Raisin

iTrader: (2)

Hi all,

First I apologize for the long read, but I want to be as clear as possible about the rundown of what I've found happen to my engine.

I've recently had an engine fully rebuilt (full bottom end, new pistons, ceramic coating, dynamic balanced crank, BE oil pump, full port & polished head, dual valve springs) - basically the works.

After less than 5000km (about 3100miles), I see the one odd puff of blue smoke one day. I drive along with a buddy of mine after on the highway and he notices blue smoke as well. Ok... strange. This engine has never smoked once during break-in and now it starts to have oil burning symptoms?

The question: Rings or Valve stem seals?

At this point I haven't taken anything apart, and after parking it overnight I cold start - no blue smoke. This has me worried at this point because it could point to poor engine break-in even though I have followed a good procedure for seating the rings. I did a bit of digging and it seems that one odd person had an issue seating his Wiseco XX rings and they actually recommend 5000miles until switching to synthetic oil. I was highly suspect of the rings at this point.

Next step: Compression and Leak down

So how healthy is this motor, it has low mileage and shouldn't be that bad right? Turns out Cylinders 3 and Cylinders 4 have poor leakdown, roughly 30% leakage. Cylinders 1 and 2 are sealing at about 5% (within reason). Something isn't sealing right in 3 & 4. Compression tests show that Cyl1 and Cyl2 are consistent - 3 & 4 again have a slight drop in compression.

At this point I'm thinking:
1) If it is the rings, it would be strange to see good leakdown and compression results in 1&2 and not 3&4. Usually all cylinders wear quite evenly during break in and its not like I could isolate 1&2.
2) If it is the valve stem seals - why didn't I see more blue smoke during cold starts?

I'm ready to pull off the head, and get to the bottom of things. Sure enough the exhaust side is covered in oil. It looks like a high mileage carboned up engine. I couldn't believe my eyes how bad it looked. The oil was definitely coming from the valve guide area. I took it too the machinist who did the head work as he couldn't believe what I was telling him over the phone. Sure enough, we take it apart during at his shop later that afternoon. Valve guides were tight, no valve wobbling or any sorts of weird play. We spin the valve on the valve grinder and it spins straight. We lap the valve to see how evenly it would leave a trace around the carbon and sure enough it looks fine. The only explanation he had was that these valve seals weren't doing their job anymore. Why at such low KM? He suspects product defect.

So, what did the pistons look like? Piston tops were dry, obviously a lot of carbon build up from the oil consumption but nothing out of the ordinary, no scores on the cylinder walls or abnormal wear. I talked to the machine shop who did the block and they are fairly confident that nothing was wrong with the bottom end considering my leak down and compression test results.

Why did I decide to pull the head much later after noticing the blue smoke? I mentioned earlier, there was honestly no cold start puff after that ONE event I saw. It was enough to make me feel uneasy and that something weird was happening. I wanted to be sure and did the compression test and leak down after driving it around for a bit just to see if anyone could notice anything coming out of the tailpipe. In conjunction with this, while I was dyno tuning my tuner had mentioned that it was a bit prone to knock while at very conservative ignition timing. Could it be that the oil consumption was bringing my octane rating so low then that it started to knock? Something just wasnt sitting right and thats when I decided to pull the head and get down to the bottom of things.

I have pictures to show and yes, I know this thread is worthless without pictures but my SD card reader isn't playing nice at the moment. Just wanted to get the info typed up while it was still fresh in my head.

Has anyone seen failures like this before? The last Supertechs valve stem seals I used had nothing like this happen.

pdexta

iTrader: (17)

This almost has me hopeful. I had so many repeat issues with my last car that I ended up parting it out when I started finding oil in cylinder #4 on my built motor. The motor has been sitting in the garage for a few months now and I've been too depressed to look at it. I'd love to think it was just a failed valve stem seal.

Definitely interested in seeing the pics. Maybe they'll get me motivated to dig into it and hope that I find something similar.

fredb

iTrader: (1)

Doesn't sound good , no way failed valve stem seals are causing those leak down numbers. There is more going on there. Sorry to be the bearer of bad news ,but that's my take on it. Fred B

Raisin

iTrader: (2)

I am not saying that these valve stem seals are the direct cause of these leakdown numbers, HOWEVER, there is definitely oil coming from the direction of the valve guide locations. In the pictures below, you'll see what I'm talking about. This oil is causing a lot of carbon buildup in the port and tells a part of the story.

These are some pictures I took the other day:

Lots of carbon on the tops of the piston, notice the valve relief areas. (Sidenote: for those that were doubting ceramic coating, sure enough still there lol)



Oil in the exhaust ports themselves. You can see two streams of bare aluminum and that is how much oil there is. The oil leaking from the valve stem seal already is coming out in such amounts that its actually cleaning the carbon off the head. I apologize for the pictures but its hard to get the camera to focus on a dark area when most light reflects off the shiny part of the head.



I took the head to another machine shop to get a second opinion and they also said that no matter the issue, you cannot deny the fact that oil is coming down the valves somehow.

dr.auto

Nothing on the intake (oil) ? are you using a oil catch can? Is the pcv valve vacuum port between #3and 4 at the intake? . So, the oil came down trough the seals? just on #3 and 4? brand new seals. and no oil cloud in the morning? are you sure that the oil doesnt come from the intake?.

Raisin

iTrader: (2)

The intake port was clean, no signs of any seal failure. I am using a catch can, no PCV anymore.

The head came as an assembly with brand new seals that I supplied the head builder with. Oil is definitely not coming from the intake side.

If anyone is curious about the latest updates:

I took it to another machine shop as the original opinion I got was that the valve seats had shifted and that it was caused by detonation. I wasn't convinced, no signs of det on the spark plugs and the pistons looked fine. I then took it to the machine shop that built my block.

What was though to be a "valve seat shift" was actually just carbon build up. As for how there was that much carbon and how it would create an outline identical to the valve seat shape? It's speculated that after a drive, the oil would pool around the valve as the engine was shutoff and the oil would cool and condense around the valve.

After cleaning up the carbon, valves would checked for straighness and relapped in. Just waiting on gaskets to arrive to put everything back together. Then I will do a compression and leakdown test just to be sure the bottom end is fine.

The answer still remains unanswered:

- How did the valve seals fail in the first place?

Miater

Poor instalation, maybe.

The tiny spring that keeps tention on the valve stem might have been stretched just a tiny bit. It could be missing all together.

hornetball

iTrader: (4)

I think you know this, but to be clear, a valve stem seal has nothing to do with sealing compression or combustion pressures. That's the job of the valves and rings.

Are you running a solid-lifter cam (99+ head)? If you are, have you checked for proper cam-lifter clearance? You might be too tight and the valves may not be closing all the way.

rleete

iTrader: (21)

Not sure what the material of the seal is, but we've had issues at work with Teflon seals in the past. Lubing at assembly (white lithium grease) eliminated the problem.

TheScaryOne

iTrader: (3)

These should be Viton seals, which is standard for positive retaining style like we have, IIRC.

On my SBC viton valve seals came with a piece of plastic straw with the ID of the OD of the valve stem, so you didn't cut the seal on the tip of the valve during installation, but I think that's a pushrod engine problem, not something that'd affect our DOHC's.

Raisin

iTrader: (2)

Agreed, the reason why I posted some information regarding a perfect seal is that I've seen on other boards when guys are pushing very high boost pressures (30psi+) it's possible to have valve stem seals pop off... but this is usually on the intake side. And... I'm nowhere near pushing as much boost as those guys.

I'm running a 1.6 head with hydraulic lifters. Stems were trimmed for appropriate valve height as compared to OEM. Currently the head has a light lap job and is pressure testing well.


These are Viton seals as someone else already posted. In the past I've installed them myself with a light amount of engine oil and didn't have any problems with oil leaks. This time however I did not install the seals, I had the head built as an assembly and I simply torqued it down.

Raisin

iTrader: (2)

So, bump from the dead.

Want to know what happened? - Read below.

With so many issues, its really hard to trace back what the hell happened and which came first (the whole chicken or egg theory), and I have narrowed it down after talking to many people about my issues I've had.

1) It is NOT the rings, I have the new cylinder head back on the car and leakdown is damn perfect. This is after getting the valves relapped and carbon all cleaned off. Terry and Donnie at TBR Engine and Machining did a great job of cleaning things up and went over everything again to make sure nothing was out of wack from the previous machinist.

2) It is not the head either - as mentioned above the head was cleaned and valves re-lapped. Everything seals perfectly now.

3) There was detonation, why this happened is the suspected amount of oil dropping the octane rating way too low, causing some det.

EDIT:

4) Even though initially I had suspected something to do with the original head builder, in the end I doubt there was anything there except poor customer service and attention to detail.

Heres the kicker: It was the cams.

No no, not the OEM cams I'm running now but infact the cams I had bought from Chikara Motorsports. I had initial done break-in on these cams, and after consulting with many people I decided to take them out. Why? Because I was IDLING AT 70KPA. That is pretty ridiculous even for a so called "street" cam on the aggressive side of things. People I have talked to running huge cams do see a drop in vacuum pressure, but nothing as crazy as 70kPa.

I neglected to mention this in the first place because I honestly felt that it may add too much confusion to the topic discussed, nor did I know at the time that these cams would have caused the issues I was seeing.

So how exactly does a camshaft relate to leaking exhaust valve seals?

Valve overlap. There is just too much with these cams. This is the only thing that makes sense to me as it is the only thing changing between something with perfect leakdown results and an engine that was seeing oil leaks that was a fresh build. After talking to many engine builders and tuners, it started to make sense that too much overlap would essentially roast the exhaust. Combustion would be occurring so late in the cycle that it would be happening in the exhaust manifold.

It also makes sense now since the head I purchased along with these cams was coated in carbon in the exhaust ports. The excuse given was that the engine had suffered from blowby. It doesn't make sense to me how much carbon was in the ports was caused just from ring blow by.

Judging by the roundabout answers I received when asking about these cams, I have absolutely no faith in Chikara's product let alone their knowledge in building engines. No apologies, and basically was told that the ball was in my court the whole time. "This setup worked fine on another customers car but that car was involved in a total loss accident". There was a laundry list of excuses when I talked to Ocean over the phone.

Just wanted to wrap this open ended discussion up, and hopefully this information should prove useful to anyone faced with similar symptoms.

Oh yeah, and I'll be going with Kelford cam's instead now.

NiklasFalk

iTrader: (1)

How did you time the cams (one tooth off)?

With my cams timed "straight" (105 on both) I idle at between 65 and 75 kPa (noisy as hell). But I assume the Chikara cams had less than 305 duration?

Raisin

iTrader: (2)

I have adjustable cam gears so I followed the diagram I was given. I have them dialed in at 111.5/110.5 IN/EX.

It's a bit of a messy and ugly situation as these cams used to be on a friend's old engine. That was until he was told by Ocean that his engine had blowby issues and needed to be rebuilt. After buying the complete setup from him (Cams, head, valves, etc.) I had only planned on using the cams.

The cams are spec'd by Ocean then outsourced to a place called Colt Cams, and I only was able to find out ALL the specs after I was told the cam cards were "lost". Did a lot of back peddling and calling around just to figure this information out.

When asked if I should be idling that high the answer was "I forget."

The Chikara cam specs are as follows:

INT 210 duration @ 0.050"
EXH 211 duration @ 0.050"

Lift: Intake - 0.340", Exhaust - 0.333"

I could understand on a large race cam that you could be idling that high. However, with this setup I feel that it is due to poor cam design.

bcrx7

iTrader: (5)

Hold on a second here, am I making a mistake about overlap. Doesn't overlap means there is overlap between exhaust and intake stroke? How does the combustion cycle comes into this? Is the duration of these exhaust cams that long that is actually cutting into the combustion cycle?

Here is the definition of overlap: Overlap is the angle in crankshaft degrees that both the intake and exhaust valves are open. This occurs at the end of the exhaust stroke and the beginning of the intake stroke. Increasing lift duration and/or decreasing lobe separation increases overlap.

So if you are combusting into your exhaust cycles, it's not the overlap that is a problem, it's the cam location (where the belt is) that is most likely the issue.

The black exhaust ports are an aftermath of the leak. With overlap, the intake would suck exhaust and with it oil since your seals were leaking and then it would coat the exhaust port and heat would take care of the rest.

Raisin

iTrader: (2)

First off, the thing is I don't know who to believe regarding cam specs, one guy doesn't want to give them to me, and the cam grinder only has some identification marks I can go off of, which I can only assume to be correct.

So based on what you wrote above, you suspect that it is poor cam timing that caused these issues?

Some things I think worth mentioning regarding these cams. I was told a few things, and this is all after the fact after calling in and asking directly - what gives with these issues.

1) I was told that they had never dyno'd the car with the cam timing I was given (which was hand written on a piece of paper) and that the same setup was run on a car that was eventually involved in a total loss accident. This tells me that these cams weren't even dialed in properly nor do they know of any net effects of adjusting the cams any further since it has never seen any dyno time.

2) I followed what I was given, and I noticed the same symptoms on the cylinder head I was given along with the cams. My judgement is that the same operation conditions caused a valve stem failure as well in the other engine.

3) After telling me that I didn't dial in the cams properly (I followed what was on the spec sheet), I was told that if it was indeed too much overlap I should have decreased the LSA. Well, I only know and suspect that it was too much overlap since these issues occured.

4) I was also told that the locator pin for the cam gears is offset in a random location and also the keyway for the cam angle sensor is offset. I was told that I need to calibrate base ignition timing AFTER the cams have been dialed in, and if I adjust them any more, that I need to also readjust the CAS. This doesn't make sense to me, since the CAS should be calibrated referencing crank rotation, NOT cam rotation, so I'm scratching my head at this one. I would love to hear if someone has an explanation for this.

EDIT: I see I missed something here:

This I know, I get that there is oil leaking from the seals causing carbon build up, however seals don't all magically die and I have been tracing these issues for a long time. Both on my old factory motor and now on my new build. What I'm saying is that there is enough overlap in these cams to cook the exhaust and eventually the seals fail. Seals were snug when they came off so the only explanation is that the spring on the seals has annealed from the heat. There are some very BS claims from these guys that their race motors run at 1900EGT, even factoring where that is measured and how... that is a ridiculous amount of heat from their N/A motors.

bcrx7

iTrader: (5)

I would suspect if the combustion is the cause of the valve seal failure, the reason is that the cam is causing the exhaust valve to open way too early. This is not same as overlap is when intake and exhaust are both open. So what you are most likely having (again if that is the cause of the seal failure) is the "overlap" of exhaust stroke and combustion stroke (which is really bad). The only reason I can think of is really bad grind or the cam gear or timing belt at wrong place.

What you really need to do is get a degree wheel for the crank and put the engine together and without the intake and exhaust manifold and without the spark plug turn the engine and see when valves open and close and so on. Unless you are tired of dealing with this and then just get stock cams and cam gears and go from there.

HHammerly

iTrader: (3)

I just finished tearing down my motor with the same issues, oil on 3 and 4 3k mi on build engine, well i did have low oil pressure so it had to come apart anyways but the oil was coming from the OEM PCV
System

Ended up building my spare botom end and going to a catch can system for the valve cover vents.

Der_Idiot

iTrader: (2)

Edit: Disregard.

Raisin

iTrader: (2)

I had a replied typed for you on my phone but the page crashed as I pressed submit. I agree with what you're saying and perhaps my wording wasn't as clear while typing it in the heat of the moment.

I won't be running these cams again, I think there are just too many unknowns. The weird location of the cam gear pin is enough to steer me away, don't get me wrong when they were in the car they made power, but the misfire issues and shitty vacuum idle for a relatively "small" cam was enough to tell me to just buy something better.