Head pitting in combustion area

Absolutely true.

Another way to tell, on an engine dyno at least, is to watch the exhaust, if it's open in the cell. Put a white board behind the pipes for a background....watch for puffs of black smoke at higher rpm....generally around the peak torque point, give or take. I can elaborate on this if you're interested...don't wanna sidetrack the thread any more than I have.

 

Just a side note to "dimpling."
The heads - new from AFR - that we use on our B/STR at Bonneville this year - a BBC 427 bored to 449 c.i. has a VERY distinct series of "dimples" in the combustion chamber. (like a golf ball)

The dimpling according to AFR is used to introduce optimum turbulence of the fuel/air mix in the chamber.

Netted an additional 8 MPH.

 

So with the practice of dimpling being considered a performance ADVANTAGE, should a person really be worried at ALL about pitting in combustion chambers? Seems based on what both of you are saying, it's imporoving performance. Now grant it, that's strategically placed dimples we're talking about, but seems the theory itself on the level of plain old head saturation would apply the same to a heavily pitted or a plain casted surface. Am I on track?

 

For what it's worth.My friend had a toyota truck with 22r and a weber carb years ago. 2 different times it swallowed a nut for the air cleaner and tore up the piston head and cylinder head in 2 different cylinders.Him being a cheap ******* would not let me change the head. Ran fine.I used it to haul concrete, and he was in construction.Brandy you are a Kick.

 

No, I'm a Sagitarius. The baking method works REALLY well on SUPER nasty, gross, overly hairy engines and components. The junk actually sets fire to itself and burns off cleaner then you'd think.

Problem is, the oven is REALLY expensive so most shops don't have one.

Here's Rat Bastads hemi:

 

The coating deal is awesome. It does a lot- like spreading out the heat so hot spots can't form. If the ports and valves are coated too, it'll serve to '******' the cool air/fuel charge into the chamber and then '******' the hot exhaust to the header pipe with a minimum of temp change either way.

Pics? Sure.

This is my personal 383. With 9.7:1 compression, it runs pretty good on 87-octane.

(pretty good is defined as 545 hp and 500 ft-lbs. I've got the build well chronicled if anyone is interested).

The dimpling thing is cool too, but I wouldn't put "pitting due to corrosion" in the same league just yet. That's like saying you intended your patina to look cool, which everyone knows is a load of ****.

In this same engine, I left the CNC marks in the chamber prior to coating for the same effect as dimpling. Keeping the air/fuel in suspension and tumbling throughout the intake and comrpession strokes is a good thing. These are small parts of the bigger puzzle, but they're important parts.

Matching the cam to the flow potential of the heads, getting a corresponding intake design to work in the same rpm range, and fine-tuning the fuel and ignition curves are all part of the equation.


~Scotch~

 

WOW!!!! Great info Scotch!!! Thank you!!!!! What is the ACTUAL coating you used there? In other words, if I walk into my local engine machinist's shop, what process and/or coating would I ask for?

Brandy, that Hemi is takin' shape! Has RB seen that yet??? Are you going to send it to him in pieces??

 

Well, what can I say? As I walk the line, I look back onto the ring of fire I've been thru with that hemi and I've decided that shipping it to Rat Bastad one piece at a time is the ONLY way to go.

http://www.swaintech.com/store.asp?pid=10322

http://www.engineceramics.com/help.htm

And then of course there is epoxy.....DUH.

 

OHHH!!!! DAMN!!!

Awesome!

 

I sent my heads, valves, and springs to www.calicocoatings.com and let them do what they do.

I spoke with them at length about what this engine would be doing and took their advice on what to do. The valvesprings were coated with graphite to lessen friction between the inner and outer coils. The results are longer-lasting springs and...significantly less heat!

Making power is largely a matter of temperature control- keeping heat where you want it (like inside an insulated combustion chamber in an aluminum head) and getting it away from where you don't (like at the springs). Coatings help do this in many ways, and Calico has a complete line of coatings and the experience applying them. I was very pleased with their service and product performance. Their most-popular product is pre-coated engine bearings, which are almost a standard now.

I had never applied coatings before, and I needed it done right, the first time, on a fresh set of heads on an engine I have no intention of rebuilding for a long time. It'll see nitrous, too, and these coatings will take the heat.

I dig this stuff...

They also have coatings to shed oil (like for the rotating ***embly- rods and cranks) and coatings that shed heat (they make your oil pan an oil cooler)...

Aerospace developed these coatings, and there are more uses being figured out all the time. They keep getting cheaper, too!

~Scotch~

 

WOW! Graphite coated springs??? Scotch, brotha'... you are ********!! LOL!! Some more great info though! Good stuff here! Your addition is appreciated!

Is this the same engine backed by that T-56?

 

Matter of fact, it is...!



The car and I lived in HB for a long time, too. I just moved here in '04. Too bad I missed ya.

Anyways- The 383 and the T56 are in my station wagon. I just got it back on the road before winter. It's pretty insane. I'm still working on it (I have one gauge that works- engine temp- no speedo, tach, oil pressure, nuthin') so it'll be ready for '08. I've got a few other minor things to do (like get the parking brake to work) and some other tidbits (yes, a stereo would be nice, wouldn't it?) but I've got all winter...

The rest of the car is...well...you can pick your own word.
http://flickr.com/photos/11929667@N00/sets/72057594110671642/

~Scotch~