Valve Guide Material?

[VmazKen]

I know that the best guide material used to be 'Nickle- aluminium- bronze. But I've also been given 'cast Iron' guides to work with, (customer brought in to save$$. Valve guide knurling, and cast iron guides work OK, but only on 'shim, and bucket' valve trains' Rocker arms 'side load' too much.
I will never install knurled, or the (cheap) cast iron on 'rocker arm' motors besides, the cheapest valve guides also seem to have the valve bore, and guide O.D eccentricities.

[John Hasler]

An ideal application for Loctite.

[wlw-19958]

Hi There,

Some hot-rod engine builders will drill and tap a
small hole for a set screw that comes into valve
guide area so the set screw will bear against the
pressed in guide. Start from the valve spring seat
and angle the hole in towards the guide.

An oversized guide may be available (depending
on what your engine uses). Loctite® is another
possibility. Standard Loctite® will give up at
300°F but there is a high temp version that is
good up to 500°F.

Good Luck!
-Blue Chips-
Webb

[John Hasler]

An ideal application for Loctite.

Intake or exhaust?

[GlennW]

Knurling is nothing more than a poor repair.

If bronze is the chosen material use Ampco 18 or Beryllium Copper and fit them into the head properly. Let them set over night and then hone the ID to the proper size so you have a round, straight bore with a proper finish. Proper fit and finish is a contributing factor to getting life out of valves and valve guides.

The valve guides "other" job is to transfer heat from the valve stem back into the head, so knurling or the use of Loctite can impede that function due to improper surface contact.

YMMV

[warmstrong1955]

Aluminum bronze used to be the hot set up, but it's been a while since I built any high performance engines.
Manganese bronze guides were also available.

[John Hasler]

> The valve guides "other" job is to transfer heat from the valve stem back into the head,
> so knurling or the use of Loctite can impede that function due to improper surface contact.

That's why I asked if it is intake or exhaust.

[Weedy64]

I am replacing the valve guides in my sportbike, with c630 bronze from KibbleWhite. They are a .0015"' to .0025" press-fit into either AL. or CI head. The guides then need to be honed to size(clearance) in place with a suitable flex-hone (BRM), I bought a couple zz gage pins for honing targets for the I and E valves. c630 bronze doesn't ream very well, it grabs.

KW makes has an online form for custom valve guides if that is what you need, maybe others do as well. Good Luck.

[GlennW]

A dingle berry hone won't do it, as it will not straighten the bore after the guide has been installed.

You need a rigid Sunnen type hone and a bore gauge to be able to see that the bore is not tapered, hour glass shaped, barrel shaped, or bell mouthed.

[Harold_V]

I'm in agreement with Glenn. If you're not aware, the geometry of a rigid hone is such that the action of honing provides correction. As long as you stroke the part correctly, and it doesn't overwhelm the mandrel (by its weight) it will straighten a bore, and round it, even if it starts out incorrectly (assuming there's enough material left in the bore to correct the errors). A spring loaded hone can do none of those things. I would advise against the use of a spring loaded hone for pretty much everything aside from breaking glaze. Even then it would not be my first choice.

H

[VmazKen]

Yes. We only knurl guides in 'shim,and bucket motors', But on rocker arm engines it's a 'No-No', Especially Harley Davidson 'push rod twins'.

[armscor 1]

I used Phosphor Bronze to make valve guides for a Briggs 8 HP engine, failed miserably, flogged out in no time.