Is there a way to preserve new valve guides?

H.G.P. · 04-28-2005, 09:50 AM

Is there a way to preserve new valve guides on a freshly new rebuild?

randywebb · 04-28-2005, 10:35 AM

I just keep mine in the wine cellar....

Can you post more about what you mean?

H.G.P. · 04-28-2005, 04:40 PM

Quote:

Originally posted by randywebb
I just keep mine in the wine cellar....

Can you post more about what you mean?

From what I've read, valve guides are one of the first to go, so I thought maybe how one runs, warms-up, or other factor(s) have any influence on their longevity.

island911 · 04-28-2005, 04:48 PM

Clean oil (coughsytheticcough)

and clean air.

bfegan · 04-28-2005, 04:49 PM

Not a dumb question. Running in a new engine (primarily seating the rings) means run it like you want it to perform from the getgo. Is or is not this the same for the top end?

patkeefe · 04-28-2005, 04:53 PM

Use leaded gas, preferably Sunoco 260

H.G.P. · 04-28-2005, 04:56 PM

Quote:

Originally posted by island911
Clean oil (coughsytheticcough) and clean air.

So does this mean changing the oil more frequently? I currently have zero smoke, including at deceleration. I'd like to keep it this way for as long as possible.

H.G.P. · 04-28-2005, 04:59 PM

Quote:

Originally posted by patkeefe
Use leaded gas, preferably Sunoco 260

Is this to prevent carbon build up on the valves, or heat? effect on the guides maybe?

patkeefe · 04-28-2005, 05:14 PM

Please forgive me, HGP. You're not going to find any Sunoco 260 leaded unless you use a "time machine" and go back to about 1969. The downside of the oil companies removal of lead, at the behest of the government, was that you lost the anti-knock (detonation) properties. Thus, you could no longer run 12:1 compression ratios in the everyday car. The secondary fallout is that lead was a real good lubricant for valve guides. Valve guides, IMHO, are the most difficult area to get lubrication to...they're in a tough spot. If you send to much oil down the guide to lube the valve stem, you will either burn it on the exhaust side, or suck it into the chamber on the intake side, and oil foul your plugs.

The manufacturers are pretty hip to alloying materials to minimize guide wear; they have had a thirty year learning curve. What material guides did you put in your heads?

Unless you know that someone put in really cheap guides, or reamed them too big, I wouldn't freak about it.

Pat

stlrj · 04-28-2005, 05:49 PM

Keep your cylinder head temperature below 400 degrees F.

Wil Ferch · 04-28-2005, 06:28 PM

First...don't use the German guides but use American Silicon Bronze...make sure they're sized, honed and installed correctly per factory workshop specs.

It's been said that intake valve guide wear *may* be occuring due to "too good" ot "too tight" Viton oil seals don't allow adequate stem lubrication. Maybe a different or "looser" fit on the stem seals?

Perhaps Steve Weiner can chime in....

Wil

randywebb · 04-28-2005, 06:52 PM

I don't have anything more ot add except to summarize the above:
- proper installation
- Mobil One oil; change it every year no matter what mileage, otherwise every 12k
- avoid cold starts
- warm up the engine right, no lugging ever
- keep an eye on the oil temperature

They should last on the order of 100k and that's enough I think.

snowman · 04-28-2005, 07:07 PM

Properly installed Silicon Bronze valve guides should outlast you. If they were properly honed and the proper cross hatch machined into them they will last a very very long time. The materials used in modern guides will outlast old ones indefinately, if properly honed. So all you can hope for is that your machinest did the right thing.

H.G.P. · 04-28-2005, 07:33 PM

OK, sounds like what I believed might have been a weak link, is really a strong one.

Thanks

randywebb · 04-28-2005, 08:20 PM

Yes - they are a weak link only in relation to the crank bearings, which often go 200-300,000 miles.

dd74 · 04-28-2005, 08:21 PM

Was synthetic oil reccommended by PGA for the 3.0 and 3.2 engines? I always thought it was sort of a toss up whether to use it or just regular dino oil?

Randy - "avoid cold starts." I'm not familiar with that. What do you mean?

The post about leaded gas lubricating valve guides is interesting. Would a splash or two of race gas perform the same lubrication?

wastintime · 04-28-2005, 08:23 PM

don't let the car idle for ridiculus periods of time on hot days... fastest way to kill your valve guides I know of

randywebb · 04-28-2005, 08:43 PM

A cold start means the engine is started cold, not warmed up. If you make repeated short trips - driving all over town shopping, etc. for different items, then the engine will cool each time you start it. Idling (see Andrew's post above) causes stress on the valve train in the 911 engine. A cold start is even worse - not only is the engine rpm low, but the fule mix is not optimal - with carbs, raw gas is pumped into the cylinder, washing the lubrication off the walls, and causing more friction and ring wear. prob. more valve wear too.

Repeated cold starts for multiple short trips also generates a lot more pollution than just doing all the errands in one trip.

So, cutting air pollution also cuts engine wear sometimes.

dd74 · 04-28-2005, 08:52 PM

Cool...thanks, Randy - no, I'm not a cold starter. How about my idea with the splash of race gas helping lubricate the valves? Oh, and synthetic oil? Is it a necessity?

randywebb · 04-28-2005, 08:56 PM

Synthetic can't be a necessity b/c 911s ran on 'dino' oil for decades and many of those engines lasted 200,000 or more miles. But synthetic is bound to be better - only if it leaks more with synthetic would I avoid it.

Not sure re adding race gas to lubricate. I guess it would depend on what additives are in it -- and if they've found anything besides lead that acts a lubricant....