New valve prep

[BOOT]

New valves slap em in or what? Polish, radius, back-cut, stem finish? Interested in what others do with brand new performance type valves.

[mag2555]

Why did you need to replace the valves?

[Keith Morganstein]

New valves slap em in or what? Polish, radius, back-cut, stem finish? Interested in what others do with brand new performance type valves.

At minimum, I look at the stem finish. An easy way to polish the stem is to chuck the valve lightly in a cordless drill, then use crocus cloth (fine) to polish.

Don’t polish a black nitro finished valve...

[BOOT]

At minimum, I look at the stem finish. An easy way to polish the stem is to chuck the valve lightly in a cordless drill, then use crocus cloth (fine) to polish.

What bout maroon scotchbrite?

[groberts101]

At minimum, I look at the stem finish. An easy way to polish the stem is to chuck the valve lightly in a cordless drill, then use crocus cloth (fine) to polish.

What bout maroon scotchbrite?

I've tried most everything to fully polish entire valves and that stuff works great for paint, composites and softer non-ferrous but not abrasive enough to cut metal. I use 3,000 grit wet paper under the faucet while spinning in a drill. Then follow up with diamond cut 2.0 paint cutting compound. Shines the stems up like chrome.

[houser45]

I use maroon sctchbrite with solvent in the lathe at high speed if they are rough. If they are not too bad i use the ultra fine. Just make sure to measure them with a mic across the stem to make sure they dont have much taper in them.

[racear2865]

I chuck mine in a 3 jaw chuck and then put stem end in a concave center in tail stock. Then I use my crank polisher with jewelers rouge. Finish can be as desired.
reed

[pamotorman]

chrome stems I used 220 emery paper to put a cross hatch patterns on the stems to hold the oil. the engineers at TRW told me to do this

[Newold1]

Polishing off hard chrome and rough metal on valve stems WON"T correct worn valve guides or correct stems to a point of getting back to good valve stem to guide clearances. Measure the stems carefully especially after removing material measure the guide and subtract to see if you are going to far out on good valve stem to guide clearance. If the stems are too far under their proper OD and the guides are ovaled, tapered or opened to far from their proper ID then my NON MICKEY MOUSE way of correcting the issues is to LOOSE the valves and REPLACE the goddamn guides.

If you don't own a couple of quality measuring tools like a small mic or some go-no go hole gauges and you are going to disassemble and build or rebuild good engines then damn it buy some!

This site sometimes starts sounding like a dirt floor machine and engine rebuild shop!

Sorry, but we are talking "SPEED HOME OF RACING" and high performance and racing engines here! Not your grand dads old 53 6 cylinder Chevy farm pickup out in the barn!

Sorry, just my reasonable REALISTIC professional opinion.

[Dave Koehler]

Yup ^^^

[modok]

I feel it is good policy to reface OR check runout on all valve faces on any head I assemble.
If you do not, it is only a matter of time before you accidentally build an engine with a bent valve.
I have disassembled a dozen that you could see the valve was bent to start, and slowly wearing straighter. I've found op to .005 runout taking apart new heads that haven't run yet several times. Only once did it myself, but once was enough, you know? A lot of folks would just vac test, but that doesn't tell the full story.

[DJ58]

He is talking about NEW valves. i would hope no polishing is needed.

Dan
S.W. Mi

[houser45]

I am talking about polishing stems of used valves for use in new valve guides. Stainless or titanium valves. You are not always going to replace the valves on a freshen. Sometimes new guides sized to the used valves will be in order. Its not half assing it at all if you have the correct measuring equipment and know how to use it.

[BOOT]

New was what I orig wanted to know but I have some real low used(2hrs) that look pretty bad that I'm gonna attempt to clean up. I wouldn't slap new valves into worn out guides, I was asking if any prep for new valves should be done other than measuring of course. Of course I wouldn't expect to make the valve stem smaller and use the same guides or worn out guides. I also wouldn't bother until the stem was measured to be sure it wasn't tapered and then checked again after.

I assume the best course of action would be smooth stems and crosshatch on the guides but I'm sure some rough use had to resort to w/e kept it alive for the need.

A performance machine shop told me to use scotch brite to clean those 2hr used valve stems, they didn't specify on color but I have some red/maroon or w/e that is finer than household green. Now more detail is these valves are the exhaust side only, the intakes looked normal. After I cleaned one of the exhaust valves with scotch brite I noticed the crosshatch and wondered if some did this for oil retention, so I made my post and asked a few other people I know if any prep was done to new valves.

After reading some of the responses it gave me a few ideas. I decided to try what I had, 1000grit wet/dry(barely tried it on a spot), 1500-2000 crocus cloth, mothers mag & alum, mothers billet, mothers chrome, turtle wax chrome, meguirs swirl X. My results for the best finish so far after the scotch brite is mothers mag & alum, then turtle wax chrome. I orig stole some of those face cotton rounds for w/e from the bathroom LOL but then I rem a wheel polish tip I read long ago, finish with a rubber gloved finger. So I just took some of the sauce and used two gloved fingers up n down the stem. I use my drill press on lowest setting with the chuck only finger tight, I've cleaned some high mileage valve faces that way before. Compared to a brand new valve(after wiped off with brake clean), the polished valves look slightly very small pitted(no more crosshatch) but shine the same. I still would like to try some compound but my cheap drill press pulley came loose so I loctited it and took a break to see if anything else was suggested. So far I am happy with the finish and valve measures consistent along the stem with my caliper. Of course I'll have the shop i take the heads too for new guides check the valves and if they don't approve I'll use the new set.

Thanks for the suggestions!

edit: details added

[DJ58]

I use maroon sctchbrite with solvent in the lathe at high speed if they are rough. If they are not too bad i use the ultra fine. Just make sure to measure them with a mic across the stem to make sure they dont have much taper in them.

I agree


Dan