Engine: B18C1
Cams: BC3+
Valvetrain: Rocket SL springs+retainers

I'm about to install new valve springs/retainers without removing the head. I don't have an air compressor or spark plug adapter. I've heard of the rope trick where you put a few feet inside the spark plug hole and then jam the piston up against it. I'd like to avoid this route if possible.

I have an alternative idea to pressurize the cylinder without the use of an air compressor. It involves using a compression tester.

1. Remove spark plug and cams

2. Insert compression tester into spark plug hole

3. Crank engine over with key until gauge reads over 100 psi

4. Install valvetrain

5. Use release valve on compression tester

6. Repeat on remaining cylinders

Anyone tried this or heard of anyone trying this before? Basically it's the same as doing a compression test except the valves stay closed.

Also, the pressure reading on the gauge will be the peak pressure reading and not necessarily the actual pressure inside the cylinder if the piston is not at TDC. If I can somehow ensure the piston is at TDC when I begin working, I might be alright. I might also consider making sure the piston is at BDC before I begin cranking over the engine.

Another problem is that if i have any leakdown, I'll slowly be losing pressure as I install the springs. That might easily be fixed by simply cranking over the engine again, but I just don't know how the engine will react if the valves stay closed the whole time.

I really wish I had a beater to try this on, but for some crazy reason I think this will work. I'll be attempting it on Friday, but if anyone has any suggestions or any other potential problems that I missed, please let me know before it's too late!

Thanks in advance

 

that 100 psi on the gauge doesn't not read amount the pressure inside the combustion chamber, it reads pressure inside the gauge behind the check valve produced by the cylinder. You do that an there goes a valve.

 

Thx for the quick reply.

I won't be changing out the valve seals as they are still relatively new, <10k miles. The valve seals should prevent the valve from dropping into the cylinder if there's not enough pressure inside the cylinder, right? At least that's what I remember last time I installed the valve seals, they held the valve in place when the springs were out.

Worse comes to worst, I could always just leave the spark plug in there, move piston to BDC, and then crank engine over and not worry about using the compression tester.. I still won't know the pressure inside the cylinder but as long as it's near TDC I think I can be confident it's over 100 psi.

 

lol oh man that bitch would fall into the cylinder like the coyote falling off the cliff in a roadrunner cartoon. lolol

borrow an air cmopressor or just do this:

call machine shop. say "can you resurface my head on saturday morning?"

friday night, just after you buy a new headgasket, park your car.

pull the head off. clean it up a little. sat morning, bum a ride to the machine shop. have them resurface it. pay the man and leave. go home.

reassemble. enjoy. that is how i would do it if i had to put cams and a VT in my only means of transpo.

 

If you don't have a compressor the rope trick works 100%. Don't worry about bending a rod or breaking a piston while your turning the motor by hand. If your not jumping on it with a 6' strong arm after it hits TDC and stops, you'll be OK. And as long as you use a soft fiber rope (nylon/cotton)......no scratches or dents.

As for your theory on using a compression tester. What happens when you see that your starting to loose pressure and your at TDC? As soon as you start to turn the crank the pressure drops and so do your valves. Unless you hold them up with clips until you build up enough pressure again.

I still say the rope trick would be 100x easier and faster if you don't have air.

 

What happens when the cylinders pressure bleeds off before your finished? Oh *****...

 

Get a rope, a nylon rope.

 

The pressure will be fully bled off within a few seconds.

 

this is the way i would do it