05-25-06, 11:40 PM
I'm planning some spring cleaning for the old '94 Fltwd. Any tips, or pointers to cleaning the throttle body. I've never done this on the LT1, so I'm looking for any gotchas before they get me.
Is removal the best way to go?
Any gaskets that need replacing after tear down/removal?
Is there a rebuild kit?
What can I screw up in the process?
05-28-06, 02:55 PM
So, I guess no one cleans their throttle body anymore?
I got some help from another source. Thanks.
There is a TB gasket kit which is nice. I've purchased it through GM once before and contains just about everything you need to remove, clean, and reinstall the TB.
IMO, unless you have something bad in the TB then there is no reason to remove it just for the purposes of cleaning. With some good TB cleaner spray (basically same stuff as carb cleaner, I think) you can hose down the TB blades and remove the gunk that forms on it. All you need to do is remove the oval elbow for the air intake that mounts on the front of the TB. You can manually open and close the throttle on the side.
Removal of the TB is straightforward, there are four bolts on the front. I can't remember exactly, but there may be either thread sealant (for coolant routed through TB?) -or- thread locker on here that you may need to reapply.
This is a great time to do TB bypass if you haven't done it yet.
Here is how to do it:
Proof of why it is good:
The last thing I will add is that over time and high mileage the bushings on the sides of the blade for the TB can get worn, to the point where some people complain of poor idle (blade does not fully close due to bad bushings, even when not pressing on gas pedal).
There is a guy named David Koldos who can add bearings to your TB for maximum lifespan and operation of TB blades (as well as machine TB to be larger). He does a great job of cleaning it when he has it as well. I used his service for porting stock 48mm TB to 52mm and adding bushings. Very nice work and great turn around time, cost was $180 (much cheaper than buying new 52mm TB from Holley and the like).
Here's my last contact for David:
dkoldos @ ameritech.net
Is that possibly why my LT1 throttle is smiggin sticky at just off idle? Worn bushings?
Yes, by all means I clean mine, but I don't remove, just a can of X66A and an old toothbrush. If really bad, a brass brush, but I don't like to take a chance on messing up the metal.
05-30-06, 11:46 PM
Hey, thanks for the advice. As much as I use to clean the TB on my 3.8L V-6 I just couldn't imagine no one would answer my question on thie engine forum. Every tip is greatly appreciated when I'm moving into new territory. I have to say I've been damn spoiled with the Fltwd, as it has given me so many non-problem miles. That is why I haven't torn into it like I use to tear things down, just for fun. :bouncy:
I've read somewhere an evaluation article on the 52mm TB. It basically said (and had HP graphs) the 52mm TB only added a few HP. I think the Edelbrock unit was used in the test. Any comments on that issue? Could you tell much difference with the 52mm installed? Any notice in gas mileage?
I know what you mean about the worn butterfly mounts. The same issue is seen on high mileage Carburetors. Air starts leaking in places that were meant to be sealed. That's a good price on the TB modification, I'll see if David is still in the business.
To tell you the truth, the 52mm TB is for another project I started and have yet to finish. So the motor is built and sitting on an engine stand in my garage - unfortunately I didn't put it between the fenders of the intended project car yet (not my Fleetwood). So I can't answer your questions, yet.
My thinking is that a 52mm TB is something you'd add to a car that is far from stock and looking for big power. This would be for forced induction, ported heads, big cam change, bigger displacement, etc. Not sure my cammed Fleetwood with stock heads would benefit much from a bigger TB. The stock MAF is an equal or more of a restriction than the TB. An LT1 3.5" MAF from an F-body is a nice upgrade since it is bigger and the calibration tables are already well known for updating the PCM. I will be using this combo for that prolonged project I mentioned, as I am using ported heads on that LT1.