Valve Guide Seals

I pulled the head to replace a leaky headgasket a while ago and during the process decided to replace the valve guide seals. Once i pulled the head and had a look i found them to be teflon with a spring wrapped around the top and bottom. I pushed on a new seal for fit and with little up and down movement of the valve I could get the guide to pop off. At the time i was thinking there was no oil on the valve stem for a little lubrication and i was imagining how much movement there was compared to a fully open valve. So i popped them both on, slapped the head on and now she smokes. I can clearly see with the intake valve open and the plug out, the lip of the valve is wet, and oily. I imagine the seal is just floating around for the ride. I was so excited to get the damn thing running that i overlooked this minor thing, i should know better. Oh well an excuse to pull it off again, this time twice as fast and an excuse to buy a taylor headsteady. Retorques are a pita with the stock headsteady!

Now that i look at a parts diagram, i see a "CIRCLIP - VALVE GUIDE,850 ONLY" on the intake AND exhaust side (which i see no reason for.) Should this circlip positively locate the seal to the guide?

Excuse the ignorance ~Gavin

i should note new seals came from klempfs, assuming viton.

Another question, i just read a post from britbike and someone explained

It depends upon what valve/guide material you have. Ampco45 (phosphor bronze) wears well with seals, copper alloy does not, iron is alright but a little oil does not hurt. If you have the original soft stem valves, do not use seals, hard chrome or hardened steel will work with seals. There is no reason not to use seals on the exhaust as well. The pressure is both positive and negative. Pulling oil down the guide will coke the stem and cause it to stick and smoke.

Click to expand...

http://www.britbike.com/ubb/noncgi/ulti ... 09964.html

Any thoughts on this?

The circlips on 850 guides are used to locate them in the head. These guides are larger diameter and have no shoulder like 750 guides. You install them by pressing them in until the circlip seats at the top of the head. They have nothing to do with the valve seals.

So nothing other than the seal holds the seal in place?

Hmm well let me ask this, what requirements would there have been to run a teflon seal? A modification of the guide itself, or something new altogether? I just want seals that stay in place, but what to do!

There are seals fit to the intake guides only. These guides are machined with a groove for the lip of the seal to fit into. The exhaust guides are not machined for a seal.

You say you have teflon seals? I have not seen these, but in an article Alan Goldwater wrote, he tested different seals (teflon, nitrile, viton), he tested teflon seals from Perfect Circle and mentioned that the guide must be machined to fit. I am not sure what he meant by that.

Here's the article. http://nortonclub.com/docs/NortonValveSealTests.pdf

Also, I have seen sets of 4 850 guides sold on eBay without any machining for seals and sets of 4 from the same supplier with machining on all 4. I just assume this vendor doesn't realize that a set should have two with (intake) and two without (exhaust).

well if thats the case i should have left the damn things on. I read that article before and it was my reasoning towards replacing with the viton.

i wonder if anyone could shine some light on the modification required.

GavinJuice,
The guides in the picture are cas iron 750 guides, the top two are intakes and the bottom exhaust. You can see the groove that the stock seal lip snaps into.

Your 850 guides are thicker. If you are using non-factory guides, the configuration for the seal may be different. For instance, MAP guides have a series of ridges to help hold the seal on.