More engine work on the tank this week, Ive set about porting and reliving the block but havent taken phots yet. Also been making a new center main bearing cap to cope with the extra umph from the supercharger. So here's a mini tech on machining a billet center main cap. Step one find a nice chunk of cold rolled steel and dimention to size, chop saw followed by squaring up with a fly cutter in the mill. Step two drill some holes for the bolts and have a quick test fit make sure there in the right place. Then on to the lathe, the cap must be perfectly centerd in the chuck so that when the circular tangs are cut they will align the cap correctly on the block. Then back to the mill to rough out the journal seat with a hole saw Followed up by a few passes with the boring head, leaving the jounal seat a litle under size so the cap can be line bored in the block Last job was to counter bore the bolt holes to a deapth that replicates the original Ford cap so the main cap bolts have the same amout of thread in the block as Henry intended. Finaly finished main cap ready to line bore in the block.
Wow Jamie that's really good work. All done on home gamer tools too. Very impressive. What is your experience with line boring, or is that something you would farm out? I've watched Cutting Edge Engineering in Australia do some line boring and he makes it look easy. The kit he has is impressive. I look forward to seeing how the build progresses.
Cheers Mart, I'm planning to do a part two for the line boring stage, nothing fancy just a 1 1/2" boring bar with two bushings in the front and rear main bearings, drive it with a slow speed drill. Will set up a stop with a fine thread that can be slowly unwound to give some control to the cut. If I was doing all three main bearings then I would definitely look into farming it out, but my "home gamer tools" should cope with doing just the center one. I checked out cutting edge's YouTube channel.... looks good.
Wow I was pretty impressed as the thread progressed but when you machined up a new main cap, I am now completely floored. I love what you’ve got going on here
More work on the engine, finaly finished all the porting and and deck relief, put at least 40 hours in to this stage and I'm glad to put the die grinders away for a while. Also dug out my old Black and Decker vibro centric and did the valve seats. My temp and oil gauge arrived last week so I mounted them and put a few switches in the dash, I'd like to run all aircraft gauges eventualy similar to the tach but getting them all to work might be a bit chalenging so I've stuck with the Stewart Warners for now.
I knew a past record holder running blown flatties and he'd add metal to the web as well as the cap, he showed it to me.
That sounds interesting, have you any more info.. photos of this?, the webs are definitely the next week point after the caps. I've got John Lawson's flathead facts book and he describes a method of bolting through in to the lifter valley to reinforce the webs.
No, I really didn't study how it was done, I was trying to reconcile what appeared to be a stock connecting rod.
Been a busy couple of weeks on the tank got lots of the little jobs done finished all the machine work on the engine which is now ready for a severe scrubbing and cleaning tomorrow and start putting it all back together. Made a start on the fuel injection setup, plan is to cam drive a Hilborn P150 pump that will be regulated to provide fuel for carburetors to start with and in the future be ready to go fuel injection. This is the before shot Then after a bit of machine work Done quite a bit of finishing work on the lower half of the body, neatening up all the cutouts and final bits of panel beating, I havent gone over the top with geting a perfect finish, a "twenty yard finish" looks good when you stand back And finally a shot showing the plumbing all coming together,
very nice One thing I have wondered about whenever I have looked at front covers modified to mount Hilborn injection pumps is how do you establish the axial alignment of the centerline of the cam and Hilborn pump? It would seem to me that the two must align fairly closely. Or is there some wiggle room built into the drive adapter?
Yep thats a good question. I think the alignment has to be fairly accurate, dont quote me on this but I do remember reading that it has to be less than .005" runout or it will damage the pump, but sould be easy enough to get minimul run out, definetly less than .005" This is how I centralised before boring the hole in the timing cover, using the inside of the cam thrust boss. The outer pump mount is press fitted onto the bored hole in the timing cover. Will have to mount a dial gauge to the cam spud and check runout once its all asembled.
AaHa - I see. At least I see how you did it on this engine. Having the boss on the backside made it a lot easier. Thank you. I suppose if you found out the hole was more than .005" out you could remove the bushing and make one with the necessary offset in it and clock it into the hole and eliminate the runout, similar to truing up a bellhousing for a transmission pilot bearing retainer. I wonder how it is done when the front cover does not have anything on the backside to indicate? Test bore and offset bush accordingly after measuring?
I suppose you could make a simple tool and fit it to the front of the camshaft, then spin the camshaft to provide a reference point.
When I did my 4 cyl, I used the cam. I sharpened a 3/8 bolt to a point, screwed it in the cam and at the rear of the cam I gave it a tap. Made a prefect center punch mark in my front plate to line up with. I am within .001 run out.
I finished the line boring of the center main cap this week so this is my part two mini tech artical "How to make a heavy duty center main cap and line bore in your back yard", well not quite back yard buy very DIY. Fist I turned up a couple of bushes to clamp in the front and back main bearing housings with 1 1/2" center bores. Then got a lenght of 1 1/2" cold rolled bar and drilled for a boring bar cutter with a couple of grub screw holes to lock the cutter in place. I forgot to take a pic of the set up in the block but I'm sure you can figure out the setup from the next pic. The bar is being driven buy a big slow speed drill with a 1/2 socket UJ and an old socket welded to the end of the boring bar, the other end buts up to a strap of metal with a unf bolt in it so as the bolt is undone the cutter travels through the bearing housing. Next step was to ring my mate Steve and get him to come wind out the bolt while I spin the boring bar. This was a scary procedure especialy the final cut, you can see the concentracion, but it came out spot on. last thing left to do will be to cut a small notch in the cap for the bearing shell tang to sit in.
I've got a similar make-a-cam-drive-hole task to do on a GM Holden grey motor timing cover. A question though - is 5-thou accuracy really necessary for mounting a Hilborn pump? My mental picture is that the old tang-drives (like the image below that I borrowed from the HAMB) have a lot more slop in them than that. The other picture I have in my head is of the many Hilborn pumps that are belt driven. That must put a pretty fair sideways loading on the shaft/bearing assembly. Cheers, Harv
Great stuff man. I’m really enjoying this thread, especially the block mods. Eventually I’ll need to do this on one of my V12s so thank you for sharing your technique on how to control the cutting feed rate.
The Jalopy Journal
