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'92 3.0 valve guides

Posted: Mon Jun 10, 2013 1:43 pm
by Bruce
I'm confused.
I've taken the heads off to replace leaking head-gaskets.
Now, I was expecting to find steel valve guides but they appear to be bronze/bronze coloured.
I also have an old 75 head and that's the same too.
I assumed, maybe wrongly, steel was the way to go.
Were early smoky 3.0 litre engines (and 2.5) fitted with steel guides or/and was there differences in valve material?

Re: '92 3.0 valve guides

Posted: Mon Jun 10, 2013 10:12 pm
by Mats
Steele guides? Never heard of it to be honest..?

Re: '92 3.0 valve guides

Posted: Mon Jun 10, 2013 11:33 pm
by Bruce
Early V6's had smokey engines due to guides, which I presumed was due to bronze guides.

Re: '92 3.0 valve guides

Posted: Mon Jun 10, 2013 11:37 pm
by 75evo
The 3.0s had the steel guides. But they are not good either. Both the bronze (which wear quickly) and the steel guides (apparently they shatter, according to my mechanic) should be replaced by the newer style manganese bronze guides.

BTW, I have stainless 3.0 valves (brand new never used) in case you are interested. Will sell for cheap.

Re: '92 3.0 valve guides

Posted: Tue Jun 11, 2013 12:57 am
by Bruce
Unless they are bronze manganese..... they are bronze coloured

Re: '92 3.0 valve guides

Posted: Fri Jan 10, 2014 7:14 am
by SimonB
How big a job is it to change them? My 2.5 has been smoking a bit on the over-run since about 2004. Must sort it out one of the days...

Re: '92 3.0 valve guides

Posted: Tue Jan 14, 2014 2:02 am
by Bruce
I didn't change them, just changed the valve seals, cleaned the valves up and lapped them in.
I would suggest you take the heads to a machine shop and at the same time have 1mm off them to give you a bump in power - I've taken 1.5m (standard v6) and 1.1mm (QV) and use 95 RON with no issues.

Re: '92 3.0 valve guides

Posted: Tue Jan 14, 2014 2:47 am
by SimonB
I had the head done in 2000 in Spain and they skimmed the head then, I don't know how much. Used to pink on 95 ron so I used to use 98 or 100 when it was available. In the UK, I am using Tesco or Shell's 99 fuel, which the car likes. I think I am going to live with the wisps of smoke for now, ever see a classic Lambo that didn't smoke a little through the valve guides?