Achieve necessary ra with sandpaper/polish?..

[kawkoretsx]

I either just had an idea or a brain fart, and I'm sure one of you will let me know. I don't know much about lapping except that you need a special tool and some sort of gritty stuff to do it. If you checked your head and block and all was well (strait, flat, clean). Could you take the factory ra down to the ra required for a MHG with something long and flat (maybe an air file or some sort of other similar body working tool) and then a metal polish or buffing compound? Any thoughts/farts to go along? How hard would lapping be for someone who cleans their car window seals with Q-tips, because he doesn't like the dirt that gets on the glass from them when you put your window up and knows theirs no such thing as a left handed screw driver. Read: has mechanical ability and extreme attention to detail.

 

[Yellow 13]

http://kalecoauto.com/index.php?main_page=product_info&cPath=5&products_id=21

 

[kawkoretsx]

Get the ef outa here. But seriously, what do you guys think about sanding your mating surfaces.

 

[GotBoost?]

A very good product right there. But you'll need two, one for each side. Seriously, i recently got my bloack back from the machinist, and in looking at how smooth the deck is, i don't see how any human could sand that surface so smooth. Let alone so flat. Maybe is possible, but why risk damage by getting it wrong?

 

[kawkoretsx]

You think you could get a couple pics. All the ones I've seen are strait down. I'd like to see a shot from an angle, kinda from the side if possible.

 

[GrimJack]

No, I don't think it can be done. Besides, then you'd have to take it BACK to the machine shop to get it cleaned, because the slightest amount of that 'gritty compound' in your oil is going to eat the engine alive in about a minute flat.

 

[GotBoost?]

I took some pics, but my cheapie cam can't show anything close enough to see. But trust me, is smooth as glass to the touch. I say bite the bullet and have a good shop machine the block smooth. I think i read down to ra 20. Others might chime in on that. GL.

 

[kawkoretsx]

I'm definitely having one motor professionally built by justice racing engines. I was just kinda thinking out loud. Good point about the cleaning, didnt think of that.

 

[pimptrizkit]

pull the engine it's not worth it,

i have tried, and i faild missibly.

 

[IJ.]

Human physiology being what it is you'll never "sand" it flat, while it may be smooth the surface will have ups and downs unless you use a Lapping Plate.

Mine is huge and heavy (12"x12") to cancel out the "muscle effect".

 

[kawkoretsx]

IJ-What substance do you use to lap with? Is it like a polishing compound? Is it possible/plausible to do an non machined block that's been checked and is flat? Obviously your best possible result would come from lapping a freshened block, but do people do this with good results? Sorry about all the question marks. I never heard of lapping until I started researching my Supra. I'm having my engine machined by someone who can achieve the required ra, I am just kinda wondering about the process.

 

[JustAnotherVictim]

Usually Diamond paste is used with a lapping plate.

 

[IJ.]

Kawk: I use Diamond paste as it's much faster than Carbide.

Lapping is only a finishing process and I wouldn't bother doing a used block as they're rarely flat/true.

Ric: Only by Ballers