Could it be an exhaust leak?

[SamSnyder]

Not your usual tictictictic, I've developer a louder tacktacktacktack that's very noticeable on startup, but quiets down after a few when it starts to heat up. Would that be possible for an exhaust leak? I've got ancient Mac unequal shorties that have seen better days. How would I tell the difference from a noisy lifter that pumps up?

 

[Daniel50]

injectors tend to also make a tickin noise. if the sounds goes away i doubt its an exhaust leak

 

[mustangjoe87]

if it goes away, perhaps it is the lifters or rocker arms

 

[HISSIN50]

Can you use a mechanic's stethoscope to isolate the noise further?

Or (though i am sure you dont want to do it), after pressure builds in the am, slowly bring the revs up to 2K and hold it. That should pump a flattened lifter up pretty quick. If the noise persists, I like the exhaust leak idea. Perhaps the metals swell to fill the void more once you warm the motor up a bit.

Good luck.

 

[Black 93 Fox]

I was also thinking the lifters, roller rockers.

 

[SamSnyder]

Stock sled mounted rockers in GT40 iron heads on an E303. I ask about exhaust because I'm in denial about the idea of lifters since I have been uber-religious about oil changes every 3-5k miles for the entire 75k miles I've had the motor in the car, and it has been a street driver with relatively little abuse. Of course, if it is the lifters, I suppose it would be the right time to bolt on that Explorer manifold and set up the 24lb injectors a good buddy passed on to me as a gift, and which have been sitting in my garage for months now. Hmmm. Any further thoughts on how to differentiate between valvetrain and leaking exhaust noise?

 

[mustangjoe87]

take a long screw driver put it on a header tube with your ear on the handle. this can help you check for an irregular exhaust leak. but if it goes away id say valvetrain