giant sewing machine
03-07-2005, 07:38 PM
#1
giant sewing machine, need advice
The head and cam install has been a bitch, the guy who did it for me didnt torque the rocker arms correctly and they backed off on me when I was driving to get it tuned. So I got a tow to my tuner guy who was luckily only 15 miles away after the one hour drive. After removing both valve covers and finding a couple that were just flopping around freely one had put some nice gashes on the undeer side of the driver cover!!!! I torqued them down and got a mediocre tune just so it would idle and run. I didnt fully dyno tune it becuase of noisy valves.
Now the problem is Ive got alot of valve clatter and claking sounds.
Ive had the heads milled .050 and so I went with 7.35 pushrods evidently the ratio isnt 1:1 and Im thinking of putting the stock size 7.4 rods back in and hoping the valve chatter goes away.
Aside from all the above the thing is a beast, the whole truck shakes at idle and is alot louder than stock with the gt2-5 cam. Ive havent opened it up but got to around 4500 and it pulls like a mother.
Any thought are appreciated!
If your running with milled heads Id like to hear what length rods your using, how much youve milled and if youve checked valve train geometry.
Now the problem is Ive got alot of valve clatter and claking sounds.
Ive had the heads milled .050 and so I went with 7.35 pushrods evidently the ratio isnt 1:1 and Im thinking of putting the stock size 7.4 rods back in and hoping the valve chatter goes away.
Aside from all the above the thing is a beast, the whole truck shakes at idle and is alot louder than stock with the gt2-5 cam. Ive havent opened it up but got to around 4500 and it pulls like a mother.
Any thought are appreciated!
If your running with milled heads Id like to hear what length rods your using, how much youve milled and if youve checked valve train geometry.
03-07-2005, 08:00 PM
#2
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When I switched to Harland Sharp rockers I had more than the recommended preload it was quiet as hell (2 1/2 turns of preload) I went to 7.350 pushrods and it got alittle louder I was still a 2 turns when I should have been a 1 1/2 turns. I got 7.325 push rods and it got the right preload, 1 1/2 turns as it says with the rockers and it sounds like a dam sewing machine. When the new heads get done they will have 30 thousands off them and I am going to use the 7.325 with them.
I would put the 7.400 back in there and see if it quiets it down any, I think it will. There ia alot of debate over in the Internal section about correct preload anywhere from .60 to .120. I think alittle more won't hurt. You just have to be careful with the stock pushrods and different springs you could end up with a few bent ones.
I would put the 7.400 back in there and see if it quiets it down any, I think it will. There ia alot of debate over in the Internal section about correct preload anywhere from .60 to .120. I think alittle more won't hurt. You just have to be careful with the stock pushrods and different springs you could end up with a few bent ones.
03-07-2005, 08:50 PM
#3
So what is the recommended preload?
how do I figure what pushrod size I will need with the heads milled .05, theres got to be a certain ratio or formula?
Will it be ok to turn it 6500 with less preload like I have in my current setup?
Im assuming the valve clatter/chatter is from less preload.
The engine feels very tight its just noisy.
how do I figure what pushrod size I will need with the heads milled .05, theres got to be a certain ratio or formula?
Will it be ok to turn it 6500 with less preload like I have in my current setup?
Im assuming the valve clatter/chatter is from less preload.
The engine feels very tight its just noisy.
03-07-2005, 09:01 PM
#4
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Is it a valve tap or does it sound like lifters tapping? These motors a known to have this problem. Does it get worse after it is hot? Another theory I heard is the injectors working harder to keep up with the increased need of fuel with a bigger cam.
I was told that the recommended preload is 60 thousands, but there are people using as much as 120 thousands. I wish I could figure it out myself I have been messing around with dfferent pushrod lengths also. Nothing has been awful nosiey though. More preload is definately quieter.
What rockers are you using?
I was told that the recommended preload is 60 thousands, but there are people using as much as 120 thousands. I wish I could figure it out myself I have been messing around with dfferent pushrod lengths also. Nothing has been awful nosiey though. More preload is definately quieter.
What rockers are you using?
03-07-2005, 09:07 PM
#5
What cam did you install? How much lift and what lobes? .050 mill is large. I'd think a 7.35" pushrod would be about right, but without knowing the cam specs, its hard to say. Some valvetrain noise is normal, but after your experience with the lifters, I'm sure you are worried.
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03-07-2005, 09:56 PM
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I think that lobe could be some of the sound you are hearing. How long ago did you put this in? Mine was loud, but after awhile it got quieter. I have 1000 miles on it now and it really isn't that bad. How many miles do you have on it?