Post #4 - Engine: Heads

This is where - for some special readers - you'll likely glaze over & lose interest as I'm gonna dig into the engine details for the next few posts. Look for the first post after the next few where the words "Engine" or "Bike" aren't in the title - you're likely safe again to resume reading.
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The primary reason for a Pan revival was the engine. Since my dad's detuning work conducted in a chicken coop on his home-farm near Canby - the engine hadn't received any work besides basic maintenance and a lifter block & pushrod replacement. So I set off on the revival by digging into a part that I was fairly familiar with - the engine cylinder heads.

The heads were the first sign that this pan had been probed a few times as the heads weren't original 48's - but rather from a 55. Generally - after I popped off the heads, rockers, valve springs & valves - I took a closer look at the heads in search of cracks and anything that may warrant them unusable. I found a slight crack between the rear head's spark plug hole & the exhaust valve. According to my dad - he knew about that crack from back when he did the detuning & didn't find it to ever be a problem. Some of the fins had been broken off & the exhaust spigots were also really tapered & cracking away in spots. The gasket surface & head bolt bosses were all where they were supposed to be without any cracking or pulling out. The head bolt hole threads all felt and appeared to be fine along with all of the valve cover bolt hole threads - which my dad had Heli-coiled every one some time ago. The head gasket surfaces had some scratches but generally checked out without warpage. The only other negative finding was, for some reason, the rear cylinder's exhaust valve guide had been ground down at an angle... I think that was the work of the Dude. The heads still had the original, brass valve seats & the valves I pulled were relatively clean (not much carbon build-up indicative of oil burning because of loose valve stems or leaky stem seals).

I figured - based on the state of the heads and the cost for some new / reconditioned heads - I was better off working with what I had. Butch @ Wart Hog helped replace the exhaust spigots with some new aluminum. I worked with the original valve seats & ground them round again (I think only ~20% of each valve was touching at any one time before I ground - imagine the compression). I didn't replace the valve seats because I've heard of too many horror stories about the replaced seats falling out because a Dude didn't heat the head properly before setting the seat in - even if they actually knew what they were doing - it was risky business I wasn't about to partake in. Looks like I'll be carrying some lead additive for the gasoline instead. Some light hand reaming straightened the valve guides & some planing of the head gasket surface resulted in quite a solid set of heads to work with again. No port work was required - someone had already done a bit of light work in that area & I knew any more opening would only hurt port velocity & fuel atomization - so I left that alone (seriously - the head's ports aren't the problem - the obvious problem is the T-shaped intake manifold, 90 degree port bends = poor port utilization).

Now - back when I did some engine simulations - the result was telling me to work with a camshaft that had ~ 0.600" total valve lift & start that lift asap - so the best solution I found was S&S's 514. When I received this cam and compared it to the piece I pulled from the Pan - the S&S was huge. Significantly more lift w/ a bit more of a gradual slope leading to 100% open - as compared to the Pan's nearly square cam profile. I was a bit worried - but charged on anyway - which will later result in nothing but shit.

On the same order I got the S&S cam - I picked up some new valves (stock diameter Rowe's) & a stock replacement Crane Cams valve spring & retainer setup. First check was valve seat height on both the valve & valve seat - which resulted in me looking a whole lot closer at the original hardware. Apparently - the Pan's valves were HD's +5/32" exhaust valves on every port - obviously the original hardware wasn't gonna work. So I found some new Rowe black melonite (sp?) +5/32" valves & checked these against the seats & everything was good. Solid seating around the whole valve, mid seat on the valve seats & mid to lower on the valves. Valve stem fit was pretty good too - maybe just slightly loose - but better than the fit of the original valves.

After I had a good valve & seat - I checked installed height & valve stem to valve keeper clearances @ 100% lift & found about 0.100" interference (including valve stem seal height). I ground a bit of the valve stem & checked again - and as I continued to work the stems down - I got to a point where I wasn't comfortable removing more materials as nearly nothing was left for a good valve stem seal to grip to. Another measurement & I found the valve spring kit I was working with would result in coil binding before complete valve opening anyway - so fuck it - reality check complete - I call complete bullshit on S&S's book claiming good to mild midrange performance without affecting idle and only needing some valve stem clearancing to fit. I chucked the S&S cam back in the box & purchased an Andrew's B grind, some Sifton +0.060" valve retainers & modified some neoprene with spring retainer valve spring seals. A double check of the measurements & everything looked good.

The rocker & rocker blocks diametrically were ok. No significant grooving or wear to note of. The end play registered a bit much @ ~0.015" max, 0.013" min - so I did nothing but clean these up & install. Note that even the rocker blocks weren't original hardware. Three of the blocks appear to be the latest Harley rev for blocks with the oil hole drilled on the top-front; the fourth appeared to be a middle rev without that hole. The rocker block nuts felt ok - so I reused them too.

The intake valve oilers all cleaned up ok & had the check balls inside - so I reused these as well, until I effed up & let up on a valve spring installer without realizing the oiler was to be hit. As the steel on these oilers wer pretty brittle - that one broke. So now I am in the process of finding another.

The tins are a bit rough - but I'm not looking for visual perfection - so they'll get reused as well. I'm using Adam's head gaskets with impregnated silicone sealing stuff & Adam's cork valve cover gaskets.

One thing I haven't verified is if the valves will hit during rev's - once I have the engine installed in the bike and have a better way to rotate the whole assy - I'll let you know what I find.

Can't think of any other head related business - so that's it for the heads. They're assembled and already on the refreshed engine.