VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 What is the ultimate chevy 4 race specification?

Hello,

I am planning on building a 1920s special using a chevy engine in a 1920s english / european chassis. I have opted for the chevy engine as I have a 27 and a 28 engine in running order. They are also a change from the model A engines used in many specials over here. The car will be used for all round vscc competition. Trials and hillclimbs generally. I realise a good competition engine costs so I will have to be content with a fairly standard engine at first that hopefully I can slowly develop into the ultimate chevy 4.

I've read all the stuff on olds three ports head but are there other choices to look out for? I've seen several pictures of these roof heads made for chevy blocks: Does anyone have any info on these?

http://www.nwvs.org/Technical/Engines/AllE123.shtml

Frazer
This head configuration is new to me, but I am sure one of the old timers knows all about it.

good luck
Ken 45145

I have an used original racing exhaust manifold pipe for a 1928 engine, which you may buy.

:vcca:

Most of the performance engine people say to use a '28 Chevy head on a Chevy 4 cylinder block. The old racers fit a Model C crank, Durant rods etc. For your initial efforts and to keep the cost down a relatively stock '28 will do for a start. Then you can put in higher compression pistons, etc.

I have a 1923 Olds 1 ton truck which uses a 224 cid mason designed engine which is the same basic engine (below the head)used in the 1922 chevy model FB ( Chevy dropped that engine in 22 and Olds used it till 23 in the model 43A and the trucks). I run my truck in the Newport Antique Auto Hillclimb in Newport, Indiana and hold 1st place in my class. My truck is very heavy and has the areodynamics of an outhouse. It has a wooden cab and a full flair side grain box on back. I can tell you that truck laughs at that hill and flys up it in high gear all the way. The hill at the steepest point near the top is about 26% grade. It is a long stroke engine but has the same bore as the smaller Chevy engine. The 3 port head is Ok and has two intake ports(3 ports on intake side, but center intake port is for manifold heat) and 3 exhaust. I have heard that a 2 port 28 Chevy head might flow exhaust better as it is more balanced and has bigger valves, but I couln't say for sure. That would take a good look at both heads all taken apart and considering the firing order with what ports dump at what time. Exhaust crosstalk is what you want to watch for. I would say you could increase valve size as most heads like this are very thick, but also are prone to cracking around the exhaust pockets and valve seats due to poor water circulation in those recessed areas and that alone could cause you a failure if ran hard for very long with out some modifacations. I think an Olds 43A roadster or a Chevy FB roadster could set and hold a class record at Newport. Forget about High RPM, not going to happen and live. My truck as it goes up the hill is wound out at the bottom and as the hill gets steeper, it slows down somewhat till it finds its sweet spot RPM and stays there. I hit about 29 MPH at the bottom and it slows to about 16-17 at the steep part at the top and sounds like an old tractor pulling a 2 bottom plow through sticky clay. It is all about torque and that motor makes a lot of it for its age! Bad news it they are a bit hard to find. I have been looking for a spare myself and any parts I can find. Some parts like valve train are the same as 490 Chevys. Just for some info, Louis Chevrolet and his brother had a machine shop in Indianapolis in the teens and early 20s and made the "Frontenac" OHV engines (or "Frontys" as they were known) and parts using mostly Ford blocks (yeah I know, go figure) but they did make some parts that would fit Chevys, but I think that deal with W.C.Durant left a bad taste in his mouth so they only did a few parts that would make them quick money. They would have to be rare and HIGH $$$$ if you could find any. I would say bring your car to Newport when you get it done, but they only have a modified "T" class for cars that are not stock. They have let some old 10s and 20s Indy cars run though, but mostly for exhibition. The "Golden Submarine" Barney Oldfield replica was there last year!

Bob,
Another factor in the trucks hill climbing performance is the rear end ratio and tire size. The setup is not fast but will "climb the side of a mountain" as evidenced by its history.

Thanks everyone for your replies. Its all really useful info.
I only discovered this excellent forum yesterday so Im still catching up on all the past topics!

Im getting the impression that the most economic basis for a fast chevy is a 1925 block with a 28 twin port head.
(with potential to have different crank, rods, cam etc.)
Has the early long stroke block got any advantage over the 25 block?

It would be intresting to know how good the 'roof' and 'frontenac'heads were. If there was a period specialist head that worked very well it might be worth making a replica batch. (this would be a long way off for me though)

Several guys in the Uk have developed the model A engine with period sohc miller head to produce 130+ mph racing cars. However, they have spent $20,000 to $30,000 dollars in devlopment costs. I wonder what you could do with a chevy with that money.

Good point about the rear end ratios, I did leave that out last night. My truck is geared to the moon and it uses a Torbensen-Eaton double reduction rear end. It has about 1.6:1 on the ring and pinion and has the rear wheel drive axles going to the inside of the brake drums which has a set of gears on the inside. It all rests on a I beam type solid axle. Not sure what the final ratio is, but suspect it could be as high as 6:1 or even higher. Top speed on the GPS at Newport was 29 and I have had it to 30 on flat ground. The hill at Newport is evident at the start line but is just a slight upgrade at that point. The rear 24" rims were changed back in 1924 to locking sidewall type with 2 rings from a Graham Bros truck. The original owner wrote in a book that he had trouble hauling loads with the split rim type as they gave him tire trouble where the rim flexed at the split as the load went between the rim clamps. He then was able to go to a larger size rear tire (still on a 24" rim but wider and much taller) which gave the top speed a boost from 23-24 MPH to 30. I start out in 2nd gear and go to 3rd fairly quick and when I advance the spark and mash the gas the ol girl acually sets you back in the seat. With the heavy wooden cab and large bed and all the other heavy duty underpinnings it moves suprisingly well. The overall hill climb record is owned by a "ferd" flat head pickup truck of around 1941 vintage.

Hey Guys
When I am rolling down hill I can hit 40
lookin 4 50
Ken

Hi

I have a similar project in a beginning stage here a little bit north from you. I'm using a -28 Chevy chassis and engine+gearbox. and a light body of some sort. I've understood, you are trying to stay in a budget, so in a sense we're in a same mental milieu.
First the head, If we forget the Roof, the next best thing is the pre -23 Olds three port. Such are, however, hard to find and their weekest link is the rocker arm ratio, so you need to fit the other, like -28 Chevy rocker assembly, and also bigger valves to make it a killer. There are people currently looking for modern replacement option for the rockers in HAMP (which I believe is the other forum you mentioned, if not TELL ME TOO). Stock -28 Chevy head is the easiest and cheapest way to go. By the way, few weeks back there were a thread in this forum about the complete Olds engine in Norway. Look for old posts.
Then to the engine. Speed info seems to be generally hard to find Chevies were used in racing, but most of the stories are about the Poor Mans Rajo. There is an Aussie lad hanging in the HAMP, who knows a lot and, of course, I'm expecting also Herb to join this thread. My current plan for my project is to use stock crank (balanced) and Ford A conrods, which small ends are milled to fit the Mercedes Benz 230 (-73 or younger) pistons. Small ends need to be milled to fit the pins (1" to 26mm). Big end diameter is the same. I don't remember whether the correct piston size was the first oversize or some other. Anyhow the engine has to be bored to metrics. This set gives you an option to use cheap spares like pistons and rings and it also gives you a moderate 6:1 compression ratio, which is still tolerable for the poured babbits, I believe.
THen there is lots of other "little" things like fully pressurised oiling, cam grinding etc. The semiautomatic -28 distributor should work fine as is and since you are in England there is a plenty of various SU carbs to use.

There were some thought that popped up in the mind in this short notice. Let's keep in touch with ideas.

Risto Nurmi
Oulu, Finland

Hi Rizhto,

Its great to hear from someone with similar ideas. We should definitely keep swapping ideas. My plan is to build the car around a bog standard 28 engine to start with, but slowly develop a 'hot' spare engine. Im keen to research the ultimate spec for an engine so that I can look out for any rare parts etc. The spare also needs to be easily interchangable. I think the very early chevy blocks had a different engine mount so this might cause problems if I don't plan ahead.
From just surfing the web you can find three original chevy racers from the prewar period. They all use the 28 head. However, when looking at lots of period shots most seem to use the olds head. Here are the links to three chevy racers:

http://www.conceptcarz.com/vehicle/chassisNum.aspx?carID=17528&iDNumID=9017

http://www.race-cars.com/carsold/chevy/1122872057/1122872057pp.htm

http://automobiliart.blogspot.com/2009/10/hubley-bluenose-special-gift-to-canada.html

There's a bloke down here in Victoria Australia who is using International dome top pistons that bring the compression ratio up to about 10:1 I can send his his details if you wish.
I had visions of doing something like this but now too old to try and I have 2 FA FB Chev 3 port heads that I now use for wheel chocks. (same as Olds) They need a hell of a lot of work to get them up to the performance of a 28 head let alone better and if using a Chev firewall it needs a fair bit of modification as the rear exhaust port protrudes past the end of the head
Chris

as Chevguroo said you will need to recess the firewall if you run a 3-port head that is what I did. I am building my roadster up so I can drive it regularly and when I build my '25 engine I want to race it at the local Speed on Tweed event.



http://img.photobucket.com/albums/v605/jimmyschev/My%201925%20Chev/DSCF9006.jpg
build overview http://www.d1082234.domain.com/25chevproject.html


If you build a Chev 4 right you can spin the motor up to 5,500rpm this involves quite a bit of work best to read this article to give you an idea of what you need. http://www.hotrodhotline.com/featur...er100/The_Little_Roadster_That_Could.pdf The Spurgin Giovanine roadster developed 150bhp and that was in 1948 it ran a fastest 1-way of 127.65mph 2-way record of 123.65mph This famous roadster is being restored and looks like it will make the field at Pebble Beach this year.


This is an article from the 1970s

What did you end up with,? I'm starting on a 28 racer with twin SU carbies and would kill fir a 3 port head. I'm going with taller dished pistons to raise my compression. A 29 oil pump and an oil line to the main journals . Ray

Hi Chris,

Can you send me details of the dome top pistons.

I will also send you an email about a follow up to last years Chev 4 tour.

Regards

Ray

Just a small side note; The Poor Mans RAJO is what the T guys refer to using a 28 Chevrolet head on a Model T (and Model A) engine. An adapter plate is used between the T or A block and Chev head. Some guys use the Chevrolet crank also as it is a lot stronger and keeps the same stroke.
Re the Old's heads, there have been a couple for sale on ebay in the past 6 months, so they are out there.

to Ken... that is easy to hit 50mph, just find a steeper hill