What preload, what cam, noisy?
04-15-2014, 01:50 AM
#1
Drifting
Thread Starter
What preload, what cam, noisy?
What lifter preload, what lifter, and what cam are you running? Is it noisy?
228/232 .571/.573 112
.080", comp cam OEM style
Yes, very noisy.
228/232 .571/.573 112
.080", comp cam OEM style
Yes, very noisy.
Last edited by reactor2; 04-16-2014 at 09:21 AM.
04-15-2014, 04:38 PM
#2
Drifting
Thread Starter
Anybody?
Just trying to get an idea what the secret sauce is. I understand that there are multiple variables at play but is like to see what preload people are generally using that generally results in a quieter valvetrain.
I think the tendency is to increase preload to quiet valvetrain when it probably makes sense to reduce preload.
Just trying to get an idea what the secret sauce is. I understand that there are multiple variables at play but is like to see what preload people are generally using that generally results in a quieter valvetrain.
I think the tendency is to increase preload to quiet valvetrain when it probably makes sense to reduce preload.
04-15-2014, 06:42 PM
#3
Drifting
I was shooting for 0.062" preload for my install:
TSP 228r, 588, 112LCA, stock heads, stock lifters.
Pushrods ended up being 7.375". For the most part its still fairly quiet. Noisier than stock but it does not have the sewing machine sound.
TSP 228r, 588, 112LCA, stock heads, stock lifters.
Pushrods ended up being 7.375". For the most part its still fairly quiet. Noisier than stock but it does not have the sewing machine sound.
04-15-2014, 09:19 PM
#4
Drifting
Thread Starter
Were your heads milled? Or is the stock preload > .062"
04-16-2014, 09:18 AM
#5
Drifting
Thread Starter
It seems like lifter preload is the biggest piece of black magic in engine building. I've read that lifter preload should be anywhere from .01"-.1" and the contradicting info even on the same lifter (e.g. stock, LS7, etc.) is also all over the board.
The biggest issue to aftermarket cams is the valvetrain noise. Some have it and some claim they don't.
The reason for this thread is to help determine what the magic sauce is for low noise aftermarket cams. Is it less preload, more preload, etc.
So, c'mon, guys post up your info. What cam, what lifter, what preload, and how noisy is your valvetrain?
The biggest issue to aftermarket cams is the valvetrain noise. Some have it and some claim they don't.
The reason for this thread is to help determine what the magic sauce is for low noise aftermarket cams. Is it less preload, more preload, etc.
So, c'mon, guys post up your info. What cam, what lifter, what preload, and how noisy is your valvetrain?
04-16-2014, 04:31 PM
#7
Drifting
Heads not milled, never removed.
I was told to shoot for .050 to .090" preload. I thought shorter pushrods seemed weird as well. I also tried figuring out the length based solely on base circle measurements of both cams. That resulted in 7.4364 (assuming 7.38 OEM). I was told to believe the length as determined by the length checking tool and told not to assume GM’s setup was anywhere near ideal, because there is a lot of variance in stock engines and they use one pushrod for all of them.
I was told to shoot for .050 to .090" preload. I thought shorter pushrods seemed weird as well. I also tried figuring out the length based solely on base circle measurements of both cams. That resulted in 7.4364 (assuming 7.38 OEM). I was told to believe the length as determined by the length checking tool and told not to assume GM’s setup was anywhere near ideal, because there is a lot of variance in stock engines and they use one pushrod for all of them.
Just out of curiosity, if the stock pushrods are 7.385" (GM says 7.4" but they aren't really), and you went stock heads with a higher lift cam, shouldn't you have ended up with a longer pushrod since the cam's base circle is smaller than stock?
Were your heads milled? Or is the stock preload > .062"
Were your heads milled? Or is the stock preload > .062"