Injector Housing to Head Port Match Issue

[LGAFF]

Ya gotta go all in....

These are from when I was still working on the port match!

[KJL]

Wow! you removed all of the material between the ports then cut back on the head ports. Looks like a lot of work! What tools would you recommend? I have a dremel and air powered die grinder as well.

I just receive the dyno info from where he had it tested, 392 max rwhp and 356 rwtq. There is also a chip that I need to look at. Not sure what brand. I hope I can tell. My plan is to get her back together, and stick her on a dyno to get the air/fuel ratio data. Send data to Marc Haibeck and have a chip setup for me. Hopefully this will also take of the backfire issue.

[We Gone]

Marc will be able to add the anti-backfire to the chip for ya for sure. Good luck.

[KJL]

Here is a picture of the intake plenum porting.

[Paul Workman]

Several of the "FBI" gang have aluminum chips in their fingers!

By the time I went from the intake plenum, progressing to the IHs and onto the heads, I wore out a couple cheap pneumatic die grinders, and ended up with these two work horses - a Snap-On PT200L (actually about a foot long, tho the picture makes is look small) and a the small one (purchased at the same tool and die supplier where I bought my bits).



I also tried the Makita GD800C. It is a powerful, variable speed control with constant speed feature. It is an excellent, durable tool, if one prefers electric. (Pete liked it so much that he's offered to keep it at his place for safe keeping - now that I'm done with it) (Oh! BTW, they're on sale at Amazon right now for $219, if you're interested!)



The bits that worked best for a relative novice like me were the fine, single cut fluted carbide burr (pictured). However, Marc Haibeck uses the very aggressive aluminum burr that has maybe a dozen flutes. I don't recommend them for anyone except the very experienced person, as I can attest that those big fluted SOBs cut like crazy, and are difficult to control; a two-handed, locked elbow, both fists around the grinder, with position controlled by swiveling one's hips...seriously!

The small grinder got the majority of the flap wheel work on the ports, and a Dremel with its tiny flap wheels came in handy to polish the curves in the valve bowl area.

Also pictured are "Pete's balls" - made of steel (what else?) - one a 36mm diameter, and one a 35mm diameter. One of those magnetic wands holds the ball nicely for taking measurements. A snap gauge is essential tooling and a precision caliper (dial is fine, but digitals are available for a little more $$).

Pictured is another of Pete's balls - a bit larger than 36mm; threaded to accept a threaded bolt shank (or the like) as a handle.



This wasn't my first rodeo, far as porting goes, but it was my first aluminum project, and first LT5. So, I'm not portending to be an expert here - just passing on what I experienced and what I learned from the masters: Pete and Marc Haibeck and Bob G and "Flyin Ryan", and a couple things I picked up along the way. Runner length, size, Siamese'ed or not ...lots of ideas and different ways to 'skin a cat"; opportunities for "Carbide Cowboys" (as Ryan call 'em) to experiment with an LT5! Intrigued??

P.

[KJL]

Paul-
Thanks for all that great info!! I have a snap gauge set and several types of calipers. I could see if one was going to do full Siemens porting that an aggressive bit in experienced hands would be the way to go. That is a lot of aluminum! Luckily, all I am looking to do is some port matching. I don't want to go crazy on the heads, just enough. I plan on following Jerry's advice and use one of his gaskets as the guide. I will also mark the actual IH foot print on the heads to see how much they differ from the gaskets.

The Makita is slick, but for what I want to do, I am hoping to find one similar in features for less money. I will also try to stay away from using any "grit" based bits. I am afraid bits of grit may make it into the the cylinder. I plan on plugging the ports but you know how that goes. If a couple of small flecks of aluminum get in there probably wont damage anything but small bits of carbide grit?....

My existing port job is fairly smooth but could use a bit more polishing, maybe with ultra fine 500-600 grit wet sand paper? How smooth does a port job need to be?

[LGAFF]

Smooth is bad for airflow, as it creates a boundry layer next to the wall were air speed slows, 60 grit flap wheels are a perfect finish

[Bob Eyres]

Does someone have CNC capability to do the porting? It would seem impossible to match the flow exactly, by hand.

[KJL]

Are there any coolant passages in the Dunn heads near the ports that I should be concerned about?

[Paul Workman]

Originally Posted by Bob Eyres

Does someone have CNC capability to do the porting? It would seem impossible to match the flow exactly, by hand.

Yes. Pete has access to a CNC program based on his heads, at least. I've not heard of anyone that has CNC for the IHs or the plenum, but wouldn't be too surprised if someone like Lingenfelter has a CNC program for them as well.

P.