bent rods again
11-06-2015, 10:42 AM
#1
bent rods again Hey guys i took the truck out for a quick hit last night. Ended up spiking 20psi and busting rev limiter 3 times. Pulled over and heard the rods tapping the crank.
Compression test shows 3 rods hurt so far. Would rev limiter hurt rods at that power? Log showed 4 degress knock on 2 rev limiter hits. Ill have it tore down this weekend for more info.
Compression test shows 3 rods hurt so far. Would rev limiter hurt rods at that power? Log showed 4 degress knock on 2 rev limiter hits. Ill have it tore down this weekend for more info.
11-06-2015, 11:52 AM
#2
On The Tree
Was this the stock PCM rev limiter? Stock PCM pulls fuel and not spark, so that might of made it go lean. Not saying that did the rods in, but probably didn't help the pistons / rings either.
11-06-2015, 01:28 PM
#5
9 Second Club
Not a damn thing wrong with pulling fuel as a rev limiter. Almost every ecu will do this including aftermarket, although they give you the option of fuel, spark or both.
Pulling fuel is a wrong term anyway, it simply doesnt fire the fuel injector for all power cycles in order to control rpm. It doesnt actually reduce the amount of fuel going into the cylinder on any given firing event.
Pulling fuel is a wrong term anyway, it simply doesnt fire the fuel injector for all power cycles in order to control rpm. It doesnt actually reduce the amount of fuel going into the cylinder on any given firing event.
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11-06-2015, 01:49 PM
#9
9 Second Club
No idea what the problem or cause is.
Not saying that in some shape or form you hitting the limiter was good....but shutting fuel down is a perfectly normal approach and the very reason OEM's use fuel is so unburnt fuel doesnt get dumped into the catalytic convertors etc.
But even some aftermarket dont like chucking lots of fuel into the cylinder during a limiter either, so even if they have the option of using a spark shutdown, they still choose fuel.
Not saying that in some shape or form you hitting the limiter was good....but shutting fuel down is a perfectly normal approach and the very reason OEM's use fuel is so unburnt fuel doesnt get dumped into the catalytic convertors etc.
But even some aftermarket dont like chucking lots of fuel into the cylinder during a limiter either, so even if they have the option of using a spark shutdown, they still choose fuel.
11-06-2015, 01:51 PM
#10
Did you pedal it when it hit the limiter? Lot of spark maps leave high timing numbers at low load high rpms. This and lean coditions getting in and out of the throttle can be destructive. The ecu can only correct so fast. If this wasn't the case, than ignore my response.
11-06-2015, 02:35 PM
#12
From the logs it starts making boost around 2800 rpm. So im pretty sure 20psi was around 5k.
I just very well may have pedald it when the limiter hit. The sum bitch popped back so hard it kinda worried me to stay in it lol. I geuss leason learned. Do u think its worth it to throw another set of floating rods in it on the cheap? Pistons should be fine. No specks on plugs. Oil looks good no metal.
I just very well may have pedald it when the limiter hit. The sum bitch popped back so hard it kinda worried me to stay in it lol. I geuss leason learned. Do u think its worth it to throw another set of floating rods in it on the cheap? Pistons should be fine. No specks on plugs. Oil looks good no metal.
11-06-2015, 02:56 PM
#16
I'd set the limiter well above your shift point/trap rpm, 500 rpms or so. It's there in case if a F&@k up during a shift or if something comes apart (like a driveshaft or trans). Avoid hitting the limiter if you can. As far as pedaling it, no reason to just cruising around or racing for that matter unless you REALLY think it's gonna make a difference. If it kills the tires, just let off. Let John Force tear up his parts. Lol!! I cringe every time I see these guy's video of a burnout and they're in and out of the throttle 30 times. Then a week later they wonder why their ***** blown up. But hey whatever, it's their stuff.
11-06-2015, 03:10 PM
#17
Well thats the thing the truck has very good suspension. Alot of time and money in it. Caltracs, relocated shocks etc. With a 275 radial outback it will hook up and run from a 30mph dig. Havnt tried from a stop just yet. Its actually hooking and running better than i thought for the power its making on the street. Awesome!!
11-07-2015, 12:03 AM
#18
Got it torn down tonight. Rods 7 and 8 were bent pretty bad. 1 and 4 was slightly bent just enough to scuff the bottom of pistons.
Im thinkin if 7 and 8 was bent pretty bad is there a possiblity that those cylinders are hotter as ive always heard of? Coolant steam tubes are blocked at rear only on the front. I may run a 4 corner one this time around. Im also running the tbss intake. I wonder if distribution could be.suffering toward the rear cylinders exspecially on the meth. Thoughts?
Im thinkin if 7 and 8 was bent pretty bad is there a possiblity that those cylinders are hotter as ive always heard of? Coolant steam tubes are blocked at rear only on the front. I may run a 4 corner one this time around. Im also running the tbss intake. I wonder if distribution could be.suffering toward the rear cylinders exspecially on the meth. Thoughts?
11-07-2015, 08:26 AM
#20
Originally Posted by watman02
Are you sure the water/method kit is not the problem and your not on the verge of hydrolocking it? Just a thought