Slight knock/tick at startup

#1
Hello all. So ive been doing a minor restoration on my GN. its ben sitting since February with only a handful of startups. So I am finally all done with the paint/bodywork and I have a slight knock at startup. Only does it after sttting for 30 minutes or more does not make any noise after engine is running. Its a very distinctive knock....maybe 4-5 times. What are the chances its a lifter leaking down(fingers crossed) Am I correct in assuming this since it doesn't make the noise at all after the is running? Its kind of hard for me to diagnose as I have to let it sit and it only knocks for a second.
 

NY Twin Turbo

All the good stuff.....Times 2.
#8
Its a Napa gold 1258. does this have one? I have the RJC biggie filter adapter, no oil cooler
I too was going to ask you this very same question about the oil filter.

I was going to also mention that you could unplug the fuel pump and crank the motor until oil pressure builds. Then plug the fuel pump back in and start it. If the noise goes away, then this is an indication that your engine is taking too long to build oil pressure after start up. And this means your pump's prime is somehow bleeding down.

Another reason for knock at start up is too much timing during cranking. Only just enough timing to get a motor to spin over should be used for cranking. But this is more for a conversation on XFI set up. Not for a guy with a stock computer.

But an oil pressure gauge is needed to diagnose this issue. Your going to want to look at how long your oil pressure takes to build after your motor starts. Or if you can even build oil pressure just by cranking it with no fuel.
 

earlbrown

runs with scissors
#10
It might be something as easy as a bad filter drainback. It might be a broken rocker shaft that hasn't curled up enough to fully unload too.

Only way to know is to listen and find the source of the noise and go from there.
 
#11
My car does something similar too but has to sit much longer than 30 min; maybe a day or something. Not sure as I don't crank it up every day. Come to think about it, I don't remember It much before I installed a new NAPA 1258 back in May....... maybe I should change mine too.


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#15
My car does something similar too but has to sit much longer than 30 min; maybe a day or something. Not sure as I don't crank it up every day. Come to think about it, I don't remember It much before I installed a new NAPA 1258 back in May....... maybe I should change mine too.


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Come to think of it.......... Before I left the car sitting for all the body and paint work, I changed the oil and the 1258 Napa filter. It never made the noise before sitting. And we only pushed the car around for all the painting. Now I have the noise I wonder if I got a bad filter also. I'll still bring a pressure gauge home this weekend and try to pinpoint the noise. But seems like a filter would be the cheapest thing to try.


Crazy the things we forget and then remember by having conversations.
 

ek02

Well-Known Member
#17
I have been using the NAPA 1258 for years. Never had a problem with bleed down. Something has changed on those filters other than the color because the last two I used had bleed down. I cut them open and they looked fine. No reason found for bleeding down overnight. The latest filter I used is fine. Maybe a bad batch?