Watts Brothers drill was a three sided (triangular) drill that ran in square hole in a hardened steel plate above the part. Ever try to start a two flute drill and ended up with a lopsided, but three sided hole? Same principle. Watts drill comes with a special "chuck" that allows the drill to walk around radially while rotating. The size of the drill triangle from base to apex, is the same size as the square hole, side to side, in the hardened plate, and also the same as the intended hole in the part. Has to be run slowly, and is noisy, but will do the job. Incapable of cutting a square hole with sharp corners so the preceding round hole is made a bit oversize--and the result gives a radii in the corners. In video the guy is cutting aluminum--if it were steel, he would have to make the initial hole a little larger--which would make the corners of the square hole more evident. In the overdrive parts pix, this is carried to an extreme, probably to cut down the machine time in a high alloy content steel (good gear material). After typing all this, found a video-- After looking at th OD pix again, it looks like they cut the corners of the square hole in the gear with a shaper, to remove the radius. Herb
Excellent! You can see from this picture how that gear mates with the output shaft of the transmission if you take off the castle nut.
Now that I see the shaft it attaches to, I don't see why it has to be a blind hole. Why not use a thick washer that covers the square hole? Cool video by the way.
Great thread guys loads of information I need myself right now glad to see threads like this that just won't die.
Bit off topic but can anyone answer me these questions. I have a 27 coupe. the engine is seized at the moment. I have a spare engine but if possible I want to salvage the engine I have in case its a matching numbers car. Can anyone advise how I would be able to find out if it is a matching numbers car on such an old motor? After reading this thread I think I'd like to use the spare engine for a more performance build for a future midget project. I've whipped off the head and the valves have water damage. the car came with 3 spare heads. I suspect however one is a truck head but I could be wrong. However, My original head sports flat valves that sit a little proud. One of my spare heads has dished or concaved valves that also sit proud. This head looks to have been skimmed but I would rather use the original head if possible. The second spare head has 6 valves and two valves have 3 dots stamped. These appear to be recessed into the head. Any clues? Thanks My original heads part number is 345453 with the numbers 10 E31 by the second rocker set. My recessed valve heads part number is 345453 with the numbers 8 D76 by the second rocker set. My proud skimmed heads part number is 345453 with the numbers 10 D207 by the second rocker set.
I think there was a post on here about casting numbers but I haven't found it. I think the dots and slots in your valves are for lapping tools. It was not uncommon to replace only the broken or worn out parts back then.
Ok cool thanks for the reply. I will pull the valves and check the numbers on them tomorrow eve and try find a full matched set of usable valves. Thanks.
I think 1927 single port head has slightly larger valves than pre 27 heads. 1 1/2 vs 1 21/32 - Herb may be the person to ask.
There are 2 1928/1927 engines on C.L. down here...check crags list,"MEDFORD OREGON" there in "CENTRAL POINT.....PRICE...$150 I can't find a phone number....
BET- Yes it is a one year piece only '28's used it. However, you only have half---there is a bottom piece, which is much more difficult to find. It's a sort of large funnel, square where it fits to the radiator, then transitions to round where it shrouds the fan. The thing was a bitch to R & R and was usually thrown away, the first time that the water pump needed replacing. Not necessary for the operation of the car--unless your route to work takes you through the Sahara desert, as most of the cars that aren't going for a show prize seem to run just fine without either piece. Chevy thought that it was needed because of the space between the fan, and the radiator---the frame was stretched in '28 in anticipation of the six cylinder which the '28 was supposed to get. The engines weren't ready in time. Lot of changes were made in the '28 engine--which makes it a one year item also.\ Herb
Kume-- You are correct--the '27 head took the 1 21/32" valves that the '28 head used also --but had 1 / 1 rockers vs the '28 1/ 1 ½ rockers. Interesting thing is that the '27 1 ton truck used the old 1 ½'' valves. Judder-- 345453 is a 1912-27 head with 1½ valves. The '27 head with the 1/21/32" valves is part #346886 Date code works like this letter (A=Jan, B= Feb C= Mar etc) then a space, one or two digit number (day of month) space, then number, which only last digit = year SO---- J 22 86 would have been cast on October 22 1926 What you have, I think, are parts that were cast later, as replacements after the code changed. IF they are not replacements the surface where the exhaust elbow bolts to should have the serial number of the engine it was bolted to. This was supposed to be a check against re-stamped numbers on a stolen car. The manifold surface and the block are the only places on the car where the serial number appears, besides the brass tag (usually long gone) nailed to the right hand seat frame down near the floor--should be visible when you open passengers door. BE SURE to pressure test ANY single exhaust port head. They are VERY prone to cracking in the exhaust port, if the engine was ever run low on water. There were quite a few "aftermarket'' single port heads available at places like Pep Boys, or Western Auto, which generally worse than the real Chevy ones. Herb
cool, thanks for the info so all the heads are suitable for my engine. I'll crack on with the rebuild.
judder_man, Herb made a good point about '27 and earlier heads cracking- if your car is going to be a driver, I'd recommend finding a '28 to rebuild. You can always keep a '27 head in storage, in case you decide to sell the car later.
Forgot to mention that added bonus, AND the better breathing through that wicked dual exhaust - thanks Herb!
Very funny... You could always try to find an Olds 3 port head... but they are getting pretty hard to find and ugly-expensive
Wasn't it on this thread that I read that the '28 head actually out flows the Olds? bct, That is nice!
Didn't see that post, but I can't see how that would be correct. The '28 head intake ports are actually steel tubes that are pressed into the head- behind that is a big boxy chamber that leads to the exhaust. It will outflow the pre '28 heads easily because of the dual exhaust, but Olds head has nice, smooth intake and exhaust ports
Be aware that the Olds head (also used on the '22-'23 Chevy 224 CI engine in big cars) won't fit on the 171 CI block in a stock Chevy body--unless you want to beat a large dent in the firewall where the rear exhaust passage and manifold flange are. Somewhat interesting note. the '21 224" engine used a single exhaust port head. Must have set a record for backpressure! Also, Unless you want to run at the drags, or salt flats, the two port '28 head wont hold you back. I always intended to do a rough home flow test comparison of the 2 port VS the three. Too late now, as I sold my last 3 port over a year ago. I have heard the claim, about better flow from the 2 port, think that it came from down under. How about it Aussies? Anybody know if it is based on anything, of just KS? (Kangaroo S**t) Herb
Glad to pick up that info before sourcing a Olds head. I sure as hell don't wanna modify the firewall/bulkhead area. I'll keep searching for that 28.
Two plug problems with the C4 heads. First, you want the spark to happen out in the chamber, instead of down in a hole, and second, 7/8 plugs of anything other than Model A ford heat range are almost impossible to find--and too expensive if you do. I don't know the modern numbers for 7/8 plugs, both Champ and AC changed their numbering systems a while back. I think that this was because the old systems made some sense, and too many people knew what to ask for if they wanted to go one range hotter or colder. Old numbers where C4 (or later C16C) for Champ which most folks with stock cars used. I never liked Champ plugs--only got half the mileage other plugs gave. Here is a chart, with modern numbers crossed over to other manufactures. http://www.angelfire.com/extreme4/skidoolympique/SPARK_PLUG_CROSS_REFERENCE.htm If you want to stay with 7/8" would recommend NKG--about the best made now IMHO. NGK stock #1010, Plug # A6 NGK plugs seem to have a heat range that spans a much wider band than any of the other makes But, as I said earlier, it has been years since long reach 7/8" plugs have been made, and the best results (because there is no turbulence to speak of in the C/4combustion chamber) is to get the plug points out as far as you can into the main part of the chamber---without any threads being exposed to cause pre-ignition. What is needed is a 7/8 to 14mm adapter, long enough to accept 14mm long reach plugs. I made 4 of these up for the last engine that I built. Another tip--but not exclusive to C-4's-- is to re-bend the ground electrode so that the spark can't "hide" behind it Makes for a much better, and slower, if you want, idle in engines with no turbulence in the chamber. Herb Wonder if there is a market for 7/8" to 14mm long reach adapters? Could crank up the CNC---- The plug on the right is modified--the one on the left is stock. Ive only been able to do this with 7/8 plugs--the ground prong is too stiff and small to bend like this, even with heat
I've been using the Model-A Ford spark plug adapters with either the Bosch Platinum +4 or Fusion 25mm long-reach plugs like the 4514. They work great. Here is a comparison between the Champion W89D, the Bosch-in-adapter, and the Champion W18.
I was told by the Chevy guy that i got the head from to run Champion W89D plugs, so ill probably do that, but if anyone knows somthing bether, shout out!
The W89D is a hot plug and you might have trouble with pre-ignition in the hills. I did. That's why I started investigating other options such as the spark plug adapters.
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