Professional engine for for a good price!!

[Rey]

If anybody wants to get more out of their engine for a pretty damn good price, this would be the place. I was thinking of a port and polish, and I think 150 bucks for 10 HP is awsome ;)

http://www.dh-racing.com/



****especially when we pay 200+ for an intake upgrade :o

[ATRIOT]

What are the gains from a Port and Polish?
I was under the impression that K-series heads flowed alot better than the B series.

[!@#$%]

supposedly the intake runners can be cleaned up for only about a 5% increase in airflow. It is great, however I heard that on the k20a2 the exhaust side was greatly improved by upwards of 15%.

Can myeverlovin clarify just how different the exhaust ports are between the a2 and a3?

[myeverlovinsir]

Can myeverlovin clarify just how different the exhaust ports are between the a2 and a3?

Yes I can, the intake and exhaust ports are EXACTLY the same size for the A3 and A2 heads. The Intake and Exhaust valves for the K20A3 are EXACTLY the same dimensions as the K20A2 head. These heads are near identical with the exception of lost motion assemblies on the K20A2.

Here is a pic of some of the less refined points on the K20A3 cast (quench areas). You can see the sharp edges...the A2 is smooth throughout.

[SiRman]

Damm lost motion springs!!:yellm: :yellm:
I wish there was a solution to those. :sadm:

[myeverlovinsir]

Originally posted by SiRman
Damm lost motion springs!!:yellm: :yellm:
I wish there was a solution to those. :sadm:

Yeah, I have been doing some research on the welding subject. Here is a portion of this THREAD (http://www.theoldone.com/archive/welding_cylinder_heads.htm)


I haven't read enough of this "discussion" to fully understand the dispute, but I will say this: Welding cylinder heads is a most traumatic process for the parent aluminum alloy used in the head. The amount of heat necessary to properly weld in additional quench areas, will destroy the heat treat of the casting. As the casting is now "softer" after welding, it allows the valve seats to "walk", and many other parts of the casting will also "change" dimensionally, even if they are remachined after the welding process. The only way to weld a head and not end up with "junk" is to first strip the casting of the seats, guides, studs, and anything else that is not part of the parent aluminum casting. The area where the material is to be added should be milled open to allow water the same access to the new welded area as it has around the remaining combustion chamber, ie. all the chamber and surrounding areas would be of the same relative thickness.
After the welding is complete, the casting must be normalized (a process that heats the entire casting and destroys any stress and former heat treat), and then re-heat treated to the same specs. as the factory casting.
During normalization and re-heat treatment, the entire head will "warp" to some degree, and now it's time to remachine all necessary surfaces, including valve guide and seat registers, deck surface, intake surface, exhaust surface, and camshaft bores...to mention a few. The head will now be as structurally sound as a new casting, and it will also have proper cooling characteristics.
If the "easy does it" welded head is for drag strip only, and you're willing to have several valve jobs done before the head "work hardens", do it the simple way, but remember that each new valve job costs compression and also flow, as the seats are lower with each re-do.
Welding aluminum correctly is an expensive and lengthy procedure...that's why ProStock heads cost so much.

[SiRman]

I knew there must be some major issues with welding the head, but that petty much spells it out.

The level of jargon in that link is crazy.

Nice find.