Can 60#valve springs cause lower oil pressure?

[bgilbert]

Ever since I installed my 60# valve springs my oil pressure is slightly lower. 5-8psi lower at idle. Cruise about 3-5psi lower. Could this just be a weak engine throwing up the white flag? Does it take more to work the heavier valve springs? I set the valves to 8/18. Tight valve lash contribute to lower oil pressure? What about incorrect valve adjust prodecure? Hands are too big to get to the timing pin. Used the valve overlap procedure. - Watch #1 intake rise, as soon as #1 exhaust starts to drop I stop. #1 at tdc. This is how I did the valve spring install and didn't drop any valves. That will be another thread on valve adjust.



All fluid levels, color, smell and taste are normal. Torqued all headbolts to 120ftlbs after install.



Once I noticed this lower oil pressure I parked the truck and been driving the crew cab all week. I've removed the rocker towers to check to make sure the dowel on the bottom of each tower is aligned on the head properly and not damaged from not being flat or aligned correctly on reinstall after the valve spring job. Each one checks out ok. I've got them all torqued back down, just now have to adjust the valves again... . Any thoughts on this?

 

[Greenleaf]

When I installed John's valve springs, he told me that it lowered boost by a number of pounds.



I cannot help you there Bill. Everything should remain the same.



I have often wonered about destroying the cam with the tight springs but I'm told it has no effect.



If you are for sure certain that you did everything right you should be ok. The rocker tower has oil pressure running through them right? If the dowels are in place and you didn't fudge anything I have no clue. You torqued the head bolts and all right?



GL

 

[MMiller]

I can't see how v/s can have any effect on oil pressure, or the cam for that matter, as the lifters have rollers, right? I can't see that valve adjust would cause problems with oil pressure either.



No new oil leaks, right bill? Have you changed the oil lately? IMHO oil pressure is regulated by a spring loaded valve, and then of course wear on the main/rod bearings, oil pump, etc.



I would change the oil if its been a while, pull an oil sample and see what is says. See if there is more beaing material floating around. If that does not change it, then I would try another gauge. Then I suppose it would be time to look at the releif valve.



What pressure are you running? What does the FSM say is "spec"? Any new noises?



Michael

 

[Will24]

B engines all use flat tappets



-Will

 

[bgilbert]

No new noises, leaks. Spec is 10 hot idle, 30 hot cruise. Prior to this I seen 24-25psi hot idle, 50ish psi hot cruise. I haven't gotten the oil up to operating temp to get a check of hot idle pressure yet. Oil has been changed recently, right before the Cookout in Peru.



I was wondering about the relief valve. After the turbo install, seemed like oil pressure was slightly higher. Cold mornings, 3rd gear 2k rpm I would see way up there, like 70-80psi. I thought the relief valve cuts it at 65psi. Now after this job, oil pressure is lower. Relief valve stuck open? Looks like I'll have to open the good book and read up on that.



As far as oil sample, I might try that. But I don't have anything to compare it to, also have new parts being broken in- turbo, pump etc. Three oil changes with different type of oil since last sample was taken.



I'm thinking I'm gonna cancel this autometer mechanical oil pressure gauge. Get an electrical. Tired of waiting for the pressure to climb to max with the mech gauge. Electrical would read immediately after pressure at the sensor was read. Plus it doesn't matter what type of fitting, how tight etc, I can't keep it from leaking at the oil filter adaptor. Not a big leak that has ever affected oil level. Just one over time gets the filter housing greasy.

 

[Greenleaf]

I have a mechanical. It reads the following when hot.

Slow idle 19 psi

Fast 39psi



When engine is cold and driving down the road the gauge will read 80 psi +

 

[MMiller]

I had a 3208 that had a stuck relief valve, and oil pressure was very low. I took it apart and found a chunck of aluminium in there. Cleaned it up and put it back in and it worked fine, however I did replace it. Dunno how easy it is to get at in the Lil B, had to pull the oil pan on the 3208 to get at it.



I did not know what the tappets were like in a B, I can think of many Cat engines that have roller lifters.



Michael

 

[Greenleaf]

B,



When I start the school's engines, they operate at VERY high psi when cold. After a run, they will show about 10-20 psi at slow idle speed.



You probably do not have any relief valve problem(s)



Gauges differ and can certainly change over a period of time. Electrical gauges vary the most.



-S

 

[bgilbert]

I'm thinking kinked oil pressure tubing. Plumbed a different mechanical gauge with new tubing and oil pressure came up quicker and read normal, not low. Hooked the old tubing back up. Then hooked the new gauge up in the cab with the old tubing and it was slow to come up, and read lower pressure. Also didn't react as fast with throttle. So there ya go. Instrumentation.