Built 2.18L Stroker Flattens above 6k rpm

[subiblue2002]

Hey built motor discussion.
Its been a while since I've visited.
My 2.18L stroker has been so reliable the last 8 years, I haven't found the need to change anything power wise, just routine maintenance.

If you're interested in trying to solve this problem, I'd be very appreciative!
Have a look at this thread I started in Tuning.

https://forums.nasioc.com/forums/sho....php?t=2950866

Where I'm at currently:
The coil packs I pulled off the engine had been on there as long as I can remember.
They were the gray diamond ones.
When I ordered new coil packs, I ordered NGK. Very reputable brand. They are all black.
I googled OEM coil packs for my year (2002), they're all black.
This got me thinking, why were they're gray diamond ones on my engine..?
Was my car specifically tuned for the gray diamond coil packs?
I had asked my tuner about dwell times, but he didn't mention anything about this in his response to me.

I'm really leaning towards it being the new NGK coil packs.

Has anyone experienced something like this?
I'm sure the answer must be yes..

Sent from my SM-N960U using Tapatalk

* Registered users of the site do not see these ads.

[subaru_gc8]

nope, but if you need coil packs let me know

[benflynn]

They are the same settings black and gray, get some low mile take offs a 2019 or so

Dwell for my 05 and the 2020 take offs was the same table, connectors are different, a lil tab to cut off or just get the newer connectors as they break anyways

[benflynn]

Also my $ is on bad valve spring. They don’t last for ever esp and the rates go up

[subiblue2002]

Update
So I spoke with several reputable tuners and builders in my area and beyond. General consensus is that the OEM coil packs are the best option.
So I broke down and ordered them.
Oh BTW I looked through some photos of my engine and determined I had Black Diamond coils, not the Gray Diamond ones as I originally thought...

Anyways I removed the NGK coils as well as the spark plugs to open up the gap back to .028
Re-installed the spark plugs and then the new OEM coil packs.
Took it out for a test drive... Same.
Was feeling pretty defeated...I've never been met with an adversary such as this...
Pulled the car in, shut the garage door, turned off the lights, then shortly after had an "AhHa" moment.

I thought - What if I remove the vacuum line from the fuel pressure regulator and perform the same driving test as I have been, will I get a rich or lean condition when I get to 6k rpm under boost.
So I removed the vacuum line and plugged it.
Then started up the car and checked what the pressure was. It was at 45psi.
Took it for a spin. 1st gear up to 6k rpm then applied small amount of boost and the engine did not experience the rich condition. AFR did not go to 10...
Tested again up to 6k rpm with a little more boost in 2nd gear, engine did not experience the rich condition.

OMG I think I'm on to something... perhaps the most promising evidence yet..
What's really getting to me now is that I had recorded the FPR with my GoPro early on in this whole endeavor...I could have sworn that I saw the pressure increase 1:1 during boost...

With this new evidence I have a strong suspicion the FPR is the culprit..
I went ahead and ordered a replacement.
Pretty much have to wait another week to see if this is the fix...

[subiblue2002]

UPDATE:

I swapped out the FPR for a new one. The problem still exists.

I also threw in some copper plugs for the hell of it.. Still exists.

Pulled the charge pipes off and did a pressure test on them, they're good.. Still exist.

Not sure if I mentioned this in previous posts, but I used my scope to inspect the crank sprocket trigger... it's good..

This sputtering doesn't arise until 6k. Nowhere else. And only under boost.

I can drive around over 6k with no boost and there's no problem..

I've just about had it with this problem.

I feel like calling up Injector Dynamics and asking them if I should send the Injectors back to them for a double check.

I'm running out of ideas at this point.. If it was an electrical/wiring problem you think it would arise with or without boost...but this problem is only with boost applied.

Sent from my SM-N960U using Tapatalk

[blurred]

Originally Posted by subiblue2002

UPDATE:

I swapped out the FPR for a new one. The problem still exists.

I also threw in some copper plugs for the hell of it.. Still exists.

Pulled the charge pipes off and did a pressure test on them, they're good.. Still exist.

Not sure if I mentioned this in previous posts, but I used my scope to inspect the crank sprocket trigger... it's good..

This sputtering doesn't arise until 6k. Nowhere else. And only under boost.

I can drive around over 6k with no boost and there's no problem..

I've just about had it with this problem.

I feel like calling up Injector Dynamics and asking them if I should send the Injectors back to them for a double check.

I'm running out of ideas at this point.. If it was an electrical/wiring problem you think it would arise with or without boost...but this problem is only with boost applied.

Sent from my SM-N960U using Tapatalk

Honestly your best bet is to put the car on a load dyno with your tuner in the car to diagnose... It's the safest way to try to narrow down possibilities and he will be able to play with the ecu side more easily to rule things out.

Provided everything else is fine you could be having valve float issues as well, as you mention how many years it's been running, it could simply be time for a refresh

Have you done a leak down test to rule out valve sealing issues?

[subiblue2002]

Originally Posted by blurred

Honestly your best bet is to put the car on a load dyno with your tuner in the car to diagnose... It's the safest way to try to narrow down possibilities and he will be able to play with the ecu side more easily to rule things out.

Provided everything else is fine you could be having valve float issues as well, as you mention how many years it's been running, it could simply be time for a refresh

Have you done a leak down test to rule out valve sealing issues?

Hey Blurred.
I haven't done a leak down test.
Just pressure tested the charge tubes and compression test of the cylinders.
The thought did cross my mind to take it to the tuner.
Its just a mish and a half...
What gets me the most is that the engine hits hard up until 6k, then she just says no after that..
But I can drive around over 6k rpm with no problems.. soon as boost come in to play.. bamo.. sputtering.

Sent from my SM-N960U using Tapatalk

[that11guy]

Thats a +1 for me on Kakarots post. I looked at your log as well and its pulling 10 degrees at the 14 second point in the log. The car had a total timing of 2.5 degrees, lol.

[subaru_gc8]

Id say maybe you need to rering your engine. do a compesssion test to see, its part of the problem with forged blocks, they only live for about 75000

[Eccoved40]

geometry dash

Originally Posted by subiblue2002

Hey built motor discussion.
Its been a while since I've visited.
My 2.18L stroker has been so reliable the last 8 years, I haven't found the need to change anything power wise, just routine maintenance.

If you're interested in trying to solve this problem, I'd be very appreciative!
Have a look at this thread I started in Tuning.

https://forums.nasioc.com/forums/sho....php?t=2950866

Where I'm at currently:
The coil packs I pulled off the engine had been on there as long as I can remember.
They were the gray diamond ones.
When I ordered new coil packs, I ordered NGK. Very reputable brand. They are all black.
I googled OEM coil packs for my year (2002), they're all black.
This got me thinking, why were they're gray diamond ones on my engine..?
Was my car specifically tuned for the gray diamond coil packs?
I had asked my tuner about dwell times, but he didn't mention anything about this in his response to me.

I'm really leaning towards it being the new NGK coil packs.

Has anyone experienced something like this?
I'm sure the answer must be yes..

Sent from my SM-N960U using Tapatalk

Regarding the coil packs, it's possible that the gray diamond ones you had on your engine were aftermarket or non-OEM coil packs that were previously installed. Aftermarket parts can vary in terms of their performance characteristics and specifications compared to the original equipment manufacturer (OEM) parts. It's also possible that your previous tuner specifically selected or recommended those gray diamond coil packs for your setup.

[runner19]

I have a 2002 bugeye.

I had the oem black coilpacks. Change to the newer grey ones and had to change the dwell.

Car runs the same after the dwell changes

[runner19]

Qr dbl quote

[subiblue2002]

*UPDATE*

Took the car to the tuner.
Put it on the Dyna Pac and he went to work.
Didn't take very many pulls for him to determine the sputtering and rich condition could not be tuned out.

Fast forward to this week.
I've performed a leak down test. All cylinders are holding pressure quite nicely.
I also pulled the timing covers off to ensure timing was on the mark. It was.
I'm running out of tests and inspections to perform...

Originally Posted by benflynn

Also my $ is on bad valve spring. They don’t last for ever esp and the rates go up

I'm beginning to feel this may be the problem..
Maybe there's a broken valve spring and it only shows on the upper RPM range.
But how the hell can the valve stay completely shut during the leak down test???

[subiblue2002]

Update
Yesterday I decided to pressurize the entire intake system.
Blocked off the turbo inlet, pressurized to about 15psi and rotated the engine so that there would be pressure at each cylinder.
Result was good. No leaks.
Thats pretty much every test on earth now..

Is my ECU bad?? Hell if I know..
Is an injector getting stuck open at 5800rpm ..? Idk I've spoke with injector dynamics and they said they passed all tests and I have the graph.
Maybe I should send the injectors back..?

Sent from my SM-N960U using Tapatalk

[Jedi03]

i have heard of the term seat pressure...if the spring is weak I would think of either pulling them or find out how to measure seat pressure

[subiblue2002]

Originally Posted by Jedi03

i have heard of the term seat pressure...if the spring is weak I would think of either pulling them or find out how to measure seat pressure

Agreed.
The valves have to he floating in the upper rpm range.
I spoke with several valve spring manufacturers today to get some more information on life expectancy.
General consensus is that the valve springs are consumables.
While this engine may not have a ton of miles on it.. the miles it has were extremely taxing. I wasn't exactly nice to it.. but then again. That's what I built if for..
I'll just pull the engine and tear it down.
Not sure if ill be the one to remove and test the springs... I'd like to know what pressure they're at.
Outfront motor sports built the heads originally..

Will keep this thread updated with the outcome.

Sent from my SM-N960U using Tapatalk

[that11guy]

If you run it on wastegate pressure and run it out does it still do the same thing? When the valve is open typically you would see the same pressure on each side of the valve but this would at least show if there are other limitations of you mechanical bits.

[subiblue2002]

UPDATE

Engine is out and I've got it on the stand.
Headers and intake manifold are removed as well as the valve covers.
I checked valve lash.
Intake:
Cylinder 1: Front - .006 Rear - .006
Cylinder 2: Front - .008 Rear - .007
Cylinder 3: Front - .006 Rear - .006
Cylinder 4: Front - .007 Rear - .005 (.003 tight)
Exhaust:
Cylinder 1: Front - .010 Rear - .010
Cylinder 2: Front - .009 Rear - .010
Cylinder 3: Front - .010 Rear - .010
Cylinder 4: Front - .010 Rear - .010

I pulled out the receipt for the engine build.
I have SuperTech Dual Valve springs
I'm going to give Supertech a call tomorrow to see if they've ever had reports of valve spring fatigue.
I bought the valve spring removal tool. What I'd really like to do is have the valve springs tested to see what the seat pressure is at on them. Hopefully Supertech can provide this inspection for free.

Originally Posted by benflynn

Also my $ is on bad valve spring. They don’t last for ever esp and the rates go up

Check out the next post to see a photo of cylinder 4 exhaust port.
It has a glossy black color to it. All other ports are a nice charcoal color..
This leads me to believe it a rich condition... but I can't say for certain..

Still have yet to find the elusive smoking gun...

[subiblue2002]

Pic of cylinder 4 exhaust port

Sent from my SM-N960U using Tapatalk

[undyjr]

How did the sludge smell? How long had the motor been off before that pic was taken? I'm leaning towards oil residue. Maybe its an old or improperly installed and new valve guide? Can you see up into the exhaust port and inspect each valve independently?