NatB

This week-end I finally replaced the valve springs on my 2002 Z06 with 33.5k miles. I did it as preventative maintenance due to all the reports of spring failures. That said- I remain a bit skeptical and generally believe if something is not broke why fix it.

Anyhow- I replaced the oem springs with PAC 1218's ( I have a box of the new GM springs- but the label sais made in Mexico- and I say no way Jose); all new retainers; all new keepers; and new valve seals. I held the valves up using the TDC and Rope method. I was going to use compressd air- but when I had it hooked up I heard air hissing - so decided to go the fail safe method.-

I was fairly meticulous- so it took me most of yesterday afternoon to replace all the valve springs. Then most of this afternoon adjusting the rocker arms and getting everything put back together.

The spark plugs and wires are a PITA.

I did use the Crane Dual Valve Spring Compressor tool- nice tool.

I did carefully cover up the valve train with rags to avoid loosing a stray keeper ( and some do pop of and fly ).

You have to be careful installing the keepers- easy to get one out of line if not careful when releasing the spring compressor. Also- use Vaseline on the keepers so they stick to the valves , a real time saver.

Honestly- the job is not too hard if you aren't afraid to work on your engine. For me, the most tedious part was torquing down the rocker arms ( I used the GM manual). I did something dumb- I used a wooden dowel inserted in cylinder #1 to find TDC . The concept works great- as the piston moves up it pushed up the dowel. My son was holding the dowel as I turned the crank - and he said, the dowel is moving up and I hear it cracking. OMG- luckily, it cracked but stayed together. Otherwise I would have had to pull the cylinder head off to get it out. I think a steel rod would be better next time. The rockers are torqued down at 22 foot pounds - use a torque wrench. Also the rocker arm bolt are on real tight ( seemingly a lot more than the 22 ft lbs they are installed at) - I followed others advice and got an 8MM impact socket after hearing about broken sockets.

Anyhow- It fired up and runs smooth. I think it gained 100 HP ( just kidding). I drove it easily and got the engine fully warmed up- then shut down to let it cool - this I am told is needed to temper the new springs and break them in.

Thanks for all the help and guidance from the forum !!

dragon84

Nice, I'm about to do mine tomorrow. I've read up and it doesnt seem that hard but its always good to see what others have done and what snags they hit along the way.

Tom

NatB

Just take your time - turning the crank manually is a bit of a PITA with a 15/16th offset wrench. Maybe raising the rear and turning the wheel with the tranny is 6th gears would be easier if you have a helper.

dragon84

I might just raise the rear since I have to bleed the brakes anyway .

Paul 75 L82

I've been told that the springs require 3 heat cycles to be broke in.

NatB

I have completed three heat cycles- evrything seems to be running well.

Trash

NatB,

Glad to hear you got it all done. I too was a little intimidated by it but having done it and working out all the process bugs I'd do it again in a heartbeat if I had to.

I have to second the torque on the rocker arms. That 22 ft-lbs seems like 220 ft-lbs. for such a small bolt! I was a little surprised at the force required to break them loose when I did the tear down. I thought the head of the bolt was going to twist off.

NatB

Yeah- those little 8mm rocker arm bolts are on tight! Some have posted here that they've busted standard sockets trying to get them off- so I followed their advice and got an impact socket

Really- the only somewhat tedious part of the job for me was torquing down the rockers in the correct sequence . I used the GM Manual and actually drew a diagram to check off which bolts I had tightened. I went back over the bolts several times to make sure none were missed.

dragon84

Did you put loctite on your rocker arm bolts when you reassembled? I have different directions. one says to do it, the other doesn't mention it. Also there was no sign of loctite when I removed the bolts and rocker arms.

Thanks

Tom

ZeeOSix

Not 100% sure ... but I think the GM Service Manual does not have any mention of using lock-tite on the rocker arm bolts.

Trash

Echoing what Zee0Six said, I too used the GM service manual as a guide during the process and do not recall the manual ever requiring loc-tite for the rockers.

NatB

I followed my GM Manual and did not use locktite.

Having read through many many posts on replacing the valve springs - and now having just completed the project, the one area underemphasized in the many write ups is the importance of correctly reinstalling the rockers in the correct sequence and applying the correct 22 foot pounds of torque. Trust me- it is easy to miss one, I knew this so I made several passes.

If you torque the rocker arm down when the lifter is up (valve open) - you will not get the correct torque. I was very careful- and hopefully everything is good. I believe the proper re-installation /torquing of the rocker arms was the more challenging part of the job. Take your time- you don't want one come loose. Find TDC on Cylinder #1 and follow the correct torquing sequence outlined in the GM Manual - then for good measure repeat the process re-checking each rocker bolt torque I plan also to pull the valve covers this week-end and perform a visual check just to ensure everything is A'OK and re-check torque on the bolts.

Also- I cannot stress enough to carefully recheck the keepers after you get the new springs installed. Easy for one to slip out of alignment- or worse to somehow install one upside down. This is all self evident when you are into the work.

Hope this helps someone else about to take on the job. I don't work on my cars to save money - I do it cause it provide me a sense of accomplishment. I trust my own work more than others- but I always weigh the risk reward.

So know there is the risk of dropping a valve and having to remove a cylinder head- or worse. I believe the whole valve spring failure thing is overblown - but I did the job for peace of mind....

ZeeOSix

One thing I would suggest is making sure the threads are dry before assembly and torquing unless the manual specifically says to lube the threads. Any lube on them will change the stress in the bolt at the specified 22 ft-lbs of tightening torque.

Z06X

Still pissin around and haven't replaced mine. I have them on the shelf. 51k and counting....

ZeeOSix

I'm going to use the TDC with rope method also ... no chance of dropping a valve with that way IMO.

budnate

has anyone copied the procedure out of a manual and have it to post?

NatB

I drove her today - new valve springs will set you free of worries

Very pleased with the results- questionable whether the springs really needed replacing, but having read more than several stories of catastrophic engine failure resulting from a dropped valve I succumbed.

The rope and tdc method is pretty foolproof - just make certain the rocker arms have been removed!! That said , I have a good compressor and the air method would have been mucho faster.

Get the Crane Style Dual Spring Compressor - this tool is a delight to use and a time saver.

My only suggestion - if you are the least bit uncomfortable working on your car, save yourself a lot of worries and pay someone 300-500 dollars for the labor. There's a lot of things that could result in a costly mistake taking on this job. I do this stuff cause its fun and I can afford to screw things up .

dragon84

So I finally finished the valve spring replacement. The kit came with new seals, retainers, and seats.

So after doing 3 heat cycles then driving it about 100 miles I am getting a few puffs of whitish smoke out of my exhaust pipes every so often. I can smell a little bit of burnt oil but figure its because of me rubbing some against the headers from my hands when I was working.

Any thoughts?

Thanks

Tom

ZeeOSix

Rubbing oil on the outside of the headers isn't going to make puffs of smoke come out the exhaust pipes. Any external oil on the exhaust should be well burnt off after a 100 miles of driving.

What kit did you install? I'm thinking it must have been a dual spring kit if it came with new spring seats and guide seals.

dragon84

Its a Patriot Gold dual spring kit.

I agree about the external oil being burnt off by now.