Burning oil bad on a fresh rebuild...

[JIMBOkye]

So I rebuilt my M20B25 not too long ago and I have 2000 miles on the rebuild. I replaced these things on the rebuild:

New bearings, rod and crank all around
new rings
new valve guides
new exhaust valves
head re-machined flush (blew the head gasket and it nicked the head decently)
new cam and rockers
Re honed cylinder walls

I am running 20W50 like a good boy too.

I'm burning a quart of oil every 150 miles.

So I took the spark plugs out and did a compression test with a crappy compression tester (engine cold, will try again hot with a new test gauge)

This is what I got: (cylinder 1 being front)

Cylinder 1: 120 psig - spark plug normal
Cylinder 2: 138 psig - spark plug fouled with oil very badly
Cylinder 3: 132 psig - spark plug fouled with oil very very badly
Cylinder 4: 142 psig - spark plug shows a little oil fouling
Cylinder 5: 145 psig - spark plug shows more than a little oil fouling
Cylinder 6: 140 psig - spark plug shows a little oil fouling

So this doesn't really make sense to me. You'd think that if I screwed the clocking up of the rings on a cylinder or two, or valve guides were bad, you would see both low compression and oil fouling on that cylinder...

I know there is no PCV valve on these engines, but is there some restrictive orifice or something to prevent oil from going into the intake manifold through that dumb tube thang that I could have forgotten to put in?

I'll try the compression test again with a new gauge when I get it, but any ideas before I start pulling the engine back out?

Thanks.

[EatsHondas]

How did you torque the head? Did you use new cylinder head bolts? How did you break the motor in?

[cabriodster87]

Did you forget to install the valve seals?

[JIMBOkye]

I followed the Haynes manual for torquing the head bolts which were new.

In all honesty I gave the new valve seals to the machine shop that refinished the head because the were re-seating the valves anyway. I know they were in there, but I can't talk to if they were done right or if they were the new ones I gave them. Any way to check if oil comes through the valve seals vs the rings vs the intake?

I tried to break in the motor according to the rules of thumb, no heavy acceleration until warm, no maintaining high rpms, no taking it to red line repeatedly, lots of engine braking. I did these things for the first 1000 miles consciously, then starting driving more normally.

[ForcedFirebird]

Do a leak down, but judging by those numbers something went wrong during the assembly. A fresh rebuilt m20 should see about 180psi across the board.

[JIMBOkye]

Never done a leak down test but it looks straight forward enough. I'll get a kit and do it and report back with what I find.

[whodwho]

It's not so much what the numbers say as it is the different between cylinders and yours for a new motor is way off.

Pull all the plugs and make sure to open the throttle when checking the compression and crank roughly the same amount of revolutions or you can try cranking until the gauge stops increasing.

Did you check the ring gaps when you assembled it? Also did you check the rings, there is typically a top side to the compression rings

[JIMBOkye]

I should have my new compression tester Monday, the other one was messed up; it sits at 20 psig resting. I didn't open the throttle when doing it. I'll do the leak down test and compression test Monday.

I did check the ring gap and I put the rings in in the correct orientation though. Unless somehow the clocking got messed up?

I doubt it is a crack in the head or block because I checked everything with dye penetrant

[JIMBOkye]

I appreciate all the ideas and suggestions guys. R3v is a great community.

[ahlem]

Did you deck the block?
If not, did you use gasket sealer on the head gasket?
After two similar results on M20, I finally used the spray gasket sealer on the head gasket and it did make a difference. There are a number of threads floating around complaining about a certain brand of head gasket. The gasket sealer also helped on the slow oozing of oil. I did not deck the block in any of the three projects but did skim the head.

[JIMBOkye]

I did not deck the block. I did have the machine shop shave the head though. I forget off the top of my head but I think it was 30 thousandths. That is interesting about the head gasket. I used a Viktor reins.

[CrazyPrime]

My guess would be rings, oil ring maybe didn't seat properly?

[TobyB]

Did the machine shop measure the pistons?

It really looks/sounds like the oil rings aren't sealing, and maybe compression rings as well.

Did you make sure the rings were right side up? It matters for some and not for others...

Yuk.

t

[JIMBOkye]

I did make sure the rings were right side up and I measured the pistons and the bore of the cylinder. It was all in spec.

My compression tester and leak down tester were lost by FedEx so not sure when I will be able to do that
>:(

I'm also dropping the gas tank this weekend because it is so full of rust it is clogging the fuel pump's intake screen and I'm losing fuel pressure...

[dasmanschaft012]

VR head gasket is notoriously bad. in for the story.