Country Boy

iTrader: (24)

thats probably too tight. On the Old small block chevy motors, you tighten the rocker untill there was no more play in the pushrod, then another 1/2 turn. I dont know about these LS1s, I havent cracked mine open yet...

<small>[ June 19, 2002, 09:29 PM: Message edited by: Country Boy ]</small>

steve

there not like that. rockers are torqued out and left alone. they are not adjustable. not like the old school small blocks.

go ahead and get a gauge that is made for checking compression.
your finger method is good for initial testing but you might not have a good seal.

i am putting money on bent valves. sorry to say it, but with the timing marks off like they where, your valve timing was off enough that you bent the valves.

what are the specs on the cam ? with enough valve lift/duration, it would be easy to bend the valves in this situation.

another check is this. try to induce air into the cycl like your going to do with a leak down tester. the kits have a rubber line that would use an air hose. if your cycl wont hold air, you got bent valves.

steve frank

Plum Crazy Rob

iTrader: (3)

The LS1 is designed so that when you torque the rocker down to 22 ft-lbs, with the stock deck height, stock head gasket thickness, and stock head deck surface height and pushrod length (and the tolerances on all of the above), the valve lash comes out "net" or essentially zero (probably HALFWAY on lifter preload. Some people here have figured that out for certain. I usually start to nod off during those threads, though <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> ).

Once you start changing components, all bets are off on this. Unfortunately, you really haven't changed any components (unless your cam was ground on a different base circle <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> )

<small>[ June 19, 2002, 09:48 PM: Message edited by: Plum Crazy Rob ]</small>

Ryoga

Okay... So now what am I supposed to do? I think I'll call it a night for now, I'm sleepy and depressed <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

98blackSS

The compression test is basically your last step that I can think of. If it shows what we're all suspecting, then the heads will be coming off...

Country Boy

iTrader: (24)

Damn, dont listen to me about checking on the rocker preload <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> lol

Good luck and Im keepin tabs on this one <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

XLR8NSS

iTrader: (4)

Good night? I hope anyway <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" alt="[whiner]" title="" src="graemlins/gr_cry.gif" />

I really need some <img border="0" alt="[boring]" title="" src="graemlins/gr_zzz.gif" />

John

PS - Get yourself a compression tester tomorrow so we can all rest easy knowing its a bent valve. <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

It would be a good reason to have a little head work done. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

steve

ill be waiting.
my bet is on on the valves....

steve frank

N2Ofreak

Do the comp. test.If you have a few cyl. with no compresion.That means the cam is out of fase!
you don't just do dot to dot.You have to go dot to dot on the compression stroke on No.1 cylinder!When no.1 cyl. blows comp. turn the crank until No.1 cylinder is at tdc. then check your dots! I bet they are off!

mjf454

Im betting the cam is 180 off.The dots will still line up, car wont start, compression test will show valves are open on the comp stroke.Set # 1 on tdc and line up the dots.Dont worry about where the dots are now, set #1 on tdc and line up the dots.

cy

Didn't he say he checked the order of the valves opening and closing and that it was fine? Although i may not know a lot, from what i've read (all of it) i am also going with bent valves.

1 Bad Z

iTrader: (8)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by GeorgeC:
<strong>One more thing you can check if all else fails...

Remove the cam you just installed, and compare the reluctor rings on the back of the cam (which is what the cam position sensor gets it's signal from). Make sure that they are both oriented in the same way.

Belive it or not, I had a bad cam where these were 180deg. out from each other and pretty much exhibited the same symptoms as you're having. A defective cam does get sent out from time to time...</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">WOW! I thought this only happened to me!!!! I installed a cam in "Poolfanatic's" car that the reluctor ring for the cam position sensor was actually ground into the cam 180 degrees off also. 15 minutes after I told myself " everything else is fine, there's gotta be something wrong with that damn cam" that cam was out of that car and on it's way back to the manufacturer!

GeorgeC, was that a Lunati or CompCams cam?

I have a stock cam sitting next to my tool box that I check EVERY aftermarket cam with before I install it now.

cy

But this cam was in his friend's LS1 before, and was working fine. So i think that rules out flaws in the cam itself.

horist

Go to sears and get a compression checker.. it's like 20 bux... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Tools made for the application are generally more accurate than thumbs <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

1 Bad Z

iTrader: (8)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by cy:
<strong>But this cam was in his friend's LS1 before, and was working fine. So i think that rules out flaws in the cam itself.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Oh, I did'nt read that...well then yes, that does rule that out.

Liquidnutz

When you pulled the tubes and pump? "thinkin you said you did it at the same time as install" did anyone pull on the wiring harness at the rear of the engine? If so the ground wire for the pcm might have got tugged on a bit and could be throwing your pcm into insanity especially if the wire has a break and getting connection then losing it again quickly. Your atap should show a code for the pcm ground if this is the problem. Hope ya get it fixed. Later
<img border="0" alt="[pimp]" title="" src="graemlins/gr_pimp.gif" />

Ryoga

Okay, so Today's 'checklist' includes checking the torque on the rockers, getting a compression tool, and fretting over the possibility of a 180 degree off cam now.

On the 180 degrees off, how is that possible? I tried to draw a picture and visualize it, but it doesn't play out. If both of the dots are lined up can it really be 180 off? Don't tell me that for that portion of the test I've got to rip the valve covers and coil packs off again. Although I must say that it is better than the heads.

I'm going to be just as sick if I've got to see that timing chain one more time on this install!

cantdrv65

iTrader: (3)

If the engine was spinning over and could not blow your thumb off, you've lost compression due to bent valves. Without the spark plug in you really shouldn't have to even use a thumb to see if you have some type of compression. You would be able to HEAR the air being forced out. IT'S LOUD! Still think you bent some valves....With a T1 being off more than 30, I do not see how you COULDN'T have bent valves. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Ryoga

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by cantdrv65:
<strong>If the engine was spinning over and could not blow your thumb off, you've lost compression due to bent valves. Without the spark plug in you really shouldn't have to even use a thumb to see if you have some type of compression. You would be able to HEAR the air being forced out. IT'S LOUD! Still think you bent some valves....With a T1 being off more than 30, I do not see how you COULDN'T have bent valves. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That's the strange part. On the first hit when I turned the key over it 'did' blow out gas with pressure. It only did it that once though until I stopped trying to crank it and let it sit for 5 or more minutes and tried it again. It then blows gas again, just for the initial turn, but doesn't do it again until it sits again.

TA_2001

To be clear..

this is dot2dot

http://www.ls1info.com/article.php?sid=192

if there is gas and spark. they must not be happening
at the correct time..

Terry