port/polish questions and more

[srvblues00]

I have been trying to read up a bit on porting/polishing the upper and lower intakes. Most of what I have seen says you should NOT polish the intakes. now is that just for the lower, or both intakes? If the reason not to polish is to increase turbulence and therefore fuel mixture, then wouldn't it be a good idea, in fact, to polish the upper? a polished upper would create faster airflow, allowing a faster entrance speed into the lower (in theory). am I anywhere close?

i'm all for hearing the different ideas and approaches, but if possible, could you post some URLs of sites to back up your argument, if you can? that would really help. is there somewhere that I can go and get information? any books anywhere?

here's why i am asking. i have a spare upper and lower intake coming to me for my explorer, and i am going to gasket match them and hopefully port them as best i can with my dremel. I need a carbide bit, right?

also, the guy that i'm picking up the intakes off of is including the injectors because he doesn't feel like removing them himself. these injectors have 80K miles on them, whereas mine have 117K+ on them. i know there's some way to test injectors (using a ohmeter?).. anyone know how? if they are good, I am probably going to use his. i'll be putting new seals on whatever injectors i do end up using.

thanks

 

[Bughracing]

As far as porting/polishing intakes it can go both ways. If you are doing a cabureted intake (which you aren't) you want to have the intake somewhat rough. For fuel injected intakes, you can make the upper as smooth as possible, and that is what we recommend. Just knock out any casting bumps there might be with a carbide cutter, then use sanding stones to clean it up. What we then do is use an old pushrod and put some 600 grit sandpaper on it and get it to a mirror finish. The reason you don't want to have a perfectly smooth lower intake is the fuel comes in on the lower (same a carbureted). You want the fuel to atomize and not drip, which could cause detonation. If the fuel keeps hitting rough spots, it is more prone to atomizing then it would if it were able to flow freely along a smooth finish. Just gasket match the lower to the cylinder head and MAKE SURE the upper and lower intakes line up.

 

[srvblues00]

Bughracing - Thanks, that's exaclty the info I wanted to hear. I had figured that's what would work best, but I wanted to confirm my theory with someone else

Also, how hard is it going to be to polish the middle section of the runners on the upper intake? i don't have a pushrod, but I could probably find another similar object. Any tips on this?

 

[Bughracing]

You could do it the way we do, but I doubt you will want to do this. We cut the upper intake into 2 pieces (for V8 Explorers). I haven't seen a 6 cylinder upper intake in a long time. You will probably have to cut it at least once in the middle, port/polish it, and then re-weld it. Unless you are doing all out racing, the small amount in the middle that you don't do isn't going to make that much difference. Just make sure that everything is pretty smooth on the upper and that the upper/lower and lower/head openings all line up correctly. That is the most important thing.

 

[srvblues00]

Ok sounds good, that's what I figured. I won't be cutting them apart, I'm not at that point/need yet I'll just get 'em the best I can from the two ends. Thanks a lot!