So, I stayed up late last night and read this thread from start to finish. That took a while but was on one page so was like a book. I saw this linked here: http://www.chev4parts.com/ I spoke to Rob and he was very helpful. He has the rocker gear. So I will be able to use that as a base to look at roller rockers.
how do i separate the torque tube from the axle housing , ive undone the bolts all around the casting but it will only slide apart 1/2".....do i need to remove the three pinion bearing set screws? anyone got a tips on how to mark it so i can put it back together in the same tooth? p.s. this is for a 28 chev rear, and i realize this thread is about the engines but this is the go to thread for all info 28 chev, so thanks for the o/t.
This is a 27 rear (I think) but it is the same construction aside from the brakes as you can see the torque tube is riveted to the center section. Herb
bct- been there! I have a rough axle that's been cut and is headed for the scrapper, but I want to get the guts out first... just can't remember how to do it. I think there was a thread on the VCCA site about tearing down an early rear- might be worth a look?
thanks for the info .....i need to pull the axles out first. which means getting the drums off.....yay. i thought that the pinion was the only part on the center section but the whole shebang mounts to it....... so i won't have a problem marking tooth placement....actualy gathered that from one of the recently posted engine pictures above .....on the far right you can barely see a center section with the ring? gear still attached to the center.starting to make sense now.
Gents, I have two 28 engines going by the serial numbers (R4XXXXXX) but I am not sure what I have on the right here. Can anyone help? I cant see the serial number. Cheers Damo
Hey Mac, do you have any 20 or 21" rims that you would part with? I need 1 20" ('29) wheel and 2 rims 2 21" ('26) wheel 1 21" ('27) wheel 1 narrow ('26) rim 1 wide ('27) rim A full set of Jaco lugs Ron
Disk rims? Yup, I have some- will have to dig them out. PM me your email address and I'll try to send some pics when possible.
Hello I posted a question in the monthly banger meet thread, but to be fair this is probably the place for that question. What is the power potential for an engine using a Chevy 2-port? Both using stock valves and no porting and ported? Would 80hp be possible? I'm not talking about what needs to be done to the bottom end to support the revs, only the flow potential of the actual head. Thanks, Magnus
Porting is only possible on the exhaust side- the intake "ports" are actually tubes pressed into the head (will try to send a couple pics of that tonight). Still, it should be a worthwhile and inexpensive upgrade from a stock Ford head.
The intake passages in the '28 head are typical of manifold design in the '20's. Lots of square corners, and the sheet metal tubes mentioned by Mac, which contain sheet metal inserts which look like a daisy. the concept was to get a lot of turbulence in the incoming mixture to keep the gas in suspension. The three port Oldsmobile head although designed 5-6 years earlier has much more smooth transitions, very modern in appearance, but still had the "daisy" tubes. It did however have a direct connection through the head from the center exhaust port to heat the intake manifold, with the same purpose ( keeping th gas in suspension)- but this time by vaporizing it. I have read claims, which I think originated in OZ, that the '28 head flowed "almost as good" as the Olds three port. This I find hard to believe, and I have in the past asked for documentation on this, but it has never been forthcoming, This MAY be the case, at the low revs that the engines were designed to run at, but not at higher RPM. A good project for some one with access to a flow bench? Herb
Mac, I have 5 early Chevrolet heads 4 2 port and 1 port exhaust and they all had corrugated metal inserts inside metal tubes inserted into the intake ports. I have removed both inserts from one of the heads and found that each intake port opens up into a large area around the valves. It seems that there is a smooth curve inside the port that opens up toward each valve. I haven't cut into the casting of one to see how much cast iron there is around each port but I think that they could be taken out to 1.60" without hitting the water jacket. I went out and measured the intake ports and found that the metal insert port measures 1.20", the port without the insert measures 1.31" and if the port were relieved out to the indentation where the insert flange seated they would measure the 1.60" previously mentioned. I believe that the inserts were put in to heat the intake mixture to help vaporize it for better combustion. When I use one of them I think that I will build an intake manifold that incorporates a Hot water jacket to serve that purpose. Below are some pictures of three of the heads. Dick
Dick, I'll have to take another look at the intake without the ports- if I remember correctly, I felt arounf inside the head after the tubing was removed and found it rather "cavernous" and not particularly good for flow, but there's no reason someone couldn't use larger tubing (maybe even with a bend)? Also, check your earlier heads- the single exhaust heads are prone to cracking.
Magnus, Don't let our bantering keep you from using the '28 Chevrolet head- it's a good, inexpensive route for an ohv conversion. The '23 Olds 3 port head the Herb mentioned is a better choice, but getting very hard to find and rather expensive! The only other inexpensive conversion for the Model A engine is an Olds 455 head- look for George Miller's posts about it. Wish you lived closer... I just happen to have 5 sets of 455 heads
Mac, You are right about the cavernous area in the intake. My suggestion was to only open up the first inch or so so that a larger diameter intake runner could be used. I think if the intake runner were run through a larger heated water jacket the mixture would be better vaporized. A modern carburetor would certainly help in that regard also. I don't have a 28 Chevrolet but I do have several Model A Ford bangers and want to put one of these heads on one if only to find out if the Model A Ford naysayers are right. I have been told that the 28 Chevy head won't put out as much hp as a good flat head. I cannot see how that can be true especially with larger valves and being cross flow. The exhaust side seems like it would flow pretty well and because of the high pressure of combustion the exhaust valve is usually smaller than the intake. The Model A has 4 exhaust ports but as I say I don't think that is as much of a factor as is the intake. The model intake port is 1.375" and probably could be enlarged but 1.60" of the Chevy intake port and the rocker arm ratio opening the valves more should produce more Hp. I am sure that some or most of the purpose built heads probably will produce more hp than the Chevy head but there must be a reason that back in the day some used the Chevy heads. Dick
I picked up some roller rockers dirt cheap last week, and Stevie G has a student who is in desperate need of a senior project, SO... we're going to scavenge the parts and build a set of roller rockers for the engine ! Now, if you were going to build: 1) a mildly hopped up engine 2) an all-out racing engine And even with opening up the cam bores like Pat did, the cam lobe profile is still going to be limited... what ratio would you use for the rocker arms? These will go on the 3 port head, so we'll have to mill off the rocker shaft mounts and reposition them. Little steps, but things are starting to move! Next step is to either have a Chevrolet crank counterbalanced or find a Forb B crank. PS- RichFox, I have a cam gear for you- will send to the address you gave me
Bill, we will pop a couple out in ABS for fitment, then plan to cast a set, and cut another set from billet. It will be fun to turn a kid loose and an R&D project from ideation to finished product.
Thanks but the cam gear finally came and is in the car along with the rest of the short block. Needs the oil and fuel pump mounts and stuff like that along with some sheet metal work to clear the rocker box. But is is moving along.
Oh. Yes. Thank you, you are right. I have been thinking about the Dodge Bros so much lately that it is what pops to mind when someone says "Cam Gear". I will very much appreciate the Chevy cam gear. I think the Chevy is going to be a pleasure to work on after this Dodge.
If you manage to find some, be sure that they are straight across the top. They bend very easily from over-reving. (Chevrolet's answer to keeping the rods inside where they belong) Herb
Scored this one on eBay. The owner said it was the third time he had listed it but nobody wanted it. I think because of all the heavy metal around it. Normal shipping would be a fortune. Anyway I found it a cheap ride from NY to FLA so it's now in the Swamp. The claim was that it was running a generator up until about 5 years ago when it was retired to storage. I pulled the head yesterday and it looks good. Will see what the magic magnetic powder shows but don't anticipate any problems. Always wanted to do a vintage four cyl roadster and this should be the ticket.
YeGods---It has the fan shroud for the radiator!!! Only used on the '28's because the engine was so far from the radiator--because the engine bay was designed to take a six. Rare Rare RARE! never repoped and the only one that I ever saw that was not on a restored car. Surprised that it wasn't snapped up by someone just for that. Herb
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