Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

Okay gang, our yellow Rex began smoking the other day, it's burning oil for some reason. It seemed to come on a little sudden, no really a progressive deal, just started burning it one morning.

So I ran a dry compression test and came up with 160-160-155-160, which seems pretty good to me. How does that sound to you guys? This a D16A6 engine BTW.

The oil burning seems a little erratic, none when it first starts up, then fairly steady, and much heavier under acceleration.

We replaced the valve stem seals this weekend, and it really didn't help. Also put in a new PCV Valve. Then ran compressions tests again, dry, then wet. Dry was the same, all the wets were near 200 PSI. (Not that I expected dry to change, just ran it to make sure earlier reading were correct.)

One thing I noticed is when the car is running and you open the oil filler cap, there is a bunch of air coming out. In fact it sounds almost like an exhaust pipe. Anyone else have a lot of air pressure inside the valve cover/crankcase?

So now I am thinking that there must be so much blow by, that oil is getting pushed into the combustion chambers, past either the rings or the seals.

Does this sound like a proper diagnosis? If so, how little work can I get by with? Hone and Rings? If I do those two, do I need to replace anything else while I am in there? (I realize that there are a ton of improvements I can make, but this car races in stock class, so I can't be doing any mods.)

I need to keep the car stock for this season, because I am way ahead in points. Once the season is over, I can do whatever I want to it, and prolly will. Until then, I want to do the minimum, yet keep it running correctly and reliably. (Also don't want to be a gross polluter.)

Thanks for your constructive input!

Craig @ Tuner Toys

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

more info, stock car? turboed?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

It's all stock. Actually I have a set of our Correct Inject 450cc injectors in it, but am using an SMC to pinch thme back down to stock levels. The A/F Gauge indicates a well behaved ratio, which continues to behave about the same as before the oil problem.

Thanks Onyx!

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

hows your timing?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

I am assuming it is on, but have not checked it. I didn't mentally make any connection between timing and burning oil, so it didn't come up.

Is there a possible connection?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

its possible but who knows, i would say blowby but your readings are fine..

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

Did you change your oil or do any matenence on your car recently?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

Nothing other than what was described above...

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

damnit for the life of me i cant remember what was wrong withthe motor the last time i had this hapening...

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

if ur racing this engine then its probably the rings,

u might have overheated them

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

I have never seen anybody have good luck with that setup. You're timing maps must be horrid. :-\
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Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

The SMC is running pretty well, except for transitions from decel to accel, it always stumbles if the transition is slow, okay if you romp on it. Keep in mind that I am not running any boost, so timing really isn't an issue.

I'm thinking that timing and fuel are still unrelated to blow-by and oil burning.

Does anyone else have a bunch of air blowing out of the oil filler hole when they remove the cap?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

I understand, but without boost your timing maps will not move. They will stay at the same point where vac leaves off.

I also agree that it probably has nothing to do with your oil burning issue though.

Is the vent hooked up to the intake? I'm guessing your rings have to be shot. :-\
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Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

I too, am leaning towards the rings. So how do I interpret the compression figures? is 155-160 normal for a D16, and is the increase to 200 with the wet check indicative of anything?

Also, if it is just worn rings, can I get away with a hone and ring, without replacing anything else? What should I look for during unspection? Do the Conn Rods have big end bearings that must be checked and/or replaced?

THanks, my record for consecutive questions is quite high!

Craig

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

Bump for more help...

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

If you are looking to rebuild properly the ball hone really isn't the best route. It works fine for me atleast a little burning oil is not a big issue to me, I built my old sohc vtec that way with 89 teg pistons. Personally your compression #'s are fine and really aren't effecting performance that much. 180 is very good for a d16 anything below 140 is poor so your in the middle. Your motor is just showing wear/tear at the rings.

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

So I'm thinking I'll locate a D16 short blok that just needs a hone and rings, and throw another engine together. Probably match it up with a D16Y8 head for a little Mini-me action.

What do you think?

Anyone got a D16A6 compete block they want to sell?

Re:Looking for your help - Engine Diagnosis - Help! (YooHoo Jeff!)
 

I think it is fixed! But I don't know why. A day after I did the valve stem seals, it just quit smoking. Maybe it took a while for them to seat?

Oh well, guess I'm cool with whatever it was.

Tnanks for all your help!