Cam vs static compression

[farmall]

Given the original heads were crude as they could be like most sand cast parts of the era (HD was no MV Agusta or BMW airhead) and the simplicity of the head design why not check a set out? There isn't some secret sauce to casting such basic parts in the modern world.

I'm ordering repop heads for my Pan and per Dragstews sensible advice replacing the valve springs since the usual place to cut quality where no one can see it is using inferior steel. Bike parts tend to have boat-style ripoff markups and if ya do cars the comparison is interesting. Ya can buy aluminum V8 heads for about 550 each which have a LOT more alloy, hardware and machining than a dead simple Shovel repop. S&S management know they've a captive audience and per other posters some of their recent QC has been funky.

Post results to help the next guy.

The Ultima website is a triumph of poor web design.

http://www.ultimaproducts.com/headsshovelhead.html

The remarks on flow are interesting:

https://www.hdforums.com/forum/shovelhead/1263476-ultima-heads.html

[pansshovelsandknucks]

Regarding the ultima stuff - go to jirehcycles.com and download the catalog. I've ordered a bunch of stuff through there. Most of the time it's cheaper than anywhere else you'll find. But you have to look the part number up in the catalog and then search on the site

[rockman96]

Well, so much for 1/2 the cost of S&S... Just looked up on the Jireh site, heads are $579 each. Still saves around $400(?) or so. It appears to me that the cost of raw materials may have had a big impact on cost, metals have really taken a hit on cost these days. I was thinking that a year ago they could be had for under $900/set.

[Guest]

not cheap but are on my 'WANT ' list,

https://www.speedandscience.com/product-tag/shovelhead/

[rockman96]

not cheap but are on my 'WANT ' list,
https://www.speedandscience.com/product-tag/shovelhead/

Oh yeah, he makes nice stuff. He usually runs an annual sale sometime around October(?).

[Ratty78]

So I decided to go against the grain and do it myself, that's how you learn right?

Ordered the kibblewhite stuff from goodson. I pulled out 4 +.002 iron Rowe guides, and when I mic'd the ID all but one were still factory spec. So I ordered 4 KB iron guides 3 @ .002 and 1 @ .003. I also ordered a .377 reamer and a 3/8 ball hone. The .379 reamer was out of stock and the KB exhaust valves are supposed to be .0005 under, but I'm hoping I can open things up a bit more on the exhaust guides with the ball hone. If shit gets weird I'll try again for the .379 reamer. Also got the Jim's guide punch set. Still planning on ordering a set of higher pressure springs to open up my cam options a bit.

I'll probably pop the new guides in and size them this weekend, but you're probably wondering what I'm planning on doing about the seats, right?

Sweet, so am I.

I found some really affordable (meaning probably shit) seat cutting kits on ebay. They are for a 3 angle job, and are carbide tipped, but the blades are not replaceable. Other than that they seem to be the same concept as the neway stuff. I'll probably give them a try unless someone can show me a neway kit that is specifically for shovels and not a $1200 generic "all Harley engines" kit that I can't afford.

My question is about the cutting range. The dies are listed as 2.125 and 1.95 respectively, where my valves are 1.94 and 1.75. They are, however, conical. Will I be able to cut my seat to the correct valve Dia AND set the correct spring height with this kit? Has anybody used one of these Indian kits before?

Thanks as always, looking forward to building these back up!

[JBinNC]

On these aluminum heads, normally the guide size will be increased 1 or 2 thou when replacing, for a good tight press fit in the casting. Those KB iron guides you picked seem to be very good; I use them frequently. Your pick of the .377 reamer is right on the money IF you are using the KB valves. (Each mfg. uses slightly different stem sizes.) With the black nitrided valves you can run much tighter clearance than the old manuals list. .0015 intake and .0020 exhaust is about the low limit on clearance and will give long life.

When I did my pan heads many decades ago, after a "motorcycle mechanic" essentially charged me money for doing next to nothing to them, I found and replaced the guides myself and took the heads to an automotive machine shop of good repute. The head guy there sized the guides and did a beautiful job on the seats. Those heads ran for over a decade of hard use.

Jim

[Ratty78]

On these aluminum heads, normally the guide size will be increased 1 or 2 thou when replacing, for a good tight press fit in the casting. Those KB iron guides you picked seem to be very good; I use them frequently. Your pick of the .377 reamer is right on the money IF you are using the KB valves. (Each mfg. uses slightly different stem sizes.) With the black nitrided valves you can run much tighter clearance than the old manuals list. .0015 intake and .0020 exhaust is about the low limit on clearance and will give long life.

When I did my pan heads many decades ago, after a "motorcycle mechanic" essentially charged me money for doing next to nothing to them, I found and replaced the guides myself and took the heads to an automotive machine shop of good repute. The head guy there sized the guides and did a beautiful job on the seats. Those heads ran for over a decade of hard use.

Jim

Really great info here, thanks Jim!

I was planning to size based on the manuals recommendation of .002-.004 intake and .004-.006 exhaust. Sounds like I can go tighter, and now I understand why the guides I took out were only .0015-.002, I just thought they did it wrong.

I was concerned when I saw the price of the KB guides, they are about 1/3 what everyone else charges. Pleasantly surprised! The finish on them is beautiful, and the OD is true to the OS. I also like that the spring side is spec'd for seals, no trimming required, and the port side is tapered at the tip, which should yield a bit more flow. The ID is undersized (the brand new valves will not fit into the guide) but that is neither here nor there, since they will need to be reamed after installation anyways, I suspect that the undersized ID minimizes distortion during installation making the bore more parallel for reaming and honing. Or maybe they are just cut for a naked stem, not accounting for the nitride build-up. Regardless, I am happy with all the parts, and I did get KB valves. I think that maybe everything, including the reamer and ball hone are KB products. I also ordered a seal installer tool that looks nice, although I don't know that it's any better than just using a deep 7/16 x 1/4 drive socket, but hey no reason not to have the right tool, especially considering I had to order a lifetime supply of valve stem seals!

[farmall]

Neway are absurdly overpriced for simple tools compared to (for example) much more advanced machine shop insert milling cutters.

If a tool cuts to spec it's fine. If not, then it isn't. Get some thick Sharpies instead of blue dye if ya don't already know that machinist trick. They lay on thin and their ink doesn't chip.

[Ratty78]

Neway are absurdly overpriced for simple tools compared to (for example) much more advanced machine shop insert milling cutters.

If a tool cuts to spec it's fine. If not, then it isn't. Get some thick Sharpies instead of blue dye if ya don't already know that machinist trick. They lay on thin and their ink doesn't chip.

Totally agree. I will say that they appear to be very high quality tools designed for a lifetime of service, but considering I will most likely only use them a handful of times, I just can't justify that cost. Especially considering I will most likely not need all the extras. The Neway kit comes with at least 9 different guide rods so you can service all the potential oversizes of 3 different common HD valve stems. So that kit is basically $300 worth of cutters and $800 worth of precision ground steel bars. Useful in a service shop where you might need to grind seats without replacing guides.

Thanks for the sharpie tip, that's a really smart idea!

Regarding the Ebay cutters, I had been concerned about the size; 2.125/1.95 vs my VALVES @ 1.94/1.75 respectively - then it occurred to me that the cutters are spec'd based on the size of the SEAT, and everything starts to make sense. These particular cutters have 30/45/60 angles, and also a 90 angle. Didn't understand what that was for until the above revelation, then it clicked. I THINK I could use these to cut the old seats out if I needed to completely replace them. I don't think I'll need to do that, but if the tools hold up it's good to know I have the option. It also comes with its own reamers sized to the guide rods, so I'll do a pass with those to cut the seats before I do a final sizing and finish for the valve stems.

[Ratty78]

Well shit

Things were going pretty well, then I noticed there are some fractures in both guide bosses of one head. The last time I had the heads off I noticed that they were not the same. Different markings in different places. One seems to be a '75 and the other might be a 77, but the way the castings appear one or the other might be a re-pop. The one marked 75 seems kinda shitty, there is a bit casting flaw on the ceiling where it turns down to the exhaust valve and the flow paths around the intake guide are not equal and poorly defined, the seats have large shelfs where they overlap the castings, plus the guide bosses are very thick (more on this later), the head marked 77 is a better head from a performance standpoint - the flow paths are all smoothly transitioned, seats aren't blended but they fit closely, and the guide bosses are very thin on the leading edges of both ports, almost like they've been ported, except the sand cast surface is still present. This is where the problem is. The intake guide boss has one fine crack that I only noticed when I inspected it after seeing the exhaust boss. The exhaust boss has 3 distinct cracks wher the metal is barely more than a flake. The cracks have rounded edges which makes me think they've been there for a while. That portion of the boss was also ovalled slightly, so naturally I tried to tap it down against the newly installed guide, which promptly cracked it further. These cracks are also spreading at the opening, presumably from the ovaling I mentioned before. I would estimate the cracks to only be about 1/32-3/64 into the leading edge of the guide boss that is only about 1/32 wall thickness (the other head is about 1-16-3/32 in this area).

Blah blah blah

So options:

Obviously we could go back to the option of replacing the heads. This is expensive and I really would prefer not to have to go this direction especially since I just bought all the shit to rebuild these ones.

Next option, weld up the cracks and re-bore the bosses. I don't love this idea, even though it would take little more than a couple tacks, it's about a 50/50 chance that the aluminum simply fuses back together, or instantly collapses into the bore as soon as the arc is struck.

Last option is the simplest - simply porting away the affected portion. This has a couple advantages. Obviously simplicity and cost are looking pretty good here, and going back to the flaws in the other head, there is good reason to do this otherwise. I also noticed that the tapered section of the KB guides (where the guide extends into the port) is too long, extending a little ways into the guide boss, thus leaving the outermost edge of the boss unsupported, which happens to be where the cracks are. Obviously the issue here is changing the ports, which could be done minimally, and is maybe needed on the other head, and maybe should be done anyways to accommodate the KB guides.

And then there's the ever-appealing final option of just finishing the heads as is and running this old bitch to the moon.

I'm liking option 3 and 4 the best. Any input would be much appreciated.

[JBinNC]

Cracks in the guide bosses in the ports are fairly common, and usually it's because some well-meaning soul thinned out the boss while "porting." Or, an oversize guide that was too big was driven into the hole. If the cracks are shallow you can ignore them. But you really need to have the guides out so you can see how deep the cracks go. If the head can remain oil tight, it will run just fine.

All this stuff is old now, way past its service life, and a testament to the original designers that it has lasted this long. And of course that is why there are any number of replacement heads on the market.

Jim

[Ratty78]

So let's say the crack hasn't migrated into the actual bore and that it will still hold oil effectively. Would you recommend grinding the cracked portion away to prevent further migration? Or literally just ignore it?