Hagarr

iTrader: (6)

When changing valve springs? I am going to do a cam swap sometime in the future but would like to go ahead and do the springs/pushrods myself so I don't waste the time of my helpers.

TIA

Brian

blkZ28spt

Spark plugs? No, you do not. Motor will be a little harder to turn over by hand as you will be building compression, but it's not a big deal. Go for it.

Hagarr

iTrader: (6)

Thanks. Take care.

B

GuitsBoy

iTrader: (4)

I never pull plugs for head or cam swaps, unless theyre gonna get changed. If youre doing a cam swap and the timing cover is off you can find TDC that way, otherwise you would have to remove atleast the #1 sparkplug to find TDC.

MrDude_1

iTrader: (4)

how are you planning on holding the valve up for the spring change?

normally i take them out, not because i want to, but because i have to remove them to connect the airline.

speedracer5532

iTrader: (8)

You can bring the piston to TDC which will keep the valve up and change the springs.

GuitsBoy

iTrader: (4)

TDC method. Ive heard too many stories about people dropping valves down because the valve compressor pushed on the stem using the air method.

erikthegoalie

iTrader: (29)

not meaning to hijack the thread, but what exactly is TDC, top dead center?
Also, what does the plugs have to do with this...do you look into the hole with amirror or something to see if the piston is as high as it can go?? is that what this whoe TDC process is?
THANKS

MrDude_1

iTrader: (4)

on the LS1s, the valve hits the cyl wall before it can fall all the way out.... then you just roatate the motor by hand....but i havent dropped one yet using air..

GuitsBoy

iTrader: (4)

TDC does indeed mean Top Dead Center, the point at which the piston is at the top of the bore. This will hold up the valves so they dont fall down into the cylinder bore when theyre no long held up by the springs.

If youve got the timing cover off you can find TDC when the timing dots are facing eachother. If the cover is on, then you need to pull the #1 plug and feel for TDC with a straw or pencil or something.

The ls1howto.com guide calls for you to take the plugs out, but its not necessary if youre gonna use the TDC method, and odnt mind going a little slower waiting for compression to bleed off.

GuitsBoy

iTrader: (4)

Yes, with a 3.898 bore, but not with a 4.000 bore. Id still rather not potentially bend a valve if the stem jams up in the guide rather then sliding up smoothly. Just less to worry about, i guess. Not to mention I have a weak compressor.

erikthegoalie

iTrader: (29)

hmm I see, can you be a little more specific on the whole timing dot thing....
I think I know what youre saying....dont you need to know the firing order of the pistons to determine which piston is at TDC after each revolution of teh timing gears?
THANKS MAN!!

GuitsBoy

iTrader: (4)

The cam needs to be installed so that it is clocked correctly in relation to teh crank. To do this, there are dots on the cam and crank sprockets. When you put teh timing chain back on, make sure the two dots are lined up facing one another. This will clock both the crank and the cam at #1 TDC.

blkZ28spt

Read through the cam swap guide at www.ls1howto.com

http://www.ls1howto.com/index.php?article=23