Ticking after lq swap and cam.
07-08-2012, 03:17 PM
#1
Ticking after lq swap and cam. Well I just finished putting in my 390ci lq4. Brand new shortblock with compstar rods, compstar crank, diamond pistons. Its pretty much a brand new engine. Every seal and gasket was replaced. I put in a custom grind comp cam, ls7 lifters, ls2 Lifter trays, 7.400 pushrods, slp oil pump, jp double roller timing chain, new monster clutch, new slave, Texas speed longtubes, ati balancer. I think that sums it up. But its ticking it seems to be coming from the front passenger side valve cover. It valve train noise for sure but I don't know what's causing it. I pulled the valve cover and re torqued the rocker bolts, they were all ok. I did not measure pushrod length so that is my first guess is wrong length pushrods. But the tick only come from only 1 place. Wouldent they all be making noise if the pushrods were the wrong length? I'm so lost at this point. Any help would be appreciated. The noise seems allot louder on cold starts then when its warm its quieter but still there. Any ideas?
07-08-2012, 06:20 PM
#3
... What does spelling have to do with my post. You got the idea. I'm on my touch screen phone... Anyone have any helpful info. If it was wrong pushrod length, is it possible for only one to be making noise.
07-08-2012, 07:03 PM
#5
I soaked them over night. And before I started it I pulled the fuel pump fuse and plug wires and primed it. It better now be a bad Lifter because I don't feel like pulling the head off again. Any other ideas? Or a way to tell if it is a Lifter for sure?
07-08-2012, 08:21 PM
#7
Correction fail. Next time find the Edit Post button. 
Back to your problem, it's possible that the sound is just a noisy injector.
Before you open up the engine, grab a mechanic's stethoscope for $15 or whatever and probe around to narrow down the source of the noise:
1.) Probe the valve cover at various points and note where the noise is loudest. Then probe the same point on the opposite cylinder bank, and compare the volume/intensity of the sound.
2.) Probe the injector nearest that point, and then probe a few other injectors to compare the volume/intensity of the injector sound.
Some Delphi injectors are just noisier than others, so I'd rule it out as the source before diving into the engine.
If the injector isn't the noisemaker, check your exhaust manifold gasket and bolts. Did you follow the GM procedure for torquing the bolts, from inside to outside, in 2 separate steps? If not, an exhaust leak is possible and should be ruled out by removing the exhaust manifold and checking for black streaks indicative of a leak. I like Cometic MLS exhaust gaskets over GM ones, as the newer GM design has whacky port shapes whereas Cometics are symmetric and should seal better. During reinstallation, follow the GM 2-step procedure *exactly* including a torque wrench so the gaskets lay smoothly and get uniform pressure applied to them.
If still no luck finding the source, it's time to grab a Comp pushrod measurement tool for $20 and follow the procedure posted here on the board. Let us know what you find for zero-lash pushrod length.
Good hunting!
Back to your problem, it's possible that the sound is just a noisy injector.
Before you open up the engine, grab a mechanic's stethoscope for $15 or whatever and probe around to narrow down the source of the noise:
1.) Probe the valve cover at various points and note where the noise is loudest. Then probe the same point on the opposite cylinder bank, and compare the volume/intensity of the sound.
2.) Probe the injector nearest that point, and then probe a few other injectors to compare the volume/intensity of the injector sound.
Some Delphi injectors are just noisier than others, so I'd rule it out as the source before diving into the engine.
If the injector isn't the noisemaker, check your exhaust manifold gasket and bolts. Did you follow the GM procedure for torquing the bolts, from inside to outside, in 2 separate steps? If not, an exhaust leak is possible and should be ruled out by removing the exhaust manifold and checking for black streaks indicative of a leak. I like Cometic MLS exhaust gaskets over GM ones, as the newer GM design has whacky port shapes whereas Cometics are symmetric and should seal better. During reinstallation, follow the GM 2-step procedure *exactly* including a torque wrench so the gaskets lay smoothly and get uniform pressure applied to them.
If still no luck finding the source, it's time to grab a Comp pushrod measurement tool for $20 and follow the procedure posted here on the board. Let us know what you find for zero-lash pushrod length.
Good hunting!
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07-08-2012, 08:39 PM
#8
Thanks for the help. I already used a stethoscope. It sounded like one rocker was a little noisier then the others. I didn't try listening to the injectors though. And iv double checked the exhaust bolts already there all tight. I haven't removed the header yet though to look at gasket. There was an exhaust leak there before but some of the studs worked them selves lose. I re tightened and it went away. But it sounded different then the noise now. Il check the injector next.
07-08-2012, 09:17 PM
#10
Thanks for the help. I already used a stethoscope. It sounded like one rocker was a little noisier then the others. I didn't try listening to the injectors though. And iv double checked the exhaust bolts already there all tight. I haven't removed the header yet though to look at gasket. There was an exhaust leak there before but some of the studs worked them selves lose. I re tightened and it went away. But it sounded different then the noise now. Il check the injector next.
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Exhaust sounds can vary quite a bit depending on the size, location, and direction of the exit stream. Downward-facing leaks vs. upward-facing ones, for example. And MLS gaskets generally won't completely re-seal after a carbon track has built up between the layers.
07-08-2012, 09:31 PM
#12
And that GM exhaust torquing procedure I listed is very critical, both in terms of the sequence and fastener torque.
It's like smoothing a wrinkle out of a rug from the center outward, and if you don't follow it you risk putting a wrinkle into your MLS gasket which will permanently leak.
