48mm head boring for Spree BBK

[mustangwagz]

ahhh ok, i call them..."The Treeeeee!!"

i did mine on a small HAAS.

[toboggan]

Nice. We've always used this and it's always worked perfectly!

[tazland001]

Keep up the good work tobaggan. I have never heard one complaint from my customers so you must be doing something right. hehe

Taz

[evilone]

What exactly do you do to the chamber side? Do you make it wider or wider and deeper?

[martynkim]

He won't tell or show you.

[Trafficjamz]

I would think just wider. any deeper would mess with compression ratio.

I just widen them with a dremel.

Them use some sand paper to smooth out any rough spots

[CharlotteSpreeRider]

I would think just wider. any deeper would mess with compression ratio.

I just widen them with a dremel.

Them use some sand paper to smooth out any rough spots

Seriously? That seems incredibly imprecise, in a place where precision matters.

[Bear45-70]

Making the chamber bigger with a major bore increase is not a bad thing, since the bigger bore boost compression anyway. Way to many guys are ending up with TOO MUCH compression as it is. I agree with Charlotte to some extent. Smooth is much more important than precise.

[Trafficjamz]

I would think just wider. any deeper would mess with compression ratio.

I just widen them with a dremel.

Them use some sand paper to smooth out any rough spots

Seriously? That seems incredibly imprecise, in a place where precision matters.

I have done this a total of three times now.
I was very careful and marked it all out using a sharpie.

I used the new head gasket as a template.

I am not sure the 44mm piston would even hit the stock head. (unless you have the 84 spree head)

Honestly I think Taz should just come up with a thicker head gasket, and call it a bolt on kit.

[evilone]

I see, i was thinking i could get my compression with the mini-stroker under control by cutting head instead of extra head gasket/s.

[Bear45-70]

I see, i was thinking i could get my compression with the mini-stroker under control by cutting head instead of extra head gasket/s.

Cutting the head makes the chamber smaller, not bigger, which is needed to lower the compression.

As to the last head shown. That is asking for a pre-igniting motor. Each of those dings from the broken rings create a hot spot because of the edges of the holes. That head is not serviceable, especially on a high compression or high performance motor..

[Trafficjamz]

I see, i was thinking i could get my compression with the mini-stroker under control by cutting head instead of extra head gasket/s.

Yes you can do that. but that is beyond what one can do with a dremel.
A mill or cnc is needed to open up the head.

[Bear45-70]

Drastically changing the shape of the combustion chamber can cause bad things to happen in your motor. Small changes are best.

[Trafficjamz]

I see, i was thinking i could get my compression with the mini-stroker under control by cutting head instead of extra head gasket/s.

Cutting the head makes the chamber smaller, not bigger, which is needed to lower the compression.

As to the last head shown. That is asking for a pre-igniting motor. Each of those dings from the broken rings create a hot spot because of the edges of the holes. That head is not serviceable, especially on a high compression or high performance motor..

Cutting the head's combustion chamber lowers compression.
Milling the head's mating surface to the jug raises it.

All of those pics are of the same head. All the nicks out of it is why I chose it for carving up.

Those tiny nicks in the head all sanded out smooth.(in the bead blast cabinet) after I masked off the headgasket area.

[Bear45-70]

Maybe I did this stuff too long professionally, but that head would never go back on an engine I was doing, blasted or not I still see dings in it.