When you put the piston @ TDC and fill the cylinder with pressure does it move? Also, how can you slide the cylinder up and down during the compression stroke while keeping the crank stationary?


thanks

 

#1=NO
#2 =You can't

 

Now that I took another look at the second question, I relize it doesn't make sense.
What I meant to ask was, how can you check the leakage when the piston is at different positions during the compression stroke for example, when the piston is half way down the cylinder.

In other words, if the piston is in any position other than TDC, will it move once the cylinder is pressurized?

thanks


[Modified by Mac8008, 4:48 PM 1/16/2003]

 

If you can move it easily when pressurized, then you probably have a leak. You are only checking it at TDC, in other positions the valves will open and the test will be useless.

 

Why can't you turn the crank forward so the piston moves down on the power stroke. Valves stay closed. Just hold the crankshaft to keep it from turning...

 

The purpose of checking for leakage when the piston is in different position through out the stroke is to check the condition of the cylinder walls.

Just as someone else said, the piston can be at any point in the cylinder during the power and compression stroke and the valves will still be closed.

 

I didn't think about doing it during the power stroke. That's good, thanks. But still, wouldn't any movement show a sudden loss of pressure and then recover. Is it possible to hold it that still with a 100psi in the cylinder?

thanks again.

 

Usually when I do a leakdown test, if the motor is not dead nuts on TDC, the pressure tends to make the motor spin.

 

Here is the standard way of doing this, me and all of the mechanics at the shop I worked at followed this procedure, as this is the same instructions as the SNap On tester I used.

If the piston is not exactly at top dead center,
the air pressure will rotate the crankshaft.
than about 5-8% leakage. When an engines' cylinders

http://www.goodson.com/instr/LDT-50.pdf

 

With 86mm bore & 97mm stroke & 100psi that's about 143lbf-ft of torque. Much less if its not exactly 90deg from TDC. You'll have to hold the flywheel with something. Like a big ***'in screwdriver in the ring gear teeth or something. Not impossible, but you sure don't want to try to hold it by putting your fingers in next to the starter...

How do you hold the crank when you're tightening the front pulley?? Got one of those tools for the inside hex?

 

No actually, I use a chain wrench. Do you thing that will work?

thanks for all the info guys! Very helpful.

 

I don't know if it would slip. Personally I'd take off the starter & find something to wedge against the ring gear & bellhousing. Maybe hold it in place with the starter mounting bolts? That way you don't have to worry about the chain slipping. (Don't pick something thats small enough to fall down inside.)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Desslok &raquo;</TD></TR><TR><TD CLASS="quote">

http://www.goodson.com/instr/LDT-50.pdf </TD></TR></TABLE>

Bump to this!

Will be printing this out tomorrow at work

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Desslok &raquo;</TD></TR><TR><TD CLASS="quote">
http://www.goodson.com/instr/LDT-50.pdf </TD></TR></TABLE>


Bump for very thorough directions and good imput on what to look for

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Desslok &raquo;</TD></TR><TR><TD CLASS="quote">
http://www.goodson.com/instr/LDT-50.pdf </TD></TR></TABLE>

im bumping this also, SUPER good info

 

I'm still actually searching out this information. Can anyone repost it, I need to find out what all is involved so I can do a leakdown test.

Nevermind, I was able to search out all the information I needed for this.

https://honda-tech.com/zerothread?id=793413

https://honda-tech.com/zerothread?id=56727

https://honda-tech.com/zerothread?id=399709

https://honda-tech.com/zerothread?id=833920

For others.


Modified by INVALID at 7:23 AM 4/26/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nerologic &raquo;</TD></TR><TR><TD CLASS="quote">im bumping this also, SUPER good info </TD></TR></TABLE>

REPOSTING THE LINK. That link is dead. As a couresty to everyone, I have located the new link for the same info.

http://www.goodson.com/technic...0.pdf