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Valve train noise Ive been holding off on posting this trying to figure it out myself but I’m not getting anywhere so before I do something stupid I’d better get some of your input. Combo is SBE 6.0, 317 heads. BTR 660 spring kit, BTR stage II turbo cam. Comp trunnion upgrade. Ls9 gaskets. Ive got a loud valve train noise that I can’t seem to figure out. First fire up I had the stock pushrods in and it was very noisy. This combo obviously isn’t out of the ordinary and most of the time the 7.4’s seem to work so I gave it a shot. I didn’t have a length checker at the time so I took a shot and installed some 7.35’s that I had, no change. So I got a comp pushrod length tool and am finding the lengths all over the place. Most valves need a 7.4 but there are a few that measure 7.5 and 7.3 by my calculations. I’m positive I’m doing the process correctly and measuring from base circle. I’m kinda at a loss right now. I had these heads and lifters on a 5.3 with an ls6 cam and it was super quiet. I’m not sure if the cam mad that big of a difference or something is off. I feel like I’m going to have to pull the heads and start from scratch but hopefully you guys can convince me otherwise. Heres a a clip of it running. I know some have the “sewing machine” sound but this seems like more than that. |
what lifters you using ? |
Stock 5.3 lifters. |
How many miles since the trunnion upgrade? The Comp needle bearing kit is not known to last long, as the trunnions themselves seem to be too soft, and start wearing at a fast rate soon after installation. The bronze bushing kits are the way to go here. |
No miles. Probably only half hour run time total. I figured I just needed the proper length pushrods. |
You might be right..... |
Ok. So I went back through everything, measured ever valve for length. I was a bit out first time I think. (First time and probably rushing) This time everything was relatively close, 7.370-7.360 with the added .070 for preload. I feel like the 7.350 pushrods should be good? I put them back in taking the time to properly set them to 22ft/lbs on each base circle. Fired it up and it’s still really noisy. Am I wrong I thinking the 7.350’s should work? I could put the 7.4’s back in but they were noisy too. It doesn’t seem like it’s just one or two bad ones, the noise seems to be consistent throughout. I’m kinda at a loss here. This ones from today after running for about 20 min. |
Forgot to add oil pressure is good. 50 psi at idle |
I'm listening on my phone so it's hard to tell much. Are there any exhaust leaks? |
No exhaust leaks. I think my next step is to try a pushrod with less preload maybe go down to a 7.25 and see what difference ,if any, it makes. |
In your first post you mentioned you measured anywhere from 7.500 - 7.300 If that is correct you are not measuring correct or not being accurate enough because that is a .200" swing which is just not happening. That's more than the lifter travel itself. I would measure again and be very precise and steady. Pull and push on the rocker arms after running to make sure a arm did not come loose or that you do not have a collapsed lifter |
I did go back and re-measure, I outlined it in post 7. Second time around was much more consistent. .010 difference max. 7.360-7.370 with adding .070 for preload. I have 7.350 in now. |
Please ignore if you've already tried this. Fwiw It might be worth measuring the actual push rods to confirm they are actually 7.35 push rods. Some folks number and measure each p-rod then measure at each position with the p-rod checker and assign to the p-rod to the best matched position. There is usually a little variation in 16 p-rods. |
Pull the oil filter and look for air bubbles, you may have a damaged o ring on the oil pump. |
For some reason the videos are not working for me. |
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