millennium cylinders

bodine · Post by **bodine** » Sun Jan 02, 2005 2:19 am

Hi gang. Any body have some info on bad exsaust guides on the millennium cylinders? I have a 52 b modle with 330 on a major and the # 5 cyl is smoked. Cant understand how in such a small amount of time. Thanks...........

Joe Moilanen · Post by **Joe Moilanen** » Tue Jan 04, 2005 7:25 am

I've had 3 exhaust guides go bad in less than 200 hrs with my Millenniums.

Joe
4518C

zero.one.victor · Post by **zero.one.victor** » Tue Jan 04, 2005 6:40 pm

Just went thru my 4th annual SMOH with ECI cylinders-- all were 76-78 over 80, after 650 hours or so. I'm satisfied, & would recomment them over Mileniums from what I've heard about both brands.
A friend who usually (

) knows what he's talking about told me that ECI uses different material for their valve guides than Superior or TCM. Joe, maybe you could check into that, & install ECI guides next time IF it's true.

Eric

N2218B · Post by **N2218B** » Tue Jan 04, 2005 8:27 pm

I have a little over 650 hours on my Milleniums. Compressions at annual a couple of weeks ago were all at or above 75/80. Is there a way to figure out the manufacturing date? I would be curious to see if the bad ones were in a certain date range.
Len

blueldr · Post by **blueldr** » Wed Jan 05, 2005 5:02 am

I had excellent service from a set of Millenium cylinders for thirteen hundred hours. I sold that engine to a club member back east and i believe his service was satisfactory too. I wouldnt hesitate a minute in buying them again.

Joe Moilanen · Post by **Joe Moilanen** » Wed Jan 05, 2005 9:03 am

Hi Len, your spinner is still going around in circles. Eric, I did have an ECI guide put in on the last one. Hopefully all will be well for awhile.

Joe

bodine · Post by **bodine** » Wed Jan 05, 2005 9:48 pm

I did some checking around and got about all the same response. The guy at sup. said it all has to do with the way the rocker arm is ground and how it pushes on the valve. if its not rite it will wear the guide out. I looked at it and you can see a little wear off to the side? We will see what the cyl guy has to say about it. Thanks for the feedback anyhow.

Post by **GAHorn** » Thu Jan 06, 2005 3:18 am

"...wear off to one side..." is intentional if you're talking about the rocker arm face against the valve-stem. This deliberately imparts a rotation to the valve to reduce seat wear.

zero.one.victor · Post by **zero.one.victor** » Thu Jan 06, 2005 4:45 pm

From what I've seen & heard over the years, it seems like the (smaller) Continentals are kinda prone to valve guide problems. Some people blame the guide material. I've always had the idea that it was a matter of valve-train geometry-- the way the rocker-arm bone connects to the valve bone.
This last remark about the way the rocker-arm face is ground at an angle is interesting. It may be to impart valve rotation, but it may also apply some side thrust on the valve stem causing the guide to wear -- eventually causing a problem due to the valve flopping around enough that the it no longer fits the seat properly.
What's the fix? A flat surface on the face of the rocker arm? This would eliminate the valve-rotating feature. Or maybe "roller rockers"?

Eric

Post by **GAHorn** » Thu Jan 06, 2005 6:05 pm

The off-set isn't the major wear causative factor. The way the rocker slides across the valve-stem pulls the stem toward the rocker shaft. This imparts a sideways motion to the valve within the guide and supposedly causes the guide to wear in an oblong manner, allowing for eventual valve-seat wear at opposite sides of the seat. (The rotation evens out that wear...or at least that's the intent.)
Rocker faces are "arc'ed" to allow a better geometry to reduce that wear. Rocker rollers are an excellent engineering idea...except...for the fact that it also adds an inordinate amount of complexity to the system. All those rollers add sloppiness to the valve-train and less accuracy to the valve opening/timing. Additionally, they add much more risk of failure and small parts-loss into the engine. The most poplular rocker-roller system in the industry suffered an AD note requiring it's complete removal as the result of that complexity.
All ist relatiff - K.I.S.S. principle, I guess.

bodine · Post by **bodine** » Thu Jan 06, 2005 11:01 pm

I just sent the cyl. out for repair should be done in a couple of weeks. Ill make a new post when i get it back and see what his 2 cents was.

Joe Moilanen · Post by **Joe Moilanen** » Fri Jan 07, 2005 4:14 am

gahorn wrote:"...wear off to one side..." is intentional if you're talking about the rocker arm face against the valve-stem. This deliberately imparts a rotation to the valve to reduce seat wear.

I've heard of cam lobes ground at an angle to cause lifters to rotate, but rocker faces?? It's seams that it would take a lot of friction against a valve stem (not much leverage this close to the center of rotation axis) to rotate a valve against the friction of the valve spring, keepers, etc.. I was always under the impression that whenever new valves were installed the rocker feet are checked for absolute flat mating to the valve stem with a thin piece of material flattened beetween them to insure "squareness". ???

Joe Moilanen
4518C

Post by **GAHorn** » Fri Jan 07, 2005 5:57 am

I don't believe I've ever heard of cam lobes ground "at an angle" to rotate lifters. They are usually ground true, but are offset against the lifter (which of course, would do nothing to rotate the valve.)
In large bore Continentals rotators are common, but in the C145/O300 it's merely the offset rocker face that is supposed to do it (and you're correct,....not very much.)

auxtank · Post by **auxtank** » Fri Jan 07, 2005 7:21 am

I know this discussion began on the topic of Millennium cylinders. But valve rotation seems to be germane, so I will mention that ECI's new "Titan" 0200-0300 cylinder assemblies now have a valve rotator feature just like the big boys. Check it out at:

http://www.eci2fly.com/Tech_Ref/titan/2 ... atures.htm

They also mention "ballizing" the exhaust valve guide and other claimed improvments to help eliminate exhaust valve sticking.

A couple of months ago I replaced two high-time cylinders with very low compression (one had a broken top ring) with the new Titans. So far so good (only about 10 hours). But time will tell.

Gordon Sandy
1948 Ragwing
Juneau, Alaska

N1478D · Post by **N1478D** » Fri Jan 07, 2005 2:58 pm

That's a good link! Gordon, were those bad boys pretty expensive?