John's EZ36R H6 818R Build

[Hobby Racer]

Just a quick update to say there is no update. The car runs fine but my father past away late last week and I will not be able to try the car out for a while.

I will post back when I am able.

Thank you.

[Namrups]

So sorry for your loss. Will send a prayer your way.

[blomb11]

So sorry to hear about your dad. My condolences to you and your family!

[Frank818]

Oh John I'm really sorry about your father. My deepest sympathies to you and all of your family.

[Sgt.Gator]

Sorry to hear that. May he RIP.

[Mark Eaton]

Terribly sorry to hear about your dad. I'm really close to mine and he's nearing 90. I'm dreading the day...

[Hobby Racer]

Well the news is not good. The motor is once again broken. It went about 10 laps and died. Until I tear it down I won't know the issue or cause but no matter what it was, I'm done with this powerplant.

I'll start a new thread soon to document my new powerplant choice and implementation.

Bye bye H6

[Rob T]

Sorry to hear that Hobby, but l’m excited to see what you are going to do next. Whatever it is, I know it will be innovative and well executed.

[Sgt.Gator]

Sorry to hear about another failure. And the journey continues.....

[sparrow801]

I just wanted to thank you for your detailed posts on the timing chain issues with the EZ36. This was the motor that I had considered using in an 818, but just from reading all of your previous posts and with this failure happening on multiple occasions, I realize that you’ve given me the opportunity to learn from you without experiencing the same heartburn myself. In the back of my mind I keep thinking of a Mazda 13B-REW due to its tiny size and very limited number of moving parts etc but I’m not basing that idea on anything other than the fact that the 13B has been race-tested for many many years. I’m sure the K-Series would also be excellent.

[Hobby Racer]

No problem, I'm glad my experiences can help others. As I have said before, the EZ36 is a great motor if run in stock form. I raced it stock for two years and never had a lick of trouble in 2500 miles.

It is not a good engine for modifications with boost though.

[Hobby Racer]

I'm getting way to good at removing the powertrain quickly!




Here is the evidence of a catastrophic failure. That's bearing material!



On the plus side my fix for the timing chain worked as the timing chain never jumped!



Looking at the datalog, I can see that the oil pressure dropped steadily from 56psi until the motor blew. The log is about 5 minutes of run time. The green line is oil temp and the red line is oil pressure. I have no idea what caused the slow but steady drop in pressure yet.

[aquillen]

It's going to tease you into trying again if you figure out the source... OUCH!

[STiPWRD]

Are you running a Haltech? Unless I'm mistaken, I thought you could set an alarm if your oil pressure drops below some threshold.

[Hobby Racer]

I did have an alarm set but it's hard to see the dash light when your racing

[Hobby Racer]

For anyone currently using or thinking of using an H6 (either an EZ30 or an EZ36) in their car, I will be selling some nice custom pieces that will make your install much easier.

Off the top of my head:

• Beautiful custom made 304 stainless steel headers and full exhaust
• Aluminum coolant crossover tube (for the dual outlets at the top of the motor)
• Custom motor mounts to fit 818 chassis

[Bob_n_Cincy]

Looking at the datalog, I can see that the oil pressure dropped steadily from 56psi until the motor blew. The log is about 5 minutes of run time. The green line is oil temp and the red line is oil pressure. I have no idea what caused the slow but steady drop in pressure yet.

John,
I am surprised at your steady 56 psi of oil pressure. My stock EJ255 engine runs at 85 to 90 psi which is the stock oil pressure relief valve spring setting.

The 6 million dollar questions are:
1) Did the bearing fail because of lack of oil pressure?
2) Did oil pressure drop as a result of bearing failure?
Lets us know if you find any more clues.

[Hobby Racer]

... Lets us know if you find any more clues.

I should be tearing it down completely next week. I'll post back any findings.

[Hobby Racer]

This is the #6 rod and piston. It got so hot the rod bearing welded itself the the crank journal! I had to cut the left side of the mangled rod cap to get it out of the block. The right side was already snapped off.




#6 is the worst. I have not yet determined the cause of the oil pressure drop that caused all this damage. This is how it looked when I opened it up.

IMG_20220917_140606031.jpgIMG_20220917_163908389.jpgIMG_20220917_163950205.jpgIMG_20220917_165522110.jpgIMG_20220917_165600140.jpg

#5 got very hot as well but didn't weld itself.

IMG_20220917_165647795.jpgIMG_20220917_170349221.jpg

The rest of them looked OK! There was trash run through the bearings but no excessive heat or scoring.

[Bob_n_Cincy]

Did you check the oil pump to see if the pressure relief piston is stuck open?

[Hobby Racer]

Did you check the oil pump to see if the pressure relief piston is stuck open?

The pump seem ok. No bits in the rotor and the pressure relief valve is closed and moves ok. I'm most likely not going to spend much time trying to track down the issue since I will be switching to a different power-plant and get to do all this custom stuff all over again.

[cob427sc]

Wow! Seen a lot of bearing failures but that's got to be one of the worst. Sorry about your luck but thanks for sharing your observations.

[jforand]

John,

Man, what a saga. Sorry to hear and see all these failures.

My bet is your graph captures the moment of demise. As the bearing was eating itself, tolerances open creating an easier path for the oil to flow. Eventually, there is not enough resistance to flow for the pump to pressurize against. It declines until everything ends up metal to metal and it is anyone’s guess what goes first.

If you are taking suggestions, I recommend going TURBINE! I might even pay to see that. If anyone can pull it off it is you.

[Hobby Racer]

John,

Man, what a saga. Sorry to hear and see all these failures.

My bet is your graph captures the moment of demise. As the bearing was eating itself, tolerances open creating an easier path for the oil to flow. Eventually, there is not enough resistance to flow for the pump to pressurize against. It declines until everything ends up metal to metal and it is anyone’s guess what goes first.

If you are taking suggestions, I recommend going TURBINE! I might even pay to see that. If anyone can pull it off it is you.

My guess is in line with yours. A gradual bearing failure that turned catastrophic. Most likely some trash got into the #6 rod bearing during one or more of the three cam chain derailing failures I had and just kept eating away at the bearing, opening up the clearances.

Sad part is that I finally got the chain tensioner failure fixed. I believe the motor would have been amazing had it lived!

[DSR-3]

John, sorry to hear of your loss. As we get older "life is short" comes up more and more often.

Hate to see you bailing on the H6, but at any platform has limits (how much power were you making?). I echo your success with stock engines, but when you get pulled down the straight, it's easy to think about more.
Racing is really hard on the equipment! I remember formula ford used to be 20 hours on a crank, and anything after 18 was gambling. I lost a couple of those bets... Fortunately, they've finally figured out the 60's tech, they last longer, and I'm going back vintage FF racing! But... the cost of a Loyning or Ivey pinto engine makes eyes water.

My street/stock H6 is still running well at >5k miles, and but for an oil leak at the head/case no complaints.

Any thoughts on your next platform?

[Hobby Racer]

John, sorry to hear of your loss. As we get older "life is short" comes up more and more often.

Hate to see you bailing on the H6, but at any platform has limits (how much power were you making?). I echo your success with stock engines, but when you get pulled down the straight, it's easy to think about more.
Racing is really hard on the equipment! I remember formula ford used to be 20 hours on a crank, and anything after 18 was gambling. I lost a couple of those bets... Fortunately, they've finally figured out the 60's tech, they last longer, and I'm going back vintage FF racing! But... the cost of a Loyning or Ivey pinto engine makes eyes water.

My street/stock H6 is still running well at >5k miles, and but for an oil leak at the head/case no complaints.

Any thoughts on your next platform?

I'm sad to say goodbye to the H6 platform. I put a lot of time, $$$ and effort into it! But the cost to duplicate it again with a customized block, crank, rods and pistons is more than 3 stock engines! I do know what platform I'm going with but I want to wait until I have pulled the trigger and got an engine here to confirm my fitment plans.

I'm going with a more tried and true engine that has a lot of racing background and plenty of aftermarket support.

I'll announce it here and then start a new thread detailing the build out.

[Hobby Racer]

Well I'm committed now. New powerplant is going to be a JDM Honda K24A performance 3 lobe cam VTEC engine.



Why buy one when you can have 2 at twice the price
Now I have a spare.



As I get into it I'll start a new thread dedicated to the Honda K24 build.

[Hobby Racer]

Here is the new build thread documenting the rebuild using the JDM Honda K24A engine.

John's JDM Honda K24A 818R Rebuild

[Sgt.Gator]

Nice work. Glad you caught this before it went badly!
LOL, wrong thread!

[Sgt.Gator]

Before you have the same kind of memory issues I have...Can you write up a summation of the main issues and solutions from your journey with the EZ36?
I'm particularly interested in what you think the best oiling solution is, and any other issues that should be addressed in a race car EZ36 build.
I'm thinking a NA build, no need (for me) to address a forced induction build.
What do you think a reliable NA RWHP/TQ goal is?
BTW, for others in the H6 world, there's an interesting Facebook group: Six Swapped Subarus. https://www.facebook.com/groups/416248955247757
It's private group but I can invite you once we are friends.
Thanks,
Gator

[Hobby Racer]

Before you have the same kind of memory issues I have...Can you write up a summation of the main issues and solutions from your journey with the EZ36?

Here are my high level impressions of racing an EZ36 engine for a few years.

• In stock form they can be very reliable (see next bullet point).
• As is the case with most passenger car engines, higher G forces cause oiling issues that must be addressed.
• The lack of aftermarket support makes modifying them very expensive as parts are almost always a custom one off.
• There are not many mechanics / tuners that are proficient at working on the H6. So if you are not doing your own work, plan accordingly.

Were I to do it again, I think a better option would be the second generation EZ30R H6 for racing. The shorter stroke, stronger crank and stronger rods combined with a higher rev limit make a better starting point for a race engine. While aftermarket parts are still hard to come by, they are more available than the EZ36. Packaging is also easier with the EZ30R as it can fit into the 818 chassis without frame modifications (not counting custom motor mounts).

Bottom line, keep the power levels modest, say ~300 hp and things should be fine for a long time.

I'm particularly interested in what you think the best oiling solution is, and any other issues that should be addressed in a race car EZ36 build.
I'm thinking a NA build, no need (for me) to address a forced induction build.

The "Best Oiling Solution" is a bit subjective, but for me a solution that maintains a constant oil pressure at all RPM's and G loads during a race is good enough. It may not be the best, but it does what is required. For me that was the stock wet sump system with a custom swing arm oil pickup. It maintained the low profile of the engine (not protruding through the rear diffusor) and was simple and cost effective.

If using an EZ36 for racing, a basic tear down and rebuild should be done as these motors tend to be neglected in their daily life as commuter cars. In particular, pay close attention to the cam chain tensioning system and ensure all the oil restrictors in the tensioners are in place (three of mine loosened up and fell out)!

What do you think a reliable NA RWHP/TQ goal is?
BTW, for others in the H6 world, there's an interesting Facebook group: Six Swapped Subarus. https://www.facebook.com/groups/416248955247757
It's private group but I can invite you once we are friends.
Thanks,
Gator

With a free flowing exhaust and decent tune, a NA EZ36 should put down ~240 RWHP @ 6,000 RPM. The EZ36 will have more low end torque than an EZ30R but they will have equivalent peak HP ratings due to the EZ30R reving higher.

[J R Jones]

My wife's 2006 Tribeca EZ36 was speced at 250hp @ 6600RPM; later years at 256hp @ 6000RPM.
At 180K miles a seal between the oil pump and block split dumping a quart in 30 miles. Repair was quoted at $3500 so I did it myself.
The subsequent owner wrote me that the cam chain(s) broke at 220K miles and he was considering a DIY repair. As John can confirm, the engine design is "interference" so I recommended bailing out on that engine. YMMV.
jim