi '38 Bob Giovanine '40-'41 Schenck '40
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