Valve springs too strong?
12-20-2001, 09:53 PM
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Car: Pontiac Grand Prix GTP
Engine: 3.8L V6 SuperCharged
Valve springs too strong?
How do you know if your valve springs are too strong for the lifters and cam? The reason I ask is cause I have afr 190 heads that came with beefy springs and I only have a high energy comp cams 268 hydraulic with comp magnum pro 1.6 roller rockers, and I can't quiet them down! I do a proper valve lash adjustment and they are quiet for a short while but gradually get real loud. I even got an adjustable pushrod and consequently have the proper lenght pushrods now. could the valve springs be "overpowering" the lifters and slapping shut too hard and too fast? Would this be dangerous to the VERY expensive heads? The part # springs I have from AFR are #8020 which are 1.450" OD hydraulic Dual Springs with dampner (120 lbs. on seat and a .550" lift maximum). My cam has .484" lift with the 1.6 rockers. thanks!
John
John
Last edited by johns84bird; 12-20-2001 at 10:01 PM.
12-20-2001, 10:24 PM
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Car: No more birdy
I dont know which springs come with that head but they should be fine. That comp 268 isnt too wussy of a cam to have problems, I dont think any cam would have a problem with beefy springs. What kinda condition are your lifters in? I have to ask.
SSC
SSC
12-21-2001, 05:05 AM
#3
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Check your oil pressure when hot with a guage to see
if its too low at idle. Any of the high bleed type lifters
or cheap offshore lifters can be affected by exessive spring pressure, and low oil pressure - lifter bores could be worn also.
if its too low at idle. Any of the high bleed type lifters
or cheap offshore lifters can be affected by exessive spring pressure, and low oil pressure - lifter bores could be worn also.
12-21-2001, 10:44 AM
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Car: 88 Firebird WS6
Engine: 350 TPI
Transmission: T56
Axle/Gears: 3.42
Possibly your guide to retainer clearance is too tight and you are pulling out your studs. Then they seem to loosen....
I have seen this before.
I have seen this before.
12-21-2001, 11:30 AM
#5
Those AFR's gotta have screw-in studs. Won't loosen unless not tightened properly when istalled and Red Loctited...
I'd call Comp tech and give them your spring rates. I assume you are using the Comp lifters. They'll tell you what to do. If you used some cheapo lifters with ramps and spring pressures like that, topped off with 1.6's to make it worse, the lifter may be all done or well on there way.
I'd call Comp tech and give them your spring rates. I assume you are using the Comp lifters. They'll tell you what to do. If you used some cheapo lifters with ramps and spring pressures like that, topped off with 1.6's to make it worse, the lifter may be all done or well on there way.
12-21-2001, 11:54 AM
#6
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Just asking to to call anyone dumb or anything but
(If you have adjustable rockers)
you did tighten the little Center Allen-Key nut after Adjusting the rockers right? its responsible for holding them in place....
On another note I had that problem with one of my Rocker Arm Nuts, it would consistantly come loose over and over and over after about 4 miles or less of driving. It seemed oil-pressure / hot engine related, but i never took the time to figure out. I screwed the rocker nut to where i wanted it, tightened the center-nut, then purchased 2 Stud girdles and put those one, tighted the allen nut on them, then the little bolt on each rocker nut. The stud girdle is meant for High RPMs but in this case it hold my rocker nuts EXACTLY where i leave them.
Even with the exact place you put the Rocker nuts in, and tighted the hell outa the center allen-key nut the rocker nut can still move a little, either tighten itself, in which case the cetner-allen-key thing will stop it and cause the rocker nut to hold still, or Loosen itself, which is extremelly rare im told, but can happen in relation to Fast-bleed lifters / low oil pressure / too much oil in car (??? i never got that one but its true it happened to me) etc....
Another trick is to adjust the rocker nut where you want it, then Clamp down on the threads just above it so they squish a little. then the rocker nut tries to come loose, and hits those squished (messed up) threads and cant loosen itself. this is obviouselly meant to be a quick fix and damages rocker Studs if you have AFR's i dont recommend it but I've had to do it before to just get my car home.
Keep in mind if your Rockers are TOO tight it will damaget hell outa your cam. When you first installed the cam, you should have put that lube crap (not engine oil) all over its lobes, and some other crap on its journals. Then for the first time run and break in, you DO NOT lash the rockers like normal, since the lifters have no oil in them.<b> You give each Rocker .010 LASH (just like in solid lifters) so when it fills up with oil its where it should be. </b> this is ONLY for the first time run, and failure to do so will cause extreme cam / lifter damage in the first 5 minutes of running, because the lifters are trying to pump up but cant and so put extra pressure on the brand new cam lobes causeing a really weird Wear Pattern which can do really funky stuff to your valve train as far as erratic lift / duration and tons of noise. this happened to my first cam I did everything right except initial rocker adjustment, i did them like normal rockers, finger tight (or if running, until they clack) then an extra 1/4 turn (not 1/2 because my springs are singles and i like long lasting valve trains)
Email me if you have any odd questions.... I've made just about every damn mistake in the book so far trying to learn this stuff and Im pretty well versed on what NOT to do from bad experiences. Just ask horsepower sales how many cam changes I've done in 5 weeks.
Kingtal0n@aol.com
(If you have adjustable rockers)
you did tighten the little Center Allen-Key nut after Adjusting the rockers right? its responsible for holding them in place....
On another note I had that problem with one of my Rocker Arm Nuts, it would consistantly come loose over and over and over after about 4 miles or less of driving. It seemed oil-pressure / hot engine related, but i never took the time to figure out. I screwed the rocker nut to where i wanted it, tightened the center-nut, then purchased 2 Stud girdles and put those one, tighted the allen nut on them, then the little bolt on each rocker nut. The stud girdle is meant for High RPMs but in this case it hold my rocker nuts EXACTLY where i leave them.
Even with the exact place you put the Rocker nuts in, and tighted the hell outa the center allen-key nut the rocker nut can still move a little, either tighten itself, in which case the cetner-allen-key thing will stop it and cause the rocker nut to hold still, or Loosen itself, which is extremelly rare im told, but can happen in relation to Fast-bleed lifters / low oil pressure / too much oil in car (??? i never got that one but its true it happened to me) etc....
Another trick is to adjust the rocker nut where you want it, then Clamp down on the threads just above it so they squish a little. then the rocker nut tries to come loose, and hits those squished (messed up) threads and cant loosen itself. this is obviouselly meant to be a quick fix and damages rocker Studs if you have AFR's i dont recommend it but I've had to do it before to just get my car home.
Keep in mind if your Rockers are TOO tight it will damaget hell outa your cam. When you first installed the cam, you should have put that lube crap (not engine oil) all over its lobes, and some other crap on its journals. Then for the first time run and break in, you DO NOT lash the rockers like normal, since the lifters have no oil in them.<b> You give each Rocker .010 LASH (just like in solid lifters) so when it fills up with oil its where it should be. </b> this is ONLY for the first time run, and failure to do so will cause extreme cam / lifter damage in the first 5 minutes of running, because the lifters are trying to pump up but cant and so put extra pressure on the brand new cam lobes causeing a really weird Wear Pattern which can do really funky stuff to your valve train as far as erratic lift / duration and tons of noise. this happened to my first cam I did everything right except initial rocker adjustment, i did them like normal rockers, finger tight (or if running, until they clack) then an extra 1/4 turn (not 1/2 because my springs are singles and i like long lasting valve trains)
Email me if you have any odd questions.... I've made just about every damn mistake in the book so far trying to learn this stuff and Im pretty well versed on what NOT to do from bad experiences. Just ask horsepower sales how many cam changes I've done in 5 weeks.
Kingtal0n@aol.com
12-21-2001, 12:33 PM
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Kingtal0n,
Can't I put the new lifters in a bucket of engine oil (submerged) and pump them up with a pushrod before assembly and set the lash correctly from the start? I have heard of doing this somewhere before, what do you think?
Can't I put the new lifters in a bucket of engine oil (submerged) and pump them up with a pushrod before assembly and set the lash correctly from the start? I have heard of doing this somewhere before, what do you think?
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12-21-2001, 12:57 PM
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Car: 4
Engine: 6
Transmission: 5
For all practical purposes, there's no such thing as too much valve spring. 120 lbs on the seat and 300-ish open is what those ones that AFR supplies should give you, which is perfect.
If your rockers aren't staying adjusted, then it's probably because the nuts are backing off.
All you are trying to accomplish by the adjustment is to take up all the slack in between those 2 parts, then tighten it a bit more so that the plunger in the lifter is partly depressed. You can take a new lifter and push n the plunger with a push rod, and get a feel for how tight the spring is that pushes the plunger up, which will help you gauge your "feel" as you adjust the valves.
The way to adjust rockers without the engine running (new or used, it makes no difference whatsoever) is to start with them loose. Then slowly tighten the nut while wiggling the push rod up and down between the rocker and the lifter. As you tighten it up to the point that all the play goes away, you arrive at "zero lash", where the plunger is still fully extended but there's no clearance. Then as you continue to tighten the rocker nut, the push rod will depress the plunger into the lifter body. Ideally you want the plunger pushed about half of its total traval (centered) in the lifter.
If the engine is running, use the method of backing each one off, at a time, until it ticks; then slowly tightening it until it quits ticking. Then, when you've done all 16 that way, shut the engine off, and go around the engine and add your desired "preload" (depressing the plunger into the lifter body) to all 16. About ½ turn is good. You can add the preload while the engine is running, but if you do, it will make that valve hang open for several engine cycles, and it will run terrible and maybe die, and it will take extra long because yo uhave to go slow, and you'll end up with a quart of oil all over the scene of the crime. If you do it my way, you can get them all doen in less than a minute of running the motor with the VCs off.
With the lock-screw nuts, it is basically impossible to get tha Allen tight enough by just tightening it by itself. Instead, use a box-end wrench on the nut, and the Allen wrench on the screw, and tighten the nut along with the set screw; you can get many times the retaining force on them that way, without risking damaging anything.
Also, there is no difference whatsoever between a new motor and a used one as far as adjusting rockers; what I just described is basically how the factory does it, and as we all know, they don't fire the motor up until after it's installed in a car, and they don't have have to re-adjust anything at that time. The oil in the lifter has nothing to do with the adjustment, what you're really adjusting is pieces of metal; the oil doesn't change the size of the metal parts. What will happen in a new motor is that the lifters will tick for a short while at first startup if you don't fill them with oil by submerging them in oil overnight before installing them; but the adjustment is not affected by any of that. I've been adjusting valves this way since before most of the people on this BBS were even a gleam in their daddy's eye, including lots of street-driven solid cam motors, and haven't had it fail yet. Understanding what you're doing beats trial and error every time.
What push rods did you end up with? Hopefully they were longer than stock, probably 7.850" or 7.900", that's almost always what is needed...
If your rockers aren't staying adjusted, then it's probably because the nuts are backing off.
All you are trying to accomplish by the adjustment is to take up all the slack in between those 2 parts, then tighten it a bit more so that the plunger in the lifter is partly depressed. You can take a new lifter and push n the plunger with a push rod, and get a feel for how tight the spring is that pushes the plunger up, which will help you gauge your "feel" as you adjust the valves.
The way to adjust rockers without the engine running (new or used, it makes no difference whatsoever) is to start with them loose. Then slowly tighten the nut while wiggling the push rod up and down between the rocker and the lifter. As you tighten it up to the point that all the play goes away, you arrive at "zero lash", where the plunger is still fully extended but there's no clearance. Then as you continue to tighten the rocker nut, the push rod will depress the plunger into the lifter body. Ideally you want the plunger pushed about half of its total traval (centered) in the lifter.
If the engine is running, use the method of backing each one off, at a time, until it ticks; then slowly tightening it until it quits ticking. Then, when you've done all 16 that way, shut the engine off, and go around the engine and add your desired "preload" (depressing the plunger into the lifter body) to all 16. About ½ turn is good. You can add the preload while the engine is running, but if you do, it will make that valve hang open for several engine cycles, and it will run terrible and maybe die, and it will take extra long because yo uhave to go slow, and you'll end up with a quart of oil all over the scene of the crime. If you do it my way, you can get them all doen in less than a minute of running the motor with the VCs off.
With the lock-screw nuts, it is basically impossible to get tha Allen tight enough by just tightening it by itself. Instead, use a box-end wrench on the nut, and the Allen wrench on the screw, and tighten the nut along with the set screw; you can get many times the retaining force on them that way, without risking damaging anything.
Also, there is no difference whatsoever between a new motor and a used one as far as adjusting rockers; what I just described is basically how the factory does it, and as we all know, they don't fire the motor up until after it's installed in a car, and they don't have have to re-adjust anything at that time. The oil in the lifter has nothing to do with the adjustment, what you're really adjusting is pieces of metal; the oil doesn't change the size of the metal parts. What will happen in a new motor is that the lifters will tick for a short while at first startup if you don't fill them with oil by submerging them in oil overnight before installing them; but the adjustment is not affected by any of that. I've been adjusting valves this way since before most of the people on this BBS were even a gleam in their daddy's eye, including lots of street-driven solid cam motors, and haven't had it fail yet. Understanding what you're doing beats trial and error every time.
What push rods did you end up with? Hopefully they were longer than stock, probably 7.850" or 7.900", that's almost always what is needed...
12-21-2001, 01:18 PM
#9
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Car: Pontiac Grand Prix GTP
Engine: 3.8L V6 SuperCharged
wow thanks for all the replys guys. I am using the comp cams hydraulic lifters that came with the cam. It said in the instructions that they recommend not soaking the lifters in oil, so I didn't. I had my uncle who is a mechanic help me with this whole process. When I did the valve lash adjustment, the car was off and I brought them to 0 lash and then tightened 3/4 of a turn. Then I tightened the allen key and used the socket again on the adj. nut to tighten the rest of the way. They were very snug, and about 1 turn past 0 lash just like the install notes said. The pushrods I'm now using are longer (+.100") and stronger than stock. The studs are screw-in!
Thanks guys, I was just worried about the possibility of these springs making the loud engine compartment noise I have. It is a real loud clacking noise and it scares me to drive it. It vibrates under load, backfires out the carb if I punch it too fast and overall has no power. At idle I get a lean 02 sensor code if it sits there for a while. I've had the carb apart several times and used a rebuild kit on it, but I'm also no expert on quadrajets. I got the haynes carb book but I'm still reading it. I'm gonna try to check the timing to see if it is too far advanced or something. Any other suggestions? Thanks
John
Thanks guys, I was just worried about the possibility of these springs making the loud engine compartment noise I have. It is a real loud clacking noise and it scares me to drive it. It vibrates under load, backfires out the carb if I punch it too fast and overall has no power. At idle I get a lean 02 sensor code if it sits there for a while. I've had the carb apart several times and used a rebuild kit on it, but I'm also no expert on quadrajets. I got the haynes carb book but I'm still reading it. I'm gonna try to check the timing to see if it is too far advanced or something. Any other suggestions? Thanks
John
Last edited by johns84bird; 12-21-2001 at 01:28 PM.
12-21-2001, 01:30 PM
#10
Kingtail, hydraulic lifters have the plunger at the top (spring loaded) whether or not thre is oil in them. you adjust them the same way with/without oil. There is a difference in adjusting warm or cold, though. If you leave a gap at all, it will never fill-up as the plunger is already at the top of the lifter and cannot get any higher. It may get warmer and when filled with oil sound ok, but your method is incorrect. Adjust to no lash, then appropriate crank-down, per mfr directions.
A loud clacking noise sounds like maladjusted lifters to me, or they are loosening up on you. Maybe you should try to adjust them while the vehicle is running to make sure things are good...
EDIT: sittting the lifters in oil overnight is a waste of time and can sometimes still not allow oil into a lifter. Get a little squeeze trigger oil can with the very small nipple output end on it. Fill the lifter up by putting the nipple into the little oil feed hole on the lifter and pump until oil comes out the top near where the pushrods will seat. Done. takes a whole 3 sec per lifter.
A loud clacking noise sounds like maladjusted lifters to me, or they are loosening up on you. Maybe you should try to adjust them while the vehicle is running to make sure things are good...
EDIT: sittting the lifters in oil overnight is a waste of time and can sometimes still not allow oil into a lifter. Get a little squeeze trigger oil can with the very small nipple output end on it. Fill the lifter up by putting the nipple into the little oil feed hole on the lifter and pump until oil comes out the top near where the pushrods will seat. Done. takes a whole 3 sec per lifter.
Last edited by fast_broker; 12-21-2001 at 01:35 PM.
12-21-2001, 04:17 PM
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Car: Pontiac Grand Prix GTP
Engine: 3.8L V6 SuperCharged
Hmmm... Somebody in another post suggested using a "stethescope" to locate the sound better. I used some heater hose and a funnel and placed it over the valve covers above every cylinder and it was extremely quiet. I guess after all this it isnt even the valvetrain? I was trying to think what else it could be. Oil level is good, oil pressure is very high just like always, but I noticed the power steering pump was low on fluid. Filled it up, noise still there.
Any ideas on what to check? Would a vacumn leak, exhaust leak, or knock sound like what I described? Thanks again!
John
Any ideas on what to check? Would a vacumn leak, exhaust leak, or knock sound like what I described? Thanks again!
John
12-21-2001, 05:41 PM
#12
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Check to see if the rockers are touching the edge of the retainers
while spinning the motor over.
while spinning the motor over.
12-21-2001, 10:22 PM
#13
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Those springs are not too much for your lifters and cam. I'll give you my personal guarantee on that.
Backfiring out the carb? Running lean? No power?
You have to track down some stuff. Like.....
Do you have bent pushrods or did you maybe tighten down a rocker (s) TOO far, hold a valve off it's seat and run on 7 (or fewer) cylinders? It will ikdle like a top fuel car if you tighten a few rockers down too far. It will smooth out somewhat with increasing RPMs.
Ignition timing. What's it set at? Is the timing wire still hooked up to the distributor so you get advance supplied by the ECM? Are you still using the stock distibutor? Are you still using the stock carb?
Lean condition: Exhaust leak?? Can sound just like a valve tap but increases in volume with more engine load. Would also cause a "lean condtion" by throwing the O2 sensor out of whack. Also, a big vacuum lean (or leaks) on or near the intake/carb could cause a similar problem.
I strongly suspect multiple problems interacting here.
Backfiring out the carb? Running lean? No power?
You have to track down some stuff. Like.....
Do you have bent pushrods or did you maybe tighten down a rocker (s) TOO far, hold a valve off it's seat and run on 7 (or fewer) cylinders? It will ikdle like a top fuel car if you tighten a few rockers down too far. It will smooth out somewhat with increasing RPMs.
Ignition timing. What's it set at? Is the timing wire still hooked up to the distributor so you get advance supplied by the ECM? Are you still using the stock distibutor? Are you still using the stock carb?
Lean condition: Exhaust leak?? Can sound just like a valve tap but increases in volume with more engine load. Would also cause a "lean condtion" by throwing the O2 sensor out of whack. Also, a big vacuum lean (or leaks) on or near the intake/carb could cause a similar problem.
I strongly suspect multiple problems interacting here.
12-21-2001, 10:34 PM
#14
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Well Everyone basically said the same thing i did about 5 different ways so no point in going over it again.
My car ticks and it sound alot like rockers but i know it to be header / Collector leaks. If your collecter is leaking then under deceleration (coming down from the rpm range) the car will backfire, ALOT if theres a big leak. I know this from Experience, it is fact. somthing to do with the cold air getting into the exhaust.
If your carb backfires under heavy acceleration it is dumping too much fuel into the engine. if it only does it when you absolutelly go from no pedal to flooring it Fast, chances are your accelerator pump is squirting tons of fuel into it. I know on holley if your power valves vaccume rating is less than your cam pulls they will stay open, although this probably doesnt apply to you.
My car ticks and it sound alot like rockers but i know it to be header / Collector leaks. If your collecter is leaking then under deceleration (coming down from the rpm range) the car will backfire, ALOT if theres a big leak. I know this from Experience, it is fact. somthing to do with the cold air getting into the exhaust.
If your carb backfires under heavy acceleration it is dumping too much fuel into the engine. if it only does it when you absolutelly go from no pedal to flooring it Fast, chances are your accelerator pump is squirting tons of fuel into it. I know on holley if your power valves vaccume rating is less than your cam pulls they will stay open, although this probably doesnt apply to you.
12-21-2001, 10:36 PM
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Thank you Damon. I know that I definitely did all the valves as close as possible to 7/8 turn to 1 full turn past 0 lash. I took my time and did it right (hopefully I won't eat my words here). tonight I tried finding a vacumn leak around the edges of the intake and the edges of the carb with some water, but didn't find any. I still have to check the back edge along the firewall. I'm goin on vacation tomorrow so I'll have to call it quits until at least next weekend but now I have some ideas on what to check. You are all very helpful.
Sincerely,
John
P.S. Merry Christmas! (and if you celebrate any other holiday: happy holidays!)
Sincerely,
John
P.S. Merry Christmas! (and if you celebrate any other holiday: happy holidays!)
12-21-2001, 11:08 PM
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Car: 1987 Trans Am GTA
Engine: Miniram'd 383, 24X LS1 PCM
Transmission: TH700R4, 4200 stall
Axle/Gears: 9", 4.33:1
Originally posted by RB83L69
.......as we all know, they don't fire the motor up until after it's installed in a car.....
.......as we all know, they don't fire the motor up until after it's installed in a car.....
12-22-2001, 02:05 AM
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Originally posted by RB83L69
[B
I've been adjusting valves this way since before most of the people on this BBS were even a gleam in their daddy's eye, including lots of street-driven solid cam motors, and haven't had it fail yet. [/B]
[B
I've been adjusting valves this way since before most of the people on this BBS were even a gleam in their daddy's eye, including lots of street-driven solid cam motors, and haven't had it fail yet. [/B]
Seriously though, many thanks for all the advive you've given us here. I know I wouldn't be on the road with out it.
02-05-2023, 05:13 PM
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Re: Valve springs too strong?
hi i had a simular problem .so i thort.turned out to be shot big end bearing would run fine then tap like lifter then shut up then do it again was nothing to do with top end
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