Chamber Mods vs Material Volume Removed Question

[steve cowan]

Something very timely from Weingartner Racing.
At about the 5 minute mark he describes exactly the condition of my combustion chambers.

https://www.youtube.com/watch?v=iVR0BctDhjM

The general consensus of the crowd here aligns with his approach to correcting the problem as well.


Weingartner.jpg


Weingartner (Brodix IK200)


Mine.jpg


Mine (RHS Pro Torker)

Time to grind.

I think PRH mentioned earlier-
Just sand roll sharp edge and I would not grind that area out just to try to blend that shallow top cut.
You can possibly do some work around the spark plug area but again you need to know the why and how to do it correctly.
Looking at Larry's 292 combustion chamber is a work of art in my opinion I hope we can see a picture of the valve job.
Larry has done extensive valve unshrouding but it is not dug out like a lot of people do,you can see how Larry has tried to make the top cut transition all the way to the cylinder wall diameter,impossible to do on a 23 deg head.
I am wondering if Larry angle milled those heads and how much to achieve said chamber volume.
I have done no valve unshrouding on those Dart heads but remember it has 1.94" - 1.5" valves.
If I wanted to lose compression I would keep the chamber tight on shape and CC and take it out with piston dish and quench area not exceeding 40 thou piston to head.just my opinion

[skinny z]

I watched that video the other day .
I couldnt figure out if he was recommending to smmoth out the step on both the intake and exhaust or just the intake.
I have a set of heads that have about a .040 step on the exhaust seat and when I mentioned it to the porter he said to leave it alone .

IIRC, it was said to blend the intake for flow and blend the exhaust so as to eliminate any potential hot spot due to a sharp edge.

[skinny z]

Something very timely from Weingartner Racing.
At about the 5 minute mark he describes exactly the condition of my combustion chambers.

https://www.youtube.com/watch?v=iVR0BctDhjM

The general consensus of the crowd here aligns with his approach to correcting the problem as well.


Weingartner.jpg


Weingartner (Brodix IK200)


Mine.jpg


Mine (RHS Pro Torker)

Time to grind.

I think PRH mentioned earlier-
Just sand roll sharp edge and I would not grind that area out just to try to blend that shallow top cut.
You can possibly do some work around the spark plug area but again you need to know the why and how to do it correctly.
Looking at Larry's 292 combustion chamber is a work of art in my opinion I hope we can see a picture of the valve job.
Larry has done extensive valve unshrouding but it is not dug out like a lot of people do,you can see how Larry has tried to make the top cut transition all the way to the cylinder wall diameter,impossible to do on a 23 deg head.
I am wondering if Larry angle milled those heads and how much to achieve said chamber volume.
I have done no valve unshrouding on those Dart heads but remember it has 1.94" - 1.5" valves.
If I wanted to lose compression I would keep the chamber tight on shape and CC and take it out with piston dish and quench area not exceeding 40 thou piston to head.just my opinion

Yes. I'd sand rather than grind.

That the engine is in pieces is a milestone really (I think it's been nearly 2 years since I knew it was hurt). I haven't finalized the CR just yet or figured out which mix of components will get me there. Chamber volume is variable at this point and so is the piston profile. I'm working with a .014" piston below deck so a .040" quench is an easy target as I've got that already.
The rest will fall into place.
Wait until you see some of the destruction from the cam lobe that was taken out by a wayward roller lifter. I've got an engine full of metal to deal with.

[skinny z]

Looking at Larry's 292 combustion chamber is a work of art in my opinion I hope we can see a picture of the valve job.

Would that be this picture?

Turbo292_SunkenSeatsAfterPorting.jpg

[PRH]

Looking at Larry's 292 combustion chamber is a work of art in my opinion

Larry’s stuff always looks like mechanical art!!