Now this a process that most people couldn't be stuffed doing, but some people like me are silly enough to embark on such an activity on something hardly anyone will see!
First of all I used an 80 grit sanding flap wheel wiht a die grinder (not at full speed) to smooth out the major casting marks in the gearbox ribs...
Next came the tape up and paint with high temp engine enamel - 3 coats. Now before we start the debate over heat retention with painted gearbox housings (like engine cases), I checked with the (reputable) gearbox mechanic who built the box before I painted it.
Although he noted that more heat retention will occur with a painted box (moreso with a gloss finish), he said that with a box that will be used for street (and not race) use, the paint on the case will not be a big issue. Racing is another kettle of fish all together though - a big no-no because of the extra high temps generated in those situations.
After the paint had sufficient drying time, I hit the ribs again with a 120 grit flap wheel to take off the paint and further smooth out the ribs (be careful not to take too much material off since the case is quite soft).
Next I used a sisal buffing wheel with appropriate compound (again in the die grinder but on slow speed as possible - trigger control is important otherwise the buffing wheel may explode! - they have a max rpm).
Following this I used a cotton (not sure exact material) polishing wheel with finer compound to really shine up the ribs.
Well almost it, I have all new stainless nuts etc but have to get a torque wrench before replacing them.
If you do this, the gearbox mechanic recommended replacing one at a time (ie. undo one, replace it with new nut and torque it up, then move on etc). Around 14ft lbs of torque was suggested (but please check this for yourself, I don't want to take responsibility for your nuts coming loose!). Also make sure the flat washers are replaced with high tensile (not stainless) washers.
Thanks guys, was going to clear coat the ribs but wasn't sure how the clear coat will hold up if it is not designed to be heat resistant. If my mate has a bit of POR15 clearcoat left after he does his wheels, I might pop a bit of that on and see how it goes.
Was going to get the wheels the other day Matt but I decided I want to bolt up all suspension up first and trial fit body to work out right offset (the replica turbo twists come in a +25, +32 and +52 offset [different suppliers] in a 7.5in rim). Touch wood will have them within the next few weeks though!
but I have just enquired at local wheel and tyre shops.
Not sure about exact completion date for the bug (trying to do house reno's at the same time!!) - fingers crossed before christmas (that is a safe estimate!).
I did a similar thing to a rotary engine years ago and in time I really regretted not just painting the whole thing because it took too much time and effort to maintain the look and consequently ended up very dull and let down the engine bay everytime I looked at it, everything else looked awesome with the pink and magenta and light and dark purple components and these once shiny but now dull grey rotor housings.
If you have the time and energy to maintain the polished/painted look then thats cool, but it takes dedication.
Looks good, I must admit.
there is a process available like reverse electroplating where the top few microns of metal are evicted and leave a mirror type finnish, I cant remember what its called but I think its something obscure like electro-polishing, that would look very cool too, if you were motivated enough.
Cheers Tony
I will be doing a similar excerise on a new gearbox for my Orange Smoothieee
No guessing what colour it will be.
Looks great in grey, I dont think a gearbox would be worried about heat retention as they were paint black in the VW factory... or at least most of the 1200 and 1500s were. they probally stopped painting the later ones to reduce costs
A few hours work can certainly make a big difference. I figure whilst it is out of the car and fully rebuilt, I may as well do it now, because once it is in I can't see myself pulling the engine and the box just to polish and paint it all!!
Forgot to mention that before you hit it with the sisal wheel I used some 400 then 800 grit sandpaper used with a sanding block (or just fingers) to really smooth out the sanding scratches left from the 120 grit flap wheel.
The sisal and cotton (material??) wheels are available in a kit including the correct buffing compounds from bunnings for around $30 in the tool section. I'm sure other places sell them as well though.
I used the Por Glisten PC clear coat paint on my V6 intake and valve covers after I polished those. The clear coat still looks good and hasn't yellowed. I brushed it on too.
The only prob is I let it get real thick where it built up in the corners (near the mounting flanges), and the thicker parts of the paint have cracked (you won't notice unless you look for it). If you just paint the ribs on the gearbox you should be fine.
There's a place at Brendale next to the CBC bearing shop that sells por stuff. I think it is MPA refinishing paints or something.
Thanks for that Wes, I think I will give the ribs a lick of glisten pc to keep them shiny! (if Brad (blup58) is kind enough to give me a bit of scrap if there are any leftovers) 😀
Very nice Alan and Wes.
I just painted My Gearbox with spray cans of Engine enamel..... along with My engine etc... as its VERY difficult to fit the single port inlet manifold without chipping the paint... I don't think I would go to all that trouble again..... if it all goes dull etc... I'll probably paint everything BLACK..
or maybe a clear coat to make it all shine again.... but Dull black looks much better than Dull Yellow-Red-Green etc....
You can see a bit of the gearbox in the photo...
Lee
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
