Valve paste

[beavy69]

Hey all, gonna try some basic porting n polishing of the head on my 1.3L

Just wondered if its worth grinding in the valves as I have found an old tub of paste.

Should I use rough the fine, or just fine as they will not have been re cut just polished/lightly sandpapered acordingly(exhaust/inlet)?:confused:

Is it just a question of applying the paste, incerting the valve and spinning it round with a rubber stopper on the end of a drill?:D

[Stuart]

no its not a case of banging them on a drill lol.
you need to do it by hand ideally.

course paste first, then fine, was it all off with petrol/parafin.
Just look up on google for valve lapping procedure (you can use a drill on the stem etc but i personally wouldnt)

out of ingrest did you actually get any metal out of your ports or did you simply attack it with sandpaper cartidges? and did you do the right areas or go for the "ill make it bigger everywhere as that will make it faster?"

[Jon_nova1]

the points not to make the ports bigger, merely to make them smoother lol

[beavy69]

Hey Stuart,

I havn't started yet. I'll begin with the inlet manifold by matching the size of the two holes to my new (well very old and dusty at the mo) 32/34 carb as the peirburg holes are 25/30 or somthing.

Then i'm gonna link the holes together and round off the inner edge of the '8' shape I have created for better/more airflow. And then check for any casting burrs and do them. Like this guy has:(go down to the 1st picture)

http://www.migweb.co.uk/forums/showthread.php?s=&threadid=34317

My webber came with an old astra manifold, I think it's steel and mine aluminium but was just gonna use the one that looked the best flowing and the biggest bore:D WHAT WOULD YOU ADVISE?

With regard to the head, I don't even know what the inside looks like yet all I have seen is the general idea from pix of other heads in the research I have been doing.

First i'll de coke it and clean it with PETROL? Then rid it of any burrs/casting seams. Then match the inlet ports using a gasket and blend them down to the size of the rest of the port inside over a length of about 3/4cm

I'll then check that the exhaust mainifold holes are the same size or a bit larger than the exhaust ports, otherwise i'll match them too.

Before polishing the exaust areas and ensuring all inlet areas are slightly rough, I might have a go at the typical corners and edges such as the short side radius. But I certainly wont be making anything bigger as I don't have a flow bench and have never done it before. (the phrase 'don't even go there' spings to mind)

I'll be using a black and decker multitool (like a dremmel) on a spare head as I can't affort a die grinder.

ANYTHING ELSE YOU'D RECCOMEND? HOW DOGDY/WORTH IT IS NARROWING THE VALVE STEMS AND WHERE SHOULD YOU DO IT? HAVING NO LATHE THO WOULD PUTTING THEM IN A DRILL (PROTECTED FROM THE CHUCK OF COURSE) AND SANDPAPERING THEM BE IN ORDER?

I'm not goning to do it till Easter when I have time.

[beavy69]

woops just read again that you wouldn't use a drill for the stem. But wouldn't it make sure it's a bit more even? How do you do it?

[Stuart]

personally id buy wasited stem valves.... not worth modding std ones unless you ahve all the nessecary gear to do so. and the porting your likely to do wont show any real gains with wasited stems.
for porting guides check out past issues of PPC and also most/any books by david vizzard (leg-end)

[beavy69]

whats PPC? Can I fine previous issures online or is it and actual mag?

Do you mean its not worth the other stuff if I don't have waisted valves?

[Stuart]

Practical Performance Car. Good mag i think you can ge them online.

I mean wasited stem valves wont get you much more than the 2-3bhp your going to get from the port job. You could try to waste the valves yourself but its not wise unless youve got a kick ass lathe.

[Jon_nova1]

I think a port & polish is worth it, you don't get many performance gains for free ;)

[thirdeyeblindman]

dont even think about wasting the stems on a 2 piece valve

[beavy69]

Do you think I should get a 1.2 head to do or stick to a 1.3?

will my cam and case go on a 1.2 head?

[Stuart]

1.2 head is fine. cam etc will fit.

[beavy69]

Stu I know a 1.2 head is better compression but is there less room for bigger valves than 1.3? If i'm just doing some basic porting though which should I go for as I have a choice of both?

cheers bud,

7im.