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Re: KR Heads

PostPosted: Wed Aug 09, 2017 10:26 pm
by wz507
This is a continuation of the -69R cylinder head images.

-69R combustion chamber castings
LR -69R combustion chamber castings.jpg
LR -69R combustion chamber castings.jpg (92.19 KiB) Viewed 14639 times


Comparison of -52R combustion chamber for flat top piston (R) and -69R combustion chamber for domed piston (L)
LR comparison of -52R and -69 R combustion chamber casting.jpg
LR comparison of -52R and -69 R combustion chamber casting.jpg (53.76 KiB) Viewed 14639 times


52R (on left) and -69R (on right) combustion chambers adhered to glass plate. Note at top of picture the -69R combustion chamber (on right) has a more fully developed radius in the circumferential clearance between valve and head vs the flatter less developed radius on the -52R head.
LR arc of circumferential valve relief in -69R head.jpg
LR arc of circumferential valve relief in -69R head.jpg (29.05 KiB) Viewed 14639 times

Re: KR Heads

PostPosted: Thu Aug 10, 2017 1:12 am
by Simon
Wow - what a find! I note there is a domed piston on ebay at the moment, overpriced though...

I am enjoying this thread immensely!

Re: KR Heads

PostPosted: Sun Feb 25, 2018 3:34 pm
by MIKE100M
Simon wrote:Wow - what a find! I note there is a domed piston on ebay at the moment, overpriced though...

I am enjoying this thread immensely!

I had Arias Pistons make me a set of #8 dome pistons from the factory drawings for the Andres short rod motor I built . They have also done flattops for me. I like using modern pistons for the choice of slipper skirt and narrower low tension rings.

Re: KR Heads

PostPosted: Sun Feb 25, 2018 4:11 pm
by EKHKHK56
Mike, did you get one from Jim Carpenter? My K R heads are being mapped. They have only faint R stamps. And X Marks the spot where other heads say 7 etc. Erik

Re: KR Heads

PostPosted: Thu May 31, 2018 9:41 am
by starcain
I picked up a couple of KR heads at Oley this year. Thought I would post a few pictures of them to see if anyone had any thoughts. First of all I am no expert on KR heads. I find them interesting but often have difficulty wrapping my brain around what you guys are talking about when it comes to design and flow characteristics. The one head is a 60R and is numbered 6. Not knowing any better I might think of this head as a typical design? The other seems to me to be quit unusual. It is marked X 1. There is no casting number on the top and the bottom has been milled so no casting number on the bottom either. Since there is no casting number on the top I am going to guess it may be a 52R head but really have no clue. It doesn't look anything like the other 52R head that I have. The other 52R head I have has a different bronze or brass spark plug insert. In the picture with the four heads you can see how different the insert looks compared to the others. Anyone know if all 52R heads had that type of spark plug insert? To me, the weirdest thing about this head is that the piston and exhaust shelf are on the same plane. Right where they meet in the middle they are the same but towards the outside in the exhaust area it tappers down a little bit. I don't think I have ever seen that on any K head "R" or not. The # 6 head is completely different then the other two #6 heads I have that have the radiused piston shelf pictured earlier in this thread. I don't understand a lot of it but it's fun to look.

Re: KR Heads

PostPosted: Thu May 31, 2018 9:43 am
by starcain
More Pics

Re: KR Heads

PostPosted: Thu May 31, 2018 10:01 am
by starcain
While I was checking out all the KR heads I have, I happened to notice that the two heads that are radiused and are marked #6 have these unusual outcroppings (for lack of a better term) coming out of the inside wall. It almost looks like wire coming out of a hole???? Both heads have this peculiar feature. I know I have never seen this before on any K head that I have ever looked at. Anyone have any idea what the heck that is and why it would be like that. Something in the sand cast technique?

Re: KR Heads

PostPosted: Thu May 31, 2018 4:27 pm
by thefrenchowl
Starcain,

All genuine KR heads are cast with their casting xxxxx-xxR number cast between the fins on the valve side...

If there is no R casting number, they are NOT KR heads, just messed up K/KH heads by poor racers...

KR heads are not machined at all apart from spotface reliefs on top of valves like on proper KHK heads.

The one you note as #6 with a straight shelf angle (bottom right on photo 4) is the one that is the factory cast profile, similar to known factory head drawings.

All the others heads in your photos look like variations done by individuals.

Patrick

Re: KR Heads

PostPosted: Thu May 31, 2018 9:28 pm
by wz507
thefrenchowl wrote:Starcain,
All genuine KR heads are cast with their casting xxxxx-xxR number cast between the fins on the valve side...
Patrick

The above is true with the exception of the -52R heads, where there were different versions of these heads....but all had the brass sparkplug insert.

Early ones had no casting number on the top of the head between the fins, but rather on the underside of the head as shown in the 2 images below.
CC of -52R from valve side.jpg
CC of -52R from valve side.jpg (122.09 KiB) Viewed 13991 times
LR 52R bottom label.jpg
LR 52R bottom label.jpg (120.09 KiB) Viewed 13990 times

Later versions of the -52R heads had casting numbers on top as described by Patrick. In the case shown below, this -52R head had both an R casting number on the top side and the "circle E" casting number on the bottom side. As would be common with the late "circle E" castings these particular heads had the short window with the fins fully encircling the spark plug hole, as I believe did all the subsequent KR heads.
LR late style 52R Head.jpg
LR late style 52R Head.jpg (70.5 KiB) Viewed 13991 times

Re: KR Heads

PostPosted: Sun Jun 10, 2018 11:40 am
by wz507
Have a bit more to add about the last -52R image in the above post. I believe we’ve unearthed a distant relative to one of the heads Starcain posted above with the stamping “X1”. From the stamping on this head "XX2", one might surmise that it is the 2nd cousin twice removed. As noted in the previous post, this head started life as a later style -52R head (casting number on top, “circle E” casting number on the bottom, short window and continuous fins encircling the sparkplug hole) and appears to this observer to be essentially unmolested – shelf in correct locale, gasket surface not milled to death, etc. The “X” nomenclature just caught my eye and thought it worth mentioning.
LR XX2 Stamping.jpg
LR XX2 Stamping.jpg (71.28 KiB) Viewed 13915 times

LR XX2 combustion chamber.jpg
LR XX2 combustion chamber.jpg (49.94 KiB) Viewed 13915 times

PS – for those that aren’t genealogists or statisticians, a 2nd cousin twice removed shares only a minute amount of the bloodline, thus X1 and XX2 may not share many common genes.