Does anyone have a setup/fixture for "pinning" the Flathead heads, be it either Aluminum or Cast Iron, to the block???? Am trying to use the same method as most manufacturers to "locate" the heads on the block, much like the SBC with the "solid" locating pins. It appears that a 1/4" pin would be required due to some space limitations. Would like the "pinning" to be symmetrical seeing as how both the right and left head bolt holes are in a symmetrical location with respect to the cylinder bores! (Add) I see this as adding to the life of the head gaskets. Most aftermarket heads (have some new Edelbrock 1116's in here) are now drilled for 1/2" bolts/studs. When the heads are mounted without any way to locate them, there's simply too much "top-to-bottom" & and "front-to-rear" movement. If there were some "large" valves in the build, there is a risk of the them contacting the castings. Had this recently on some new "early" style Edelbrock 1125 heads. Ended up "flycutting" the valve pockets! Thanks, Gary in N.Y. P.S. I believe I know what's required, but any add'l opinions would be much appreciated. Also, as I stated above, if anyone here knows if it's already been accomplished by someone!
GOFAST...the up/down, side to side movement doesn't cause any problem. simply screw all headbolts in by hand, then lineup head location and tighten 1 bolt snug. that should keep it in position for tighting the others. or better yet talk to 1 of our flathead mech. search flathead...good luck...POP.
How about pinning with two hollow dowels around two studs on each side?? Usual way would involve settind dowel into a countrbore around the stud...this might be undesirable due to cutting into thread engagement depth in a rather thin deck...but the "dowel" sleeve could be a floater with a tight slip fit on the studs chosen as the locators. You could then make a head fixture fron an iron head...
Thanks, Bruce, this is what I'm looking for, some ideas! I don't believe there's enough material below the head bolt bosses to safely machine the required outside diameter or the depth required to fit the dowel rings. What you are recommending, I believe, is a setup similar to the BBC's and most Fords? Also trying to keep the labor under control, with minimal machining operations as possible! Thanks, Gary in N.Y. P.S. Anyone here know Edelbrock's reason for the extra large head bolt holes? The older Offenhauser's are smaller, not sure about their newer ones!
Iron block and aluminum heads? I'd think the heads would crack. Wouldn't the expansion rates be too different?
Expansion rate and electrolysis are the only two reasons I can think of. I know the corrosion can really build between two dissimilar metals but you would think that they (Edelbrock)would at least bush a couple of stud holes so the heads won't slip and slide so much or provide some special shouldered studs for a few holes or something. They might slide down to the point of valve to head contact during torque up.
We now have the tooling done here in-house using the block-plate as a foundation for the entire layout! The honing plate incorporates the head locating dowel pin holes and remains bolted in position while both dowel holes are drilled. They are drilled with a letter "D" drill and leaves the correct hole size to "press" the .248" SBC timing cover dowel pins in the Flathead decks. The heads are then mounted on the block plate and back-drilled the same size, later when removed these holes are reamed .250" for clearance on the deck pins! Also while doing this operation the head gaskets would be mounted here at the same time and also drilled. You end up with 2 "clean" holes through the gaskets and now in all are components are in perfect alignment with the dowel-pinned block!! A pair of stepped/doweled guides, .470" x .500" are used to locate the plate on the block and heads. The holes through the block plate are .468" and the Edelbrock heads are .501". The smaller end of the dowels fit the plate snug, the larger ends fit the heads also snug! We chose to locate off the 2 head bolt holes at the end of the block and place the pins between them and the end of the casting. Not a single hole goes into the water jackets, therefore, no chance of water leaks at the deck/head surface. Took a few hours/days to configure it all, but now we can "pin" the heads and know exactly the locations with respect to the valve pockets. (Add) I see no issues with "cracking" from movement, it's basically the same deal as any other iron block/aluminum head combos! Thanks Gary in N.Y. P.S. I'll put a few shots here, most machinists/builder should understand it for the most part! Ended up as a fairly easy procedure and it WILL keep everything stable and should help the head gaskets from "sliding/moving" around!
Real nice work Gosfast.....what a shame you live in Long Island and Im on the other side of the pond. Those TQ plates look real nice too !! Rat
I see you have a solution, but another way may be to machine some bushings that go around a couple of the head bolts/studs and fit snugly in the heads. It wouldn't index the head to the block, but to the bolts/studs - which should be close enough.
That's the mark II version in my post...using the block plate as a fixture, though, is neat. I went to the Mark II idea because drilling away deck around stud is a dodgy idea when deck should be thicker anyway... Remember that when the accountants attacked the flathead in 1949 the dowels for intake went away too...meaning that your port matching on a late flathead ain't gonna do much. Any ideas there? I'm thinking through the sleeved stud idea for that. Biggest problem in both cases is with aftermarket stuff, which seems to be drilled sloppy to avoid any possible installation headaches. Another thing about the head plate is that it allows the doweling to repeat properly if you change heads...many easy ways would go bad here, leaving no good way to transfer location to new hardware.
One idea..........I have done this on relieving blocks with different heads as I don't believe in relieving the block past the combustion chambers as some people do...............is to take a flat piece of 1/4" plexiglass..................lap the top and bottom to a known flat surface..... then bolt it to the block, (this is when the block is empty and on an engine stand) mark exactly where the bores are. Mark and drill for your dowels.........insert the dowels in the block then place the plexiglass template on the head and drill for the dowel. Unfortunately you will have to do this for each side of the block/head. It does work. This was only done after all the macine work was done to the block/heads. IMHO
Modern engines use dowel pins to locate aluminum heads on iron blocks. Thermal expansion isn't a problem.
Hi Bruce, the way we worked this entire procedure out is a "blessing in disguise" to put it mildly! We can now take any head, mount it on the block plate, drill the dowel holes, and have it fit perfectly on ANY block that we have predrilled for the pins! I spent the entire weekend on this project and there is only one drawback I can foresee and it's a minor one. This would be if the 2 head bolt/stud holes in the heads directly next to the "pins", were on a slightly "different" C/C from "vendor-to-vendor", and I've fixed that as well now! I've made some add'l "guide dowels" in -.005" increments from the original .500" O.D. (that fits the Edelbrock heads), and choose the one that now fits the stud and "slides" most easily into the one remaining head hole! Remember, no matter what the C/C span on the 2 head bolt holes measures, one of them will be always lined up "perfect" on the deck surface with the plate and with one of the .500" dowels (the Edelbrock head sizes). This is a "given"! We can also make add'l "guides" for heads such as the "Offenhauser's" which have smaller I.D. head bolt holes. These are .468" as opposed to Edelbrocks .500"?? Drilling through the block plate for the pins all but guarantee's the C/C distance on the pins themselves is "constant" and the C/C distance on the heads being drilled on the block plate is also "constant"! Drilling/pinning the intake for the best gasket alignment and gasket matching (porting) is something we've been doing for years now on the Chevy's (and most others), with 100% accuracy. It would be just as easy doing the identical procedure on the Flatheads, I'm positive! I will place the procedure here for the intakes later, presently out of time! (Add) I would like to add a very important point here, if anyone up here "contract's" to have a shop build any Flathead, I would demand to at least "see" the actual block plate as finish honing these casting's without the plate is leaving much less ring-seal and some HP "on-the-plate". They need to be "block-plate finish-honed", I don't care who agrees or disagrees here! These have very "flimsy" deck surfaces/thicknesses! Thanks, Gary in N.Y. P.S. As complicated as we thought this whole dilemma was going to be, it turned out to be rather simple once we "attacked" all the angles! What I really needed was "consistency", and now we have that! Now if we can get guy's like "BHJ" to pay attention and incorporate this item into their Flathead block plates', I believe they would have a very superior piece in the marketplace!
The Jalopy Journal
