So I have a gsr swap from hmo that has only been driven about 8k miles (since the swap was put in, ive put 3k miles on it) if what I was told is correct upon purchasing my vehicle... I have noticed that when cracking Vtec let’s say 3 times in one day, like ***** to the wall first to third then two days after when I check my oil (I check it religiously) it shows up in between the two dots or 3/4 of the way tonthw second dot, completely cold which makes me worry quite a bit as it did this too when I was just learning how to drive stick, It currently has Mobil one 5w30 full synthetic in it I heard somewhere that Mobil one and Vtec engines don’t like each other lol oh and also my oil has a strong odor of gas when I check it that doesn’t seem normal to me other.. narrowing it down it could be either my valve seals or piston rings correct? Oh also forgot to mention that it does not smoke whatsoever I have never noticed any smoke cruising around, I had a couple of friends look at my rear end when I cracked Vtec and they said that they noticed some smoke coming out of the exhaust. I feel like it burns some oil in the higher rpms?
I am also planning on doing a leak down test as I’ve seen that’s the best way to really diagnose the issue.. also I have thoroughly checked under the car for any leaks and nothing was leaking I thought that it was my rear main seal but it was dry down there. Would like to know what other people think it is as I don’t have a ton of knowledge in this field so it’s better to ask people that do, anyway please help me this issue that I am having any help is appreciated and any other questions or things that you want to know to further diagnose this would gladly be answered and provided.

All the gaskets on the engine look relatively new, I believe that they were replaced two months prior of me buying the car.. head was also rebuilt at the same time

I also haven’t really noticed any loss of power just the oil consumption is a bit more than normal but yet again I do crack Vtec pretty often as I like having fun with my car, while in Vtec you burn a bit more oil right? Maybe that’s my issue because it’s only after I do a couple of pulls not after driving normally I don’t think. Also the engine is from HMO which in reality it should be super healthy unless the previous owner just absolutely beat the **** out of it lol

 

So first off you rebuilt the head so leave HMO out of the picture because they will not be responsible for a bad rebuild on the cylinder head. Not to say its a bad head job but your valve seals may very well be bad from installation error and the list goes on.

One thing to remember the C5 and C1 will burn oil when you use VTEC its just the way it goes! So i suggest just to keep an eye on the oil level in the morning when you check it. When you check the oil in the morning you get the accurate level amount on the dip stick.

You can try and add a simple catch can using the cylinder head to vent to the can using either a modified valve cover with AN fittings or buy the level 7 oil cap vent and its a bolt affair! this is what i have on my setup to vent the head. This will put the pressure off the piston rings as well as the valve seals and should help if you are pushing oil past the rings and seals in vtec due to excessive crank case pressure.

You can also try a can of engine restore! its in a silver can from the auto stores! use the 4cyl formula, just pour the can in and then pour the fresh oil over it when you do your oil changes, this stuff works magic trust me! it will restore any lost compression and help stop oil burning, ive used this stuff many times and its great! ill be using one on my HMO SOHC engine. They come low miles but you can never guarantee the miles or condition, just hope the engine was pulled from a stock civic that a old Japanese lady must of drove and never beet on..

 

I didn’t personally rebuild the head, the previous owner rebuilt the head a couple of months prior to me purchasing the vehicle. Also I only said that the engine was from hmo just to specify that it is low mileage. Not blaming them for anything lol that is just dumb. Maybe there person who rebuilt the head installed the valve seals incorrectly or they wore out prematurely..
I notice no smoke at all just cruising around or getting on it in each gear so it makes me even more confused as to what it could be

I’ll take your advice and install a catch can setup on mine to see if that will help! Or even some of that engine restore. Thanks for the input!

 

Also how does that oil cap work? How would the installation go? I don’t think I’ve heard of it but I’m open to purchasing it. Maybe you could show me how yours is set up?

 

Just buy a universal baffled catch can and fittings, this is the one i bought, you might need a different angle for the can fittings depending on where you put it. You just remove your oil cap and screw in the the level 7 unit.

Polished Aluminum 10AN Oil Catch Can Reservoir Tank W/ Breather Filter Baffled | eBay

2PC Straight Push on Lock Hose Fitting Oil/Fuel/Gas Line Adapter 6AN 8AN 10AN | eBay

2PC Push on Lock Hose Fitting 90 Degrees Oil/Fuel/Gas Line Adapter 6AN 8AN 10AN | eBay

 

Also don't use Mobile 1 synthetic, it just seems to burn faster in honda engines. I personally like Pennzoil platinum but vtec consumes oil, it just does. My 07 Si doesn't use oil when I don't use vtec, then uses a liter in days if I vtec it everywhere. It's the life of vtec.

 

Can anyone explain why oil consumption increases due to using VTEC? I'm not sure I follow, what is "opening" that is allowing oil to get past the rings and get burned? If an engine is properly sealed, I wouldn't think VTEC would make any difference, it's merely adjusting timing and such, not opening up the rings for blowby?

Or is it really more simply that these engines have very loose rings so blowby is happening because of the revs, not the VTEC (which makes more sense in my head based on engine design).

I mean, oil can only get though in a few places, valves, valve seals, rings (outside of leaks or a cracked block/heads) and get burned.

 

Higher RPM means more force and force changes. This also applies to the rings.

I suspect the transitions from up to down at the higher rpm induces a slightly greater angle in the rings allowing a little more oil past. Also the warp in the cylinder will be a bit more at the higher rpm due to the higher forces at work as well as even more rapid combustion. Knowing that the metal flexes as it's strength also allows for dynamic shape changes as it's running.

These are the only things that come to mind when I think about it.

 

Sure, I'm completely get that.

So really when we are talking about this, VTEC is not the issue or "causing" this, it's simply high rpm use will consume more oil in these engines because of of ring gap flex.

Makes sense, thanks.

 

I wouldn't even say ring gap, as much as ring flex and cylinder wall flex.

I can only imagine what a formula 1 engine running at 12,000 rpm would consume as a daily driver.

 

It's literally regulated because it's a trick that can be used to cool the engine and also to burn purposefully for fuel. that's why this struck me as so strange because a simple engine shouldn't be burning fuel, seems like a defective design if it's flexing.
https://motorsport.tech/formula-1/oil-burning-explained

In case you ever want to read about it.

 

With the forces in play, it's well known the metal flexes. The caps flex as the piston is suddenly slammed to a stop to be pulled/pushed down. The explosion on the thrust side pushes the piston into the cylinder wall and the floating sleeve design allows the metal to take the force causing an oval/egg-shape to happen that eventually is permanent from wear.

It's not defective design it's effective design to contain the insane forces at play.

As for why vtec consumes more oil, those were my guesses based on my understanding of metallurgy and the forces at play. I assume the rings are also going to flex a bit from those same forces. And everyone reports higher oil consumption during heavy vtec operation. Thus I can only assume the higher forces induced by higher rpm allow a little more oil to pass, quite possibly for cooling like you mentioned. The heat definitely goes up with the higher rpm running of the engine.