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Sporty Pump Conversion Longetivity Update


Posts: 1676
Location: Interlaken, NY USA

Just pulled the top end off my 44U Bobber big twin last week, one of my valve stem oil seals had worked loose, so I took a look inside. After 8 K miles, cylinders show no visible wear, pistons look great as well. I had just returned from the annual trek to Rhinebeck, then Worchester Mass to see my son. A 700 mile weekend, no noticeable oil consumption via the dip stick. The return trip was via the turnpike/thruway, kept it down to 63-65, no use in pushing too hard :-)
I'm willing to say at this point that adding extra oil to the bottom of the pistons via the oilers I've installed definitely seems to prolong engine life.
I also noticed that the "hot spot" on the edge of the piston near the intake valve area has gone away since I've stroked it and thereby created about .030" popup into the cylinder head. I, of course, milled the head to accommodate.
I'm guessing the nature of the gas burn has been changed as a result, moving or eliminating that hot spot.
Just thought I'd pass on what I consider good news to those who have considered or are undertaking these modifications.
Sorry I didn't have my mics last weekend to give specific data, loaned them out to a friend, but eyeball inspection looks good, and the motor definitely does not have any piston slap
DD


Posts: 976
Location: Markt Einersheim, Germany

Dick....err.......Herr Dr

Thanks for the update.

George

jib

Posts: 575
Location: devon,england
good shout dr dick. :)
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years


Posts: 641
Location: Wisconsin, USA
8,000 miles and no visible wear in the cylinders! Sounds like you have it figured out Dick. What are you using for rings?


Posts: 976
Location: Markt Einersheim, Germany

Herr Dr...

I forgot, are your oilers pointed at the bottom of the pistons,,,,,,,,,, OR, at the walls of the cylinders?

Getting old and forgetful sucks

George


Posts: 1676
Location: Interlaken, NY USA

Know the feeling George, CRS. Anyway, they're pointed a the bottom of the pistons. Also, I changed from full flow to the crank back to one shot per rev system, to up the pressure to the jets last year. Pressure would drop below 15 psi when the oil was hot. Bench testing showed that it took 20 psi to create a jet of oil that would reach the bottom of the pistons. However, I suspect bench testing doesn't accurately reflect what's going on in the engine. Windage, piston travel creating suction drawing oil up onto the piston, etc.
Just as background information, I, and many others had only been getting only about 19K miles before needing a rebore with these engines in the past. I was going to wait until I had done 10ki miles, but the results to date were so encouraging, that I just couldn't wait. :lol:
DD


Posts: 1676
Location: Interlaken, NY USA

I missed the question earlier, I'm using a 3 piece oil ring and chrome/cast compression rings.
DD


Posts: 641
Location: Wisconsin, USA
Thanks Dick. I have a theory that a lot of the premature wear on the cylinders was caused by the crappy high tension rings that came with most of the aftermarket piston sets. The idea to use a bathroom scale to check ring tension came from our friend Tom C. on this forum.


Posts: 1676
Location: Interlaken, NY USA

Glad you brought up the scale, I don't remember seeing that post. And I double checked the rings, turns out I was wrong. they are the Hastings replacement ringset offered through Vtwin, and are 2 cast compression and the 3 piece vented oil. I dug out the box to double check (never throw away anything!)
DD


Posts: 83
Hey Dr Dick Frankenstein,
Good to know your UL sportypump is running great!!! Because I'm doing the same to my engine :)
I already changed a pump so I can use it as a distribution unit, as per your instructions.
Also bought a good 72 sporty pump and a screw in set of valve covers to keep it just like your project instructions.
I was wondering if there is any harm in using rubber in the feed lines (sporty pump to distribution pump and distribution pump to oilers) instead of the metal tubes you used. Do you think it would drop the pressure too much?


Posts: 1676
Location: Interlaken, NY USA

I don't think there will be a problem with using rubber in the line, I've used it in the past and didn't notice any difference in pressure readings at the pump. I'm thinking that 5/16" line would be a safe bet to avoid restriction.
Glad to hear you're following up on my conversion ideas, I think you'll be happy with the results!
DD


Posts: 543
Location: Wa, USA
I did not test the my pump with rubber lines on the feed pump, but I did test with a flexible nylon line to the top oilers and found that the pressure drop was enough to cause the oilers to not work. I had good results with copper line, but the line had to be 1/4 inch line to have enough volume.


Posts: 1676
Location: Interlaken, NY USA

Thanks for the input Woody, good to know. I've never made tests of the different materials and pressure loss. Glad there are more than one of us working on this,
DD


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