1995_maro_z

iTrader: (1)

I will soon be replacing my valve springs in my '02 C5 Z06 out of paranoia. I do not have an air compressor so I have been researching alternate methods of keeping the valves up. One method that I found was to stick some rope in the plug hole and bring that cylinder to TDC. I am confused as to how this would hold the valves up. Do they stick a lot of rope into the cylinder so that it kind of coils up? What length and diameter rope would I need? Also, how will I be able to tell when a cylinder is at TDC? This seems like a straight forward job, and I have dealt with much smaller scale small engine valve spring swaps so i understand the basics. I'm just a bit unclear on the details.

JoeNova

I don't like using any method other than the air compressor method. The problem with jamming something in there is that if the valve isn't completely closed, it can be hard to get the keepers back in even with the spring fully compressed.

If you're going to stick rope in there, use Nylon rope that is as large of a diameter as you can get that still fits in the hole. Nylon will be less likely tear and leave bits in the cylinder.

1995_maro_z

iTrader: (1)

So, would you just stick a few inches of rope in the hole, or would you stick as much as you can cram in so that it kind of coils up and forms a compressible barrier b/t the valves and the piston? Essentially, that's all compressed air does. I'm just unclear exactly what people do with the rope! Lol

JoeNova

Cram it full.

dsadsdaiouser

+1

Do you have a buddy who will loan you a compressor or a place to rent one? I wouldn't try to do springs without one. The valves need to be COMPLETELY closed to get the locks on and I don't know that a rope would do that.

slogo

You take the rockers off first, valves won't be open. Just get some rope that fits the spark
plug hole put it in till you can't fit anymore in
leave some out, rotate crank around easily till it
won't rotate anymore. Don't overthink it.
soft cotton rope works great, I have used that
method lots of times swapping out valve seals.

1995_maro_z

iTrader: (1)

Good deal! So how should I insert the rope when the cylinder is at BDC? And how can I tell when a cylinder is at BDC/TDC?

slogo

Very simple, remove all plugs, remove all rocker arms, pick a cylinder start feeding
rope into spark plug hole, if you only get a little rope in, rotate crank till piston moves down some, you want a good amount of rope to get under both valves, doesn't have to be exactly BDC.
You might can look down plug hole with light and mirror, or simply stick something down spark plug hole and see how deep it is, use something stiff but nothing that will scratch,
like the straw on a WD-40 can? When hole is full of rope, GENTLY turn crank till you feel
piston pushing rope against valves, I like the cotton rope because it compresses nice
against valves, of course use clean rope, its cheap at hardware store $5 or 6 in a package.
If you are tearing rope in there you are being a little rough, don't do that.
I like it better than air because you can step away from job if you need to, air will bleed out if you loose air supply, rope is solid. When you are finished swapping whatever,
rotate crank off of rope and pull it out, go to next cylinder. Do 1 cylinder at at time.
When all 8 holes are swapped then start putting rockers back on and finish up.
Hope that was a little more clear than mud.

stockA4

I have always used the Top dead center method I learned on LS1howto.com back in the day. I've never had any problems doing it this way and it doesn't require any extra tools besides the valve spring compressor and a pen magnet to catch the locks should they pop off.

1995_maro_z

iTrader: (1)

This is perfect. Thank you!

patSS/00

iTrader: (6)

I also used the TDC method, worked fine no rope or air needed. Once the spring is compressed you need to pull the valve up all the way using a screwdriver on the slot at the top of the valve to give you enough extra space to glue on the keepers with grease. You just need to keep track of which cylinder is at TDC if you rotate 1/4 turn of the crank to go to the next one.

Spaceboy1980

I use twine when doing it that way and feed it in with needle nose. I'd hate for rope to pull a knot while trying to remove it where a knot in twine can fit through the spark plug hole.

alaska_guy

TDC method or air. Don't use rope. I know a lot of people get away with it and it's been done for a LONG time... But all it takes is for one strand to fray and get stuck in the piston ring lands or worse and you have a nightmare of a problem. If I didn't own a compressor I would just use the TDC method. Good luck!

slogo

Somebody please share what they are doing when all this rope damage is happening,
in a cylinder that is not moving, if you are doing this while the engine is running,
you are doing it wrong.

IDriveChevy

iTrader: (5)

Just use the TDC method, don't overthink it. Its a straightforward process

Bluewire

iTrader: (9)

TDC method here as well, worked without issue. I just picked up one the cheap USB boroscope cameras on amazon for like 20 bucks, put in the sparkplug hole and found TDC. Also great for checking the condition of the cylinder/piston.

alaska_guy

This would be my guess....

Someone who hasn't worked on engines before is not getting that cylinder to TDC. They then decide to stuff in 5' of rope or more and realize its not enough and instead of pulling it all out and rotating the crank to get the cylinder in the correct position they decide to just rotate the crank with all that rope in the cylinder. Some of the rope frays on the sidewalls, gets caught in the rings of the piston and now they have a big issue.

Again I am guessing here, but that's about the only way I can see it happening. If they have already removed all the rockers, then all the valves are closed, so I don't see them getting the rope stuck in a valve.

Common sense goes a LONG ways.

irrational

i just did my valvespring swap, its my first in-vehicle swap. Out of all the motors ive built ive never done a swap in car. I was tenative at first about the tdc method but really you have alot of leeway before you drop a valve, you need to be pretty far off before the valve falls completely out of the guide. If you need a little more length and didnt quite get tdc, stick two pen magnets on top of the valves and rotate the motor very slowly and watch them go up/down (be careful not to bind the valves into the pistons of course). And as a heads up, make sure you use a brass or rubber mallet and tap the edges of the retainers, not the stems at a slight angle to break them free so when you start running down the spring compressor it doesnt shove the valves into the pistons.

1995_maro_z

iTrader: (1)

I know this is old, but I never updated, and would like to make sure this helps any future searchers. The rope method works very nicely. I used nylon rope, burned the ends to prevent fraying, and turned the engine over by spinning the rear wheels by hand with the rear jacked up and the car in 4th gear (manual). With all the plugs out, the engine turned over very easily using this method. It was a very easy process, and the car was raced often after the swap with no ill side effects.

Che70velle

iTrader: (6)

Appreciate the update!