Corrupt Tune File?

[Cringer]

I was doing some testing yesterday and after a WOT pull the car started acting "funny". It was running rough and fuel trims went from -2% to -20 to -30%. I was convinced it is was a broken rocker/spring/spark problem. I haven't started turning wrenches yet.

This AM I was reviewing the log and see that shortly after the pull the MAF went into a failed state. I have never seen this before randomly in the middle of driving.

I tried to open the tune file and got this message

unk tune.jpg

Then I noticed the file size was over 6 mb when they are normally 1.5 mb

file size.jpg

I wonder if the failure was related to a real issue with the MAF or a corrupt tune? I see the spikes in the reported Hz from the MAF before the fail.

funky maf.jpg

I was going post the log file...but now...it is gone!

Anyway...gonna read codes, reboot, and flash a new tune.

Edit: found the log file
MAF issue corrupt tune.hpl

[GHuggins]

I've started seeing that message on a few that people are posting on here in the gen V section. Just thought it may have read wrong in regards to theirs.

I do know it's possible to have a corrupt file. If you ever get or have suspicion of a corrupt file all you have to do is either one of three things. First you can open the original read file from your vehicle then copy over all of the changes from your current tune file then write entire with that.

Next you can open your current file, then swap OS's from the original file. This sometimes is better to make sure you get background tables or just for peace of mind. Then you still have to copy over the differences and write entire.

Worst case and for further peace of mind if you're not sure if something in the background was corrupted by a different tuning device you can use Tis, but due to OS changes you'll often have to re-license.

I've gone in behind on cars that have had several different tuning shops working on them where they wouldn't even idle right because of corrupt systems. At one time it was bad to go in behind SCT and have bank 2 dead O2 controls because SCT was corrupting something once their file was removed or returned to stock. Anything's possible, but still doesn't mean that something else isn't wrong causing the problem.

[Alvin]

We had laptops that would "go bad" and start doing similar things after years of normal use.

[Cringer]

Well looks like the file corruption was something else. The funky MAF Hz and MAF failure appears to be related to the fact that the ARP nut backed off the stud on the #8 intake rocker. It chewed up the rocker stand too. I don't know what I would actually be capable of in life if I didn't have bad luck.

20240429_103846 - Copy.jpg20240429_103726 - Copy.jpg

[07GTS]

spose one good side of it is its an intake rocker and not the exhaust

[blindsquirrel]

https://briantooleyracing.com/btr-ls...ocker-kit.html

[Cringer]

https://briantooleyracing.com/btr-ls...ocker-kit.html

Turns out I am an idiot...I installed the trunnion upside down. The flat chamfer for the nut was facing down.

Also that BTR kit...looks like they have an option for the M311 heads! Tempting...

But it uses the crappy aftermarket needle bearing trunnion kit. Seems like I have heard of other complaining about the hardness (like all other aftermarket needle bearing kits). Have you any experience with these?


I can't afford the Jesel kit. It uses needle bearings too...but somehow I trust this more.
https://frankensteined.net/product/j...m-series-m311/

[pannetron]

Yella Terra Ultra Lite??

[Cringer]

Yella Terra Ultra Lite??

OEM rockers with CHE guts and ARP studs.

[pannetron]

Understood. I was suggesting the Yella Terras if you were looking for an alternative. I'm a fan of rockers that run or pair on a shaft to improve stability.

[blindsquirrel]

The BTR shafts are real 52100 steel the same as real bearing races are made of (and same as Jesel/T&D would use), not 4140 like nearly all of the needle bearing trunnion kits. It's not possible to heat treat 4140 to a level where it will tolerate direct-running needle bearings. 4140 is just not the right material for this and it's frustrating that the public doesn't know any better and the sellers don't care to tell them, they just keep selling the garbage and cashing the checks.

Needle bearings are better as long as they are running on the right material. This is splash-lubed-only, not pressure fed like the big diesels that everyone loves to cite as to why bushings are better.

(and last time I brought this up it got pointed out "yeahbut wrist pin rod bushings are splash lubed and they do fine" and that's someone who doesn't understand that the wrist pin does not rotate in the rod bushing when the engine is running, it rotates in the piston.)

[LS ROB]

I run comps shaft mounted rockers for LS7. Seem to be doing fine as of now. Got a little over 10k miles on the engine, FWIW.

https://www.summitracing.com/parts/c...RoCucMQAvD_BwE

[Cringer]

I run comps shaft mounted rockers for LS7. Seem to be doing fine as of now. Got a little over 10k miles on the engine, FWIW.

https://www.summitracing.com/parts/c...RoCucMQAvD_BwE

Based on my personal results and experience with the Comp needle bearing trunnion kit, I will never ever give Comp Cams any of my money again and refuse to run any of their hardware on anything until the end of time. I have also scrapped all Comp stickers off my toolboxes.

[Cringer]

The BTR shafts are real 52100 steel the same as real bearing races are made of (and same as Jesel/T&D would use), not 4140 like nearly all of the needle bearing trunnion kits. It's not possible to heat treat 4140 to a level where it will tolerate direct-running needle bearings. 4140 is just not the right material for this and it's frustrating that the public doesn't know any better and the sellers don't care to tell them, they just keep selling the garbage and cashing the checks.

Needle bearings are better as long as they are running on the right material. This is splash-lubed-only, not pressure fed like the big diesels that everyone loves to cite as to why bushings are better.

(and last time I brought this up it got pointed out "yeahbut wrist pin rod bushings are splash lubed and they do fine" and that's someone who doesn't understand that the wrist pin does not rotate in the rod bushing when the engine is running, it rotates in the piston.)

Great info, thanks!

[blindsquirrel]

I run comps shaft mounted rockers for LS7. Seem to be doing fine as of now. Got a little over 10k miles on the engine, FWIW.

https://www.summitracing.com/parts/cca-1983-16(removed tracking info from URL)

The thing I don't like about 1-piece-shafts is, there's always gonna be at least one valve on each bank way far open no matter where you put the crank/cam. Depending on your springs pulling the shaft down with a valve open is either annoying or mildly dangerous. Even with studs instead of bolts it's still hinky. The BTR is nice in that you can bolt them down in pairs when valves are all closed.

[LS ROB]

The thing I don't like about 1-piece-shafts is, there's always gonna be at least one valve on each bank way far open no matter where you put the crank/cam. Depending on your springs pulling the shaft down with a valve open is either annoying or mildly dangerous. Even with studs instead of bolts it's still hinky. The BTR is nice in that you can bolt them down in pairs when valves are all closed.

Hmm...I didn't know that was even a thing and still not able to wrap my simple mind around the mechanics of it just yet. Are you saying that 1 valve per bank will be opening more than its supposed to?

[LS ROB]

Based on my personal results and experience with the Comp needle bearing trunnion kit, I will never ever give Comp Cams any of my money again and refuse to run any of their hardware on anything until the end of time. I have also scrapped all Comp stickers off my toolboxes.

I understand that 100%! Had a bad experience with comp when I was building a 396bbc. I swore them off back years ago until my budget talked me into these shaft mounts lol.

[blindsquirrel]

Hmm...I didn't know that was even a thing and still not able to wrap my simple mind around the mechanics of it just yet. Are you saying that 1 valve per bank will be opening more than its supposed to?

No, you shouldn't bolt down a rocker while the cam lobe is up, even if it's one single rocker by itself. With all the rockers on a common shaft it's not possible to bolt it down when zero valves are open, you're using the one or two rocker studs or bolts to compress the spring. It's very hard on the threaded hole in the head if bolts, and still really hard on the one or two studs in the area of whichever valve is open. They are not meant to be tightened against spring loads; once they're bolted down and tensioned it's very different.

[LS ROB]

No, you shouldn't bolt down a rocker while the cam lobe is up, even if it's one single rocker by itself. With all the rockers on a common shaft it's not possible to bolt it down when zero valves are open, you're using the one or two rocker studs or bolts to compress the spring. It's very hard on the threaded hole in the head if bolts, and still really hard on the one or two studs in the area of whichever valve is open. They are not meant to be tightened against spring loads; once they're bolted down and tensioned it's very different.

Ahh.. now i follow. Thank you!