Edelbrock 75mm throttle body, only a few weeks old, pulled it a couple days ago after my idle suddenly jumped to 2500 RPM while driving to work:





Judging by the divots that I can see through the S-tube and the spark plug hole, it made its way through the supercharger, causing some minor damage to the lobes, but nothing serious and the blower is fine. From there it went through cylinder #2, beating the expletive out of the top of the piston (I can see the divots through the spark plug hole) before it left the motor.

The compression readings are all fine, it's not burning any oil, and leakdown is 2%, 2%, 3%, 1% (all on a cold motor), so it looks like my motor successfully digested the screw. I made a few full throttle runs and I get no detonation at high boost/RPM, so I may not have any excessively hot spots, and the plugs look fine. I contacted the shop where I bought the TB, and they had a new one in stock and agreed to handle the RMA process through their distributor. I think I dodged the bullet on this one.

I put a new Edelbrock 75mm TB on it, gave the broken one back to the shop. The new one is much smoother. The old one was pretty sticky, even when new, but I thought it was just my cable sticking. I actually ordered a new cable for it, but this one is very smooth, even with the old cable. I think the old one was messed up from the start. Hopefully this one doesn't disintegrate and spit more chunks of metal into my motor.

 

lucky but...id pull the head to be safe not worth a dropped valve at a later date and you'll never know if the walls were damaged

 

Have you tried contacting their warranty department?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gotboostedvr6 &raquo;</TD></TR><TR><TD CLASS="quote">lucky but...id pull the head to be safe not worth a dropped valve at a later date and you'll never know if the walls were damaged </TD></TR></TABLE>

If the cylinder wall is scored, then there's nothing I can do about it anyway, and I can't think of any damage to the valves or seats that wouldn't show up in compression and leakdown tests, and especially not anything that would cause it to drop a valve. If you've got some more info on this, then I'd love to hear it.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Trooper &raquo;</TD></TR><TR><TD CLASS="quote">Have you tried contacting their warranty department? </TD></TR></TABLE>

I called them. It's a "racing" part, so their only responsibility is replacement of the TB if it is defective. They told me to RMA it through the shop that I bought it at, so I did.

 

Damn! You're lucky!

I'd ask for $ to rebuild anyway

 

Speaking in terms of throttle bodies, reading your story makes me less angry of the hassle I dealt with installing a DH Racing throttle body that a customer purchased on-line.

That damn thing was all bling looking but performed like crap. The bore and throttle plate were not precisely machined causing a sticking throttle and the machined provisions for the MAP sensor caused poor performance. I was later told that my customer had bought an early one with those problems.

Nice that people throw crap on the market like that without even testing first.

 

Did you loctite the screws on the plate on the new one?

I would take it upon myself to make sure the part does not fail again, as you may not be so lucky next time.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Reid &raquo;</TD></TR><TR><TD CLASS="quote">Did you loctite the screws on the plate on the new one?

I would take it upon myself to make sure the part does not fail again, as you may not be so lucky next time.</TD></TR></TABLE>

I did that, used red loctite on them, but the new one is so much smoother than the one that broke that I think there must have been something wrong with the other one. At the time I figured it was just my old throttle cable making it sticky, but even with my crappy old throttle cable the new one is as smooth as butter. I think this one is going to be allright.