TURBO6.0L

iTrader: (1)

Looking for some alternatives to PRC duals and Patriot duals. I have the patriot duals now and they are too noisy.
Car runs 12 to 13lbs of boost at less than 6200 rpm. Lift on cam is around .620.

Thanks for everyone's time

ls1 1990 VN

PAC 1518s

TURBO6.0L

iTrader: (1)

I was checking out the PAC 1518 springs and the pressures are quite a bit lower than what I have.
What are the safest minimum specs I can get away with?

ls1 1990 VN

PAC 1518s are .650. Your patriots are what? .650

TURBO6.0L

iTrader: (1)

Yes. .650. I am more worried about what spring pressures I need.
Thanks

XtraCajunSS

iTrader: (2)

What heads are you using with what valves? Are you using stock rockers? What lobe family is your cam cut on?

Also, just and FYI, springs WILL NOT have any affect on valvetrain noise UNLESS they are already inadequate for your application and you are already destroying parts...

Shane

TURBO6.0L

iTrader: (1)

GM 317 heads with factory valves. Machine shop touched up seats and valves. 1.85 ratio slp rockers. I have tried stock 1.7's and Harland sharp 1.8 roller tips with same noisy results.
Cam has XER lobes.

My dual springs are noisy. They are adequate for the application and nothing is broken, just noisy as hell. I have swapped rocker arms, push rods, changed pre-load higher and lower, swapped springs from quiet valves to noisy ones and they remain noisy. The engine has been completely torn down and nothing was found. Lifters and trays were replaced as well. Only thing that has helped was removing the inner spring from dual setup. The noise was finally gone then.
This is why I am looking into seeing what springs will work for my application.

Thanks again for everyones time.

XtraCajunSS

iTrader: (2)

The springs are not causing the noise. The rocker arms you are using along with XE-R lobes are causing the issue. Have you looked at the cam lobes? How long did you run this setup with rockers other than stock? I've been down this road before. If you would like, discussing this issue over the phone would be much easier. You can give me a call at the shop tomorrow if you like.

Also, I hate to ask what might sound like a stupid question, but what spring locators are you using and what is your installed height?

Thanks,
Shane

TURBO6.0L

iTrader: (1)

I started off the build with the harland sharp roller tip rockers which were on the car for about 3500 miles. The engine was then torn down and everything was inspected by the machine shop and myself. The lifters and trays were replaced at that time since no issues were found. The cam lobes barely had a track on them where the rollers on the lifters were riding.
I have about 9000 miles on the engine now and have used the other 2 sets of rockers with the same results. The car runs strong and makes good power on the dyno.

I will try to give you a call tomorrow. Thanks again for your time.

TURBO6.0L

iTrader: (1)

I have been working with Shane at thunder racing for the last few weeks. The springs were indeed causing most of the ticking noise I was hearing. They were loose enough on the seat and the retainer that they could move around and were hitting the valve seals as well as making noise on the retainers. These were a PRC spring setup that was good to .650 lift. After talking with Shane and troubleshooting further I ended up swapping out the whole spring setup and setting the install heights .050 to .075 from coil bind. I used the comp 26926 kit with the tool steel retainers. Also due to the xER lobe cam I am using I put rebuilt stock rockers in. The car has never been this quite and now just has the sewing machine noise that comes and goes. To hear it in the car now I have to turn everything off and listen for it. I can certainly live with this for now but will call Shane in the future when the time comes to upgrade to a different custom cam.

I would like to thank Shane at Thunder Racing for all his help and the knowledge that he shared. He spent plenty of his precious time on the phone with me and did not even try to sell me any parts. I have been working on this now for almost 2 years consulting many experts local and abroad that said everything looked normal even though none of them felt the noise was.

Thanks again Shane. You are a true forum sponsor and a great guy to have gotten to know!! Other than flying out here with free parts there was nothing more you could have done. I will certainly do business with you again.

XtraCajunSS

iTrader: (2)

Thank you so much for the kind words, Brent. Posts like this make my day!

I am glad I could help you.

Thanks again,
Shane