About a month ago I broke a valvespring just as I crossed the finished line. As I let off the gas the car shuddered badly and then wouldn't idle hardly at all. I pull out of line and loaded it on the trailer. I did a quick inspection thinking plug wire or something stupid, but nothing obvious. So later that week I figure start with the easy stuff, plugs, wires etc. I also pulled the valve covers that when I found the exhaust valvespring on #7 was looking like this:
Luckily I didn't drop the valve and cause all hell to break loose. I thought the car had dual springs on it and figured that the inner spring saved me. Turns out it only had single springs on it. Shame on me for not knowing my own car better.
My initial reaction was to drop the motor and tear into it. But under the advice of some trusted friends (198esp1 and others) I decided to simply swap out the springs on the bad cylinder, then do a leak down test to see if there was any collateral damage like a bent valve, nicked valve seat, pushrod damage etc. Never having done a valve spring swap on a car, I was in new territory.
I picked up a PRC Gold springs Kit with new Ti retainers, bases, seals and locks (good reputation and affordable) NIB and then got lucky and scored a Crane Valve Spring Tool on LS1Tech which fit my needs nicely.
The tool
So tonight after work I dove in head first. First I brought #7 to TDC (just in case the air failed to hold the valve it wouldn't drop all the way to the bottom). Then removed the rockers (Comp Cams Pro Mag) and pushrods (Comp Cams) and inspected them for obvious wear. Everthing looked good. Pushrods rolled true on a plate of glass. So far so good.
Then I slid the base of the tool over the studs with some hardened washers and tightend it down.
Pressurized the cylinder with air, about 80 psi or so.
Then you slide the clamp bar over the center stud (which is attached to the base of the tool) being careful to keep it centered over the retainers. Lube the threads of the stud and slowly tighten down the bar, compressing the valve springs and releasing the locks.
Pluck the locks with pen magnet, loosen the bar and pull the old hardware. Install the new hardware, line up the bar, compress the springs and insert the locks. This was a little tricky, never having done this before I had to kinda feel my way through it. Compress the springs too far and the locks sit too deep and don't seat properly. Don't compress enough and you can't get them in. So a little trial and error to me to the finished product. Sorry for not taking pics of the all these steps, but I was paranoid of the valves dropping for some crazy reason.
Springs are installed on that one cylinder. So I decided to put it back together, lash the valves and do a quick test to see how it ran. If it still ran like pooh, indicating something more that just the spring got hurt then the motor would have to come out and I'd to the rest out of the car. But it fired right up and runs great. I think it runs even better that it did. The valvesprings must be tired, so this Saturday I'll do the rest of the cylinders one at a time.
I got lucky. My cam is small by today's standards and the old springs were Manely singles best I can tell from my pile of receipts. So no junk, but time took its toll. Lots of cycles from the drag strip, autox, track days etc. Learn from this example and change out the valvespring once they get some miles on them. Once I get this heap back together I'm gonna go back to Atco and see if the MPH pics up? Just changing that one cylinder feels like it made a difference, but it could be in my head?
Chris
Broken Valvespring while Autox.....Fixed (fingers crossed)
Not so lucky afterall.................
I look closely at the rocker and saw this
and I'm not feeling the love anymore.
