there is nothing to be worried about. watch the valves, crank the engine over, do the cylinders that are at TDC, 2 at a time. nothing will fall. I did this last summer. not a chance of error if you pay attention to what you are doing.. do 2, turn 90 degrees, do 2, turn, etc. if you are nervous and want to make sure you're at 100% TDC, stick a drinking straw in the spark plug hole while you ratchet the crank. when the straw gets pinched, youre there. no doubt.

I was all paranoid at first, believe me. I had bought my 1.6 rockers, new springs, and a bud was supposed to show me how. he moved, so that never happened. they sat on my shelf for a couple months, till I said screw it, read up, and did it.

 

The thing is: You want to increase your HP/Performance---so you need more fuel and more air and the proper way to do this is to increase the intake by increasing your air flow by having the heads and valves ported and pocketed.

A cam swap may get you more HP depending on the profile of the cam and your proposed use (driving). You leave a lot of ponies in the barn by not having your heads cleaned up and maybe going with some larger valves.

You also need to consider purging the cyls by increasing the ability to expel the combusted gases thus allowing a more complete filling of the cyls with fresh fuel and O2 so this is where headers come in.

Bottom line: Depending on your finances and your intentions, doing it all right the first time will save you money in the long run and provide you with a delightful experience.

And...when you do the springs while your heads are off and after the machine work you will only need to adjust your RRs after the install and install the headers which you will have mated up to the heads while they are off to ensure a perfect fit.

An alternative and reletively inexpensive way to do this is also to get yourself a good set of used heads and have this all done before you even pull your old heads off--this way you are ready to go with short down time.

But...if you can't afford to do it this way and don't want to wait til you are financially ready then, put your pistons at TDC or use the cord method and you should be good to go--valves shouldn't drop more than a 1/4".

Compressed air method may be good idea on some cars, but if you think changing the plugs is a b.tch...wait til you try to thread an air compressor into those damn holes (16 of'em) so I must agree that pulling the heads is probably the ideal way to go and will take less time even if you don't do a big job on the heads. And...depending upon your cam, you are looking at the difference between a gain of 12-20 rwhp (with cam and RRs) and 75-110 rwhp. JMHO

 

The TDC method worked perfectly, the valves will not fall out unless you have holey pistons, which means you have biger problems. The air fitting in the spark plug method would suck because of access.

 

Which part? If you are referring to using the TDC method then I can only type from what I've experienced. And that is even when I was able to get a spring compressed to the fullest extent there was still too much play between the valve and the valve relief of the piston to get enough slack for the retainer to pop off the keepers. And that's after positively knowing the piston was at TDC (by using a McDonalds straw to stab into the spark plug hole, crushing the straw between the piston and quench area). Maybe it was because the springs I have done had a tall install height. Dunno. I've only done one set of stock springs and I ran into the same problem.
The rope trick is a quick, dirty way to know the piston is close enough at TDC to use the compressor and it's nice to have a bit of a cushon for the valves if you have to tap on the compressor to get the retainer off the keepers.

 

ok, I think I see what you did now.. you dont want the valves to rest on the piston while you put the new spring on, there will not be enough stem sticking out, but, you should have put on new valve stem seals while the old springs were off. they will hold the valves up while you get the new springs installed.

so, put cylinder at TDC, pull old spring, pull old seal, put on new seal, pull up valve, stick on spring...

 

The retainers have a tendancy to stick in place. A light tap on the stem while compressing the spring is enough to get them to pop loose. Once their loose, you just compress the spring fully and remove the keepers and retainer off.

Sometimes the valve stem will stay up because the valve seal has enough resistance to hold it up. Sometimes the valve will slide down and rest on the piston leaving pleanty of stem sticking up through the head to just pull it back up with your fingers or a pencil magent.

Thomas.

 

pretty much... except for some reason on any of the lt's i changed springs on, having the piston at TDC had too much clearence for me to get the retainers off the locks.

 

that's the thing... none of the retainers i've dealt with that were stuck took more than just a light tap and the springs i dealt with wouldn't compress enough for the locks to be removed. maybe i'm just not strong enough to compress the springs. as said i've only dealt with one engine that had stock springs and i tried it on a few and didn't have any luck. using nylon rope was a great alternative.

 

Huh, maybe it was the spring compressor you were using?
When I used the proform tool, I had no problem compressing the stock springs enough to remove the locks and retainers.

edit: Actually, now that I think about it, on some of my springs I had to use a magnet to lift the stem up while the spring was compressed to get enough clearence to remove the locks.......

Thomas.

 

Stoopalini,

I obviously HAVE done it before or I wouldnt be suggesting it. As long as you have the right tools, its not that hard to use the compressed air. And I garentee you I spent more time under the hood of my 4th gen than you could imagine.

I bought it totaled with no engine or tranny in it. No accesories on the engine, wiring harness all twisted up. So don't say that I obviously never worked on a fourth gen. It can't be done. The only cylinders that fought me at all hooking up an airline was number 2 and bumber 4. The rest it went right in some from the top some from the bottom. I didn't have any real problems though.

To the origional poster:

A traditional compressor will drive you insane. Your hand will hurt, and it really really sucks to try and hook onto the back (#7 and #8) cylinder valve springs. Its very hard to crank it down too. Buy the ratcheting type compressor. Even if you plan on never doing valve springs again, its worth it. You can sell it on the Classifieds on here ... They dominate.

O and as far as getting number one to TDC and then rotating 90* for each additional cylinder ... Make sure you are actually on TDC for number one. The hubs are NOT keyed on LT1's So if anyone ever had the hub off of the car before, its very likely that it could not truely be at TDC for #1 or #6 when the pointer is facing 12-O'clock

 

O and thats funny, using compressed air, I never had any problems like this:

edit: Actually, now that I think about it, on some of my springs I had to use a magnet to lift the stem up while the spring was compressed to get enough clearence to remove the locks.......


Bubba: Compressed air method may be good idea on some cars, but if you think changing the plugs is a b.tch...wait til you try to thread an air compressor into those damn holes (16 of'em)

There is only 8 holes ... Get a air fitting with a flexable thin hose already on it. It makes life very simple. It wanst bad.

If you guys have never tried it, dont bash it. I did it. It works. It wasnt that bad. I for sure can say that my header install was much worse.

If you go ahead and run compressed air, use about 50-60lbs. Otherwise it will turn the motor over. And dont get scarred about it. A few people on here now have solid opinions against using compressed air. But it seems like none of them have actually tried it. I would rather listen to what HAS been done, not what others think would be HARD to do. Im sure there are others in LT1 Tech that have used compressed air. Get some of their opinions. Better safe than sorry. And its a perfect time to change plugs anyways.

 

Sorry, I didn't mean to offend you. I didn't say you never worked on a 4th gen before; but I did say whoever suggested using compressed air probably never did a valve spring swap on one before .... I stand corrected.

I just couldn't imagine getting my air fitting up into some of those plug holes with the exhaust in place .... just seems much easier to use the TDC method.

I found TDC on number one by watching the valves move while spinning the motor, then marked the balancer at 12 o'clock (the factory mark was at 1:30 or so .... the hub had obviously spun on the crank).

It's not really a problem when the magnet is there anyway to catch the locks so they don't fall down into the head; hence the reason I didn't remeber doing it .....

Thomas.

 

Every time I've used one it's been an Autozone rental and I've only done one set of stock springs and didn't feel like fighting with TDC trying it on a few cylinders. Other springs I've done have been duals with ~130lbs on the seat.

 

Ok ok ...

Sorry I was a little harsh ... Its late. Im tired. Long day lol ...

I didnt really mean to offend you. I shouldnt have been such a dickwad about it.

I guess I was just trying to say that it wasnt that bad. And it was a pretty relaxing installation until #2 and #4. I thought about going the way you did. Just had access to the tools to do it with air. And I figured if I have the tools, and the extra couple hours it takes to do it that way, I probably should. I had to change plugs anyways though so it only took about an extra hour or so to do it like that.

Again guys, sorry. I read what I posted before and kind of came across as being a dick about things. I dndt relaly mean it like that. I guess 2:30 AM and message boards dont mix well for me lol.

Nite, And dont take any offense to previous, somewhat ignorant, post.

 

Take the heads off. Only way to do it right, IMHO.

Rich