If you pull the heads you will need new head gaskets $.

 

The engine is out of the car and completely stripped of all obstructions.

If you pull the heads you will need new head gaskets $.

If you pull the heads you can upgrade to LT4 head gaskets for a lil bit more compression, check the hydraulic lifters …

 

On an older sbc I used air AND moved to each next valve's TDC. I had what turned out to be a poor quality spring compressor and welcomed the time to set up the following valve as a break from cussing and fighting the last one.
[EDIT] I should add that in not a single case did the valve drop with the air on it.
Since the engine's out it's closer to a toss-up whether easier working with the heads off. With an engine installed it might tip toward removing them v. a crinked back if "of a certain age". But then again, no stronger business case for reviewing and changing the head gaskets (type, thickness) than while the heads are already removed for another reason.

Sorry. I don't think I helped much.

 

You would NOT " lose " a valve at TDC but depending on gripsion of seal on stem, the valve dropping down to the piston might cause you grief as you would have the effective height as you assemble lower . This would make you compress the spring more or "F" around trying the hold the valve up.

Also the valve not staying up to full height will make dissasembly more difficult.

Re and re or not re and re
Depends on the type spring compressor which is easier.
I am lucky to have possibly the best , in my opinion, on and off compressors so ease of change does not affect my decision.

 

You would NOT " lose " a valve at TDC but depending on gripsion of seal on stem, the valve dropping down to the piston might cause you grief

This was very much the case.

I realized at a certain point that, while technically not "required", it is strongly recommended that you use either compressed air or some sort of obstruction to keep the valve stems up as high as possible while you are putting the keepers in. You also have the option of trying to wrestle a bunch of tiny pieces of metal with lubricant all over your fingers. Take your pick.

 

Iron head lt1 head gasket is .029 isnt it?
Thinnest of the production head gaskets.
Thinner than F+Y LT4 12551488 .043
Both thinner than F+Y LT1 10168457 .049-.050 depending on source.

There is a thin Mr Gasket . 026 ?
MRG-5716G
And a Cometic .027
C5645-027

.002 or .003 is less gain than the carbon on the piston and chamber

 

Iron head lt1 head gasket is .029 isnt it? Thinnest of the production head gaskets.
Thinner than F+Y LT4 12551488 .043
Both thinner than F+Y LT1 10168457 .049-.050 depending on source.

There is a thin Mr Gasket . 026 ? MRG-5716G
And a Cometic .027 C5645-027

I regret the confusion; thank you 95wagon for clearing it up for us all.
The MRG-5716G & the Cometic C5645-027 are what I was getting at.

 

I used the MRG-5716G when I put my worked over ( 52 cc) alloy heads on my undecked LT1.
What I was getting at, I wouldn't take apart a sealed up stock .029 gasket iron head, engine just to put in .003 thinner gaskets and nothing else.

 

I used the MRG-5716G when I put my worked over (52 cc) alloy heads on my undecked LT1.
What I was getting at, I wouldn't take apart a sealed up stock .029 gasket iron head engine, just to put in .003 thinner gaskets
and nothing else.

I agree with 'and nothing else'. He might think of other things to do.

 

Op

I have changed 3 sets of valve springs with heads on and motor in car. Bringing the piston to TDC the valve drops around 1/4"

with #1 at TDC you can do cyl 1 & 6
rotate 90 degrees and do 5 & 8
rotate 90 degrees and do 7 & 4
rotate 90 degrees and do 3 & 2

if doing springs, replace valve stem seals. FelPro Viton. New seals also help hold the valve up

the Crane 99473-1 spring compressor allows you to do both I & E at the same time. Back when I bought mine it was $100, worth every penny

 

Get a leakdown tester and compressed air and just use that to hold the valves in place. That's what I've done; never a problem. Maybe 10 minutes a cylinder to replace springs and seals.

 

I use air as well, but also turn it to TDC. +1 on not taking the heads off.

 

I am getting ready to perform my first cam install, and am also upgrading the valve springs. I'm curious … If I have to go cylinder by cylinder with a compressor or a piece of rope or whatever, is that really going to be less labor than just unbolting the heads and doing the springs while comfortably seated at a table? The engine is out of the car and completely stripped of all obstructions.

Since the LT1's out of the car in the open, AND you're upgrading the cam, might as well totally overhaul / upgrade the entire valvetrain, including bearings & whatnot.
Now you can also clean the combustion chambers & piston faces too.

 

including bearings

Others will disagree,
I stand on, changing cam bearings in an assembled short block is an invitation to disaster.
During re&re the annular oil groove behind the bearing invariably will put a shaving or some bit of crap in the groove and has an express ticket to a main bearing.

 

From what you've added it's making me squint as to why you're messing with the cam either. If there's an SO in that house you'll get scads more ROI and value/OCD working on that.

 

I need to learn, and it makes sense to practice on an engine that is low-risk.

I'm 31 and single with no kids. I thoroughly enjoy being unobligated. If I feel like spending time tinkering with stupid **** in my garage, then that's what I'm going to do.

 

What about something like this?

15 lb. Capacity Telescoping Magnetic Pickup Tool

Amazing deals on this 15Lb Telescoping Magnetic Pickup Tool at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

If it holds 15 lbs, that seems like more than enough to hold the valve.

 

What about something like this?

15 lb. Capacity Telescoping Magnetic Pickup Tool

Amazing deals on this 15Lb Telescoping Magnetic Pickup Tool at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

That "can" be used after the new spring has been compressed to "lift" valve up if needed assuming you are using a spring compressor like the Crane one I posted in #9 or another type that does not cover the top of the spring.

Given, with cyl at TDC, the valve drops very little I am able to compress the new spring enough to lift valve up all the way to get valve locks on without needing the pen magnet...but I do use it more to extract the keepers once old spring is compressed so they don't fall in/onto head...of course you always want to stuff paper towels/rags into any oil drip cavity to prevent any part from going into motor when doing spring swap on a assembled motor

Also you can put an air hose fitting with spark plug threaded end to use compressed air. My issue with that method is the compressor runs alot, fing noise, and if you use 2 much air pressure the motor spins pushing the cyl down unless you put trans (stick) in gear or otherwise prevent motor from spinning. If piston is at bottom of stroke....a valve will drop all the way in the cyl if you lose air pressure.

Fortunately the LT1 with piston up the valve drops very little

 

Alrighty... I'm about to do these springs. I'm just going to rotate the engine like BALLSS outlined, and dare the valves to fall.

I am using the cheapo Harbor Freight spring compressor that does one spring at a time.

Side note: If anybody has a use for the little inner springs that our cars don't have, shoot me a PM before I throw them out.

 

Here's a question...

One of the sixteen valve stem seals was installed without the little elastic metal ring on it. Is this a big deal? Do I need to R&R this spring?

 

The lip of seal requires the force of the garter spring.

Exhaust, a deal
Intake , a big deal

Take it apart

 

Since the engine is out of the car, you can just invert the whole thing, and gravity will hold the valves in place while you change the springs.

 

I am going to treat this as a legitimate question.
Pros,
valve would stay up

Cons,
springs, retainers and keepers would fall.
You would be laying on your back under the engine which I would not do with 99% of the engine stands out there.
If the pan is in place, years of sludge you didnt know was there ,is all over the botton of pistons, bores etc.
That last bit of coolant that didn't come out will ,on your head.

The list goes on and on why this would be a bad idea.

The one good take away here.
NEVER , turn a used engine assembly upside down before you have removed the oil pan .
You never know what is in there.
The old days, it was often a bunch of nylon teeth and a lifter or two.

 

Yeah... Turning the engine upside down seems like a net loss. Putting the retainers in that way sounds especially frustrating.