408 engine noise **VID**
408 engine noise **VID** Ok I asked if 408s were normally noisey and couldnt really get a clear answer, yes a little but no not really. Anyway heres a vid of it so if you could listen to it and let me know if it sounds a little noisey or not and what it might be if it is I would appreciate it.
http://necrocannibal.mine.nu/Power%2...20%20noise.mpg
http://necrocannibal.mine.nu/Power%2...20%20noise.mpg
Originally Posted by Country Boy
What rockers are you using? When the lash was getting loose on my old rockers, it would make the same noise.
The rockers are stock rockers. Should I upgrade them to a better rocker?? And would that stop the noise? Is it anything to worry about?
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Joined: Dec 2001
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From: Ft. Lauderdale, FL, USA
Originally Posted by necrocannibal
The rockers are stock rockers. Should I upgrade them to a better rocker?? And would that stop the noise? Is it anything to worry about?
Why would you use stock rockers on a big stroker motor?
My bud BLKWS on here has a 408 stroker from FMS with stock rockers and it is as quiet as (valvetrain wise) as any stock LS1 I have ever heard...although we had to have 7.35 lenght PR's to get it to crank/run.
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That is way too noisy. The valve train geometry is off. I run stock rockers and they are close to stock noise wise. Your motor seems to be running really ruff. I would pull those valve covers off immediately and readjust the valve train. May be wrong size pushrods, or may need to add shims. Have the heads been milled. Is the base circle on the cam .030 under? What lifters and what size pushrods?
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Verdad Gallardo I do not have poly motor mounts. My heads as far as I know have not been milled. They are PP LS6 style stage 3s, I do not believe they come milled. The lifters are stock ,I do believe, and the pushrods are stock length hardened pushrods. Ill ask the guy who built it for sure today if the lifters are stck nut I do think they are. I dont not know about the base circle on the cam. Not really sure what you are asking as I am not a mechanic and do not know that much about all of it. Will I be loosing horsepower with valve train geometry being off or the pushrods being too short, if thats an issue?
Originally Posted by Quickin
Why would you use stock rockers on a big stroker motor?
Whe I had tis motor built I wasnt in the market for a new motor or more horsepower but my LS1 went down and I got a really good deal through a friend on it. I didnt have enough money to do the rockers, intake, TB or bigger headers. Is was kind of a budget 408.
Shoot me a PM. If you're going to be in Nashville anytime soon, I can help you fix it. It does sound like a loose rocker or rocker hitting the valvecover. Could be a weak lifter or spring or just about any of the stuff mentioned above. I have all the stuff to check it out...gimme a shout.
You could definitely be losing some power. I don't know if I would go back to the shop that built the motor. They are shady to release a car like that as is. You need to take it to someone who knows what they are doing. May need to shim up some of those rocker arms.
Originally Posted by Unaffiliated Racing
You say that as if you know all the details. I built that motor in that car.It wasn't released to him like that.This motor has been built for a year.
Wayne..the owner has changed the heads on the car after the motor had been built.I know what I'm doing...valvetrain is my job.
I think the problem is that when you(wayne) changed the heads on the car. They were not milled like the heads we built the motor with. That will affect pushrod length but it will need to be checked with a dial indicator to see if you actually need new pushrods.
Wayne..the owner has changed the heads on the car after the motor had been built.I know what I'm doing...valvetrain is my job.
I think the problem is that when you(wayne) changed the heads on the car. They were not milled like the heads we built the motor with. That will affect pushrod length but it will need to be checked with a dial indicator to see if you actually need new pushrods.
Sorry bud, I appologize to you. From the post it sounded like the motor was just built and is noisy. If he swapped the heads then the valve train is definitely where the problem started.
Brian I was thinking about the pushrod length as maybe being an issue but wasnt sure, I really wasnt thinking about it when I was hearing the noise as being the cause of it. I dont know what length pushrods you used or what lifters you used or anything so I couldnt answer any of those questions. After seeing the vid what would you say the noise might be?? Or would you really have to check it to know for sure?
To clear things up this motor was built last April-May, 2004, and has been running in the car with no issues until now. My cousin and I switched out the heads ourselves because the heads I had were stage 2s and I needed stage 3s and we decided we could do it ourselves. The car still runs fine but has the noise I dont like.
To clear things up this motor was built last April-May, 2004, and has been running in the car with no issues until now. My cousin and I switched out the heads ourselves because the heads I had were stage 2s and I needed stage 3s and we decided we could do it ourselves. The car still runs fine but has the noise I dont like.
Originally Posted by 00PwtrSS
every ls1 head and cam car i have heard of has that sound, mine does, and i have been driving my car for a year like that, have checked the geometry and everything checks out good
Mine doesnt have any topend knock that goes away...
