Ironhead valve seals?

[Len PA]

I will be doing a top end on my 71, in the process of looking for valves and guides I came across "valve seals".
https://www.ebay.com/itm/Harley-IRON...a/313323098700
not seeing any valve seals in my parts manual. Any thoughts on these?

[ryder rick]

They were not offered as original equipment on an Ironhead.

Some swear by them

Some swear at them

I say no need.....

[Tim The Grim]

I have some in a little sealed bag hanging on a peg board hook. That’s were they belong.

[Piemonte]

I was talking to a local mechanic just yesterday about valve stem seals, among other topics. He has been working on Ironheads for decades, including his own ‘74 XLCH. In a word, unnecessary. He will install them if a customer insists, but he has never seen the need for them. ‘Harley would have put them there if they were required’, he says. A little puff of smoke when started from cold is fine, perhaps indicating a slightly worn guide. Should then be clear after that, as the metal expands and correct tolerances come into play.

[brucstoudt]

one drawback with those are the tops of the guides have to be machined for them to fit on.machine time = higher labor cost.

[11B40]

"..... A little puff of smoke when started from cold is fine, perhaps indicating a slightly worn guide. Should then be clear after that, as the metal expands and correct tolerances come into play.[/QUOTE]

In pre-AMF engines worn valve guides come into play most when the engine is suddenly put under an engine braking situation. That is fairly high speed and suddenly close the throttle. The engine becomes an air compressor and it will suck oil past the guides into the combustion chamber. These engines are smokers when they are brand new. As I understand it, the oiling system is made to operate at a certain RPM where the scraper comes into play and cuts the oil off the flywheels to the oil gallery to be returned into the oil pump. At low RPMs the flywheels pick up oil from the crankcase but it is too slow to let it fly into the chamber behind the flywheels. It builds up and some smoke will result around town and in traffic jams. Oil flow to the valve area of the engine is as much for cooling as anything else. The timed oil pump is responsible for a lot of the oil moving from one place to another. As pistons move up just past BDC the pump is closed and a vacuum results, sucking oil down the drains onto the piston skirts. At TDC the pistons start down and the pump is closed making the cases pressurized to help blow the oil from the gallery to the pump area. It is just for a tiny bit of time but if you are not timed exactly right, the engine becomes an air compressor and will be a real slug. Since these engines are as much oil cooled as they are air cooled, I would be very reluctant to change anything related to the system. I would not put an oil filter or seals on the valves but that is just my opinion and I don't know enough to change my opinion.

[ryder rick]

A little smoke is OK,

Watch a radial airplane motor start up!

[11B40]

Amen to that. Movies of a FW 190D9 with all flags flying it is blowing smoke like crazy. Probably MW50 the water methanol injection kicking in making a 1800HP engine crank out 2100. The German synthetic fuel was 89 Octane US was 100-150. Running a 35L V12 on unleaded?
You want smoke? Try a J79 X 2 on a Phantom.

[ericfreeman]

Interesting tidbit: in my original 1977 Owner's Manual under the 'Operation' section it states that you should periodically snap the throttle shut while cruising at speed. This obviously sucks a little oil into the guides for extra lubrication. Considering my new 1977 back in the day used to seize valves until I opened the guide clearances I guess the factory knew something about their engine assembly. My 1978 Owner's Manual deleted that throttle mention.

Eric

[Serious Blac]

Used them on my 82 bike. No problems and reduced oil consumption. I'm happy with them.