First of all, I have some pent up need for ironhead questions, I have a few, and I'll try not to clog things up. Great forum!

I have my heads on the bench, will soon deliver 'em to a machine ship for a valve grind. I see valve stem seals advertised for the 1000cc Ironhead (mine's an '80) but know that it did not leave the factory with 'em.

What's the forum wisdom concerning valve stem seals?

When I was in the Navy, they explained that if the Navy wanted you to have a wife, you'd have found one in your seabag.

Same principle here?

 

If you are installing new valve guides, grinding the seats and either new valves or reground what you have, I would vote for using the valve stem seals.
If you are not replacing the guides, then I would pass on the seals until the next time when you will need new guides.
That's my 2¢ worth anyway........... pg

 

I "have heard" that the seals are a bad idea on one side and a reasonably good but not necessary idea on the other. I do not recall whether the bad idea side is the intake or the exhaust.

A machine shop that worked on my heads a few years ago installed seals. They were not familiar with IronHead heads. There is apparently some machining that must be done to install the seals. They did not do that. The next guy to work on the heads said that the seals were just kind of hanging there so he tossed them.

So ensure that you know exactly what info the machine shop guys need to know.

I do not have the knowledge or experience to advise on this. Just sharing my limited experience.

 

from the info i gathered when i had my stuff machined....and i cant say 100% sure its accurate its justhe best info i have...
they did not use seals from the fact. i dunno why exactly some say it helped with cooling valves.i dunno. and like pinion said you need to have it machined out or i beleive i have seen valve ads stating that they were made for seals as opposed to factory ones.all that would jive with what iron mick said as well as his seals did not fit they were just put on.the machine shop i went to highly recomended i use them.as another imo more qualified machinist.i also think i read somewhere that not using them was ok but when you get a little wear it will then happen at an accelerated rate.again i dunno fer sure.hope this helps a little.

 

To the best of my knowledge [which is quite limited] the downside of not having seals is that you get little bits of oil leaking thru and making a dark spot on the tip of the spark plug. Not a significant event. But i could be all wrong about this. Someone who knows will straighten us all out, hopefully.

 

Thanks to each of you for your thoughts on the matter. While I've not yet visited the machine shop (on the valve stem guide issue) I don't expect to replace the guides as the bike had 14,000 on the clock, and does not need boring.

Think I'll muddle through w/o the seals.

 

I've gone with valve guide seals and without. When I used cast iron guides I went with seals. When I used AMPCO-45 (nickel-bronze) guides I went without. Odd as it may seem, I got 19-yrs of service with the nickel-bronze guides without seals....

The old-timers told me that the nickel-bronze guides dissipate heat faster and can be used at a closer tolerance than the cast guides.

To keep things simple, either cast or nickel-bronze will serve you fine for the street...It's all a matter of preference. Just make sure that whoever cuts your valve seats knows what they are doing!

 

Good point Mick! Thirty-plus years ago I had my heads done by an old-school drag racer who "knurled" only the exhaust guides..It was nothing more than a spiral fluting down the ID of the exhaust guides to allow a small amout of oil to transfer heat from the exhaust valve stem. The cut was no more than .002" deep....Not enough to allow oil to dump into the cumbustion chamber.

 

I just did guides on my '73 XL. I did them like I do my race engines, seal on the intake since it sucks, no seal on the exhaust, since it blows. My Sporty doesn't even hint at smoking.

 

Bought a new XLCH in "70", decided to bore and stroke it in "71",at less than 2,000 miles it had a bad exhaust guide in the front. It is no telling how long cast iron guides will last, that engine has another bad guide right now in less than 3,000 miles! If it were me, I would go with bronze guides. If the guides are fit good enough you won't need seals in my opinion.