rkcarguy

Is it possible to only port the 12A's exhaust port from the OUTSIDE with the engine together, if you used a vacuum with the grinder and carefully packed the chamber with rags/paper towel to keep metal shavings out? I'm going to be pulling my engine to put a turbo on it, and I think it would benefit a cooler running engine/faster spooling turbo to port the exhaust out. I realize it's hairy but with machinist attention to detail and cleaning afterwards I think it can be done. What do you think? I've done similair porting on piston engines using grease and a vacuum with a small tube taped into the end to suck the chips out.

t-von

iTrader: (8)

The 12a engine gasket kit isn't that expensive. Since your going turbo anyways, spend the extra change and open up the engine and do it right. To correctly port the exhaust, you need to leave the 2mm bevel around the port.

Zero R

iTrader: (1)

My guess is you will take out a seal in only a short time.

R.P.M.

iTrader: (3)

Yes....your crazy! lol

peejay

Technically, yes. It will flow even worse than stock, though, and without a way to chamfer the port, seal life will be next to nonexistent.

Then you'll be able to pull the engine apart and do it correctly, only with more money spent.

"If you can't afford to do it right, you probably can't afford to do it twice, either."

rkcarguy

Ok that's kind of what I figured. Reason being the engine is an unknown as far as it's condition. I bought is as a rebuild in 2000, but it's seen alot of auto-x and track days, and got beat on when the street car it was in got stolen. It's not that I'm cheap and can't afford it, just I don't want to throw money at a questionable engine. I will probably just leave it alone and add the turbo. I am wondering however if I have a new engine built, would it benefit from an exhaust porting only to help get the heat out of the engine and spool the turbo faster? I don't really like the way a street or race port moves the power band up, I need a broad range of power and torque.

fastrotaries

Not just a NO but a HELL NO!!!

grantmac

In theory if the exhaust opened sooner you would end-up with a better spool. However your exhaust manifold will effect things more.
Grant

BDC

Don't even think about doing this.

B

RandomHero

iTrader: (2)

^ haha, there you have it. If there is anyone whos word you should trust on this matter, its BDC's.

rkcarguy

Grantmac, that's what I figure too. My manifold is pretty free flowing it's all thick mandrel bends from racing beat. It's a common practice for engines(like billy bob small block chevys) built for towing or boats to be ported on the exhaust side only to keep heat out of the engine.

And yes don't worry I will save the port job for the next engine BEFORE it goes together.

peejay

So strip it down and figure out the engine's condition!

Then put it back together with a new gasket kit. Or if you are livin' *really* cheap, hardware store O-rings, silicone, and 18-gauge wire. Might as well port t a bit too while you're in there.

Look at it from this pholosophical perspective: If you just use it as-is, then you're blindly accepting whatever condition the internals are in. If you strip it down, port it, then throw it right back together with all of the same internals, the engine's lifespan has not changed ONE IOTA. Only now it's ported. And you know for *sure* what the insides are like instead of just guessing. And you now have porting experience for when you *do* throw down mucho bucks for new parts.

Do you want to learn to port on a cheap core engine, or several thousand bucks worth of new housings?