Blew the motor

[cam98aro]

Re: Blew the motor

well although I have not taken the motor back apart...after all the reading Ive done on here, and google etc etc...my best guess is that I probably broke a valvespring in the new motor and bent a valve which means I need to replace atleast one piston and all my gaskets yet again (not even 3000km on the bloody thing) Ive been pricing some stuff out and Im debating that if higher compression pistons are only 200$ or so more, than I mine as well upgrade them if the stuff needs to be swapped anyways...right now Ive found out that I can get a single new piston for about 35$ but they only sell the rings in a pack of 6 and its like 165$...then I think I might need wrist pins as well...and maybe a rod? not sure...i dont know...honestly I just want to drive the f'n thing at this point. If I get the ARH pistons I get everything I need except for rods for $699...my best guess at this point for stock stuff is it will cost me 200ish + wrist pins...plus 174 for an mls headgasket...where if I go with the high cr pistons I would just go felpro headgasket

If I broke a 130# valvespring I dont know why the hell it broke...I dont think I will know either and I dont know what to think of that...makes me skeptical about whether or not that might happen again...maybe 130# is not enough for the cam which is 230/240 .512/.512 lift and 113LSA @ .050

contact the piston ring manufacture, and tell them what happened, im sure they will send you a set of rings for one piston.

[Bird_Of_Prey]

Re: Blew the motor

If I broke a 130# valvespring I dont know why the hell it broke...I dont think I will know either and I dont know what to think of that...makes me skeptical about whether or not that might happen again...maybe 130# is not enough for the cam which is 230/240 .512/.512 lift and 113LSA @ .050

Valve springs, especially stiff aftermarket springs HATE cold weather. It's probably been well below freezing up there in America's hat. Romping on it while they are cold is always a recipe to snap a spring.

Side note, you're about 10 steps ahead of yourself. Find out what is wrong before worrying about what pistons to get. I've popped more than one valve spring in my life time and NEVER had to replace a piston. Why don't you actually get it apart and see what the problem is. 10.3-10.5 is completely pump gas friendly compression. Stock LS motors are 10.5-11.0 all day and run pump gas.

[Bird_Of_Prey]

Re: Blew the motor

if you want to run that compression with pump gas i would suggest getting a water/methonal injection kit, it will act like ~110 octane

Really? I've never heard anyone recommend water/meth for a N/A application. lol.

[techsan23]

Re: Blew the motor

ugh...more bad news...found yet another valve to be bent...this ones bent about 20thou...was originally bent about 23 thou and we were able to bend it back a tad...I dont have a replacement for this valve as we didnt realize it was this bent until today.

Did u end up reusing this valve? If so do you remember which cylinder its on? You have enough spring for the lift on that cam. If you end up needing a rod I can help you out there. How long until you tear this thing down?

Im also curious why you would go with the cometic steel head gaskets on the stock block, but then switch to the fel-pro's if you were to increase the compression. Maybe because the new pistons would decrease the piston to valve clearance?

[bluex]

Re: Blew the motor

Side note, you're about 10 steps ahead of yourself. Find out what is wrong before worrying about what pistons to get. I've popped more than one valve spring in my life time and NEVER had to replace a piston. Why don't you actually get it apart and see what the problem is. 10.3-10.5 is completely pump gas friendly compression. Stock LS motors are 10.5-11.0 all day and run pump gas.

I agree your ahead of yourself and worrying/planning too much before you find out exactly what happend.

LS motors are also all aluminum and can run slightly higher compression without detination than an all iron motor. An Iron block/aluminum head can also get by with a tad more than all iron. That said I still think you would be ok with the 10.3 on 93 or whatever the highest octane you can get.

[LETZRIDE]

Re: Blew the motor

I know I'm ahead of myself, but I won't be able to start taking anything apart until probably atleast friday, so all I can do is think about it right now and kinda plan for the worst and hope for the best. I honestly hope I dont need to rebuild the bottom end, that would suck.

As for the cold and the valvesprings, I am aware of that...I let the car warm up a few minutes in the morning before I drive it, and I never get on it until my temp gauge is at the 1/4 mark and I am sure it is nice and warm (which is usually atleast 10 minutes after startup)

techsan, I didnt end up reusing that valve no, I rush ordered a replacement from intense and put the project off for another couple of days just to play it safe...there should of been no bent valves in the car at all...

And like stated, the LS motors are aluminum and I believe they have aluminum heads...that could help combat KR from the high compression those motors have...but like you said, I'll travel down this road if necessary...I kinda just wanted an idea of whats available, and some thoughts on some stuff now, so I can more or less just order stuff if/when I need it and not have to research then as well.

lastly, I switched to felpro's because I didn't want to reused the ml headgaskets (although people do and they are fine) and the project was already costing quite a bit...I was just trying to save a few bucks so I went back to stock thickness...remember I had to replace a whole motor, the cam, and acquire some new parts to make the valvetrain friendly for this cam...ml headgaskets would of ran me 100$ or so more, and I just didnt think it was a necessary expense at the time...

[LETZRIDE]

Re: Blew the motor

I got 30 mins before I leave for work...pulled the driverside valvecover off...springs look ok :( ...looks like this might be leaning towards something drastic

I should also add that the first rocker arm closest to the front of the car (which is on the cylinder with no compression) seems to have a lot of play in it. Like side to side rock back and forth kinda play (not the kind that would be from a loose bolt)

[bigbrian442]

Re: Blew the motor

I got 30 mins before I leave for work...pulled the driverside valvecover off...springs look ok :( ...looks like this might be leaning towards something drastic

I should also add that the first rocker arm closest to the front of the car (which is on the cylinder with no compression) seems to have a lot of play in it. Like side to side rock back and forth kinda play (not the kind that would be from a loose bolt)

That would be because the valve is now shorter because it is bent. Makes it look like the rocker arm is out of adjustment.

[LETZRIDE]

Re: Blew the motor

That would be because the valve is now shorter because it is bent. Makes it look like the rocker arm is out of adjustment.

But wouldn't the spring still hold the valve at the right height? unless the bent valve was preventing the spring from fully snapping shut...alright, so how could I find out why that happened? I've gone WOT in the car a few times, but not that much, car was always warm when I did, and I waited about 1250-1600miles before I ever pushed it hard...

[LETZRIDE]

Re: Blew the motor

I hate to double post up...but a thought just hit me...I think both those cylinders on the drivers side were the ones that originally threw the rod and bent those valves...I *think* that that head has both the replacement exhaust valves in those two cylinders (no compression and 110 which is down from 130-140 that the others have)

The exhaust valves that intense gave me were a new batch, new product number...they were slightly different according to them because I had to ream out the guides to accomodate the thicker valve (which is stock size stem now I believe) we reamed everything to spec within the allowable tolerances...but what if those valves were maybe a few thou taller? I remember I bent two valves, exhaust valves to be exact that were side by side cylinder wise. When I look at my pictures the rod cracked the drivers side on the old block exactly where I am not getting any compression. Those are the only two cylinders with no and low compression...those are what I believe have the only two different valves...what are the odds?

When I think back even further now when I had my misfire at the beginning because the one injector wasnt in...the car should've ran decently ok on 5 cylinders...she was bucking hard...Im starting to think I bent those valves from the get go...it would explain the hard starts (having to hold the key down 2 seconds or so longer than usual) even with the new starter...much lower compression on 2 cylinders.

THEN, that could also explain the noise...my mechanic said that is sounded as if there was combustion occuring in the header when he had the stethscope to it...makes damn good sense if both those exhaust valves fried...****, that'd explain the mysterious knock to...

so I guess my question at this point is, is it possible for the valve to kiss the piston if these 2 new valves were just a few thou longer than stock sizing?

cause Im gunna go out on a limb right now and say they just kissed the piston on startup or shortly after, i.e first drive at low speeds/rpm and even though I manually cranked the motor by hand and everything seemed fine. Then being tweaked Im gunna say one valve totally burnt up, and the other one is on its way...

it's the only thing that makes sense in my mind right now...

[ssms5411]

Re: Blew the motor

Sorry to hear that. I hope it can be salvagable to get it bak on the road. Hit me back with a PM.

[Rhunadan]

Re: Blew the motor

Hey Mike,
I have a friend with a supercharged 3.8 that he's selling for $200. Let me know if you need it for parts. I was going to buy it for the top end to try and retrofit the blower to my motor but I don't have the space to keep it. I'll be buying a blower from the scrap yard instead.

[LETZRIDE]

Re: Blew the motor

I'll keep you posted...I almost have the UIM manifold off...shouldnt be much longer...hopefully I'll get an hour or two to work on it tommorrow

Good news so far...drained the oil and it was spotless...magnetic drain plug didnt have anything on it...

[LETZRIDE]

Re: Blew the motor

Well its official...down goes motor number 2 :(...the piston smashed the valve good...real good...piston is dented to sh*t...looks like its only one exhaust valve and one piston...no clue as to even why this happened...I'll post pictures when I get home...f me

It wasn't a new valve either so my theory is out the window...

[bigbrian442]

Re: Blew the motor

This is why you check valve to piston clearance after drgreeing the cam in. A few degrees off one way and smack.