Hi. I'm reaching out for advice. My car is an 03 AP1.

At idle, with the top up + windows up, i can hear a rattle / rhythmic knocking from the engine bay. The frequency is roughly equivalent to engine RPM. Worse when the car is hot. It goes away at 1200 RPM and higher. It gets worse below 1000 RPM. It's worst on an idle dip, or low RPM standing start.

The car idles fine. Car drives fine. Engine is not consuming oil.

What I've done so far:

TCT changed for Billman Gen X unit
Valve clearance adjusted
IAC valve cleaned
MAP cleaned
...A bunch of other unrelated work.

The idle is much more consistent now, but the noise persists, especially when the car is hot.

Additional information:

The noise seems to get worse when the AC compressor kicks on.

At idle, if I put my finger on the belt tensioner pulley bolt, i can feel a slow, somewhat rhythmic, "tap"

I'm working on the assumption that it's something in the accessory drive, but I don't want to just start throwing parts at it. I suspect if I take the belt off and check the pulleys individually, I won't be able to feel the problem. my hand can't put an operating RPM and load on a pulley...

So, are there "common issues" in the accessory drive? Otherwise I'm going to dig in tomorrow and puzzle a bit more about it.

 

Sounds like your going down the appropriate troubleshooting list. Next I would go ahead and remove the belt and spin/check for excessive play, crunch or some other irregularity when turning each accessory by hand. Ive had the belt tentioner itself get slop in it and create erratic clicking noises with throttle application, fortunately I had another laying around to swap in for troubleshooting. It wasn't real apparent to me there was a problem with the old one until I felt what a good one felt like. A bad bearing in one one the pulleys on a accessory is usually pretty obvious though.

 

Found it. Removed the belt, both the tensioner and the idler pulley can be rocked axially by hand. Bearings are shot.

 

SKF 6203 2RSJEM

This is the part number to replace the pulley and idler bearings.

When replacing the tensioner pulley bearing make sure you support the pulley not by the thin edges, but somewhere towards the center with more meat. The edges are delicate and can chip easily, I work on S2k's I'm also in Miami FL so if you ever need any help drop me a MSG.

http://www.ebay.com/itm/LOT-OF-2-NEW...MAAOSwNRdX97Be

These bearings are good to 19,000rpm so they should work.

The tensioner pulley is reverse threaded (lefty tighty righty loosey)

 

Awesome, good to hear you found it!

 

Ah, good to know about the reverse thread. Makes perfect sense given the procedure for removing tension from the belt, but I would have probably broken the bolt before I figured that out... The little things you overlook.

Yeah, I had tape measure lying around, and I was figuring the pulley RPM at 9000 engine RPM based on circumference. The numbers made my eyes a little wide. Those pulleys are substantially overdriven.

Actually, if you're in Miami, I do have a request. Do you have, or know anybody who has modified the seat height or fitted buckets? I'm 6'4" with a 38" waist and 50" shoulders. This car is... a bit of a squeeze for me.

I'm OK with eliminating most of the padding from the seat and having the leather re-fitted.. Or buying a bucket, but I like the car looking stock... other than that I see there's the thickness of my palm between the seat base and carpet.

 

I have buddy club low rails, they lower the seating position by a few inches with these Brides. Fitment wasn't great, had to modify one of the legs to line up with the bolt hole on the floor, I don't know what you could do with the stock seat honestly. I think they make lower rails for it.

 

Backyard special makes seat rails for oem seats. lowers it a bit, not substantial but anything lower is a plus...im 6' and the s2k is a squeeze...cant even imagine how you fit in it lol

 

Yeah... 20mm out of those rails for $350 I might as well cut and weld mine. There's only about 40mm before the lowest part of the pan hits the floor. But that padding is thick... Over 3 inches at its thinnest point. I think a dedicated person willing to cut and weld rails, and sacrifice most of the padding could pick up 8 - 10 CM of headroom. Don't know if there's enough room between the side bolsters to pull that much padding and still sit in it though.

The limited space between the glove box and the door seriously limits bucket options for this car, and my size further limits them. I'd like to see / try / sample a few examples before I go spending any money on something that may not even work.

 

Well you can permanently mount the seat as well, then you can easily drop it 35mm.