John's EZ36R H6 818R Build

[Hobby Racer]

I was tracking down some irregularities in my engine logs and stumbled onto some videos outlining fake NGK spark plugs that are being sold on Amazon and e-Bay. I purchased my plugs through e-Bay and thought to myself...hmmm... better check.

Well, turns out mine are fakes. It's amazing how good these fakes are. Externally you would be hard pressed to tell the fakes from the real ones (I guess that's the point). Anyway, the real test is to break one open and look at the electrode that runs through the plug body. The real NGK's are copper and the fakes are steel.

Live and learn, shopping for the best online price is not always the best option

Just thought I'd put this out there in case anyone else is shopping for plugs.

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[Frank818]

I heard about that recently too, I think also Denso is suffering this problem, they show pix on their website of real ones and fakes. Saw that somewhere.

We really need to be careful or possibly buy 1-2 plugs too many and break one out to check before using them.

Glad you found out early in the process!

[Hobby Racer]

Now its officially a "Race Car" because it has stickers on it! I've been wanting to do this for a while now and finally found a web site that was cheap and lets you design your own graphic.

[jforand]

Looks great!! What's the website?

[Hobby Racer]

Looks great!! What's the website?

Race Car Number Kits

[Mitch Wright]

How did your Dyno sessions go??

[Hobby Racer]

How did your Dyno sessions go??

Still trying to get it done! The guys I thought were going to help are ghosting me

So I'm at the track now tuning by the seat of my pants! Hope it doesn't go badly

[roadrashrob]

Still trying to get it done! The guys I thought were going to help are ghosting me

So I'm at the track now tuning by the seat of my pants! Hope it doesn't go badly

Is it DDA Tuned in Newburgh you are still trying to get in touch with? Did you tell him it's an FFR 818? I had mentioned you'd be reaching out, and he was excited to do it. I know from his Instagram feed he's been slammed. PM me your details if you want me to reach out and remind him to get back to you.

[Hobby Racer]

Is it DDA Tuned in Newburgh you are still trying to get in touch with? Did you tell him it's an FFR 818? I had mentioned you'd be reaching out, and he was excited to do it. I know from his Instagram feed he's been slammed. PM me your details if you want me to reach out and remind him to get back to you.

Yes its DDA Tuned. I spoke with Seven directly and then again a week later with someone else as he was out at the time, plus two emails and nothing. I did find out that the guy who does their tuning has some kind of family thing going on so that may be the issue. But really I expected at least a call back to let me know.

I'm going to try him back at the end of the week (I'm at the track now) and hopefully can find out whats going on. If I can't get anywhere I'll let you know.

[Hobby Racer]

Transmission is shifting great now. I'm getting the fueling sorted out, it was way rich. I've cut fueling back three times and its near where it needs to be now. Tomorrow should be a good day!

[Hobby Racer]

Day two at the glen was going great. Car was running well and making good power. But shortly into my 3rd session for the day the car shut down on track, requiring a tow back to the pits. It was definitely something internal to the engine so I packed it in and went home. In this short video you can hear the problem start at around 33 seconds, just after I came off the throttle on the back straight.



After removing the engine and transmission I found that the driver side cam chain jumped off the gears. I have to do some serious looking around with the borescope tomorrow, but I think I dodged a bullet. The only damage appears to be a cam sprocket and tensioner, plus some minor gouges in the aluminum case from the chain whipping around. Since this is an interference engine there could be some serious valve to piston damage. Initial looks seem to indicate no valve to piston collisions but I'll know more tomorrow.

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[Rob T]

Bummer. Sorry to hear that John. Hoping for the best....

[Frank818]

Jesus you are quick at removing an engine! Or maybe it's me who's super darn slow... on top of that, your engine bay is as clean as when it comes out from FFR! How on Earth do you do that, no wires at all.


I feel you big time, reminds me of my chain jumping on one cam, had same symptoms! But it did a high pitch PIIINNNGGGGG when it started and then all went wrong. Bent valve. Lucky that didn't happen to you. Maybe your cam bolt loosen up for some reason?

[Sgt.Gator]

Sorry to see this. I'll be amazed if you don't have bent valves.

[Hobby Racer]

Sorry to see this. I'll be amazed if you don't have bent valves.

Here is a pic of the #2 piston from my cheap HF borescope. You can see two shiny contact points on the exhaust side. All the left side pistons look the same (#2 is the worst). The intake valves do not appear to have contacted the piston that I can see. I think I may have gotten extremely lucky. I do not think this is bad enough to have bent any of the exhaust valves.

The only way to know without pulling the head (which required an entire tear down on the EZ36) is to put the new chain and gears on when they come in and do a compression / leak down test. That is what I think I'm going to do. Now just waiting for parts.



The nagging question in the back of my mind is what caused it to jump in the first place? I ordered all new guides just in cause one was slightly bent or twisted, causing the chain to not run true.

[J R Jones]

It has been several years since I had the cam chains off our Tribeca H6. It seems the guide shoes would be visibly intact or not, but, the hydraulic tensioners function dynamically requiring oil pressure. Even if they are mechanically OK it is hard to know if they lacked pressure long enough to collapse. You would have noticed if the pressure dropped. Is that data in your logger?

You could consider loosening the cam pillow blocks and do cylinder leak-downs while parts are in transit.
That photo is ominous.
jim

[Hobby Racer]

Even if they are mechanically OK it is hard to know if they lacked pressure long enough to collapse. You would have noticed if the pressure dropped. Is that data in your logger?

I log everything, including oil pressure. It never dropped during the hole event so I don't think they collapsed. I'm more inclined to think the guide / shoe was twisted or bent slightly, derailing the chain at high RPM's when there was a bit of slack from letting off the throttle.

A leak down test while waiting for parts is a good idea.

[J R Jones]

Chain design 101 says the pull (tension) side of the chain is the straight run; the push side of the chain can have the "belly" or slack, and that is where the tensioner is located.
It is not analogous to a bicycle where the pedal sprocket loads the chain during acceleration and the rear wheel loads the chain on deceleration.
The crankshaft rotating mass always pulls the chain. The cams (at half speed) never have inertia to push or pull the chains. The crank always provides tension, just more or less.
The oil pressure will provide more or less tensioning on the slack side. As you know there is a coil spring in the tensioner and oil pressure is a boost.
My theory is the chain is pulled and pushed hardest on acceleration.
If the chain has any chance of walking laterally off the sprocket teeth, it will be on the slack side.
jim

[Hobby Racer]

If the chain has any chance of walking laterally off the sprocket teeth, it will be on the slack side.
jim

And that is where I think it walked off, on the slack side guide / shoe tensioner.

[J R Jones]

Obviously you will evaluate runout on all the sprockets.
What are you thinking about the guide shoe displacement? Chicken or egg? I lean towards the shoe came off the guide and the chain became unstable.
Is that riveted and/or bonded?
jim

[Hobby Racer]

Obviously you will evaluate runout on all the sprockets.
What are you thinking about the guide shoe displacement? Chicken or egg? I lean towards the shoe came off the guide and the chain became unstable.
Is that riveted and/or bonded?
jim

It's really hard to nail down what actually happened in these situations. I tend to agree with you that the guide was the cause. The shoe is only "snapped" into place with no mechanical fastening. The shoe was off the guide when I disassembled everything but its hard to say if it came off first or was pulled off after the chain derailed.

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[Sgt.Gator]

There are posts on the LGT forum about the idler pulley bolts loosening being a known issue. But that seems to cause a lot of noise and I can't find any reports of it causing a failure like this.
If you replaced the tensioner with a Gates those are known to fail in the EJ series. Gates switched a few years ago to a Chinese supplier and the failures started. Now we only trust OEM Subaru or Aisin tensioners.

Is it possible the chain has stretched beyond the capacity of the tensioner to take up the slack? I don't know what the spec is on the chain stretch limit.

I did find this on a Subaru Parts Website:
Part Number: 13143AA081
Supersession(s): 13143AA080
Engine Timing Chain.
Fits Outback (2010 - 2019)

Timing Chain
Your engine's timing chain can stretch over time resulting in a check engine light that comes along with excessive noise from your engine's timing cover. If the chain has broken, which is a rare occurrence, the engine will not start. If your Subaru Outback has high mileage along with any of these other symptoms, contact our service department for expert diagnosis.

https://parts.classicsubaruofatlanta...3143AA081.html

[J R Jones]

John,
That design/assembly type is dependent on running dimensions and tolerances retaining the parts together. The shoe will not come off the guide as long as the guide is in place and the chain tension is maintained.
Of course a mechanical failure resulting in a stray part or debris could impact the shoe or loft the chain off of the sprocket teeth.
My preferred theory is a failure to maintain chain tension, FWIW.
Is that tensioner oil galley intact, leaking or obstructed?

Long ago I built a 421 Pontiac from a basket of (purchased) reconditioned parts. Late at night, I fired it up the first time, the left bank of hydraulic lifters were fine, the right bank was noisy.
Out came the engine, the oil pan, pick-up and pump came off, and looked fine. Desperate to trace the oil distribution I bought a pack of cigarettes and blew smoke into the oil pump mount.
A wisp of smoke appeared from the back of the block, and a vertical chamber inside the back of the block. At the top of the chamber, in line with the right lifter galley was a threaded hole where smoke came out.
On the outer wall in line with the threaded hole was a welch plug. The welch plug was removed, a NPT plug installed to the end of the oil galley and a new welch plug installed. Subsequently the engine ran fine, and powered my tow car.
jim

[Hobby Racer]

There are posts on the LGT forum about the idler pulley bolts loosening being a known issue.

There are no idler pulleys, only a single idler gear that attaches to the oil pump. It was tight when I took it off.

If you replaced the tensioner with a Gates those are known to fail in the EJ series. Gates switched a few years ago to a Chinese supplier and the failures started. Now we only trust OEM Subaru or Aisin tensioners.

I'm going with all new OEM Subaru parts, including the chain you mentioned. The aftermarket parts for this engine seem to be of dubious quality, I stick with OEM. I ended up ordering the engine idler gear (oil pump gear), the LH intake cam gear and VVT mechanism, the chain and all guides on the left side. The only things I'm reusing are the LH exhaust gear and VVT mechanism, as it looks perfect, and some of the bolts.

[Hobby Racer]

Well the leak down test confirms that there are definitely bent or stuck valves.

Now I will begin the the not so fun task of tearing it down. On the plus side, the short block is not damaged and that is were I spent the most money on this engine build.

[Frank818]

Darn it! That sucks, was predictable like Gator said, but I know how it sucks! Hope there are no other important damages, like a notch in the head and stuff like that.

[Hobby Racer]

First the carnage. This is the valve that is bent the most, intake on cylinder #2. All the intake valves are bent sightly. The exhaust valves look OK but I'm going to replace them all just to be sure (they're inexpensive ~$14 each). I'm just glad none of them broke off and trashed the entire engine.



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Now for the root cause and the the long time mystery. Those that have been following my build may recall this picture that I posted back in January 2020 post #654 IMG_20200119_162614548_HDR.jpg. It was a mystery part that I found in my oil pan and was asking if anyone knew what it was. Well now I know. When taking the pan off for this rebuild another one dropped out! I thought to myself, I really need to track this down immediately. Come to find out it's a pressure relief valve that screws into the hydraulic tensioners. There are 3 in this car, 2 of which were now OUT! These relief valves keep the hydraulic pressure in the tensioner from bleeding off too quickly when there is a drop in oil pressure. Without the valve in place the only thing holding tension on the chain is the weak mechanical spring in the tensioner. Here is a picture showing two of the tensioners side by side, one with the valve in and one with it out sitting on the tensioner.



This failure was destined to happen sooner or later since I was already missing one relief valve and then another just dropped out. These are going back in with Loctite Red and maybe I'll even peen over the threads. Trouble is I misplaced the first relief valve since it was so long ago and you can not order just the relief valve, you need to order the entire tensioner

I'm glad to have found the root cause as I would have reassembled the engine just to have it fail again and possibly do even more damage. The head, block and pistons look great. After some clean up they will be right as rain. Time to go and order some more parts.

Update: I found the old missing relief valve! Sometimes it's good to be a pack rat.

[fletch]

I remember that old post and loose part. Glad you found the root cause. Learning some of this stuff just hurts more than it should. Sorry for your troubles.

[Sgt.Gator]

That's great that you figured it out. I have to say I'm not sure you are at the root cause yet. The question being, why are they falling out? I've searched the Legacy forum and other Subaru H6 forums and have yet to find a single instance of this failure. Tensioner bolt failures (coming unscrewed) but not the valve falling out.
Having one fall out appears to be a one in a million, but now you have had two fall out, that can't be just bad luck! Whatever caused them to unscrew may manifest itself in some other part failure. Other than some weird harmonic/vibration I haven't got a clue though.

[Frank818]

Man John you rock! You got the engine out in 5mins and found the issue 10mins later. I should really hire you (high lump sump expected).

On the other side Gator's point is really interesting and should get anyone thinking! I guess he's right (yet again) that you still got some digging to do. This will be very interesting to follow, I love to learn from super weird impossible issues.

[Hobby Racer]

The question being, why are they falling out? I've searched the Legacy forum and other Subaru H6 forums and have yet to find a single instance of this failure. Tensioner bolt failures (coming unscrewed) but not the valve falling out.

I think it might have something to do with the vibrations / harmonics. As far as I know I am the only one racing this engine, there are bound to be issues that are not common to most other street applications. Like any new racing program you just move on to the next weakest link, fix it and repeat.

Remember I also had ALL the ring gear bolts back out in my 6 speed. I never heard of that happening either!

[Sgt.Gator]

Remember I also had ALL the ring gear bolts back out in my 6 speed. I never heard of that happening either!

Good point, I forgot about that. That was another one in a million odd failure.

Are you running solid motor and trans mounts? Cindi Lux's husband, Fred, who is the mechanic on her pro Trans Am car, once warned me not to use solid motor mounts because they would cause all kinds of weird failures. Everything from parts coming unscrewed to electronic sensors failing that never ever fail on a non solid motor mount car.

We do appreciate you being the pioneer!

[Hobby Racer]

Are you running solid motor and trans mounts? Cindi Lux's husband, Fred, who is the mechanic on her pro Trans Am car, once warned me not to use solid motor mounts because they would cause all kinds of weird failures. Everything from parts coming unscrewed to electronic sensors failing that never ever fail on a non solid motor mount car.

We do appreciate you being the pioneer!

No solid mounts. I use STI Group N motor mounts and a custom trans mount using poly bushings so that shouldn't be an issue.

[Hobby Racer]

The red arrow shows where I tried to drill through the tensioner and relief valve head so I could secure them with safety wire. The relief valves, or at least the cap screw heads, must be hardened as my cobalt drill bits were barely able to scratch them so I ended up putting them in with Loctite Red and then staked them in four places each to prevent them from backing out.

Hope that does the trick

[Frank818]

That's great stuff man, hope it will keep them in place.

Hard to tell on the pic but does the pinning allows you to keep track of any loosening, like when we mark a bolt or nut to see if it moved from its original location after a while?

[Hobby Racer]

That's great stuff man, hope it will keep them in place.

Hard to tell on the pic but does the pinning allows you to keep track of any loosening, like when we mark a bolt or nut to see if it moved from its original location after a while?

You could but it would require the engine be removed and the front cover taken off, its a huge job on the H6 motors.

[Frank818]

Ok I understand, very inconvenient I agree. Basically the way you can "follow-up" on this is on your next oil change...

Next time you race the car will you fear those valves or will your brain be powerful enough to not think about them? Mine would think about it all the time until I race a couple of times without finding a valve in the oil pan... not a most pleasant kind of issue one would have.

[Hobby Racer]

Next time you race the car will you fear those valves or will your brain be powerful enough to not think about them? Mine would think about it all the time until I race a couple of times without finding a valve in the oil pan... not a most pleasant kind of issue one would have.

I will be distracted during the first session for sure. After 20 minutes its either going to break or be good; in my mind anyway.

Either way we will find out on 9/22 as I'm do back at Watkins Glen!

[aquillen]

If those come out now I'd bet Loctite/Henkel corp would love to see them.

[Hobby Racer]

You know, I bet a bunch of those pressure relief valves have backed out on factory Tribeca's, Legacy's and Outback's and people are none the wiser. You hear a lot of complaints about noisy valve trains and clickity clakety noises on higher mileage H6's and people attribute it to stretched chains and the like. But I'll bet if they did a tear down a fair number of those valves have backed out. In the low stress, low rpm world of daily driving it most likely would never cause a failure, just makes noise.

Food for thought.