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Hey guys so heres the damage dynosty found after tearing the motor down
Main point of failure was cylinder 2
there was damage from heat due to detonation
skirts of the #2 piston was scored from rocking back and forth in the cylinder and the cylinder walls had some drag marks
the shiny parts at the top of the #2 piston are where it contacted the head but luckily there was no damage to the heads
basically need bearings , a rod , and need to bore out the block and get a set of new pistons (cheaper than getting a new block and 1 piston)
Sorry to see u having engine problems this early in the build but I'm gonna give my $.02 on what I see here. The scoring in the cylinders is pretty typical on a high performance engine. Every single engine I've torn apart that's made more than 600 flywheel horsepower has always had some minor scoring with good compression and leakdown numbers it's the nature of the beast. My rule of thumb is if i can catch it with my fingernail it needs to be honed/cut. The bearings are destroyed. I can't tell if they spun or not but that amount of wear in that little time signifies a significant issue with lubrication or clearance that's definitely not an issue with the tune. If the Piston touched the head it would be very clear in the cylinder head also. Those clean spots are most likely from the detonation or lean conditions. I'm going to guess that u most likely have a fuel pump or injector issue with that lean of a condition. And I would definitely be logging fuel psi. It's a big deal especially when running staged pumps and ethanol.
Sorry to see u having engine problems this early in the build but I'm gonna give my $.02 on what I see here. The scoring in the cylinders is pretty typical on a high performance engine. Every single engine I've torn apart that's made more than 600 flywheel horsepower has always had some minor scoring with good compression and leakdown numbers it's the nature of the beast. My rule of thumb is if i can catch it with my fingernail it needs to be honed/cut.
This is what I have always figured too but Dynosty thinks its enough scoring to require honing the block
I'm going for more power this time so I told them if anything seemed risky to use again to just replace it.
The bearings are destroyed. I can't tell if they spun or not but that amount of wear in that little time signifies a significant issue with lubrication or clearance that's definitely not an issue with the tune. If the Piston touched the head it would be very clear in the cylinder head also. Those clean spots are most likely from the detonation or lean conditions. I'm going to guess that u most likely have a fuel pump or injector issue with that lean of a condition.
so u don't think i was too low on fuel? That was my guess as to why it went lean. I could send the injectors out to get tested and cleaned and see what they find.
The fuel pumps i was actually suspicious about too.
And I would definitely be logging fuel psi. It's a big deal especially when running staged pumps and ethanol.
first thing I did was add a fuel pressure sensor to the parts list.
If you were low on fuel that could absolutely be why it went lean. But thats a fuel psi issue and the Haltech should've recognized the lean condition but I read that your troubleshooting that issue.
I've never tried to push the fuel level. 1/4 and above is all I'll do pulls with on fuel level. I prefer it be full so it provides weight on the rear tires. IDK how accurate the fuel level is with the cjm pump hat so I've never tried to push it.
Glad to see you getting the car back together, best of luck with the rebuild.
I always figured that with the CJM twin pump assembly you wouldn’t have issues running the tank low on fuel (unless you were obviously running the tank completely dry)?
I was a little curious about the log from the 11.4 pass you posted on the last page, was that the AFR that you were seeing consistently in boost since you got your car tuned?
Glad to see you getting the car back together, best of luck with the rebuild.
I always figured that with the CJM twin pump assembly you wouldn’t have issues running the tank low on fuel (unless you were obviously running the tank completely dry)?
I was a little curious about the log from the 11.4 pass you posted on the last page, was that the AFR that you were seeing consistently in boost since you got your car tuned?
no on the dyno i remember the afr not going above 12.0. In new hampshire maybe the higher altitude had some type of affect?
I never know when to fill up, My fuel level is never acurate. But before going to the track I had emptied the pump gas out of my tank to fill with ignite red so that I knew how much I had in there exactly. (filled with 8 gallons)
I also noticed my 255 pump is much much louder than the bigger one....is that normal?
The 255 is the primary you most likely won't even hear the 450 come on. And yes my 255 primary is pretty loud. I'm not sure how u have your pumps staged but I'm controlling mine with the Haltech. It signals the 450 to come on at 3#'s.
no on the dyno i remember the afr not going above 12.0. In new hampshire maybe the higher altitude had some type of affect?
I never know when to fill up, My fuel level is never acurate. But before going to the track I had emptied the pump gas out of my tank to fill with ignite red so that I knew how much I had in there exactly. (filled with 8 gallons)
Since you're VE based/speed density tuned I don't think the increase in elevation would cause the car to run any noticeable leaner.
I don't have a functional fuel level gauge either, I just full up the tank and make sure to refuel after 150 miles, but I'm just running pump E85 with a flex fuel sensor.
Originally Posted by silva350z
I also noticed my 255 pump is much much louder than the bigger one....is that normal?
The Walbro 255 is definitely louder than the 450 pump. When I went from a single 255 to a 450 it was a very noticeable decrease in noise.
Last edited by thatv35guy; 07-02-2018 at 12:01 PM.
If I try a hard pull with 1/4 tank or less (have CJM twin pump 255/485) I will get a fuel pressure CEL and my Haltech will kill spark and boost and trigger "limp mode" until the car is turned off and on again. I talked to Charles and Hal and they felt this is a limitation of the forward placement of the assembly within the tank. A surge tank would be a proper solution, but is a complicated build for a street car.
OP, thanks for sharing the engine tear down pics. Interesting findings that I hope never to experience personally. I am not an experienced builder, but my understanding is that knock can destroy bearings so I think it's possible you do have a root cause as opposed to some other build issue or lubrication issues. Always hard to be certain at this point.
Ya i agree theres definately a cause for what happened here that has nothing to do with the build of the engine.
On the dyno and on the street I can say 4th gear afs were always 11.8-12.0 range ....Hal had set a very um rough ? mild? (maybe the wrong word to use) boost by gear on the dyno. He never actually did pulls with it through all the gears. He was just going to adjust the boost by gear after seeing logs from the track after butt well this happened ...
So you could say it was never "tuned" for boost by gear so maybe thats why it was in the 13s ?....in 4th you can see how the afs were comming back down to 12.0 ....I'm talking out of my a$$ here, i'm just throwing **** out there but am I right in saying that the boost by gear needs to be tuned?
The boost by gear has absolutely nothing to do with your fuel map. That is simply controlling boost based on time and/or mph. If the fuel map was fine on the Dyno my guess is you had a mechanical failure be it fuel psi or injection of some kind be it lack of fuel on the tank or a failing pump/injectors. If the tune was way off or there was a lot of detonation you would see melted or cracked/broken pistons along with severely scored cylinder walls. Now with the O2 sensor failure who knows how accurate that a/f is in the log on the 11.4 pass. Yes detonation can cause bearing failure but I really don't see that being the case here. Unless u have a malfunctioning Haltech thats trying to give it all the timing and a lean a/f mixture.
Glad to hear you're getting it all back together! Having a heavily modified car has it's ups and downs.
I agree with TT03Z, your fuel map is completely separate from your boost by gear map. With ThatV35guy we got my fuel map right, and then worked on my boost by speed settings on the street. With my CJM twin pumps, I tend to fill up at around 170-190 miles on the tank of ethanol. I always reset my trip odometer, and my car averages 12mpgs. So, I know I'm at a 1/4 at about 190 miles. And I'll echo the others, my 255 is way louder than my 450.
okay now I know thanks for correcting me guys this is out of my realm
I was only getting about 130 miles on pump (19 gallons). On the street maybe about a week after i got tuned i remember trying to do a pull and the car did cut out at 130 miles so i knew I was low and had to fill up. The haltech did its job at that time.
My car guzzles gas now. Before I could never fill my tank over 12 gallons. Now after the new setup i can fill it to 19 but I still only get 130 miles. I use to get 170-200 on 12.
I get about 10 miles to the gallon (on E85) and fill up 15 gallons around 150 miles, so the calculations are pretty easy. I can easily go 200 miles on 93 pump.
Also agree with above posters that boost by gear has nothing to do with this. You've got to be able to track fuel pressures, set your failsafe to ensure it's always in a safe range, and of course always keep heat under control.
I actually put a new set in at the track for the event on sunday but the ones I had in there looked fine. hmm what ever plug was in cylinder 2 should definately look different from the others if there was a dead injector or something right? I still have those, I'll take a closer look at them later.
I never checked the new plugs after its final street pulls. Those were just sent to dynosty in the motor still.
So since boost by gear is a separate thing just wondering , trying to learn, how does it adjust the afr's with different boost levels? and why does it appear that 4th gear is different from all the others?
I actually put a new set in at the track for the event on sunday but the ones I had in there looked fine. hmm what ever plug was in cylinder 2 should definately look different from the others if there was a dead injector or something right? I still have those, I'll take a closer look at them later.
I never checked the new plugs after its final street pulls. Those were just sent to dynosty in the motor still.
So since boost by gear is a separate thing just wondering , trying to learn, how does it adjust the afr's with different boost levels? and why does it appear that 4th gear is different from all the others?
Your fuel map is solely based on load/boost psi and rpm. If your running the same amount of boost in a different gear and have a problem with log data in one gear vs another lets say 3rd and 4th there is most likely a mechanical problem via fuel psi injection ignition ect. Unless boost increased in 4th over 3rd and your fuel map isnt setup correctly for the higher boost level.
Your fuel map is solely based on load/boost psi and rpm.
(I'm just along for the ride and trying to learn something)
Am I nit-picking in that the fuel map still has outside influencers / factors such as intake air temp? ambient temp? coolant temp? individual fuel trims? target values? that are adding / subtracting fuel no matter the boost/rpm?
(I'm just along for the ride and trying to learn something)
Am I nit-picking in that the fuel map still has outside influencers / factors such as intake air temp? ambient temp? coolant temp? individual fuel trims? target values? that are adding / subtracting fuel no matter the boost/rpm?
this thread makes me want to upgrade my ECU...
Im still trying to figure out how the Haltech does those things. I've noticed on mine that it runs perfect when the weather is cool but struggles some to idle when hot outside but the A/F at idle doesn't change hot vs cold. I've also noticed the wiseband O2 sensor sees around 11.6-1 when cold and 11.3-1 when hot. Like something is not compensating for intake air temp. But I'm not 100% sure that's the issue as I have fixed 2 minor boost leaks and haven't logged since. I also want to figure out how to make the ecu auto log without having the laptop hooked up. I'd like to be able to pull a log on a pass without having to manually record it. I'm still learning the Haltech and those are the 2 things I know nothing about with it.
07-02-2018, 09:49 AM
