Reply With QuoteI am no jet expert but 35 seems high. I run mine at 12 as per Mondello's recommendation.
Olds 455 with logs.
I did a search on this but it was not much help. I have a pressure relief valve between the pump and the motor that I adjusted to 3-5 psi at idle through the no wake zone which warms the motor up by the time I get up on plane. At crusing speed the pressure is 10-12 psi and a temp of 150- 160 all day long. When I hammer it the pressure shoots to 35 psi where the guage bottoms out. The boat runs great, no water in the oil, valve covers are clean inside. I was wondering if this pressure is normal. If I adjust the pressure valve any more it will start bypassing water at idle. The pump is blueprinted and I'm afraid I'll blow a head gasket. It will idle at 180 forever except for blueing the headers. Everything seems fine but that 35 psi scares me. Any ideas from you jet experts?
I am no jet expert but 35 seems high. I run mine at 12 as per Mondello's recommendation.
Olds 455 with logs.
35 is high. Engines are designed to run at 12-20 lb block pressure. You may get away with a little more (at least for awhile). This is why radiatior caps on your cars are set to blow off at pressures within this range. Typically the first thing to blow gasket wise will be the water passage through the intake from my experience of listening to problems people have had. Depending on the type of head gasket they may blow water as well. Hope this helps.
Woah!
This is somthing I havn't considered. I'm losing the waterpump on my 455 this build and installing a blockoff cover. What kind of valving, regulation, and gauging is required when making the switch. NOBODY TOLD ME THIS!!! AAAAAAHHH! What else. I already need a whatsis, a thingamajig, a doodad, and a hooter dooter. What else does the goddess require? I think she wants blood. Old boats are a pain in the WALLET! Help
There are different ways to do it. This will give you a start.
http://free.***boat.net/ubb/ultimate...;f=11;t=001647
Ah yes, the water pressure question. I've got thoughts. But first, I'm wondering about your pressure regulater Mark. From what you describe, is it really regulating?
jer
The regulator must be working because at low rpm it's just a trickle from the dump port. At high rpm it's shooting 4 feet behind the boat.If I adjust it anymore Im afraid my headers will be starved of water for to long. I've been lucky so far but I need to address this problem before I blow a gasket and ruin a motor or a weekend.
The valve I have is idenitical to the one unchained has but mine is mounted inside the boat between the pump and motor. Thanks for the picture Glastronguy.If I set this valve so it dumps water sooner that would probably correct the excessive pressure at high rpm but wont the headers get water to late? Thanks
Mark, the reason I mentioned is cause how I'm thinking a regulator works. Below the set pressure no bleed? Once reaching set pressure things open? Your data doesn't seem to match this. Some who run regulators may comment better than me on this.
For example, if you set to 20 psi, then no trickle until you reach your set pressure/rpm. At that point, the regulator should begin releasing pressure and bleed. From then until the regulator bleed port flow limits, the regulator should keep engine pressure constant. At regulator flow limit, (bleed port choked flow?) the pressure regulator is maxed and can no longer regulate.
Where are you measuring pressure Mark? I have lots more ideas on cooling but need to get off the net now. Be back soon.
jer
Thanks for the input LVjetboy. I'm measureing pressure at the intake crossover. All the plumbing is #8 braided. I may need to bypass more water to get the pressure down,but I believe the valve is working right because the distance the water shoots out the transom is consistant with engine rpm from what I can tell. I burnt one set of headers up, luckly they were old and I have new rewarders now and I'm paranoid.
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