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Valve Guides

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67Fastbackfan

New member
Two questions:

1. I've been looking at some heads lately that have been ported . I see some that have full valve guide stems in the bowl, some that have been tapered, or some that have been completely cut off so they're flush with the port.
What are the opinions of doing them different lengths. Obviously the more you cut off, the more air can flow in and out, but are there negative issues that come with this?

2. Bronze valve guides. If you have no rules to abide by, are they worth it?
 
I do not see how bronze guides would be of any advantage honestly. About your other question, i believe it is more of a preference to who is doing the porting as to whether they leave the guide in the port, taper it, or cut it flush with the port. NR Racing leaves theirs in the port on their ported heads, but others cut them flush, and some remove them. I dont know enough about the advantages of each to give advice on that, so ill leave it to others who are more experienced. Talk to Sneaks about this, pick his brain a little, you will learn a few things.
 
Keep in mind (or Note) that there are many factors that play into 'porting' cylinder heads and it is an 'art form' in doing things right! This class (Clone) was/is intended for the 'beginner' and that includes 'porting' what-to-be's also. There is an 'old-saying' in racing (of any sorts) and that says; "Winner's aren't For Sale!" That saying is still true 'today' with a slight change in the addition of; .....'Cheap', anyhow! Suggestion....stick with the guy's that 'know' what they are doing and know why and how it works! Case in-point....Valve Guides are 'called-that' for a reason. When they are cut back...they 'can' loose their 'Guidance'! One thing about 'Clone' is that it's a great place too 'live and learn', especially if somebody else pays for the education. JMO
 
My NR head had the cut flush with the port. It is a Honda head. I would rather not have them cut down. Seem to ware out faster.
 
seumus85 said:
My NR head had the cut flush with the port. It is a Honda head. I would rather not have them cut down. Seem to ware out faster.
Click to expand...
I'm Not saying it's a Bad thing too cut them! When 'one' Knows what they are doing, it is (mostly) a Good thing. What you will loose in service life can be beneficial too 'performance'. Also, I highly suspect 'NR' Knows what they are doing. Personally....If I had a Flow Bench, a Dyno and '30' less yrs under my belt, "I'd be da-man"....Hind-sight is 20-20!....Jst say'n
 
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