Very definitely the W89D is too hot--it is meant for the hit & miss farm engines. The W18 is also, but not quite as hot. The 14mm Bosch in the ''Model A'' adapter has the 14mm threads exposed to the combustion, and under heavy load the tops of the threads can become incandescent and cause pre-ignition. That arrangement would be OK if you turned all the threads off that extend past the adapter. If you aren't familiar with the sounds of pre-ignition, and you run the engine hard especially with the two Champ plugs, you will become familiar with how poorly an engine runs with holes burnt through the tops of the pistons. Ask how I know. I think that I have a photo, if I can find it. Herb
Agreed. At the time, I too thought those exposed threads on the 14mm plug could be a potential problem but that arrangement has performed quite well in my Chevy-4 at compression ratios up to 7:1. Much better in fact than any 7/8 plugs I tried. But yes, the W89D aka Autolite 3077 are just too damn hot for my motors.
I just got some Rockers! My Plan is a G28T (if i can save the block) with inserts, a ballanced crank, a wild cam with a secret grind, the 28 head portet and smoothed out and im not sure on what im going to feed it with jet
Collected thoughts Hi I am new to the forum and have read all the previous postings. I am impressed with the knowledge out there and the lengths to which you guys are prepared to go to make the Chevy engine go. I am currently building a 1928 engine with the twin port head. I am somewhat at a loss however, to know why no one has mentioned the throat restriction in the head where the huge valve guide massively restricts the air flow into the valve area. I can sort of understand the original design idea behind it which might be to raise the flow rate, swirl the mixture and improve bottom end tractability by effectively having to ram the air through a narrow aperture. Once into the cylinder this gas’s would then potentially cool and as such condense the mixture dropping out the fuel to pool in the cylinder. However my feeling is with today’s fuel this should be far less of an issue and I have subsequently taken a die grinder to the ports and opened up this significant restriction by reducing the diameter of the guide as well as tapering it. Before I started I could not get my little finger between the outer wall and the valve guide. 10 minutes later I can fit my thumb. Question 1 is : Have I got it wrong? Have I opened the port up too much for a road engine? I want to build an engine with significant low end torque to do some VSCC off road trials work. Yet at the same time be reasonably sprightly on the road between sections. Question 2 Does anyone know the torque for a standard engine in the first place. I can find a figure for a Ford Model A but not the Chevy. The engine will be going into a shortened and Modified Model T chassis , Model A rear axle and an open prop shaft, mated to either the Chevy gearbox or the Model A box. Decision yet to be made. All up it should weigh in at around 550 kg so with 50 – 60 bhp have a good power to weight ratio. Any replies would be great
A bit off topic. But can anyone tell me if I can and how I can get a key cut for my 27 capitol from a cylinder number or the likes? My car has no keys. Thanks
I know if you take a later model (62) lock to a locksmith, he can either cut a key to fit or change the tumblers to fit a key he has.
I shortened the guides in my cylinder head by 1/2" to improve flow. Also used Olds 455ci exhaust valves which are close to original.
Mosquito--- Sorry for the protracted time in answering, but I thought that I had information on the torque--but if I do, I;m not able to find it. Hence the delay. The horsepower figure is 35.5 HP @ 2200 RPM. The torque peak is near always at a lower RPM figure, but at the quoted 2200 the torque would have to be about 81.5 ft/lbs. I doubt that you did any harm with your head porting, but at the same time I'm not sure that it will make any significant difference. If you want to build an engine for off road trials, raise the compression to around 6-1and seriously lighten the flywheel. The Ford box is better than the Chevy, but why not put a modern 4 speed, with O/D in? Quieter in the intermediate gears, better ratios and synchros to make shifting quicker. To get 60 HP, you are going to have to have something like 7-1 compression, a reground cam, and a larger carb. This is going to mean that you will have to increase the rpm, and that means pressure oiling if you go above about 2800 RPM. And if you are thinking about going that route the crank should have counterbalances welded on to prolong main bearing life, and all the rotating parts balanced, rods and pistons matched for weight Not quick, easy or cheap. Herb Kephart
Hi thanks for the reply re torque figure. and advice. I bought some years ago a set of Egge High comp pistons which are supposed to be about 6-1 . I anticipated pressure feeding the mains and big ends so have cross drilled the crank and part set up the feed for these. I have got to finish this off. I now think a set of Model A rods looks to be in order as they are better material and add a bit more compression. Looking at posts indicate I should throw the old pump away and fit something better. As I am in the UK I guess it will be from a UK car. The Vintage Sports car rules mean that I have to fit eligible transmissions which are pre 1930 hence the Model A / Chevy direction. I suspect that many of the smaller UK gearbox's would not be happy with the amount of power and torque. I am currently looking into a model B weighted crank as well. But me thinks that will be for next year. Get the car up and running first.
I know that I've fallen off the deep end on this thread (trying to put a new daily driver together while Mrs. Yankee is finishing up her last semester of grad school and all three little Yanks in school, scouts, and sports), but has anyone tried putting newer three speed guts into a '28 housing?
If someone was going to produce an intake manifold for a '28 head what would you want it to be? Down draft or side draft? Heated or not? Port size? What other cast aluminum peaces do you think you might actually buy if they were available at an affordable price? A new head is not out of the question.
Neal Jern was producing ali 28 intake manifolds for the carb of your choice - sadly I think he recently passed away - can anyone confirm.
Sorry to hear that although I did not know him. Those kinds of guys always take so much with them that we need to know. A friend is thinking of a duel single barrel down draft set up. I'm thinking Zenith 28s because they are so adjustable. I also have a pair of tiny Ball & Balls.
OT but sorta' related. I recently got a 1923 Essex four cylinder engine. Does anyone here know of a site or parts source, Essex group? I don't want to hijack this thread so PM me or post on the Inliners International thread. Thanks. http://www.inliners.org/ubbthreads/...16&PHPSESSID=8b62f622badc7181093d16f8f5d73c1e
Great find Just a thought . Given how easily these bend and the mass of the pushrods has anyone tried aluminium or titanium as a replacement? either tube with pushed in end caps or solid bar. It occurs to me that this would place significantly less strain on the rocker in an over rev situation.
I did this on my speedster engine, although I made aluminum rockers. Used aluminum tube, about 3/8" and machined the ends to take air cooled VW pieces. Herb
Herb, Are the intake ports on the '28 Chevy and the Olds heads the same? That is a great looking engine!
The Jalopy Journal
