Ok I have done a search and everything I come up with are peaople having tapping problems after it warms up or after spirited drving, I also found a few where it goes away when revving up.. These are the opposite of my problem!!

I highlighted the details I think are important, but also tried to give as much detail as possible, any more questions please ask...

I have a rather loud tap shortly after starting the engine when I rev it a little (I say loud because I hear it over my open cutout while in the car), that I have only been hearing resently, but I haven't driven the car when I has been this cold in a while either!

OK here are the details that I notice;
I start the car in the morniing, idle down the street (neighbors don't like the loud exhaust), then when I hit the gas slightly to leave the stop sign I hear the tapping, when I rev it without load I hear the tapping, under load I don't really hear it as loudly but I think that is due to the different (louder) exhaust sound under load, but it is still there. The tap gets faster as the Rpm's speed up, so I am thinking valve train??? I try not to spin it high when it is cold because of the tapping but that is hard to do with a 3500 stall!!!

It goes away after the car warms up, I have changed the oil, 300 miles ago (DEC 04), and then just again the other day, thinking something was wrong with the oil after the car was sitting for 2 months under the carport, no change in the tapping. Oil Pressure is good and how it always has been, so I am not sure what to do next?

The plugs were changed 300 miles ago also, I did a lot of things when I pulled the tranny, but I drove it and raced it for a few weeks before putting it up for the winter, with no tapping. The only thing different between before putting it up for winter and now is a new Battery, and a tune from PCMFORLESS, the tune is a custome one based off of my mods plus a fix to the stall wall I hit when trying to race with the OBD-I computer and a 3500 stall converter.. I can't see how a new battery or the tune would cause tapping when cold! Could it?

What would only tap when cold, and what damage can it do, it has been doing this for the last 2 weeks or so.

Thanks!

 

A friend had the same prob, supposedly a bent valve or something in in valvetrain. But he blew the engine before he found out what it really was.

 

I would think a bent valve tap wouldn't go away? But I could be wrong!

 

sometimes when a rod bearing is starting to spin, it will tap intermediate at first. I hope this is not your problem but worth looking into.

 

Any way to tell, like what could I check? I am down to only this car right now since I killed my truck a few weeks ago!

A rod bearing would kill me, well not the bearing itself, but telling my fiance we have to hit our wedding savings to fix one of my 3 broken vehicles will!

 

is there any squeaking when you hear the tapping? If so that is a sure bet of a spun bearing. Close off the cutout so you can hear it better and then just listen to where the tapping is coming from. It may also be a collapsed lifter. If you have a mechanics stethoscope of can get your hands on one, use it to listen in various places and get a better idea of where the tapping is coming from. If you can't get one, use a long screwdriver or pipe.

 

OK now you have me official scared not to take it to the track tomorrow night, the only time I have to check this would be on Saturday morning!
Because it will be warmed up before I get home tonight and I can't do it before work tomorrow, and then I planed on going to the track right from work! Even if I go right home it will still be too warm and I don't hear the tap then.

 

i'm not trying to scare you but i would defintely look into this tap before racing it. Does it ever happen when the car is warm? If not i would rule out rod bearing. Leaning more toward lifter

 

Hold on I forgot to mention this but I have not raced or even goten on it fully since bringing it out of storage, what could have began the bearing to tap? It had good oil and oil pressure, not even reved over 5000 Rpm's before I noticed the tapping.

What would normally cause a bearing to start tapping or start to slip/spin?? And no I don't hear anything like squeaking, when I hear the tapping!

While in the drivers seat it almost sounds like it is comming from the passenger side but that could be decieving since the center of the engine is too my right also, But I sort of thought it was just something in the valvetrain on the Pas. side..

Oh it does it consistanly when it is cold, when I leave the house in the morning, when I leave work, and even when I go anywhere where it sits for a few hours and cools down. I hate this below freezing weather!

 

Sorry I was writing my last responce and didn't see this.. I actually never hear it when it warms up and my on ramp to the highway is a steep incline so I am reving about 3000 Rpm's for an extended time after it warms up and never hear it.

Is it possible for a lifter to freeze? maybe not fill fully while cold or something? It takes my car about a mile and a half or more before the car stops tapping, I would think the friction of a stuck lifter would warm it up (that lifter) before then?

Thank you soo much for your help so far!

 

Sounds like piston slap to me, if it is, it will go away when your weather warms back up

 

As in side to side slap, like piston too small ratteling around. I had that on my bike, when that happened there was blowby, but with the bike it burned oil when this happened too. I don't notice blowby or burning oil when the car is idling, and I was walking around behind the car.

Wouldn't the oil pressure go up if there was blowby?

 

When you change your oil you can put a coffee filter in a funnel and drain the oil through that as it comes out of the motor. If you have some excess of metal glitter or metal powder that gets caught in the coffee filter you most likely have a bearing problem. You can also cut open the oil filter to see if it caught any metal shavings.

I would be more inclined to say that you have a lifter problem though. On my '91 RS it would tap a little when I first started it up. Barely noticeable at idle, but as the engine speed increased so did the speed of the tapping and the volume of it. But after driving a couple of miles it went away completely. After babying my car on cold start up for about 500 miles the tapping just went away for good. I guess a lifter got temporarily plugged or something.

 

Mine does the tapping sound right at startup until the motor warms up...i think its either a rod or a valve..but once its warm the sound goes away. motor has 132K on it and still maintains 50psi during warmup and 40 psi during normal driving. Blows my mind to try and find out what it is.

 

I had a rod bearing spin in my Nissan. The tapping sound did not go away when the motor warmed up. Also, under slightly heavier than normal acceleration the tapping went away.