Correcting bad transfer port angle

Discussion in 'Performance Mods' started by jaguar, Mar 8, 2011.

  1. jaguar

    jaguar Well-Known Member

    Here's a drawing showing how the stock Grubee cylinder has the wrong angle for one side of each transfer port (the bottom side in this drawing) which directs some of the intake gases too close to the exhaust. At this angle some of the intake charge can be drawn directly out of the exhaust port which results in power loss and increased pollution from unburnt fuel exhausted.

    The second drawing shows how if the angle is corrected that the intake charge will all be directed toward the intake side and away from the exhaust port. This results in power gains and less contamination of the air.

    More info on this is at my site (click on signature link)

    Attached Files:

    Last edited: Mar 8, 2011
    Purple Haze, Evil and bahramu like this.

  2. bahramu

    bahramu Member

    Thanks, I'm in the middle of doing this. Won't be able to say exactly how much of a difference this makes cause it's part of a bunch of other improvements I'm making all at the same time
  3. BigBlue

    BigBlue Active Member

    Not the optimal way of doing things. Suggest you start with a baseline, add a mod, develop another baseline, add another mod, develop a new baseline, etc. If you add a bunch of mods at one time, how are you going to figure which mod is causing the problem?

    Good Luck,

    AKA: BigBlue
  4. bahramu

    bahramu Member

    Yea your right, and I actually half expect it not to run when I put it all back together (although I have been careful and have done my research) but I just couldn't keep my darn hands off after I opened it up for the first time. I've been working on cars for a few years and knowing that the whole kit costs a fraction of what the price is for a single performance part for my car has me diving right in with no holds barred. In the future I will buy a new kit and methodically add upgrades one at a time while documenting, says me now.
  5. scott.d.lang

    scott.d.lang New Member

    is there anything other then JB weld that can be used from my experience using jb weld where there is ethanol running through the system is not a good thing. I like the idea but JB weld just dont seem like a good idea
  6. jaguar

    jaguar Well-Known Member

    There are pro engine tuners that use it without a gripe. I'm not sure if something else is needed with non-standard fuel.
  7. bahramu

    bahramu Member

    Been running my motor for a month now with JB Weld corrected transfer ports and have had no issues
  8. Purple Haze

    Purple Haze Active Member

    I saw a custom intake built by Bill "Grumpy" Jenkins years ago, using JB Weld to form the plenum. Doesn't seem like our little engines would be as hard on this as a high-winding SBC. Also, I'm sure Grumpy's toy wasn't running on 7Eleven pump gas!
  9. HeadSmess

    HeadSmess Well-Known Member

    i hate the concept of JB weld being used for absolutely everything, but...

    for doing this mod, its the best medium to use... why?

    a tin of "professional" port filler, costing roughly 140 dollars for just part A.... is exactly the same stuff.

    if youre running alcohol fuels, it may be better to try fibreglass resin, otherwise known as polyester resin. make it goopy by using either "microballs" or mica dust. a quick search on ebay comes up with eyeliner powder in bulk. synthetic mica powder. heat and electricity resistant. available in more colours than derwent pencils!

    i know that most epoxies can be thinned slightly with methylated spirits or acetone.

    and, theres also automotive body filler, or polyurethane. that stuff stays stuck :)

    etching the metal, or "keying" it, helps any adhesive latch on properly and stay in place if it does come unstuck.

    wash thoroughly with acetone FIRST.

    me myself, i dont fill this area up. i sink an 8mm/10mm endmill down into it, giving me both a larger transfer port and adjusting the angle :)