My cars been acting weird lately… abnormal idle that surges at times, alot of engine noise. The ls1’s are noisy engines, it just seems louder than it used to. And it just seems like it’s running rough in general.
I had an accident a few weeks ago where I accidently downshifted instead of upshifting which raised the rpm’s sky high (I thankfully caught it right away and hit the clutch pedal). I was hoping that I didn’t bend a pushrod and/or crack a spring/bend a valve.
This weekend I’m going to do a full tuneup on it to see if it helps (wires/plugs/clean MAF and throttle body/check for vaccume leaks/ect) and if not, I was going to open her up and check the valve train and pushrods to see if there is any damage going on.
With that said, does anyone have the torque specs on the rockers and the valve covers for re-installation? And has any fellow ls1 owners experienced similar symptoms? Like I said, I know these motors are noisy so it’s hard to tell where it’s coming from (not to mention, my exhaust isn’t really quiet either). My AC pulley is pretty much shot, but I don’t think that it’s the culprit. I also don’t have my CEL lit either which makes me think that I’m probably ok, but ya never know.
I’m not sure if I’m being overly paranoid or if there really is a problem going on. At any rate, after missing that shift, I’d like to check it out for piece of mind.
:tspry: FYI the actual spec on the valve covers is 106in lbs, so by hand is fine.
The service manual has the sequence for doing all of them as the lifter is on the base circle of the cam, but ive also heard of people doing them all to 22, turning the engine over and checking them again.
Yup - checking plugs and wires would be a good place to start. Even loose spark plugs will usually make a metallic clanging type of noise. Or a wire could be arcking out and screwing things up.
Also - do you have headers and/or aftermarket exhaust. A little manifold leak or gasket problem or something can make quite the noise also.
A dirty MAF will definitely cause a surging or erratic idle. It made my LT1 run much better after I cleaned mine. If they are dirty, then they will not meter the air correctly going into the engine.
How high did you rev the car to? If it wasn’t much above 6,500 or so - then I doubt you loosened up anything in the valvetrain, but you never know. How many miles are on everything and do you have stock pushrods, springs, etc.?
I guess the point is that it could be a ton of stuff. You just gotta start investigating to narrow it down. Been there done that - it can be a real pain…
Getting at the plug holes can be a pain. Its easy to get at the pushrods, and its somewhat common to bend stockers on a bad missshift, so if it started immediately after overrevving (?), and it sounds valvetrain related (?), there is a good chance it could be the culprit.
the exhaust is stock minus the mufflers being chopped. I’m not sure on what the engine speed was as it happened real quick… but just to give you a reference point, I was at the top of second gear (5500-6000ish rpm) and went to go bang 3rd and accidently went into 1st. (actually… I’m fairly certain this is how my ac pully got fubard)
Luckly the tires broke loose and right away, I hit the clutch. so most of the abuse seems to have been taken out there.
the car is an 04 GTO… plugs look really easy to get to actually. It sucks though… the car only has 32K miles and shouldn’t be running this harsh IMO. I don’t even really beat it either. 99% of the time, I’m keeping the revs under 3500rpm.
Do you think it’s possible that I got bad gas? It seems like this problem has been lingering for a while off and on, but just now seems to be getting worse… or I’m going insane. I’m also used to messing with Ford modular engines, so pushrod engines are actually pretty new to me :sword:
I’d be very concerned about the valvetrain. Even though the tires broke free, you likely seriously over-revved the engine (7-8k I’d bet). It’s easy to check out the pushrods, just do it for peace of mind if nothing else.
yup probally bent a Prod. But there make awsome fuse’s in the stock motors, for exactly what you did. As tons do it, so its not a bad thing.
Your stock setup is still perfectly fine just tourqing down the rockers. Still the “non adjustable” setup. With GM sized parts, the lifter plunger preload in its range. If your tq wrench only goes to 25# just use a deep socket or a 3inch extension (8mm). Just be aware the rocker prod cups are seated in the prod, stock cam isn’t any lift really. But on a lobe nose before the rocker trunnion gets a lined on the rocker stands, The rocker we be a little lose, before it seats and starts a lineing. If you haven’t been thu it 24512345 times, and know how they react in the tightneing process. Just look at whats going on.
04 you have updated LS1 parts so nothing specail to do. Bust be easy on the wires, just pull them off the coils. And leave the plug ends on (have more heat breakdown for removal damage) But its a GTO, super easy to work on, so you can have the heads off in 2 hrs if you wanted. You dont have a guild plate or anything for the prods, but the hole for them on the head castings in small. So you’ll see rub marks about 1/3 down when the bend. I pull them out all the time of cars with no know issues, and they had 1-3 prods bent so bad they were rubbing in the head. this car was running fine. lol
I cheak then by rolling the the surface plate at the shop, but you can use a peice of glass. Clean the oil off, so they have no film.And you can “hear” them wobble (sounds change), and see it.
VavaleCover are 106in. but hand tight with a 8mm nut driver is fine, (fast, and the bolts easy to get =GTO)
Don’t take the coils off the coil brakets. Just take the 10mm coil brakets off the VCs with the coils on them. save time there. thats about it.
FYI, we stock the stock 7.400 Prod lenghts (stronger .083 4130cromoly) sets and singles. And .025 lenths set, up and down. And can adjust the rocker stands for shop builds. But keep the stocks as a fuse for your setup, we have tons of super low milage ones around. I’ll just give you the 1-4 you need. Just call ask for me, or tell matt I said Ill hook up, your form NYspeed :wiggle:
-john
