Muckman

iTrader: (2)

You have that backwards. The non resistor plugs can introduce EFI interference into the system. The analog cam/crank position sensors are sensitive to this and can result in erratic rpm pickup in a datalog. If its bad enough it can cause ignition breakup because the ECU cant figure out where the engine is. Resistor plugs suppress this noise.

*Off topic: This is one reason to upgrade to a real EMS system and run a digital hall effect cam position sensor or an optical trigger, because they are not susceptible to EFI noise.

Correct, cylinder pressure is the most significant factor of ignition timing. More cylinder pressure as a result from forced induction and/or mechanical compression requires less ignition advance to reach peak combustion pressure. The flame front travels faster in higher pressure as the mixture is closer together. Temperature and air density also affect the mixture...

Sukebei Oni

I thought the crank was counter balanced according the weight of the rods and pistons. So I thought the crank would need to be balanced to the new parts. Not trying to disagree with you but I might need to do a rebuild soon so I wanna make sure I have things figured out.

EF9_TryMe

In for this as well. I completely avoided this process regarding my recent build.

I heard Nissan boys run the optical trigger.

So upgrading to an AEM EMS, and COP would remedy this situation ?

My buddy who tuned a Miata recently with COP said you can run a
wider spark plug gap without breaking up through higher RPM's+More
boost.

I smell secretions

how did the bearing look after tear down?

cruizinmax

iTrader: (2)

Not on these engines. When 2 pistons are down the other 2 are up, balancing each other out.

OneBadTurboCRV

That is why they are called "Zero Balance" engines...

Muckman

iTrader: (2)

Thank you, Exactly.

Ill let you know when I tear it down.

Well COP has nothing to do with it but the ability to run digital sensors means you need a true EMS like AEM, Haltech, Motec, Megasquirt etc. And yes having 4 coils instead of 1 means they have more charging time and thus more spark energy available to spark a larger gap.

Muckman

iTrader: (2)

Head update:

No bent valves but the valve guides are worn. The guides are allowing the valves to wobble .003" total which is beyond the service limit of .002". This caused the valves not to sit flush in the seat and caused them to get hammered out of round. They are able to grind the valves back to round and do a 3 angle valve job on the seats. We are replacing the OEM steel guides with Supertech manganese bronze guides. My concern is the OEM steel guides were cut vs the new guides are only tapered so Im sure that will decrease head flow slightly.

The valve wobble was responsible for my "low" compression in #4. But more concerning was this wobble allowed a good amount of oil to work its way past the valve seal and into the combustion chamber. Oil reduces the effective octane rating and makes for poor detonation control. There is also evidence of reversion going up all 4 intake runners as well. The chamber and intake ports showed signs of oily combustion.

I believe these problems are responsible for all of our tuning issues - the lower than expected vacuum at idle, the "cam surge" at low load/low rpm, and the strange fuel map shape. To be honest my tuner even said sine wave shapped fuel maps means something is wrong with valve timing or valve seal. It’s amazing this engine made the power that it did and I wonder how much power was left on the table. Imagine what it's going to make with a fresh valve job.

Charlie Moua

iTrader: (3)

that sucks...
well at least you found out the "why", cause not knowing is probably the most stressful part.

rich7777

Have you got any pictures of the pistons and combustion chambers I could see please? (the cylinders that didn't suffer oil contamination). I would like to see the carbon build up on the piston crowns and the quench areas. Thank you.

Muckman

iTrader: (2)

There isnt carbon build up on a 500 mile ethanol engine. All cylinders had oil contamination. I dont think these pics of the head will show you want you hoped to see.

Muckman

iTrader: (2)

I decided I could not risk this head, listened to good advice and tore the motor down. And it turns out the pins were already bent! Pistons 1 and 4 were difficult to tilt on the rod. They were semi seized and causing the engine to stall at idle unless throttle was added. The pins were tough to remove but the pistons and rods look fine. I’m going to have the pin bores honed for the new HD pins to make sure it’s true again.

Badge of honor or very lucky? Broken pins destroy everything. The motor would be a total loss.

rich7777

You are a lucky guy for sure Muckman.

This engine was built with a .035 piston to head clearance correct ? You're also reving up to 9000rpm... Can you notice anything peculiar about the quench area's of the pistons ? Do they seem cleaner than the rest of the piston ?

Damn, that piston pins more bent the George Michael.

Muckman

iTrader: (2)

Yes .035" p2h with OEM head gasket, revved to 9100. Quench pads show no difference nor contact. I know you're fishing for a p2h baseline

rich7777

Haha, my engines all set. I actually had a brave turn and am running .035 p2h also.

Muckman

iTrader: (2)

Im telling you its ideal. That dead air is a power killer.
Hope you upgraded your wrist pins!

rich7777

I have Mahle pistons. I know of people pushing them harder than I will be without issues so hopefully I'm fine. I hear you with the tighter quench. My view has changed a bit over the past few months...

wantboost

iTrader: (2)

I can't believe you alreary bent a pin! That should tell you just how much cylinder pressure that motor sees, due to the high compression ratio and boost levels. I wonder what your dynamic c/r is.

And I can't believe you made that kind of power with that powerband with low compression, worn valve guides, bent piston pins, and oil contamination lol. Makes me wonder how turbine response and the overall power band will change after the head is repaired.

You have all the issues of a well seasoned built motor lol, I guess that's the cost of being an innovator/ground breaker.


Oh and any time you get tired of that head feel free to send it my way

EF9_TryMe

Holy ****! I'm just wondering how much power is still available after boring out the
pin bores on what will accommodate for the HD pins. Well noted information, and
definitely inked in my notebook for future ambitions.

What kind of a procedure did you use to inspect the 'valve guide wobbling' ?

Charlie Moua

iTrader: (3)

remind me what pistons you have?

also how does a piston wrist get bent?

tepid1

When it hits the head or valves, improper pin to bushing clearances, detonation, and PTW contact.

OneBadTurboCRV

He has Wisecos with STD wrist pins. It can get bent from a tons of things but most are EXTREME cases like detonation or too high of RPM, piston contact, ect.. Most of it comes from exceeding the cylinder pressure/power rating of the pin. Most people who use 4032 forgings are building N/A vehicles, so Wiseco provides a lighter pin to facilitate the assUmed higher RPM.

I feel very naughty right now... hehe

Muckman

iTrader: (2)

Wiseco K594M845 (84.5mm, +8.25cc). To be fair its the light pin with tapered ends to save weight. .138” wall with 3.5mm taper. I should of known better. Wrist pins bend from piston contact or extreme cylinder pressure.

Are the Wiseco standard pins the tapered kind?

I didn’t even make it to the track! I think most of the blame goes to the small pin rather than the cylinder pressure. I wonder what my dynamic C/R is too but without anything to compare it to the number would be worthless. Let’s just assume its high!

This is what impresses me the most. The oil, the poor valve seal, the reversion up the intake port – this thing shouldn’t have made hardly any power. Im excited about how much power was left on the table. Plus the annoying tuning issues shuold be solved.


Someone make me a bent pin badge of honor avatar! LOL

Sure…


The HD pins are the same OD – 21mm. The wall is thicker - .225” and the material is stronger - 9310 tool steel.


Machine shop did this for me. They take a dial indicator and measure the wobble. The shop will also be installing new guides and doing the valve job. This is outside of my capabilities.

Like this but not my pic.

wantboost

iTrader: (2)

Charlie Moua

iTrader: (3)

I will keep this in mind when i build my engine.
Thank you very much for sharing your build.

Charlie Moua