Breaking Up in Boost 10+lbs
Everyone I know on e85 uses the br7ef well over 20 psi without issue.
I would try br7ef’s gapped at 0.021 first since that’s so easy. Then have injectors cleaned/inspected. If neither of those things fix it then I’d suspect valve train.
I would try br7ef’s gapped at 0.021 first since that’s so easy. Then have injectors cleaned/inspected. If neither of those things fix it then I’d suspect valve train.
That's some healthy lift. It could simply be that the added boost combined with heavier rockers is causing the valvetrain to lose stability above 6k. That still wouldn't explain your clean plugs though. If you were getting spark blowout at higher boost or poor combustion from too cold of a plug you would have rich fouled plugs and you have clean plugs.
That's some healthy lift. It could simply be that the added boost combined with heavier rockers is causing the valvetrain to lose stability above 6k. That still wouldn't explain your clean plugs though. If you were getting spark blowout at higher boost or poor combustion from too cold of a plug you would have rich fouled plugs and you have clean plugs.
My buddy had had the same issue sounded the same and everything just didn’t happen till over 20 psi and it was the valve train.
That's some healthy lift. It could simply be that the added boost combined with heavier rockers is causing the valvetrain to lose stability above 6k. That still wouldn't explain your clean plugs though. If you were getting spark blowout at higher boost or poor combustion from too cold of a plug you would have rich fouled plugs and you have clean plugs.
Pulling the injectors today to flow and clean them to see how they look. Will be interesting to see what the outcome is. Also have a set of stock rockers with the trunion w/ bushing upgrade we will throw in to test with as well. I have a lot of spring pressure to have such a bad breakup on very low boost... Just hard to imagine these springs with rockers can't handle 10lbs and up to 15lbs. Exact same breakup on any boost over wastegate. I want to make 20lbs+ so whatever it takes to get there. 1100-1200whp is the goal for the setup.
Just running the stock computer with a Boost Leash Pro controller. HP Tuners for tuning and definitely not hitting the limiter as I can rev it out to 7100 on gate pressure.
Update
Pushrod preload is within spec .080 intake and .040 exhaust. Cleaned the injectors and 1 had a small piece of trash in it but nothing major. Swapped to stock rockers and guess what!?
Still breaks up at exactly 6100rpms... This HAS to be an issue with it losing crank signal. It literally hits a limiter aka breaking up violently at 6100. I already replaced the sensor so unless it was another bad sensor it’s hard to imagine 2 are bad... Has anyone else ever had such a bad time with crank signal? Turned the motor over by hand and looked at the reluctor wheel and nothing out of the norm. It looked fine...
Pushrod preload is within spec .080 intake and .040 exhaust. Cleaned the injectors and 1 had a small piece of trash in it but nothing major. Swapped to stock rockers and guess what!?
Still breaks up at exactly 6100rpms... This HAS to be an issue with it losing crank signal. It literally hits a limiter aka breaking up violently at 6100. I already replaced the sensor so unless it was another bad sensor it’s hard to imagine 2 are bad... Has anyone else ever had such a bad time with crank signal? Turned the motor over by hand and looked at the reluctor wheel and nothing out of the norm. It looked fine...
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Pushrod preload is within spec .080 intake and .040 exhaust. Cleaned the injectors and 1 had a small piece of trash in it but nothing major. Swapped to stock rockers and guess what!?
Still breaks up at exactly 6100rpms... This HAS to be an issue with it losing crank signal. It literally hits a limiter aka breaking up violently at 6100. I already replaced the sensor so unless it was another bad sensor it’s hard to imagine 2 are bad... Has anyone else ever had such a bad time with crank signal? Turned the motor over by hand and looked at the reluctor wheel and nothing out of the norm. It looked fine...
Pushrod preload is within spec .080 intake and .040 exhaust. Cleaned the injectors and 1 had a small piece of trash in it but nothing major. Swapped to stock rockers and guess what!?
Still breaks up at exactly 6100rpms... This HAS to be an issue with it losing crank signal. It literally hits a limiter aka breaking up violently at 6100. I already replaced the sensor so unless it was another bad sensor it’s hard to imagine 2 are bad... Has anyone else ever had such a bad time with crank signal? Turned the motor over by hand and looked at the reluctor wheel and nothing out of the norm. It looked fine...
Launching!
Joined: Jun 2012
Posts: 249
Likes: 36
From: Pennsylvania
x2 need more info on fuel system.... what filters and have you checked them to make sure they are not plugged? Dual 450s running all the time or does one come on with Hobbs switch? Are you able to watch fuel pressure with a manual gauge because of the stock computer? I also had a similar problem and was losing voltage at the pumps.... just a few things I ran into best of luck to you!
TECH Fanatic
Joined: Dec 2019
Posts: 1,129
Likes: 478
God that is such a bad suggestion..
If it only happens under increased boost, it absolutely doesn't have to be a crank signal. In-fact, it is almost positively not a crank signal issue if that's the case.
You swapped out the heavy roller rockers and the issue didn't go away.
You don't have fuel delivery issues it seems.
That leaves spark.
I'm still sticking by this one.
Swap to a BR7EF, straight out of the box.
Ohm your plug wires while they are off to make sure you don't have a failing one.
Check the coil grounds, make sure they are tightly fastened to the heads on either side.
Still breaks up at exactly 6100rpms... This HAS to be an issue with it losing crank signal. It literally hits a limiter aka breaking up violently at 6100. I already replaced the sensor so unless it was another bad sensor it’s hard to imagine 2 are bad... Has anyone else ever had such a bad time with crank signal? Turned the motor over by hand and looked at the reluctor wheel and nothing out of the norm. It looked fine...
You swapped out the heavy roller rockers and the issue didn't go away.
You don't have fuel delivery issues it seems.
That leaves spark.
I'm still sticking by this one.
Swap to a BR7EF, straight out of the box.
Ohm your plug wires while they are off to make sure you don't have a failing one.
Check the coil grounds, make sure they are tightly fastened to the heads on either side.
Youre on pump gas. E85 is much more resistant to knock when leaned out and still wouldn't cause a misfire and OP said he has no indication of running lean. I agree logging fuel pressure is always a good idea but I'm more in the valvetrain camp, although I did say those plugs were cold given how fat that AFR was.