Question regarding lifter bleed down and failures
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Question regarding lifter bleed down and failures Just installed a set of Brian Tooley extreme dual springs into a 1999 FRC vette. engine has low miles like under 40000. Also, at the same time installed a set of Scorpion 1.8 roller rockers. Stock cam still.
Engine now has a noticeable tick. Sounds like prolly valvetrain like a lifter. So, after getting the engine hot, pulled the valve covers and found on the pass side all the rockers were in a rest position like the lifters bled down as all the valves were shut. Fired the engine up and checked the drivers side and there were valves open like normal on 2 cylinders. Cranked the engine over again and you could see after sitting for a minute the rocker moving to rest position.
Is it normal for the lifters to bleed down like this after sitting?
Are the lifters whipped? OR is it normal for the stock lifters to bleed down quickly?
We suspect, judging by the noise that one lifter is kinda shot and ticking, BUT the whole one side of the engine????? Not sure if they normally bleed down like this? Is this normal after installing much stronger valve springs?
BTW, engine is otherwise stock, clean and looks to be unbeaten, YET. LOL. Input would be appreciated. Thanks.
Engine now has a noticeable tick. Sounds like prolly valvetrain like a lifter. So, after getting the engine hot, pulled the valve covers and found on the pass side all the rockers were in a rest position like the lifters bled down as all the valves were shut. Fired the engine up and checked the drivers side and there were valves open like normal on 2 cylinders. Cranked the engine over again and you could see after sitting for a minute the rocker moving to rest position.
Is it normal for the lifters to bleed down like this after sitting?
Are the lifters whipped? OR is it normal for the stock lifters to bleed down quickly?
We suspect, judging by the noise that one lifter is kinda shot and ticking, BUT the whole one side of the engine????? Not sure if they normally bleed down like this? Is this normal after installing much stronger valve springs?
BTW, engine is otherwise stock, clean and looks to be unbeaten, YET. LOL. Input would be appreciated. Thanks.
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Venom. You mean the stiffer springs causing the lifter to make more noise? That is my thinking at this point. Stiffer spring aggravated the lifter. Or maybe more than one! The noise seems to be more over the intake than the valve covers
Last edited by SSZ; Aug 24, 2012 at 08:48 AM.
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Lifters are small pneumatic pistons operated by oil pressure feeding the inner housing which pressurizes the outter and thus automatically zeros valve lash. Because of laws of physics - once the lifter is pressurized it can hold this pressure with immense force and transfer the forces of the cam lobes to the pushrods.
Lifters without pressure will collapse just as hydraulic pistons do with no safety check-valves. The do not fully collapse, but they are not open either - a semi-neutral state depending on where the lifter is sitting on the lobe when the motor is shut off.
stiffer springs against stock lifters is not a problem until you get into the upper RPM's where the lifter acts like a wet sponge - unable to fully pressurize on the base of the cam before the next lift event occurs. If you're hearing ticking at idle and it does not go away once the motor is warmed up then i would look at what viscosity oil you're running, or it may be time to upgrade the 40,000 mile lifters to hold the higher spring pressures and 1.8RR.
Lifters without pressure will collapse just as hydraulic pistons do with no safety check-valves. The do not fully collapse, but they are not open either - a semi-neutral state depending on where the lifter is sitting on the lobe when the motor is shut off.
stiffer springs against stock lifters is not a problem until you get into the upper RPM's where the lifter acts like a wet sponge - unable to fully pressurize on the base of the cam before the next lift event occurs. If you're hearing ticking at idle and it does not go away once the motor is warmed up then i would look at what viscosity oil you're running, or it may be time to upgrade the 40,000 mile lifters to hold the higher spring pressures and 1.8RR.
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Two things to check:
1.) Higher rocker ratio.
The 1.8 rockers have increased the net preload on your lifters. Best next move is to get a Comp measuring tool and run the procedure posted here, get an accurate measurement, and see if you're out of preload spec range.
2.) Stiffer springs.
What is the rate of your new springs, and what installed height did you set them to?
1.) Higher rocker ratio.
The 1.8 rockers have increased the net preload on your lifters. Best next move is to get a Comp measuring tool and run the procedure posted here, get an accurate measurement, and see if you're out of preload spec range.
2.) Stiffer springs.
What is the rate of your new springs, and what installed height did you set them to?
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Yeah whats the pressure ratings on those springs?
Why a dual spring?
Did you change the pushrods with the 1.8 rocks? The geometry has changed with the new rocks. And the stock pushrods barely stay straight in stock trim much less under dual springs.
Why a dual spring?
Did you change the pushrods with the 1.8 rocks? The geometry has changed with the new rocks. And the stock pushrods barely stay straight in stock trim much less under dual springs.
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IIRC the springs seat pressure is 155lbs. Also, new pushrods were installed and yeah they werent centered in the hole well at all.
Anyhow, we removed the 1.8 RRs and reinstalled the stock rockers. Noise is gone. My friend is a little bummed but the engine has never sounded quieter.
Dual springs were used for future upgrades and he was going to replace the pushrods anyhow. They are Brian Tooley extreme spring kit. Great kit for a great price.
Anyhow, we removed the 1.8 RRs and reinstalled the stock rockers. Noise is gone. My friend is a little bummed but the engine has never sounded quieter.
Dual springs were used for future upgrades and he was going to replace the pushrods anyhow. They are Brian Tooley extreme spring kit. Great kit for a great price.
Do you think the pushrods were making the noise? I can't see the rockers making that much noise, unless they were hitting something?
I'm glad you got it quiet, now time for a camshaft!
I'm glad you got it quiet, now time for a camshaft!
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Hey Brian, sent you a pm on YB thanking you for your service. You have some great stuff. I think if my friend wants to run these rockers we will have to check pushrod length. I told him to put the cam in from the beginning but, how would i put this, HE WAS BEING A *****. LOL. Thanks for your help though Brian. Hopefully he will hook up with you for a cam.
