Accufab throttle body plate screws

[87geeinn]

Just purchased a 70mm Accufab throttle body but not without doing my homework first. For those who have had the issues in the past with the throttle plate screws breaking off at the head, did the screws look like this (left side of pic)? I'm just wondering because they don't seem to be much different in construction than the replacement screws from Lowe's (right side of pic) other than the head design. Also, notice that the Accufab screws did have red loctite on them. Just trying to see if Accufab has made any changes to their design in the past few years.

On a side note, one thing I did also notice is that the plate sticks to the inside bore of the throttle body when it is completely closed. Perhaps this is putting a torsional load on the bolts and is what has caused the failures.

 

[turbofabricator]

My guess is that Accufab was over torquing the screws and that is why the heads were breaking off. Or they were using cheapo Chinese screws which tend to be improperly heat treated and become brittle. IF you want to be SURE, you can buy replacement screws from a local bolt shop that can verify the place of manufacture. Then install with red loctite AND then stake the threaded end. I clamp a 5/8" bar (a 3/8" or 1/2" drive extension will work too) in a vise and place the throttle body over the bar with the head of a screw on the face of the bar, then while carefully holding the TB I take a center punch and hammer and smack the threaded end of the screw the flare it out a bit so it can't back out. Getting an extra hand to help will make it easier. Don't smack it too hard because you can crack the screw. Just tap it until you see a slight flaring at the end of the screw.

The standard allen socket head screws you have from Lowes will work, though they will impead air flow a little. Probably not enough to even measure on a good flow bench. They might casue a bit of turbulance, wich "might" be good for alcohol injection. Maybe sell them on E-Bay as a fuel milage improver. "The NEW Accufab Throttle Body TORNADO screws!!!!" Put a slight angular cut across the head of the bolt and it'll improve fuel economy "up to" 20%. Boost response improves "up to" 15%. People will buy them all day long. Sell them for Vtec's and you'll be a millionaire over night.

The sticking throttle blade is caused by an improperly adjusted set screw. (throttle stop adjuster) Give the screw a 1/2 turn open and it won't stick anymore. Adjust it open and closed untill it stops sticking, but it is closed as far as it can.

 

[87geeinn]

I didn't go so far as to peen the threads, however I did use red loctite and ground off the extra exposed threads. My intent of the post was to see if anyone remembers there ever being a different type of bolt in earlier models. Seriously though, maybe I shouldn't have cut the exposed threads. You see, the thread pitch may actually serve to further atomize the alcohol spray as it enters into the air stream. After extensive research and development by former soviet cosmonauts, this patented design has shown gains of 10-15 H.P. on select vehicles. This patented, proven design is the latest breakthrough in bolt-on alcohol injection performance upgrades.

I see what you mean about the sticking throttle blade. As soon as I turned the idle air screw in a bit, it freed the plate up.

 

[blackgn1]

I changed mine several years ago. That's when they were breaking off and entering the engine. Wasn't worth not changing them like you have done.

 

[87geeinn]

blackgn1: When you did change them out, do you remember if they looked like the ones in the pic above (on the left)?

 

[TurboD1987]

blackgn1: When you did change them out, do you remember if they looked like the ones in the pic above (on the left)?

Here is a pic, you were probably looking for way back then