So I have a new 4G64 2.4LR (11:5:1 CR) motor built by Buschur and I have my old 4G63 Stage III head also purchased from Buschur and I've read that the head's combustion chamber needs to be ported to match the 4G64 as it's not the same as the 4G63 and can lower the CR if it's not done. The motor and head were purchased years apart hence why this wasn't done before hand. Is there any truth to this?

This has put a kink in my timeline on getting my car done next month and I need some feedback: Does the porting of the head really need to be done and why?
What will happen if I don't do it?
What's the cost for a port job like this since I already have DB Stage III ported head? How much more can it be?

 

I've never herd of that. But i would call buschur and just make sure with him.

 

Ive got a Buschur LR 2.4 also with a Buschur stg3 mivec head and it just plops right on, no work was needed to my understanding.

 

also haven't heard that but would be interested in hearing a response to your question.

 

I believe The bore is larger on a 4g64 block. The head will perform better on this block by opening up the chambers to match the bore size. This unshrouds the valves for best performance and flow of the head.

 

I pm'd DB but not response as of yet. So it's the combustion chambers that I guess need to be ported. Since my head is already ported in other area's it's just the area that needs touching up.

Here's where I am getting some of this info.. See last two paragraphs on the first post.
http://highboostforum.com/forum/show...for-your-build

 

You can do it but you dont have to...

 

Opening the chamber on the head will reduce Chamber Volume and reduce the chance of hot spots around the valves and head gasket. It is not needed, but it is recommended for longterm reliably and a safer motor. Basically your think of the head is still formed at the stock 85mm chamber size, and im sure your motor is .20 over at least so your looking at at 87mm piston. You have 2mm chamber size difference around the headgasket which can lead to headgasket problems if you run too much timing and the chance of hot spots creating around the gasket.

Is it needed? No. Is it recommended if you have the funds for it? Most defiantly.

 

Any update?

 

Ya, I'm not gonna do it.

 

Exhaust_note thanks for the explanation first real info I have come across there is not much talk about it and seems as if its a 50/50 thing.