HiGH oil pressure breaking in 20R
 

This is my first engine rebuild. Truck is a '75. Engine is a 20R which I had bored .02 then I put in new rings, bearings, timing kit, oil pump (including housing/relief valve etc) Parts were from Engnbldr. Oil is standard valvoline, I think I got 10w-30, with lucas break-in additive, wix filter. I am reving to my best guess of 2000RPM (no tachometer)

1st run: I f-ed this one up, didn't realize I was supposed to pack to oil pump w/ grease so it was sucking air and had no oil pressure. Shut down after about 20-30 seconds. Big ˟˟˟˟ up, I know. I'm hoping the assembly lube held up.

2nd run: Primed the pump by pumping oil in where the filter goes. Started up with plenty oil pressure, then in 2-3 seconds the pressure rose until it was pegging 100 (max on the dial). I shut down after about 15 seconds.

I know that oil pressure on a cold break in is going to be high, but this seems excessive. I checked the gauge (w air compressor) and it seemed ok, maybe reading high by 5-10psi. The oil pump is brand new including the pressure relief valve so it seems unlikely that would be the issue.

Should I open the valve cover and look for oil getting to the top end while cranking the engine without spark? Will just cranking even give enough pressure to get oil to the top end? I don't have a way to spin the pump with a drill while the engine is in the truck.

Is it possible that running without oil pressure for 30 seconds chewed up enough metal grit that it clogged the oil filter? If so I guess I'm screwed anyway...

I called Todd at engnbldr and he said that high pressure on a cold break in might be normal and that I ought to run it for the break-in and see it it comes down.

Right now I'm thinking I'll change the filter, just in case, then try running it for the break-in, stopping if I hear any bad noises or if the filter starts to balloon. Is this a terrible idea? Any other tips?

remove the oil filter and cut in half to see if there are many metal particles, I think high oil pressure won't damage the engine for a short period of time, so I would start it back up with a new filter and let it warm up a bit at idle and see if the pressure goes down. Here in eastern quebec when it's -35c in the winter and we start our cars oild pressure can be damn high, I remember pegging 100+psi in my civic during winter cold starts. On my 22r, I can hit 70 psi at cold starts in the summer.

I get over 80 pounds starting with 5W30 oil when it is 90 degrees out.195,000 miles

Better to high then none at all.

As long as your not running in a new cam I would not be real worried.

You are using a mechanical gauge??

Ok, great. That's kinda what I figured - high is a lot better than none! Cam is old. I will cut open the filter too, although I almost don't want to know.

The oil pressure dropped back down a few minutes into break in and stayed there. 50-90 psi or so when I was revving it. Revved it for 1/2 hour and everything seemed to go well. Timing next. Thanks

Glad you good to go!!!

22RE Performance has a great initial start-up and break-in procedure writeup:
http://22reperformance.com/22RE_Perf..._break_in.html

Toyota owner's aren't as lucky as Chevy guys are - we can't cheat and just run a drill down the distributor shaft to prime the fuel pump. And you shouldn't pack the oil pump with grease - NOWHERE in any Toyota FSM does it say to do that. It boggles my mind that people think it is a good idea to put some dense goopy grease or vaseline in an oil pump. That ultimately alters the viscosity of the oil which in turn will artificially increase oil pressure and clog up the oil filter until your first oil change. All you need is some good quality assembly lube and the proper start-up procedure described in the link above.

I built my engine and let it sit for nearly two years before I first fired it up. I used a good moly assembly lube, zinc additive for my oil and valvoline 10w-30 conventional motor oil. I "dry cranked" mine for about 45 seconds before I got oil pressure and then she fired right up. No problems since.

Thanks, that is a great write-up on break in. So I drove the truck today for the first time, and got pulled over in it for the first time, after like 4 blocks... Cop thought my Mississippi antique plates were expired but actually they're good for 50yrs! Never had a cop apologize to me before.

Anyway, I'm really happy that it runs, but not happy yet with the way it runs. It feels kind of bogged down and slow to accelerate and then if I let the RPMS drop before downshifting I get like a farting/sputtering noise sort of like a weedwhacker. I was getting that before the rebuild, in part because I need a new exhaust pipe, but I thought it would get better. I'm not sure how to tell if this is a timing thing, a carb thing, or just a muffler thing.

Timing is set about 8 degrees BTDC but I don't have a tach to check that I'm idling at the right RPMs. Would this make a big difference?

I'm also getting a valve tap type noise. I haven't checked/adjusted the valves with the engine warm yet though, so I guess that is the first step.

I'm also not sure about the state of the carb, but I don't know much about them. Is there a good writeup anywhere on tuning/rebuilding Weber carbs?

Possible lean idle circuit. You can go to carbs unlimited's website for Weber info. Your ignition timing should be ok but you can add more until it pings, then back off. I find 10-12 works well for me.

R series have noisey rockers, it's normal. Most folks with stock to mild cams adjust them .001 tighter than stock spec.