?
my engine taps... i think..
Thread Starter
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Joined: Oct 2006
Posts: 78
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From: Morgan Hill CA
my engine taps... i think..
75 C3..
when I'm on the road and driving... I hear this rat-at-at-at-at noise whenever I pass a parked car or a divider on the road (that's when the echo of the engine bounces back, so I can hear it)
when I lay on the gas, it doesn't tap.. mostly just when I'm cruising with my foot off the accelerator when speed is built up already...
question is.. why does the engine tap so ?
doesnt happen during idling (but the engine does sound a bit like a tractor engine when idling)
whats up ?
I thought it was a plate next to the cat. converter, so I twisted that a bit and tightened it.. but the noise still comes... (surely from the engine bay)
engine is GM 350 crate. (not a high end hp engine), about 6 years old. was installed in 1999.
transmission kit and new gaskets etc just installed. (so thats fine)
when I'm on the road and driving... I hear this rat-at-at-at-at noise whenever I pass a parked car or a divider on the road (that's when the echo of the engine bounces back, so I can hear it)
when I lay on the gas, it doesn't tap.. mostly just when I'm cruising with my foot off the accelerator when speed is built up already...
question is.. why does the engine tap so ?
doesnt happen during idling (but the engine does sound a bit like a tractor engine when idling)
whats up ?
I thought it was a plate next to the cat. converter, so I twisted that a bit and tightened it.. but the noise still comes... (surely from the engine bay)
engine is GM 350 crate. (not a high end hp engine), about 6 years old. was installed in 1999.
transmission kit and new gaskets etc just installed. (so thats fine)
Burning Brakes
Joined: Sep 2006
Posts: 851
Likes: 10
From: Palm City, FL
Originally Posted by 1stC3Vette
Check for an exhaust leak. I found mine by running the engine and moving my hand around the exhaust manifolds and pipes. Sounded just like you described.
Good luck,
Dino
Good luck,
Dino
Same with me.
Melting Slicks
Joined: Jul 2004
Posts: 3,302
Likes: 8
From: Avon, Indiana
I've been meaning to ask the same question. I get that noise when slowly passing parked cars, but only after I've been driving about 45 minutes (at which time the temp guage shows about 180). The engine come up to temp before that, but I only get the noise later.
If I put it in neutral and rev the engine while I coast past the parked cars, the noise goes away.Exhaust is in good shape. Could it be something in the converter once it gets hot?
If I put it in neutral and rev the engine while I coast past the parked cars, the noise goes away.Exhaust is in good shape. Could it be something in the converter once it gets hot?
Safety Car
Joined: Dec 2005
Posts: 4,270
Likes: 20
From: Central Michigan
Originally Posted by davidm_comp
According to mapquest there are 4 Morgan Creeks in CA.
Yep, you're right....
OK, which Morgan Creek?
Just curious, thought it might be a town not far from here, as there was once a family named Morgan that owned several large tracts of land here back inthe 1800's. There are several roads here with the Morgan name(one of them cuts through my neighborhood)
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Thread Starter
Advanced
Joined: Oct 2006
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From: Morgan Hill CA
Originally Posted by 682XLR8
Yep, you're right....
OK, which Morgan Creek?
Just curious, thought it might be a town not far from here, as there was once a family named Morgan that owned several large tracts of land here back inthe 1800's. There are several roads here with the Morgan name(one of them cuts through my neighborhood)
OK, which Morgan Creek?
Just curious, thought it might be a town not far from here, as there was once a family named Morgan that owned several large tracts of land here back inthe 1800's. There are several roads here with the Morgan name(one of them cuts through my neighborhood)
You live in san ramon, thats next to Pleasanton...
thats east bay...
I live between morgan hill (south) ...not morgan creek (oops made a snafu in my profile)....but closer to Gilroy... thats if you take 101 south all the way (after you leave san jose south even), but not so far that you reach salinas or monterey...
having another Forum member in the area
Instructor
Joined: Sep 2006
Posts: 106
Likes: 2
From: Pullman WA
This isn't happening in my Corvette, but in my 76 El Camino that has a GM Crate 350 engine with auto trans in it is currently doing the same exact thing. It's been doing it for several years, I could be wrong but I think I've narrowed it down to a slightly bent flywheel/flexplate (whatever it is in that car).
-Joe
-Joe
Drifting
Joined: Feb 2005
Posts: 1,438
Likes: 2
From: Melrose Florida
Sticky lifters or valves will cause this sound. I've had good results with a two-part approach on lots of cars:
1. Oil change with a bottle of oil treatment (I Like Lucas products).
2. Drive the car as much as possible, under as many conditions as possible. Don't be afraid to accelerate hard from every light.
3. [optional] A few tanks of really good gas (Sunoco 100, or Amoco 93) will also help.
My '77 Trans Am was clicking and tapping like crazy, finally calmed down (after above) to just tapping just as you described, and this week finally got completely quiet.
Steve
1. Oil change with a bottle of oil treatment (I Like Lucas products).
2. Drive the car as much as possible, under as many conditions as possible. Don't be afraid to accelerate hard from every light.
3. [optional] A few tanks of really good gas (Sunoco 100, or Amoco 93) will also help.
My '77 Trans Am was clicking and tapping like crazy, finally calmed down (after above) to just tapping just as you described, and this week finally got completely quiet.
Steve
