Topic: wiseco 836 oil pressure

[mazingerzeca]

Hello all. I´ve just started my freshly rebuilt K0 engine with a wiseco 836 kit on it. Everything seems to work fine, but I haven´t ridden it because I´m afraid the oil pressure is too high, it reaches 50-60 psi at idle. What is this due to? Bad oil pump? Is that the normal oil pressure on this kit? If not, how can I solve it?

[KRONUS0100]

my 78 F3 motor hits 80psi cold on new oil and filter...........................maintains 60 when hot and going down the road and 40 at idle hot.  you are good to go

[mazingerzeca]

The workshop manual says that if the pressure is too high it could mean that the relief valve is not working. Maybe is that the problem? My other bike, a cb750 K7 goes at 20-30 at idle.

[nokrome]

my 78 F3 motor hits 80psi cold on new oil and filter...........................maintains 60 when hot and going down the road and 40 at idle hot.  you are good to go

+1 60 psi is totally normal on start up and cruising

[Black 750K8]

The workshop manual says that if the pressure is too high it could mean that the relief valve is not working. Maybe is that the problem? My other bike, a cb750 K7 goes at 20-30 at idle.

My 750 K8 does the same thing. There is a fix for it to get the pressure up at hot idle. You need to change 2 or 3 orings in the pump and one small one behind the shifter cover. I'm going to do it on my next oil change. It is in HondaMans book and I think it is in the FAQ or tips & tricks. I think even at 20-30 psi it will be fine but I would like to see a little more and be a little more consistant.

AT Maz After a rebuild you would have changed these o-ring so you are fine.

[mazingerzeca]

Anyway, shouldn´t the relief valve act at around 60 psi? I have 50 psi at idle, but it reaches almost 120 psi when I use the throtle. I stil think that it is too much pressure and I don´t want to have oil leaks due to it.

[Black 750K8]

120 does seem high.

[mazingerzeca]

Yes, it is. So, is there any way for making it lower? I´ve searched and found that some people insert a plug on the inner tappet covers to allow the engine to vent. I took off the tappet covers on my engine and the pressure remained the same. Also left the hose on the crankcase disconnected from the oil tank, but the pressure was the same. I´m pretty sure that if I run the´bike with this pressure it will develop an oil leak. Isn´t the relief valve on the oil pump really involved?

[Black 750K8]

Yes, it is. So, is there any way for making it lower? I´ve searched and found that some people insert a plug on the inner tappet covers to allow the engine to vent. I took off the tappet covers on my engine and the pressure remained the same. Also left the hose on the crankcase disconnected from the oil tank, but the pressure was the same. I´m pretty sure that if I run the´bike with this pressure it will develop an oil leak. Isn´t the relief valve on the oil pump really involved?

I would remove the pump and see if the relief valve is stuck. There is no pressure under the valve cover.

[Jerry Rxman Griffin aka MuthaF'er]

I have my doubts about your oil pressure measuring device. I do not see how these pumps can generate those pressures at such low rpms.

[mazingerzeca]

Itś the same gauge that I had on my other bike, in which it read normal measures. I installed it on the 836 engine to check the oil pressure.

[mazingerzeca]

I will check the relief valve. I´ve read many threads about high crankcase pressures with wiseco 836 kits involved, but I think that the oil pressure is not related to crankcase pressure, I mean, the oil pressure should be controlled by the oil pump and the relief valve, isn´t it?

[trueblue]

Pistons have 5/8th of sweet fcuk all to do with oil pressure, it's not even a factor.  The pump only creates flow, oil pressure is created by restriction to the flow.  The restriction is created at the mains, big ends and any point where the system is directly fed by the pump.  The relief valve controls the maximum pressure in the system.  I'm not sure what it is set at for the 750's but I would assume it would be around 60psi.  You may see a little over this when cold, but I wouldn't expect any more than 80psi, as when the oil is cold it doesn't flow as fast out of the relief, but if you are hitting 120psi I would say that either the gauge or the pressure relief valve are suspect.

Your K7 has issues if you are only getting 20-30 psi at idle, possibly leaky o-rings on the oil pump or worn out bearings.