Looper exhaust porting

[Captain75]

Nice work, Captain! How deep are your finger ports? They look like they barely break through the iron sleeve in the picture, so I'm guessing they're about 1/8" (3mm).
Most of the finger ported blocks I have are about .400" deep (10mm) in the finger ports.

Great idea with the little belt sander! I tried that out on some scrap cast aluminum yesterday using a 36 grit 1/2" wide belt on a sander meant for 3/8" wide belt. It cut a beautiful slot .200" deep x 2" long in about 5 minutes. Straight as an arrow and nice flat bottom.
I've already pulled the sleeves out of my project motor, so I only have to grind aluminum. I'll slot the sleeves in the mill, and end up with about .300" depth, total.

Keep the progress reports coming!

I will measure the depth this evening. I didn't dare to cut any deeper...

[baja200merk]

Tony 2.7 sleeves are .185 thicker then 3.0 and there are no finger port bosses in his block so theres not much meat to take out without adding weld or epoxy. All the early evolution ported blocks ive seen have very shallow fingers compared to the late closed deck blocks your messing with because there are no bosses.

I have a 2.7 block with finger port bosses and the block has never been painted from the factory Bush asked if I'd sell it.

[Mr. Demeanor]

Heres a pic of the finger ports Monty put in my Yamaha cylinders (very similar layout). Not sure how he cut them.

[Tony Brucato]

I'm doing my 2.0 V4, and it doesn't have the bosses either. I'm going to cut on some Ocean Pro sleeves to put in it, and lose the exhaust bridge.
I'll be doing the Epoxy around the FP area. I don't want them choked off if I'm going to all the trouble.
All of my 89-92 3.0 open deck blocks have the fingerport bosses in the casting already. My Evolution block has 1/2" wide x .400 deep finger ports.
Maybe it's just the Bridgeport blocks that lack the bosses.
I've never owned a closed deck block, so I don't know how that compares.

[Tony Brucato]

Heres a pic of the finger ports Monty put in my Yamaha cylinders (very similar layout). Not sure how he cut them.

When Monty did a Bass package for me years ago, I asked how he set that up on the mill to cut the finger ports.
He told me he did it all by hand with a grinder.
He does some amazing work! They were perfect.

[baja200merk]

I have a few early open deck 3.0 that do not have the bosses also have a couple that have them. Thats why this 2.7 i have with bosses is strange.

[wanagofass]

All of my 3.0 blocks have finger port bosses but I've never seen a bridge port with them, thats a cool find. I've got a notch back block that I'm gonna hog on once I get my bridge port for the center console back together. The notch back is a 00' and has alot more meat behind the liner than my other blocks, I don't know if they're all like that though this is the first one I've really paid attention to.

[baja200merk]

All of my 3.0 blocks have finger port bosses but I've never seen a bridge port with them, thats a cool find. I've got a notch back block that I'm gonna hog on once I get my bridge port for the center console back together. The notch back is a 00' and has alot more meat behind the liner than my other blocks, I don't know if they're all like that though this is the first one I've really paid attention to.

Yea but the chest is as horrible as a 3.3. Don't bother

my 2.7 will be bored for 3.3 sleeves when it goes together. If it ever goes together lol

[Captain75]

My fingers are 6-6,5mm deep and 10mm wide. I can't go wider because of lack of space. Right now there is only 3mm between main transfer and fingerport in the most narrow spot...
Measurements taken with the help of a piston.

[Tony Brucato]

That's pretty good then.

I didn't take into account, the thick sleeve on the 2.7.

[wanagofass]

Yea but the chest is as horrible as a 3.3. Don't bother

my 2.7 will be bored for 3.3 sleeves when it goes together. If it ever goes together lol

Haha, thinking about it that way gets me thinking about rebuilding the notch back stock for the center console and boring the bridge port for my mirage.

[NosBoss]

I didn't know you could bore the block for 3.3 sleeves.

[Captain75]

That's pretty good then.

I didn't take into account, the thick sleeve on the 2.7.

I was a bit worried by the small amount of space between transfer and finger, but i guess it will be ok, I've put ports very tight together on smaller high revving(14000rpm)motors w/o problems.
Next up is honing, but I dont feel secure with the procedure. All the bores are w/o scores, I just want the deglazed. I have two honing tools; one brand new 120grit ball hone, the other one is a spring tensioned hone with 3 stones. All portedges are chamfered except for the fingers, I will chamfer them very gently with a smooth wet paper due to the radius.
I looked at a instructionvideo from ball hone, I think they use the tool to hard!? It feels like it should be enought with 5-6 strokes in both directions to create the cross hatched pattern.
I know I've mentioned this before, its just that I'm a bit worried to mess up the bore considering all hours spent.
Anyone know the appropriate ring gap on these motors?

[racer]

I use an adjustable angle head that attaches to the quill on my mill. The block is mounted to the table so cyl is parallel to the quill, the angle head fits into the bore and I then use didgital readout to move the cutter (1/2 inch) into the cyl wall and then the power feed to run the cutter down to preset depths. Once all the stops are set its a matter of moving the head from one cyl to the next. Cuts really clean and even finger ports. Maybe Rudetim will be on and he can tell how clean they come out as he has watched me due several.

Do not use the spring hone on your bores especially with the finger ports. You need a key way hone to properly hone the engine bores.

[Onetime]

Do not use the spring hone on your bores especially with the finger ports. You need a key way hone to properly hone the engine bores.

Good advise. Expensive but it's the only way to hone cylinders with ports in them. Any spring hone and ball hones drop into the ports while rotating. Not good