Mystery of the leaky head gasket and burning oil

[HCFL]

Hi everyone.

I have a 1993 Acura Integra GS-R. It has 266,xxx km. The car has been worked hard it's whole life, but never ever ran out of oil or overheated. I bought the car two years ago and since then put 15,000 km on it. When I bought it, it burned a little bit of oil, mostly over 6000 rpm. It may have burned oil at idle or under 6000 rpm, but I could never notice it until I hit 6000 rpm, basically when vTec kicked in. It also had a leak in the head gasket, which caused an oily mess on the front of the engine.

On many occasions I asked experienced mechanics what the burning oil issue could possibly be. Most of them said either worn piston rings or valve stem seals. A lot of them said valve stem seals because it was burning oil on the higher end of the powerband.

Just recently my father traveled nearly 7000 km to help me rebuild the top end of the engine. We took the cylinder off the block and did all the valve stem seals, as well as replace the head gasket, valve cover gasket and anything else we could replace. As well we cleaned off all the valves, pistons and mating faces. We lapped the exhaust valves quite a bit and only had to lap the intake valves slightly. Valve guides seemed fine according to my father. He also said pistons seemed to be fairly tight, with very little play while he checked each piston on TDC.

We had a couple issues with locating tools and it took us nearly a week to get everything finished. We finally did, and ended up running the engine a couple times just to locate any leaks we might have from old coolant hoses. We found that oil was leaking from the drain plug and found out after that it was actually quite stripped, probably from the previous owner. Not a problem, booked an appointment with a local garage to get it drilled and tapped.


So here's the mystery. After the initial drive (my father followed behind me in another car) we found the oil leak from the head gasket has gotten worse, and also the burning oil problem has gotten worse. Now not only does it leak more on the higher end, but it leaks when I give it 100% throttle in 5th gear at 100 km/h, around 3400 rpm. That has never happened before. Compression after the rebuild was 180-180-180-180.



My father is heading home tomorrow on an early flight and we can't spend anymore time on the car.


Can anyone chime in on what these issues could possibly be?

So far we have some ideas:
- Good compression rings, bad oil rings.
- Warped head or block.
- Oil vent line routed to the wrong place, causing fumes to be burned. (Currently we have the valve cover vented upstream of the throttle body)

 

[HCFL]

Quick bump.

Started watching videos and reading forums on the idea about the leak around the head gasket. One guy posted a video showing the leak and where it puddles in the front left corner of the engine, down from the vTec solenoid. He said people mistaken it for a head gasket leak, but it's actually the seal on the vTec solenoid that leaks. So I did what he did. Took it off and used some Ultra Grey gasket maker and sealed around those gaskets. I did the same thing with the distributor, since I could see a little bit of oil leaking from around there as well.

I will have to put liability back on my car in order to test what I did. I'm pretty sure I'll only possibly see oil around that area again if I hit over 6000 rpm (in order to activate the solenoid).


As for the oil burning, me and my father have the theory that the oil rings on the pistons are shot but the compression rings are good. So maybe there's a little bit of blow-by happening when I floor it and increase the combustion pressure. Not sure why it got worse...maybe cleaning up all the carbon deposits on the valves and pistons increased the combustion pressure just enough to make the problem worse.

Anyone have any other theories? Anything at all.

 

[TeggyRussE]

This is not a fix but could help a wee bit, clean your breather box and replace your pcv. Make sure the system is 100% hoses,valve,box, etc



The leak also could be the Cam seal and distributor o ring.

Recheck valve clearences

Goodluck man

 

[Muckman]

Leaking oil from the VTEC solenoid is common but I've also built several B18 engines that seeped oil from that front passenger side corner of the head gasket. This was on freshly surfaced blocks and heads with OEM head gaskets and proper torqued head studs. Ive seen it on multiple engines. I can't explain it but my trick now is I put a thin layer of RTV on both sides of the head gasket in that corner around the oil return galleys.

As for the burning oil, no offense to your father who was pretty awesome to help you rebuild your engine but it sounds like he didn't measure anything. "Feels tight" and "looks good" aren't good indicators I want to read when talking about engine tolerances in the ten thousands of an inch. Engines with as many miles (sorry KM) as yours will burn oil from two wear pattern issues.

The primary reason is the valve guides wear which allows the valve to wobble. When the valve wobbles the vale seal at the top is broken and oil seeps down the valve stem. You can visually inspect for this on the intake valves. They should not be wet. However this is more common on the exhaust valves due to the increased heat. Unfortunately because of the hot exhaust gases its much harder to visually detect oil seepage on the exhaust valves.

The second reason is worn cylinder bores and or piston skirts. Cylinder bores wear unevenly due to the thrust sides of the piston traveling up and down they put more thrust on the front and back of the cylinders. This causes the cylinders to distort or egg shape over the years. The piston rings are flexible and can usually take up the slack to conform to the new shape but as it gets worse or engine speed exceeded their ability to move fast enough, oil finds its way past the rings.

The only way to fix either is a machine shop. The guides need to be measured and replaced. The cylinders need to be bored.

 

[HCFL]

This is not a fix but could help a wee bit, clean your breather box and replace your pcv. Make sure the system is 100% hoses,valve,box, etc



The leak also could be the Cam seal and distributor o ring.

Recheck valve clearences

Goodluck man

It's funny you say that, because my father just brought up the topic of the crankcase ventilation.

When we put out hand over the oil fill hole on the valve cover, it pushes air through it, instead of the normal push-pull-push-pull as the pistons move. To be sure about this test, I used my 1998 Toyota Camry as a baseline. When I took a piece of paper and put it over the oil fill hole, it bounced on the hole making a clapping noise. When I did the same thing on the Integra, it simply blew right out.

So tomorrow I will be removing the intake manifold and putting in a new PCV valve, as well as a new hose to go in between. I'm thinking that may help with all these issues I'm having. It may even cause the thing not to smoke during high RPM.

I only hope that all the work we did wasn't arbitrary...

 

[HCFL]

Leaking oil from the VTEC solenoid is common but I've also built several B18 engines that seeped oil from that front passenger side corner of the head gasket. This was on freshly surfaced blocks and heads with OEM head gaskets and proper torqued head studs. Ive seen it on multiple engines. I can't explain it but my trick now is I put a thin layer of RTV on both sides of the head gasket in that corner around the oil return galleys.

As for the burning oil, no offense to your father who was pretty awesome to help you rebuild your engine but it sounds like he didn't measure anything. "Feels tight" and "looks good" aren't good indicators I want to read when talking about engine tolerances in the ten thousands of an inch. Engines with as many miles (sorry KM) as yours will burn oil from two wear pattern issues.

The primary reason is the valve guides wear which allows the valve to wobble. When the valve wobbles the vale seal at the top is broken and oil seeps down the valve stem. You can visually inspect for this on the intake valves. They should not be wet. However this is more common on the exhaust valves due to the increased heat. Unfortunately because of the hot exhaust gases its much harder to visually detect oil seepage on the exhaust valves.

The second reason is worn cylinder bores and or piston skirts. Cylinder bores wear unevenly due to the thrust sides of the piston traveling up and down they put more thrust on the front and back of the cylinders. This causes the cylinders to distort or egg shape over the years. The piston rings are flexible and can usually take up the slack to conform to the new shape but as it gets worse or engine speed exceeded their ability to move fast enough, oil finds its way past the rings.

The only way to fix either is a machine shop. The guides need to be measured and replaced. The cylinders need to be bored.

Thanks for the input Muckman, sounds like you know your stuff.

A lot of the devices we needed to measure tolerances such as play in the valves and pistons we did not have readily available. As for the tolerance of the head, he was convinced at the time that we did not need to measure the block with feeler gauges to see if it was warped.

We did check the valve clearances with a feeler gauge, but they did not need to be adjusted, even with lapping of the valves.

As for everything else, there wasn't much we could do to measure in thous of an inch, but I do get your point.

I'm certain that there is a little bit of oil coming from that corner, but after using some RTV around the distributor and solenoid, it has been significantly reduced. I will however take your advice and seal that corner where the oil passage is, next time I have the head off. (which I feel way more comfortable doing by myself now that it's been done once)

One of my friends who has a brother that's a mechanic, suggested torquing down the three bolts closest to that corner an extra 10 ft-lbs over spec (71 ft-lbs instead of 61 ft-lbs). Something tells me that I'm setting myself up for more problems if I do that though.


When we had the head off my father (who's a good judge of feel) said that the valves and pistons did not have excessive play. I know you'd rather not hear that, but being a retired aircraft maintenance engineer and avid Harley fan he's taken apart his fair share of engines. If we did have the means of actually measuring the play, I'm sure he would have.



So for now I'm going to replace the PCV and see how well that goes. There's definitely an issue with that system anyhow.

Cheers

 

[HCFL]

So I removed the PCV valve from where it was mounted on the Intake Manifold, and it turns out that it wasn't plugged at all. Not sure why, but there was barely any residue inside the PCV. I would think that you'd see residue from the oil vapors that run from the crankcase to the IM. But there was none.

I destroyed the old PCV in the process of taking it out. So I have to get a new one. After doing some more research some people say to install a much bigger PCV because the Honda PCV is inadequate. Not sure how true this is, and how it'll fix my issue.

Could I possibly have a problem with the black box behind the engine? Do they ever clog up or stop flowing properly?

 

[HCFL]

Bump.

Installed the new PCV and grommet and things feel way better. Not to mention there is zero leak from that front passenger corner of the engine. Bone dry now.

I still puff blue over 6500 rpm but it's a little less now. Can I blame that on the piston rings?