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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
I had low hot idle pressure readings that turned out to be my gauge. It was a liquid filled type.
I then used a known good dry type gauge with better results. The pressures were right on as they should be.
I had low hot idle pressure readings that turned out to be my gauge. It was a liquid filled type.
I then used a known good dry type gauge with better results. The pressures were right on as they should be.
Thats a valid point , the one I have is a liquid filled too. It was around 5 psi before they switched the formula of the Synth 3 to 15/50 so I may consider looking into alternate oil thats non HD.
You don't say the mileage but if you bough a garage queen, the piston oilers may be loose. My 17 RK has typically 5-10 when hot at idle but will drop lower if the motor gets real hot. I run 15W50. Also the pressure gets a little bouncy. The early pumps have a less supported pressure relief valve which was a major flaw. The valve could hang up.. You can see the plunger here. Later ones have a boss around the plunger.
You don't say the mileage but if you bough a garage queen, the piston oilers may be loose. My 17 RK has typically 5-10 when hot at idle but will drop lower if the motor gets real hot. I run 15W50. Also the pressure gets a little bouncy. The early pumps have a less supported pressure relief valve which was a major flaw. The valve could hang up.. You can see the plunger here. Later ones have a boss around the plunger.
I bought it new , has 25,000 on it. I'm in roughly the same range and pressure variation as you. It cracks me up that HD runs these things at such low pressure at idle. Not saving much hp driving a pump at 5 instead of 10 but the lifters arent collapsing and the pressure jumps when ya blip it so I guess I'll just ride it. I sure as hell hope it isnt the oilers. This seems timed with the variation in oil viscosity so I hope going to a non HD might eliminate it . Its either swap the gauge or go with another oil . I'm thinking oil if the condition stays as is.
I bought it new , has 25,000 on it. I'm in roughly the same range and pressure variation as you. It cracks me up that HD runs these things at such low pressure at idle. Not saving much hp driving a pump at 5 instead of 10 but the lifters arent collapsing and the pressure jumps when ya blip it so I guess I'll just ride it. I sure as hell hope it isnt the oilers. This seems timed with the variation in oil viscosity so I hope going to a non HD might eliminate it . Its either swap the gauge or go with another oil . I'm thinking oil if the condition stays as is.
Why? The crank bearings are roller. You don't need pressure. All you need is flow. The crank is not pressure fed.
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