Spring Pressure Worry Wart

Alright, now I am starting to get worried. I set my valves up last weekend ranging from 440-450 psi seat pressure. Is this a bad thing with too much pressure and if so what could go wrong. I am using Jesel lifters at .905 bore and .120 wall 3/8" pushrods. BBC 14-71 with around 32-35 psi boost. 8100 RPM. Titanium intakes 2.30 and steel 1.88 exhaust. I have understood lately that you cannot really have too much spring pressure, but I am starting to second guess myself. Looking for some opinions. Thank you, Greg www.zeusracing.com

 

What heads and rocker arm setup do you have?

 

Yeah! What he said.
Too much pring pressure cannot exist for valve control. However, that spressure puts more stress on everything else in the valvetrain. No wonder pro stock teams were playing with pushrod wall dimmensions with multiple steps at around .200". And who made the valves and how old and how much heat have they seen. Cuz it can pull the head off the valve or try and tulip the seat area. If you don't have good heads and a one piece rocker stand, they can pull the threads out of the head. Lots of stuff can happen. But again, if it is a typical spring, it will lose 40 pounds in the first little while and settle in around 400. And consider that the pro stock teams start at 520 and pitch them around 465 or so. But 8100 isn't much in the rpm, so you have that going for you.

 

Dart 360 heads 2 yrs. old and Jesel pro series rockers 2 yrs old. with the intakes bar mounted and the exhaust individual. All brand new Manley valves. I did have some intakes tulip slightly years ago running in the high 300# range, but they were stainless and I think they saw too much heat. We will not be running near as much temp this year. Thanks

 

I think you will be fine, the increased spring pressure will keep your valves and seats looking new. I would keep any eye on your pushrod cups, make sure they are not turning color. If you lube these every run, you shouldn't have a problem. We had some problems with our pushrods collapsing, but we were running really old stuff with thin walls. Once we got some new push rods with a thicker wall, no problems.

 

My BBC experience says that you don't need that much spring psi for what you're trying to do, it won't gain you anything.
You will likely have problems pulling out rocker arm intake bolts (they are short and in the port) and if you don't already run exhaust bolts that are as long as possible, you might break off the exhaust boss.
I have run and some of our current motors are very near your numbers and I have got away with 280lbs (after they settled in). Our last 2 motors have more but you have to continue to experiment
I doubt that 3/8 pushrods would handle that much spring, but call Manton and see what he says. You can put 7/16 in those heads, but it will take some clearancing.
I have never run Jesel only T&D. On ours the exhaust bolts to the one piece intake bar. I've heard many stories but I beleive the key is that the exhaust gets support from the intake bar somehow wether bolting or welding.
I hope that helps.

 

Ken, are you talking chrysler hemi or Dart 360 Chevy?

 

Standard chevy stuff does not mind a little less pressure. You have the right parts, so no huge worries there. If you can weld the exhaust stands together to get them to be a one piece, it is better for geometry, stability and longevity. But not desperately needed. And remember, in a chevy, you can't have too big and heavy of a pushrod.
You should be O.K. but that is quite a bit of pressure. I have run that much on my pro stock style stuff, but never more than about 360 on standard chevy stuff.
Then it depends on if you are running 100 passes a year or 15. And how often do you tear down. But I say. run em a few. If they die down and settle in in the high 3's you should be fine. But you certainly don't need that much pressure for 8100rmp. I would think 340 would be safe.

 

watch your valve keepers real close..they will try to pull out..dave

 

Thanks for all the input, I think my worries are correct so I will take a little shim out and lighten the pressure to around 400#. And that's a great idea to weld the exhaust stand to the intake bar, that should help a lot. Have a great weekend everyone. Greg

 

Sorry, I was talking hemi. Wasn't paying attention.

 

Greg: I highly recommend giving Noel Manton a call, he is a great resource for everything valvetrain related, and will take the time to answer all of your questions.

Chris