c130nav

Kind of a newbie question here. Bought an 01 Z a couple of months ago; 4A/ 136K miles. Noticed ticking/clacking coming from the motor; not on start up but after it comes up to temp. Asked around to a few mechanics and the consensus was that lifter(s) were bad. So got a new set of factory lifters and gasket/bolt kit and swapped them out following "LS1Howto.com" guidance. Motor runs fine as long as I dont go over 55-60 mph; then ticking/clacking comes back. Pulled valve covers off to double check for bad rocker or bent pushrod(PRs are 7.40 from TS&P) and they were all straight. I tightened down the rockers on the rail w/o a pushrod and bolts bottom in the head but there's a lot of play with the rocker moving around and not seated on the rail. Is this normal, or do I need to shim up the rail so the rocker can be secured and torqued correctly. I torqued those 8mm bolts to 22 ft lbs like the book says, but it seems like I just torqued the bolt after they bottomed out in the hole.

Thanks for the help and apologize for the long windy thread.
Mike

Blacklightning744

iTrader: (7)

that sounds like bent pushrods to me, if i was u id replace ur pushrods and rockers.

Steve Gunn

Are they the stock bolts? Doesn't sound right. Not sure how the stock pedestals themselves could move at all... If your rockers are worn, missing a needle bearing here and there I could see some lateral play in the bearing, but not what you're describing. Harland Sharp rebuilds stock rockers and also sells the correct replacement bolts. I sort of remember some kind of barrel/washer thing that goes over the bolt to snug the rocker. These aren't your rockers, but scroll to the ls1 rockers and they have a picture of what I mean next to the bolts for pedestal mount rockers- http://www.harlandsharp.com/products.htm If you shim the rocker, you will change the geometry where the tip contacts the valve end.

vettenuts

iTrader: (4)

Depends on what moves. The center section that the bolt goes through shouldn't move, but the rocker will wiggle on the center section (hope this makes sense).

c130nav

The center section that the bolt goes through is loose with the stock bolt completely threaded. The bolt is either bottoming out in the hole, or the threads are bottoming against the head itself; I can't really tell for sure. I do know that both the pedestal rail and the center section of the rocker are loose under the bolt, and it seems like it needs a shim there(not much, maybe .010 or .020). I don't remember seeing any shims when I removed the rocker assemblies to remove the heads.

It seems the noise comes on whenever the RPMS exceed about 2000, then go away after some prolonged idling, or shutdown and cooldown.

vettenuts

iTrader: (4)

Would it be possible to shoot a photo? With the pushrod out, is it still loose? Can you shoot a photo of the bolts?

JFM-jr

iTrader: (23)

Vettenuts is referring to the trunion. Obviously when the bolt is torqued to 22 ft lbs the trunion should not move but as stated above by Vettenuts the rocker arm will wiggle around on the trunion a bit. I would try to install a thin washer under the bolt just to see if it seats the trunion securely. If it does you then may want to grind the tip of the bolt off just a lil bit. If I remember correctly the tips of those bolts do not have any thread on them. This is all being said with the thinking you have inspected the rails real well and they are in good order.

VIPRETR2

iTrader: (63)

If you do need shorter bolts and are afraid to grind on the stock bolts, Edelbrock sells some. 6th item down on the page, #8597.

http://www.edelbrock.com/automotive_...essories.shtml

Good luck,

Larry

studderin

iTrader: (28)

so the rocker bolts bottem out beofre the tighten the rockers????? what heads are they, is there any wleding or anything in the ports?? whats rocker bolts are they, do they have the rounder end like stocks? are the rocker stands milled down? somtimes people will do that get the swipe patterb correct.

c130nav

Stock rocker bolts(w/rounded ends) that bottom out before securing the rockers. Heads are stock 241s without any visible welding or grinding. I shimmed the bolts today with a 5/16ths washer under the bolt heads, and this secured the trunions. Still getting a lot of play in the rockers, so I'll plan on replacing them this week and see if that quites things down. I plan on also "clearancing" the ends of those bolts before installing the new rockers. I'm leaning towards GM stock but my son(its his car) saw these:

http://cgi.ebay.com/ebaymotors/ws/eB...#ht_762wt_1182

and says he'll pay the difference between GM rockers and these. Anyone used these before? Are they any good?

JFM-jr

iTrader: (23)

What kinda RPM's you plan on turning? Really the stock rocker arms are up to most tasks. I ran them for a long time now turning 7200 RPM's without issue. They are strong and light in weight where it counts. I would grind the ends off those bolts and the slight play (trunion to rocker arm) is normal belive it or not and very well may still be present with a new set of rockers.

vettenuts

iTrader: (4)

I haven't looked at a stock rocker in a while but some aftermarkets have two sides to the trunnion. Have you inspected the installation orientation?

Only way this could happen is some abnormal wear or the bosses on the heads are machined, which doesn't make sense.

JFM-jr

iTrader: (23)

Stock rocker's trunion can only sit on the pedestal one way. The stock trunion can not physically rotate around 180 degrees either.

c130nav

I don't foresee my son beating on it too much, so stock redline is what I'm thinking. I'll probably just go with stock GM rockers, and he'll live with it.
He'll need that extra coin to fill the gas tank this summer. He does want to go with a hotter cam than the stock LS1 thats in there now. I told him he'd have to pay for it himself; and possibly new springs and a tune as well; so we'll see where that goes. Can an LS6 cam run on stock LS1 springs? I think the duration is in the low 200s (208-212) and low to mid .500s lift. I'd like to thank everyone for their inputs, and I'll keep the forum posted on the outcome.

Mike

VeTTeMaNC486

No, put some ls6 springs in there too. I just did this swap two weeks ago on my 2000 trans am. I would suggest a larger cam unless you just have the ls6 cam and springs sitting there already (I did from my z06 cam swap) because it is a ton of work for minimal gains. Runs fine in my A4 on stock tune though. First start up it wanted to die for a few secs then idled fine. Great MPG still though!

vettenuts

iTrader: (4)

Thanks. Haven't looked at them in three years so I don't remember what the trunnion looks like. Could have pulled one out but they are in an oil bath and it would have been messy.

barnat

iTrader: (59)

Ide stick an end of a drill bit down threw the hole and mark the top of it and see if any of the other holes are deeper ,then you know its something in the hole that needs blown out or a shorter bolt for that hole. Ide wanna know myself why it was bottoming out LOL and not tightening