How to know valve stem seals or BHG or possibly blown piston rings

[trd_st184]

Hey all,
Well I just finished my 4age small port converison into my ae92 sedan and after getting the car started I found this:



The car was also blowing smoke on idle and I was presuming that either the oil rings or valve stem seals were worn.

Is it possible anyone would be able to provide some advice to help me work out if the bottom end is worth saving?

The valve stem seals and head gasket could be solved at the same time easy enough, i'm just worried if I go through this and find that it was the oil piston rings the whole time (I did this last time I had blue smoke out of the exhaust and ended up being the oil rings).

I would be suprised if it was the oil rings because the motor i've got is low km, just that its been sitting around for about 5 years so most of the seals have dried up quite considerably. I must admit too that the motor shuts down very quickly when I kill the ignition. I've always known that is a good indication of good compression in the motor. (doesn't tell much about the compression rings though).

[thechuckster]

Vague rule of thumb: blue smoke on heavy power/load = rings. Smoke on high-vacuum decel is stem seals.

[trd_st184]

Thanks mate. I dunno if it helps but the motor hasn't been started in 5 years and i'm not sure if it was stored in the correct process. Could this be just residual moisture in the motor? I have changed the oil, but not since running the motor (the first time was just to drain what oil was in the motor).

I couldn't see any moisture in the oil when I first drained it.

[ta22fan]

Stem seals will often be most noticable on start after the engine has been stopped for a few hours (or overnight), and smoking will ease off or stop entirely after a minute or two of running. I'd run dry/wet compression test - can often turn up an indiactor.

[BrianGT]

Stem seals will often be most noticable on start after the engine has been stopped for a few hours (or overnight), and smoking will ease off or stop entirely after a minute or two of running. I'd run dry/wet compression test - can often turn up an indiactor.

This! A compression test will eliminate valve stem seals and show you what is going on in the bigger scheme of things.

[trd_st184]

Thanks everyone for your help. Is there a good chance that the oil at idle could be a blocked ventilation fitting in the cam covers? I thoroughly cleaned the cam covers and actually needed to get a decent amount of degreaser and high pressure to actually get fluid through the ventilation fitting. There was chunks of carbon deposits coming ou. At first it was completely blocked. I heard this could be the reason for the smoke at idle.

The other thought with regards to the creamy nongoodness under the cam covers. When I first got the motor I changed the oil and got rid of the stuff that was in it originally before starting the car, it had been sitting around out of a car for about 5 years and a few oil fittings were exposed to the air such as the knock sensor fitting, oil pressure sender hole, injector holes and cold start injector. I've heard that the carbon deposits may hold moisture and may be a result of the stuff I see now under the cam covers. When I first got the motor cam covers off it was relatively clean (no sign of this cream).

I've checked the dipstick and couldn't see any of this creamy substance on it, it looked clean.

Edit:
I did notice the oil did look particularly wet in this pic (below each of the cam journals)

[lexsmaz]

This! A compression test will eliminate valve stem seals and show you what is going on in the bigger scheme of things.

I'm not sure if a typo mistake has been made by the above quote, but to clear things up there is No way a comp test will tell if its got worn Valve stem seals ..

Light amounts of Milky sludge under the cam covers as pictured can happen if the engine is doing very short runs & not getting to operating temp, a Blown head gasket normally gets a lot more sludge build up, the pic of the oil below the cams does look a bit strange ..

Why was the motor originally taken out of the car ??

[trd_st184]

I'm not sure if a typo mistake has been made by the above quote, but to clear things up there is No way a comp test will tell if its got worn Valve stem seals ..

Light amounts of Milky sludge under the cam covers as pictured can happen if the engine is doing very short runs & not getting to operating temp, a Blown head gasket normally gets a lot more sludge build up, the pic of the oil below the cams does look a bit strange ..

Why was the motor originally taken out of the car ??

Yeah thats what i thought too, when cleaning out some of the sludge as carefully as possible (only loose bits that were going to go through the motor anyway if not removed) I did notice it had a rather watery look to it. It actually resembled diahrea in its colour and thickness (or thinness in this case) loool

The motor was imported from japan about 5 years ago and has been in storage ever since. I bought it off my mate as it was checked out to be an alright motor back then, but quite a bit of time has past and things have started to deteriorate. It was from a place called Motor Heaven or The Motor house? It was checked for compression back then and all was seen to be ok.

[BrianGT]

I'm not sure if a typo mistake has been made by the above quote, but to clear things up there is No way a comp test will tell if its got worn Valve stem seals ..

Light amounts of Milky sludge under the cam covers as pictured can happen if the engine is doing very short runs & not getting to operating temp, a Blown head gasket normally gets a lot more sludge build up, the pic of the oil below the cams does look a bit strange ..

Why was the motor originally taken out of the car ??

Yeah! Sorry I worded that badly.
I meant that doing a compression test will NOT involve valve stem oil seals...it will tell you if you have low compression which could be rings or valves not seating or bent.

That's what I meant by "eliminate"....hmm.........I know what i meant!

[ta22fan]

Edit:
I did notice the oil did look particularly wet in this pic (below each of the cam journals)

Yeah - that's doesn't look right. Very old oil can sometimes breakdown into a white/grey sludge - but this looks different. Perhaps a head gasket issue? Based on the look of that oil - I don't think it's only valve stems (tho they could be shot as well). I think I'd pull the head at this point.

[trd_st184]

Yeah - that's doesn't look right. Very old oil can sometimes breakdown into a white/grey sludge - but this looks different. Perhaps a head gasket issue? Based on the look of that oil - I don't think it's only valve stems (tho they could be shot as well). I think I'd pull the head at this point.

I have a feeling that water has been introduced since it was high pressure cleaned, there was only 2 bolts holding the cam covers on (so the threads would have been exposed, so it would be a good chance that water could have been sitting (and not flushed through when I did an oil change as the motor hadn't been turned over at this stage).

[wiso]

when the engine was sitting, was it sitting with all the manifolds on and the ports sealed up? I bought a 4age not long ago that had been sitting for a couple of years with no manifolds and no cams spark plugs in. I was told the motor was good when it was pulled, blew no smoke pulled strong. but when I pulled it down water had made its way past the closed valves and into the bores, the bores were rusted as all crap and the rings were rusted in a compressed state, so they would no longer seal to the bores.

Yours may not be this issue. I guess if your rings aren't sealing a comp test will tell you. it may also tell you if HG is gone as you should get a drop between 2 cylinders compare to the rest.


How much have you run this engine since you changed the oil? if you dumped the 5year old oil then changed it, ran it and found the milky stuff it could just be that you had moisture in the engine that didn't drain originally, have you tried getting the oil warm then dump it and put new stuff. its the only way to really flush old oil?

[trd_st184]

when the engine was sitting, was it sitting with all the manifolds on and the ports sealed up? I bought a 4age not long ago that had been sitting for a couple of years with no manifolds and no cams spark plugs in. I was told the motor was good when it was pulled, blew no smoke pulled strong. but when I pulled it down water had made its way past the closed valves and into the bores, the bores were rusted as all crap and the rings were rusted in a compressed state, so they would no longer seal to the bores.

Yours may not be this issue. I guess if your rings aren't sealing a comp test will tell you. it may also tell you if HG is gone as you should get a drop between 2 cylinders compare to the rest.


How much have you run this engine since you changed the oil? if you dumped the 5year old oil then changed it, ran it and found the milky stuff it could just be that you had moisture in the engine that didn't drain originally, have you tried getting the oil warm then dump it and put new stuff. its the only way to really flush old oil?

I have a compression tester in the mail so that will definitely help with the diagnosis. I believe the throttle body was sealed, but the injector holes, vacuum lines and cam cover bolts (as well as oil pressure sensor hole) was open to air.

I have a feeling the water was introduced when the motor was washed and since a few of the cam cover threads didn't have cam cover seals or nuts on them that water got through when the motor was cleaned. I found the spark plug valley full with 1/2 inch of water so that could be a good indication of how much it was cleaned (and how much got through).

I still need to get the oil warm and dump it with new oil, as you say it could have been residual. Especially considering how mucky and thin that water was under the cam lobes. I'm hoping the rings and bores are in reasonable nick. Dunno if I feel like having to pull the whole motor all out again haha

Thanks for your help

[trd_st184]

Hey all,
I have my compression tester and leak down tester in my hands in preperation to test the condition of this motor out.

I was wondering for some advice, I must admit I have only know how to find TDC on the first cylinder, since the marker is there. I do know how to use the screw driver in the spark plug hole but there is a bit of room for error just relying on this for other cylinders?

I read up a list once which told me:

If air is escaping the exhaust pipe then exhaust valves/seats are worn
If air is escaping the intake then the intake valves/seats are worn
If air is coming out of the Oil cap it could be Valve stem seals or Piston Rings
I'd imagine if air is escaping out of the radiator cap then the HG is gone

Hoping to get this awesome little ride running just right.

I think I remember seeing 100psi as the recommended pressure on the leak down tester.

[MR22ZZ]

TDC is the same for 1 and 4 and 180 degrees for 2 and 3