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First post here and looking for a little help with my Z6 Vitara build. I'm having an issue with oil consumption and going a little crazy trying to track it down.

A little background on the motor/car. It's a D16Z6, vitara pistons, standard length rods, Delta 272-2 cam, Crower springs, stock retainers. I basically got the engine up to temp, broke the cam in and put it right on the dyno to tune it. We just got into tuning boost and had to shut it down to fix a minor coolant leak. After restarting, the car began burning a large amount of oil. Could see oil pooled on the piston, as shown in the attached image. Took it off the dyno and took it home to debug.

Did a compression test and leak down with about 120-130 psi and 5-13% leak down. I tried new valve stem seals and the problem presented itself in the same way, got up to temp, drove it a little getting into boost slightly, shut it down for 30 min and restarted with it burning a lot of oil. Could still see oil pooled on the piston, as shown in the attached image.

Next I re-ringed the bottom end thinking maybe the rings hadn't seated or I washed down the cylinder walls when trying to start it initially? This had the exact same results. Got up to temp, shut down, restart and smoke show with oil on the pistons.

At this point the only thing remaining is the valve guides which I had a reputable local machine shop sleeve and fit to my valves. I gave them the OEM Honda spec and they recommended going a little looser than stock due to my goal of 400hp. I spot checked 3 intake and 3 exhaust valve-to-guide clearances with an inside mic and got the following:

Intake
0.0019-0.0021
Exhaust
0.0035-0.0039

The spec is:
Intake
0.001-0.002
Service limit:0.003
Exhaust
0.002-0.003
Service limit:0.004

My question is, does this valve-to-guide clearance seem too loose and would this cause the large amount of oil shown in the attached pics to get into the combustion chamber/exhaust? Turbo is also freshly rebuilt and there are no signs of oil going into the intake. Sorry for the novel and thanks in advance for the help.
 

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BATSLOMAN GIVES NO FUCKS.
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what about the valve stem seals?
 

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They put in K line sleeves? or replaced the whole guide?


You may still have block issues, wrong grit used to finish the bores of the cylinder, or improper cross hatch


Also you may have a blown seal in the turbo, blowing oil into the intake runner.


if you take a moment yo think about it, the only time the guides see vacuum is when in off boost driving conditions.

When in boost you are trying to blow air up the intake guide
 

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Discussion Starter #4
Tried the valve stem seals after I took it off the dyno and it did the same thing. Lots of oil on the pistons.

The machine shop sleeved the guides.

I had the block re-honed when I did the rings, but I just can't believe that much oil is getting past the rings regardless.

Turbo seals are good, I rebuilt it before this build and there is no sign of oil in the charge pipes/intake.

I guess it does seem to smoke more when it is sitting at idle as opposed to in boost, however it still does smoke in boost. Also my PCV system from the valve cover and block are going to a catch can with a -10AN line.
 

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IMHO.. if it bad enough for liners, its bad enough for full guides

I personally hate liners, to me they are a quick way to junk a head

I have seen more of the mass rebuilders use them because they are quick and easy.

Then they end up stuck to the valve.


You have more oil in the cylinder bore than you do the valve stem

what grit stone did they use when they honed the block?
 

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Discussion Starter #6
Took the head off tonight and found the source of the problem. The intake valves were covered in oil coming from the valve guides.

I'm still confused how this is happening as I double checked my intake valve-to-guide clearance and got about 0.0018-0.0020. I'm running a Delta 272-2 cam with Crower valve springs, stock retainers and off brand aftermarket OEM valves. The stock retainers don't appear to match the springs perfectly which I suppose could allow the spring to side load the valve slightly although I have seen others running a similar combination without issues.
 

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Discussion Starter #8
Are you looking for a picture of the valve springs or the deck? The springs can move about 1/16"-1/8" under the stock retainers. I'll get a picture of that today.
 

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that much wiggle in a valve spring in a stockish engine is not going to hurt the valve seal

the spring will have to make contact with the seal

It dosent look like the the retainer has been hitting the seal either


with as even as the amount of oil is on all 4 pistons, hard to believe they fubar all the guides.

whats the inside of the intake look like?

How is the PCV set up?
 

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Discussion Starter #11
That's what I thought as well, but I'm running out of ideas.

That's something I had not thought of. Ill have to throw the cam back in and see if it does actually make contact with the seal.

Inside of the intake is clean and the PCV setup is -10AN from the valve cover and block to a catch can.
 

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i would do the guides as you already have the head off, might as well. its 250 bucks worth of peace of mind with some new valve seals. slap the head back on after the rebuild and check again to see if your still blowing smoke.
 

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Cervan, he had the head rebuilt just before this issue started, and they put liners in the guides.

Now, OP, is the catch can vented to atmosphere? or to a vacuum?
 

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Cervan, he had the head rebuilt just before this issue started, and they put liners in the guides.

Now, OP, is the catch can vented to atmosphere? or to a vacuum?
i know he had liners installed but were they split liners or solid liners? i was suggesting getting the valve guides removed and new guides installed, not liners as i dislike them as well for this very reason. might want to look inside of the bores and see what it looks like. if they are split liners the ends should be nice and tight, if not they are a direct path for oil to go into the chamber.
 

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Discussion Starter #15
BogusSVO - Catch can is vented to atmosphere

Cervan - Good point about the liners, pretty sure they are split liners so I will have to take a look at the ends. I had them do the intake and the exhaust guides with liners and the exhaust valves/guides look pretty good.

I actually had the intake guides replaced by a different shop on my first build about 8 years ago and they screwed up the tolerances which resulted in all the intake valves being galled at about 1000 miles. I'm now wondering if they didn't press them in to the correct height and now that I'm running the 272-2 cam instead of stock the retainers are actually contacting the seals. Will investigate further tomorrow night, thanks for the help.
 

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I hate that cam passionately.

Get new valve guides installed to the smaller spec, they will wear out. They always do, the guide is a sacrificial metal, and the tighter the better they heat transfer.

Your car will run better on a stock cam. Promise. It just sounds cool because it runs like shit.

And find a new machinist. Quit half assing things
 
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