GN1 exhaust valve guides

[REEDOG]

My car has been producing a little smoke lately. I pulled the motor and removed the heads since I suspected it was coming from the exhaust guides. Sure enough, lots of burnt oil in the guide area. I didn't put seals on the exhaust valves in fear of melting the guides, a common GN1 issue, hoping the oil would help keep the guide lubricated. Should I put seals on them or do I have a worn guide problem? Are those of you with GN1s using seals on the exhaust valves? Should I have the guides replaced since these are early production heads?

Yes, I'm sure the smoke is from the guides and not from the turbo.

 

[Nick Micale]

Your questions are all very good ones. I would first call Champion to find out their experience with guides and what they recommend?

 

[The Radius Kid]

Ah,the Champion guide problem.
I ported,flowed and rebuilt a set of 2nd gen Champ aluminums not too long ago[they're sold].
What they came with on the valves was Teflon seals on the intakes and exhaust valves.
Now here's the trick,the exhaust seals had the spiral "neck" springs removed.
The idea was to lower some of the "wiping" action and let a little more oil onto the stems.
Now when I tore the heads down for work,I noticed that the exhaust stems had a little carbon/black oil on them.
These heads had ~150 miles on them and six passes at the strip[they looked it when I got them,nice and clean externally].
After cleaning,I checked the guide I.D.'s and they were all within spec,no problem.
What I did was to fit the exhaust stems with brown Viton stem seals.
They're a little more forgiving than Teflon and they do last.

 

[750H.P.V6]

Champion Sucks

REEDOG,

Champion uses cheap guides and they wear out prematurely. The first thing we do when we get their heads is replace all the exhaust guides. We had several sets of heads with 1500 miles or less showing a ton of wear.

When you disassemble your heads you will find excessive clearance on the exhaust guides probably .006"+. Go with a good quality silicon bronze guide and shorten it up by .150 -.200" where it extends into the exhaust port and you'll be good to go.

Neal

 

[REEDOG]

I don't think Tom's an honest guy. 2 years ago when I was having head cracking problems. He told me I was overstressing the heads with high boost and that I should send them to him for repair at my charge. He had never heard of a GN1 cracking. I'd rather not ask for his help.

In your guys opinion, should I need seals if I've got a proper clearanced quality guide? I'll check the guides and probably just replace both intake and exhaust.

Neal, why shorten the exhaust guide? Is it prone to becoming too hot with so much exposure? Also, what seals do you recommend?

 

[49-blues]

would the same problems be present with the champion irons?

 

[REEDOG]

No, Champion iron heads are trouble free. It's just the high dollar aluminums that suck.

 

[49-blues]

thanks

 

[750H.P.V6]

REEDOG,

Sorry for the slow response. I was tied up all weekend. The idea to shorten the guides up a bit actually comes from Bill Anderson (AKA: 8secV6). Basically guides normally taper at the forward end decreasing the wall thickness. This is the same part of the guide that sees the most heat, therfore by shortening the guide it eliminates the thin portion on the forward end and has less likelyhood of coming apart.

I hope this makes sense.

Neal

Also, I use Teflon seals on both the intake and exhaust.