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Twin cams

Moderators: Curt!, Pa

Post Fri Jan 26, 2007 11:02 pm

Posts: 646
Location: Detroit
I ran gauges and I didn't run gauges. Some leaked and some didn't. Some worked better than others and some didn't work at all. These days I'd rather pay attention to the road than a gauge. I have come around to the mindset that a permanently mounted gauge is just one more thing to worry about. Does the engine have a problem or is the gauge going south? Who cares. If the engine blows up fix it or get another one. An odd attitude I suppose but the more years I ride the less I care about when and how something is going to fry on me. Good parts and proper assembly work just fine and avoid the problem as long as possible.
New Knuckleheads? Thank, you, Jesus!!

Post Sat Jan 27, 2007 6:25 am
Pa Site Admin

Posts: 5807
Location: Ohio USA

I like the added features of gauges [mechanical type] [never trusted idiot types], if only for fore warning. But I have to agree with KL. After knowing a machine for any length of time, and after living any number of years with machines, a person becomes alert to any slight changes in the operation, sounds, temps. etc., to a machine. Call it a type of sixth sense if you like, but it is true none the less. I hear or feel a bearing problem, a change in valve sounds, ticking, tapping, loss of power, miss, fouling, vibration, handling, pull, you name it, you feel and hear even the slightest changes once you have grown and become a component of a machine. Pa

Post Sat Jan 27, 2007 9:06 am

Posts: 1675
Location: Interlaken, NY USA

Don't cruise the Twin cam forum much, but caught my eye today. I have to agree with Pa, but I've gone both ways on the gauge thing. Remember my British sports car that I put a fuel pressure gauge on, That gave you about 30 sec. warning that you were going to come to a stop! (couldn't trust the British fuel gauge)
Anyhow, Billy, what's the purpose of the "Hypereutectic Aluminum Pistons with Teflon"? The only time I've run in the word "eutectic" is in reference to a solder alloy which doesn't have a pasty state. It's either solid, or liquid. Something that brings up interesting mental images when applied to pistons. You know imagining them to suddenly reach the magic temperature and turning to liquid and running down the bores :lol:
Seriously, I'm presuming in pistons it must have some special expansion properties. But I'm interested in knowing more.
Dr. Dick

Post Sun Jan 28, 2007 8:41 am

Posts: 270
Location: Grand Marais,Minnesota USA
found one that'll work....oil pressure is pretty important, yeah I know when there's something not right with the 45 by the way it feels, but I'd like to know where the pressure is at with this new modern machine I know diddly's like 75% more powerful than my little 45 and quieter....

Post Sat Feb 10, 2007 9:16 am

"Hypereutectic Aluminum Pistons"
Hyper = beyond
Eutectic = highest amount of alloying material (silicone, in this case) that will dissolve under normal conditions.
The alloy is a solid super-saturated solution of silicone in aluminum.
HE is simply a method of hardening aluminum and reducing its coefficient of friction by adding more silicone (up to 18%) than is normally possible. It works, much stronger than normal cast alloy, but more brittle than a forging, more sensitive to knock damage, runs higher crown and ring temperatures and frequently needs less spark and more end gap. See the KB site for more info.

Post Sun Feb 11, 2007 11:36 pm

Posts: 1538
Dr. Dick-

"Hypereutectic Aluminum Pistons with Teflon"?

It's a direct quote out of my newest HD shop manual, of what HD is currently using. evo's & IIRC late shovels used piston coatings as well....FWIW.

In addition the twin cams have piston oilers, (not skirt oilers) but oilers that spray a healthy squirt of oil at the undersides of the piston crowns, that have benefits, ie. reducing piston crown heat, which could help w/detonation, & help lower engine temp a bit as the fuel systems are set up extremely LEAN for EPA regs.

Post Thu Feb 15, 2007 6:22 pm

Posts: 270
Location: Grand Marais,Minnesota USA
Billy, what's the word on pipes? if you change the original exhaust system to say...SE stage 1 or two will you get busted for EPA violations and end up with a $10,000 fine? if so why are all these other types of pipes available in the aftermarket....I'd like to go two into one with a muffler at the end,but I don't want to spend all that money and get trouble for it... :?

Post Thu Feb 15, 2007 7:36 pm
Pa Site Admin

Posts: 5807
Location: Ohio USA

Why can you go to prison for possesion of a switch blade knife, yet you can buy one without the spring installed and the uninstalled spring comes with it ? Answer.... MONEY... :wink: Pa

Post Thu Feb 15, 2007 11:20 pm

Posts: 1538

best for you to check locally, what may be done in 1 state, may not be elsewhere.

That's why I follow the law EXACTLY.. :roll: Honest

Post Fri Feb 16, 2007 7:38 am

Posts: 1675
Location: Interlaken, NY USA

Billy, How do they pipe the piston oilers? pipes squirting upward somewhere? seems like things like rods and flywheels would get in the way. I've seen plain bearing engines with oil passages in the rods to route oil to piston oilers, just want to know how HD is doing it and maybe I can adapt some how to the BTSV. Obviously they're running hot pistons also.
And of course, we already knew you always follow the law to the letter

Post Fri Feb 16, 2007 10:46 pm
Pa Site Admin

Posts: 5807
Location: Ohio USA


Post Fri Feb 16, 2007 10:52 pm

Posts: 1538
Dr Dick- these Large images are here only temporarily. + I left them large to show as much detail as possible. ..
So save em if you want to..
1st 2 pics show the Twin Cams 'cam chest' with No cams in it.
But 2nd pic shows where the piston jets are fed thru, right at the lifter bores..(as noted).

Oil pump (gerotor) is entirely enclosed in the chest as shown.

3rd pic is the cam support plate & it explains itself..oil galleys etc..

Next check the lower middle picture, that is of the piston jet oilers, & where the exit to spray the piston undersides. It's just inboard of the lifters & exiting in the piston bores. No plumbing at all, just internal passage ways drilled @ precise sizes for optimum operation.
Last edited by sleeper on Sat Feb 17, 2007 11:00 pm, edited 2 times in total.

Post Sat Feb 17, 2007 12:12 am

Posts: 1538

Post Sat Feb 17, 2007 8:08 am

Posts: 1675
Location: Interlaken, NY USA

Hey, Billy, Thanks, got it. Looks like there must be an orifice in the passageway then the jet of oil hits the scoop like deflector that gives it the direction upward towards the bottom of the piston. I was trying to visualize how there could be room below the skirts and above the flywheels to allow room for the deflector. Doesn't look like there is much room, but they managed it.
I think it's a great idea, also I see we filter the oil just BEFORE it circulates through the engine. I'm going to have that option myself now on the sporty conversion on the 80. my supply oil will leave the sporty pump via an external line and go to the input of the stock supply pump. I'm seriously thinking of plumbing the standard accessory cansiter oil filter in that line. The stock supply pump is just a distribution block at this point and doesn't pump.
I'm going to have to take a close look at the twin cam idea. Not sure How I'd plumb the feed in a fail safe way. Wouldn't want some piece of pipe floating around after a 7000rpm run has shaken it loose inside. :lol:
Anyhow, Thanks for the pics, much appreciated.
Dr. Dick

Post Sat Feb 17, 2007 10:50 am

Posts: 646
Location: Detroit
Billy, what is your opinion of swapping the timing chain for something along the lines of the S&S gear driven cam set up? The idea of chain stretch or breakage isn't appealing.
New Knuckleheads? Thank, you, Jesus!!

Post Sat Feb 17, 2007 11:15 pm

Posts: 1538
Dr Dick-

Yep that's how it works, rather simple really. But effective.

& Yes the oil is run thru the oil pump & to the oil filter First, then to the motor. That's a switch.. They used a 10 micron filter that lots of evo guys thought was 'tits' & later found out it was too restrictive. HD put out a TSB on this. Not for evos...
If you need any other close-ups, I may have em. Let me know.
& I agree you don't want anything working loose @ 7K :shock:


I think the S&S gear set is the only way to go. HD may have had to use chains for the noise police ?
This motor is a tc88 A (rubber-mount) , you should see the 2 additional long chains used in the tc88B (solid mount) it's crazy.. That's 4 chains !!!!
There are 2 nylon type chain tensioners, that I have seen @ 1000 miles during a particular cam change showing some heavy wear.. Not ideal imo..

Post Sun Feb 18, 2007 12:47 pm

Posts: 202
Location: Middle England UK
BREWSKI wrote:
Just picked up my '07 ULTRA Tuesday from RENO H-D,can anyone tell me why a sidecar takes 6 months to arrive,when the ULTRA and the sidecar were ordered the same day?. Still waiting on the sidecar,it's supposed to be here in March. BREWSKI

I suspect the bike just drops off the end of the line but the sidecar is made to order. :shock:

Post Mon Feb 19, 2007 6:15 am

Posts: 1675
Location: Interlaken, NY USA

Billy, Thanks for the info, I kinda doubt that the standard aftermarket replacements for the canister filter are "10 Micron", so I'm going to follow through on that.
I played around with the drill and some 3/16 brake line over the weekend. I've got a plan for piston oilers. When the J B Weld sets up I'll give it a test run. I'm thinking that it will be an even better oiling improvement than skirt oilers, cause after you're done cooling the pistons, at least some of that oil has got to hit the cylinder walls and do some good there also.
Also looked through my assortment of old used flathead pistons, (did I mention I never throw anything away?) over the weekend. Over half of them showed abrasion on the valve side of the piston above the top ring. Maybe the oil jet won't be the answer, but surely a step in the right direction.
Thanks again for the inspiration.
Dr Dick

Post Mon Feb 19, 2007 3:17 pm

Posts: 1538
Dr Dick-

Glad some ideas came from it... & I appreciate where your mind is taking your mods..
Thanks for some insight on those..Sounds encouraging..

Post Mon Mar 26, 2007 7:29 am

Posts: 7
Location: West Bend Wi
Dr. Dick,

I'm new to this so... well...
Your oil squirters are a great idea, its good to know theres still people who work outside the latest atermarket cataloge. I have a thought for you on constrution you can make an aimable tip out of a oil bushing and some jewlers bits, the bushings can be got from a fleet farm or the like and cut to fit in the tube than brazed into place this will give you the option to drill the orfice any size you want so you can fine tune the amount of flow. I have run into problems modifying oil systems in the past because I forgot that flow is more important than pressure and the pump can only flow so much oil at idle (put more to the head loose some at the crank), this is how we learn, this is why we test. anyway have fun man.



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