[Vix76]

It has been my experience that the cylinder pressure will eventually bleed off. I use about 60 psi of constant air pressure. I would never let the piston drop to BDC because if you did bump the valve off of its seat it could fall into the cylinder. With the piston at TDC the valve could only fall slightly and you could easily retrieve it. I always remove all of the rocker arms to create some resistance so the engine won't rotate. Once the spring is removed the valve seal also helps hold the valve up.

[AndersonRacing44]

IDK if its the same on a BBC as a SBC, but when i do valve springs on my sb350 I just bring the piston allll the way to TDC and you can let the valve rest on the piston top. and if you have the valve spring tool that uses the rocker stud for leverage its quite easy.

[68NovaSS]

Without something, even air pressure, under the valve, it can be tough to pop stubborn keepers.

[T-bucket23]

I recently have used air and have never lost one yet. I have also used rope but that was long ago. Both seem to work equally as well. As mentioned above the valve seal would most likely keep the valve from dropping into the cylinder if you did lose pressure.

[1ownerT]

When I remove the springs while still installed on the engine, I use one of my soft face hammers and give the retainer a pop, usually they come right apart.

[adantessr]

Originally Posted by 454C10

I use shop air pressure (90 to 120psi).

piston always goes to bdc when I do it but it works just fine at btc.

sure, some air leaks by the rings but not a big deal.

you need air pressure to not only hold up the valves but to allow some extra force to be applied to break the locks free in the retainer.

I just replaced all the valve seals on the 355 in my T-bucket last week using an over the head valve spring compressor. I removed all the spark plugs and backed off all the rockers and used full shop air pressure (120 psi) . I used a spark plug socket and a ball pein hammer to break the locks loose after the cylinder was pressurized. If you need to leave the locks and springs off of more than one cylinder for some reason , the clothes pins with the springs work to hold the valve stems.

[cobalt327]

Originally Posted by adantessr

I used a spark plug socket and a ball pein hammer to break the locks loose after the cylinder was pressurized.

Good advice. I've always used a socket w/the open end over the retainer, to whack w/a rubber mallet to jar the locks loose.

You will find that if you whack it hard enough the locks will fly out.

Not necessarily a bad thing, just be sure the socket rests squarely on the retainer and that you don't let the locks fly away and get lost. But it's probably better to not hit it quite so hard so the locks are freed but not popped out.

[adantessr]

Originally Posted by cobalt327

Good advice. I've always used a socket w/the open end over the retainer, to whack w/a rubber mallet to jar the locks loose.

You will find that if you whack it hard enough the locks will fly out.

Not necessarily a bad thing, just be sure the socket rests squarely on the retainer and that you don't let the locks fly away and get lost. But it's probably better to not hit it quite so hard so the locks are freed but not popped out.

I like using a deep well socket because it is easier to hold on to and my plug socket is knurled so it is even easier to get a grip on . If the locks did come off they would be inside the socket so then you have to be careful to not drop them down an oil drainback hole when you pick the socket off of the retainer. Yup did drop one on the first engine I did in my teens. (flathead Ford 6) Then learned to lay a rag across the drainback holes . Lesson learned. Knew there's a reason for the screen on the oil pump pickup. LOL

[Torque454]

I use the rope trick. Ive never had any luck using air. That may be due to all the old engines i work with that probably all need valve jobs, lol.

[hoops]

I ended up using air pressure (80 psi). I did one cylinder at a time and brought each one up to TDC before removing the springs. I used a socket with a couple of taps on each spring to loosen up the keepers and then compressed them with a tool I made for the valve spring removal. I also put the trans in fourth gear to prevent the air pressure from blowing the piston down to BDC, which it did the one time I forgot to put the trans in fourth.

Part of the reason I'm doing this follow-up is because of the spring removal tool I made. I wish I could take credit for the idea, but I got the idea off the web. Anyhow, there is a picture below of the tool I made and a drawing below with dimensions. I used 3/16" thick metal, but I think 1/8" might work, which would be better because it would allow you to get a washer on between the nut (just a regular nut) and the tool. I didn't use a washer and a couple of small sliver sized pieces of metal came off.

The way the tool works is that you put the u-shaped end over the spring and the hole in the center goes onto the rocker arm stud. Then, at the opposite end you use a deep well socket to get the tool aligned correct. I have push rod guides so I ended up using a 5/8" socket. Once everything is aligned you just screw down the nut until the spring is low enough so that the keepers can be removed. When you put the springs back on you'll need to pry the spring a bit to get things lined up.

The tool worked great and it only took about 30 minutes to make it.