Another FE Power Tunnel Port Head Thread

[blykins]

Looks like there are a few builds going on with Jay's new Tunnel Port heads.  I'm doing an all-aluminum 482 with a pair and began assembly this past week.  I'm curious as to what the heads do out of the box, so there was no port work or anything fancy done to the heads:  just a good valve job, guide sizing, SI stainless valves, and a good spring package.  The valves are 11/32" stem, 2.250"/1.750" (typical off the shelf "big bore" valve package) and the springs/hardware are all PAC pieces.   Since this is going to be a solid flat tappet build, I tested the springs with the inners out and assembled the heads that way for cam break-in.  You can expect around a 1.900" install height with a standard lock/retainer package, or around 2" if you want to use a big spring with a +.100" retainer.

Don't forget to have an extended length plug when you're pouring a chamber.  The heads use the same plugs as Jay's other heads and need a long reach.  With an SI valve package, chamber volume was around 53cc, which will obviously require a custom dish on the pistons for pump gas.   I'm looking at around a 40cc dish with the 482 that I'm building.

[jayb]

I'll be curious to see how this all comes out.  I'm a little surprised at the chamber volume you are getting, with the test head I got about 60 ccs for volume.  Different valves, different valve job, etc. I suppose.  Are you using a 5 angle valve job on these?  The valve job and valves are critical to flow performance, of course.  I used some custom back cut Ferrea valves on the test head, along with the 5 angle valve job that my shop prefers.

Also I will be starting my second production batch of tunnel port heads in October.  The first batch has all been delivered except for three sets that are still at my local shop getting seats and guides installed; hopefully those are done in the next couple weeks.

[blykins]

I'll be curious to see how this all comes out.  I'm a little surprised at the chamber volume you are getting, with the test head I got about 60 ccs for volume.  Different valves, different valve job, etc. I suppose.  Are you using a 5 angle valve job on these?  The valve job and valves are critical to flow performance, of course.  I used some custom back cut Ferrea valves on the test head, along with the 5 angle valve job that my shop prefers.

Also I will be starting my second production batch of tunnel port heads in October.  The first batch has all been delivered except for three sets that are still at my local shop getting seats and guides installed; hopefully those are done in the next couple weeks.

5 angle.

I noticed in reply #50 of this post that the chamber volume came out at 55cc, so we're not too far apart. 

https://fepower.net/simplemachinesforum/index.php?topic=11821.45

[wowens]

You are building a aluminum block engine ?

[blykins]

You are building a aluminum block engine ?

I was held hostage.  Send help!

[jayb]

I'll be curious to see how this all comes out.  I'm a little surprised at the chamber volume you are getting, with the test head I got about 60 ccs for volume.  Different valves, different valve job, etc. I suppose.  Are you using a 5 angle valve job on these?  The valve job and valves are critical to flow performance, of course.  I used some custom back cut Ferrea valves on the test head, along with the 5 angle valve job that my shop prefers.

Also I will be starting my second production batch of tunnel port heads in October.  The first batch has all been delivered except for three sets that are still at my local shop getting seats and guides installed; hopefully those are done in the next couple weeks.

5 angle.

I noticed in reply #50 of this post that the chamber volume came out at 55cc, so we're not too far apart. 

https://fepower.net/simplemachinesforum/index.php?topic=11821.45

I actually made some changes to the machining program after that initial measurement, to increase the chamber volume.  Last one I checked was right about 60.  I guess I'd better double check that...

[blykins]

I'll be curious to see how this all comes out.  I'm a little surprised at the chamber volume you are getting, with the test head I got about 60 ccs for volume.  Different valves, different valve job, etc. I suppose.  Are you using a 5 angle valve job on these?  The valve job and valves are critical to flow performance, of course.  I used some custom back cut Ferrea valves on the test head, along with the 5 angle valve job that my shop prefers.

Also I will be starting my second production batch of tunnel port heads in October.  The first batch has all been delivered except for three sets that are still at my local shop getting seats and guides installed; hopefully those are done in the next couple weeks.

5 angle.

I noticed in reply #50 of this post that the chamber volume came out at 55cc, so we're not too far apart. 

https://fepower.net/simplemachinesforum/index.php?topic=11821.45

I actually made some changes to the machining program after that initial measurement, to increase the chamber volume.  Last one I checked was right about 60.  I guess I'd better double check that...

Like you said, valves play a big role in that.  My exhaust valve was a little bigger, etc. 

[PLemoine]

Brent,

Are the SI valves you are using custom valves or are they ready available?

[blykins]

Off the shelf.