Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties

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Post Wed Aug 18, 2010 5:32 am

Posts: 1642
Location: Interlaken, NY USA

That tallies with some readings I took recently after a 50 mi, 80F run. 167F oil in tank, 260 rear, 280 front head temps, didn't take engine readings.
I invariably get higher front head readings than rear., which somewhat surprises me. I was told years ago that the front cyl ran hotter because
it got less oil, which I believed. But with all the oil flying around in there now, that temperature differential still seems to be present. ???
Anyway, at 4K miles, the bores and cylinders still look good, with no ridge worn as yet. I didn't mike anything, wish I had now...

Post Wed Aug 18, 2010 7:14 am
Pa Site Admin

Posts: 5552
Location: Ohio USA

Sorry to have to interupt the topic but I had to remove F's picture because it was to large for the page and the reason for the horrific distortion. You are welcome to put it up again F if you can reduce the size of it considerably. Pa

Post Wed Aug 18, 2010 10:50 am

Posts: 216
Location: Georgia
Thanks for removing it. The one Chris put up is great.

Post Wed Aug 18, 2010 10:54 am

Posts: 216
Location: Georgia
All the information the vt guy gave me is on my last post.

If you are reading this, I think your joing the forum would be GREAT. You obviously have a wealth of information to add.

Post Mon Aug 30, 2010 5:51 am

Posts: 42
Location: Finland
More information on temperatures for comparison.

Yesterday I was driving around with my -46 UL here in Finland and made a visit to VT-Cycle.
Couple of miles before I phoned to take the thermometer ready and rode fast to his yard.

Here is results.
UL with mid comp ironheads, piston to head dist minimum,breather modified (slot widened).
Mild relieved around valves. Front baffles intact.
Otherwise original UL specs. Copper head casket. 59F day.

Oil tank: 140F
Oil pump: 140F
cam cover: 122F
Heads: 320F
cyl base: 230F
cyl top:320F

What I notice is higher head/cyl top temp and lower oiltank temp compared to VT-Cycle -38U chopper.
Concider that -38U is stroked with highed comp and hotter day made me think benefits of this oilpump.
I was happy with same temperatures between my front and rear cyls.

One original specs aluminium head -49 WL was also measured same 59F day.
Oil tank: 140F
oil pump:131F
cam cover:140F
cyl base:239F
cyl top: 338F

Amazingly same than my -46UL

Post Mon Aug 30, 2010 6:12 pm

Posts: 83
Hey Bobul, thanks for sharing your readings!
I agree, UL and WL indicating same temperature readings is a VERY surprising find! Not to mention the fact that it's an iron head UL versus an aluminum head WL.
If I were the owner of this particular WL I'd take a look at a few things - carburetor jetting/intake leaks/ignition timing.

Post Thu Jan 27, 2011 4:59 am

Posts: 575
Location: devon,england
just come across this article ,about engine temp using a termal imager. hope someone finds it interesting. ... n-a-32.htm

regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years


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