04 November 2014

major parts deliveries

I'm still waiting on a major order to come in from Max BMW, namely bottom end spacers, bearings, etc., and I still need to get the crankshaft rebuilt, but I'm beginning to see signs of a complete engine after the parts delivery today.

+2 Timing gears, 30 degree - new style

Remember that $50 box of parts I got way back when? Well, a couple things I was able to salvage for this build was a new type oil pump gear wheel and crankshaft lower timing gear. The lower gear was kinda strange because it's a 0 and the correlating timing gear in the box was a -3 (these early BMW engines don't use timing chains, they use precision gears sized to the crankcase and ranging from -10 to +10). My case is a +2 so that was a no go, but I kept the lower gear as cases shrink over time and figured I may need it when I buy +2 gears and find that they fit too tightly. Now I have +2 gears, so we'll see what happens.

These gears are the new style, meaning 30-degree (so they work with the new-style oil pump wheel I kept), and they'll accept the new style breather plate (much improved from the pin-style) which also came with the box that keeps on giving. I got these from S.Meyer in Hillesheim, Germany and they were about 30% cheaper than what BMW was asking. I was a little concerned about the price being so cheap, but they look and feel OEM and seem to be very high quality. Now I can completely cross the cam-shaft parts off my list, and with everything else for the crank on order, that'll be complete as well. Once I get the parts in and the crankshaft rebuilt I'll finally have a complete bottom end.

Concerning the top-end, I'll admit that I was kinda stressing over things. I was able to get the cylinders no problem, even got em for a great price, but good heads are somewhat difficult to find. One of the big reasons is the most commonly found heads are ones from the early to mid-1960's. The issue is heads in the 60's were prone to bad metallurgy (due to environmental concerns, the alloy used in the casting was changed) causing, exhaust threads to melt away like butter and rocker posts to literally sink into the head. Duane Ausherman actually coined the term "butterheads" to describe them.

BMW Bulletin #244 dated 7 Apr 67 claims:
The material of the heads was previously changed to avoid the use of chloric gas required to clean the equipment that handled the former "hydronalium" alloy. 
Going on to say: "it has been found that the new alloy does fully equal the hitherto used alloy concerning its resistance to heat"

They also developed cracks in the combustion chamber and tended to launch their spark plug inserts. BMW's solution was Lange Kerz (long spark plug) or "LK" heads that used an entirely new alloy. My choice was essentially either find really early heads with the quality, pre-pollution laws, that don't crack or melt, or find LK heads. I wound up getting a great deal doing the former.

1952 R51/3 Heads + Rockers

I'm pretty stoked about these heads. You may be wondering why I'd get R51/3 heads for an early R60, but the R51/3, R67, R50, R60, R50/2, and R60/2 all shared the same heads and valve sizes (with varying metallurgy as mentioned previously). Note the 2 different valve springs (per valve) and the thick cooling fins that identify this as an early head. I know a rebuild of these will occur somewhere down the line, maybe even convert to rotating valves, but once my bottom end is together I'm going to bolt these right up and test the compression. If found to be within spec, they are staying on, at least until the next winter...

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