Jackal6042

I'm looking for some suggestions as to what my issue might be before I start tearing this bitch apart.

The D15B in my EJ1 burns through a quart of oil every 200-300 miles. Compression check numbers come out fair (185, 195, 185, 195).

So I did a leak down test. Cylinders 1,2 and 4 all check out. Cylinder 3 has a strange resulting issue. I'm losing about 20% pressure and it isn't going to the oil pan so rings are good. No bubbles in radiator or air heard in other cylinders so head gasket seems its fine as well. Also there is no sound of air escaping in the exhaust or intake manifolds so bent valves is out of consideration.

The air is escaping from around where the spark plug tube is. I was thinking that would possibly mean valve seals but I'd think some of that air would be heard in the manifold respective to where the leak is. I don't think the head is cracked because besides burning oil the motor runs solid. I may go in and replace all the valve seals seals later this week but I'd hate to do all that and still have the issue.

Any suggestions would be helpful.

Danitto

id say a crack in the air intake. The only reason for overheating is either no oil(but you have oil so no) OR lack of air circulation.

Check the valves

Jackal6042

Crack in the air intake? You say check the valves, so does this mean check the intake valves and surrounding areas in your opinion?

I'm not having any issues with overheating at all. Have a low temp thermostat in there and the temp gauge never even gets to half even when I'm beating it on some mountain runs.

I think I'm going to take it apart with the intent of replacing valve seals (at least on that cylinder but more than likely all 16 valves since they are like $1.25 each.) and while it is apart check for any cracks in the head or slightly bent valves.

Like I said compression numbers are good even on that cylinder so I doubt it is a crack or badly bent valve.

I'm in the aviation side of the military so when I strip the head down I'm thinking about taking it in for NDI (Non-Destructive Inspection). I'm pretty sure they wont have a problem running it through for me. I'm hoping to get a radiographic inspection along with die-penetrant inspection.

If there aren't any other idea as to what might be causing this OIL CONSUMPTION I think I'm going to go that route. I will post results and if I can get digital copies of the NDI inspection I will be sure to post those too.

40mpg_dx00

How clean is the engine bay? you don't want to get your issues mixed up. cylinder 3 might have nothing to do with the oil consumption. if you are losing that much that fast something is leaking whether it's internal or external. If it's internal you'll see it when the smoke comes out the back. best bets are head gasket or oil pan gasket.

Jackal6042

Sorry I should have been more specific on these details. I steam cleaned the **** out of the motor when I bought the car about 2 months ago. The rear main seal had a VERY SLIGHT leak, but I replaced that with OE and no more leak, not even a drop since replacement. Oil pan gasket was also replaced at the same time again no leaks there. The whole motor is very clean. I'm OCD about stuff like that, I used simple green and a tooth brush then steam cleaned it. Currently there is absolutely no oil leaks. Cam seal is good, dizzy O ring is good.

I think it may be a valve seal, I did a sea foam treatment which probably cleaned out some gunk that was keeping everything sealed up. That or worst case I have a crack in the head (combustion chamber near spark plug possibly).

Anyone got a used D15B or D16Z6 head for sale in SoCal? LOL. But seriously though. Just in case this one is slightly cracked.

riS.I.R

a quart of oil every 200-300miles is a little much for valve seals id say, do u get any smoke on startup or driving?

Jackal6042

At startup no, or if I do its very slight. Most of the smoke comes when at WOT especially when VTEC is engaged.

See thats what I was thinking about the valve seal, especially with where the air is escaping from. But the seal could be completely shot to **** and literally pissing oil in the cylinder causing such a high consumption. As I think about it more and discuss it more I'm starting to lean more towards a cracked head.

**** I mean its a D15B, I'm looking at doing an intensive build/swap/restoration come fall so I really don't want to throw money at this engine but at the rate of oil consumption something is definitely not going right. I'd hate to blow this D series up and feel rushed into doing my swap restoration. Yeah I can get another D15B for like $550 shipped but thats kind of a waste of money in my opinion since I'm not keeping a D in her.

I mean, there is no leak-down to the oil pan, so the bottom end seems stable.

I guess my course of action is to begin looking for a used VTEC head just in case we find cracks at NDI. Tear it apart with the intent to rebuild this head if it isn't cracked but have another used head on stand-by, ready to be purchased if this fails me.

Jackal6042

So..... Anyone got a D15B or D16Z6 head for sale in SoCal (San Diego)? Or **** New Jersey for that matter I will pay to have it shipped.

riS.I.R

honestly i wouldnt bother with another head casue i had the same problem with my b16 when i got it, the rings were just shot and it bogged and burned shitloads, like u said only on WOT. i rebuilt the motor and its fine. I highly doubt its a cracked head unless its been overheated or something.

Jackal6042

Yeah she doesn't even start to get past the half way mark on the temp gauge, and that includes pushing it hard through the mountains east of here. The thing that confuses me is where the air was escaping from cylinder 3 when I did the leak down. Piston rings are cheap as are valve seals so I will be taking the motor apart here in the next few days with the intent of replacing the rings and valve seals and just keep my fingers crossed the head isn't all ****ed up. It never overheated once since I owned it but I'm still having the head decked while its apart and will probably do the NDI as well. I guess we will see how it all looks once it is apart.

g230sport

does the sparkplug thread in nice and tight? feel like it seals when tightened?

honestly, i wish my z6 went through a quart every 200-300 miles, try a quart every 2 days... well, that motors dead now, fresh y7 going in in a couple more weeks :D

id just drive it, and keep an eye on the oil... that is, if it was mine and you were planning on a build up...

Jackal6042

Yes it threads in there nice and tight, and seals well...

Well I'm doing a pretty big swap/restoration come fall/winter so this motor will be sold off at that time.
But I can't sell someone a motor with known issues like this. I'm going to tear it apart with the plan of replacing rings and valve seals. But I will have a Z6 head ready to be purchased if I have major issues with the D15B head on there now.

The Shedder

I also have a D15b in an Ef JDM civic, which is also burning approx 1 litre(1 quarter gallon) of oil every 300 miles, the valve stem seals seem to be the problem as my compression checked out fine, also power seems ok after cam rocker gap adjustment. Unfortunately this process requires removing the cylinder head (although I got away with replacing them on a B16A2 engine without doing this!)
I am looking for engine spec for D15b engine (tightening torques and set up spec) as i intend to recondition and rebuild this one. If anyone could help?