blue thunder

I plugged off my bypass valve in the remote filter pad and now I have a noisy valve train. Particulary on the even bank. Did not touch the valve train during this and it was quiet before plugging. The engine sounds like it has solid lifters in it now. Oil pressure is pegging over 80psi cold on the hose (15w-50) in the driveway. The funny thing is, the throttle response is very crisp, like solids. Much better than before. Anyone ever heard of this? Should I run it? I also re-shelled the lower end and installed a scat crank all with nominal clearances, and it sounds great. Don't think this is contributing to the noise. Advise please!

BT

DanB

I'm confused
You changed the crank without pulling the heads or valve train? I supose you could.
Or did you just plug the bypass?
Has the motor been sitting for a while? Maybe the lifters just bled down and need to be pumped up with oil. How long did it run on the hose?

blue thunder

Yes I did the lower end without pulling down the top end. I ran the engine over the 4th and it ran great, just lost a little oil pressure so I tore it down and found a problem with the main bearings. I ran it a lot more this morning on the hose. It is not getting better. I suspect there is some chit in the oil passage going to the lifters, therefore the lifters are not getting pumped up. It sounds just like it's running on very thin oil, like kerosine. Tried changing oil again, no good. Guess I'll have to pull it out again. I took a gamble doing the bottom end without doing the top end and lost

Moron

formula31

Join the club. I was praying just replacing my cracked head would do the trick. Not. Oh well, Now has nice new piston. It better run tomorow. Im tired of wrenching on this pig.

blue thunder

I'll tell you what Formula31, I about had it . Put the f--in engine in thursday, ran it friday, sounded like chit, pulled it out again tonight. Everything looks great inside. All I can figure is I should not have blocked off the bypass. Clickin like a biotch.

BT

R Addiction

So I'll see you out here tomorrow? Unplug that beeeach and lets got to Lloyds. I hear there are going to be some bead being handed out!!!

blue thunder

Thanks for the sympathy R ad. Maybe you can bring some beads back for me?

Sutphen, my setup is stock merc with 90* elbows and stock lines/cooler. I just did an experiment. I checked oil flow at the front two lifter running pump with priming tool. With the bypass plugged, I got a sputtering of oil at the front. With the plug removed (bypass port open) the flow improved significantly. I think my problem is the restriction caused by the lines, fittings and cooler is such that a certain amount of bypass flow must occur to get a sufficient supply to the top end.

That being said, I have two choices. Reinstall the spring loaded bypass so the top end get lube or leave bypass plugged and replumb the system with no 90* fitting and better lines. I am going to go back to the stock setup for the time being and correct the plumbing over the winter. I'll let you know in a day or two how I made out.

Thanks for input, it is much appreciated!

BT

Bulldog

Did you use moly paste or something that would clog the filter?? and did you try a new filter?

Are you sure you are plugging the bypass correctly?

You could be getting high pressure because of low flow.

Good luck
Bulldog

blue thunder

Bulldog, I did use an assembly lube on the main and rod bearings. Changed filter three of four time though and no change. I have a new oil cooler coming tomorrow. Something is causing restriction to flow. No I'm not sure I plugged the bypass correctly. I knocked it out (valve) then tapped in a 1/2"npt plug. Seemed solid.

Sutphen, my sender is in the oil pad, but I also mount one (mechanical) in the remote oil filter when starting up a new engine. Pressures were good in each location.

BT

blue thunder

I think the mark IV only has one. At least I can only locate one.

BT