As the title says... Is it something I could do? tool needed etc?
Cheers
As the title says... Is it something I could do? tool needed etc?
Cheers
You need a source of compressed air, some way of connecting it to the spark plug port, and if you want to be really clever, a couple of pressure gauges and a regulator. Oh, and a warm engine...
Basically, you feed a regulated 100psi supply into a pressure gauge and on into the cylinder with the piston at top dead centre and all valves closed. The reading on the gauge is the result (it doesn't really matter what pressure you use, but 100psi makes converting the result to percent easy!). That's the proper way, but it's a lot of faffing for a figure which means very little to most people beyond the balance between cylinders.
But here's the good bit. Stuff all the gauges and regulators, just connect the air straight into the plug port and listen. You can tell where the air is leaking out by where the sound comes from. Inlet valves hiss in the plenum (pull the hose off the throttle body), exhaust valves hiss in the exhaustand rings/bores hiss in the oil filler or dipstick tube. Obviously, the rings are going to leak a bit (more than 10% is not too clever, less than 5% is good ) so it helps if you can compare engines for a bit of "instant experience".
Head gasket leaks can hiss in the oil filler, blow bubbles in the rad, or even leak out the side of the head/block join into the engine bay!
Unlike a normal compression test, things like battery and starter condition make no difference, cam timing can be anything (you don't even need a cam in the engine so you can test part-built lumps) and any other mods that would normally affect a comp test are irrelevant.
Just one tip. Make sure it IS at TDC before you apply the air, or it'll be at BDC before you know it, and any spanners you left on the crank pulley will be doing nasties...
And that's the last time I'm explaining it.
It's your job now.
with the power invested in me I hereby renounce my curse....
Now if I can just find someone to post, "inlet valves mate" for me at appropriate moments...
Originally Posted by Billy
And that's the last time I'm explaining it.
It's your job now.
Now if I can just find someone to post, "inlet valves mate" for me at appropriate moments...
LOL, dude I am so not worthy
Thanks a lot, a bit more grease monkey terminology sussed - excellent job of explaining too. This ought to be one of the useful threads
Oh btw, its probs yer inlet valves mate
It'd better bloody not be, they've only done about 2k...Oh btw, its probs yer inlet valves mate
big ends then ???
ok ok I'll hush now... although about 400 miles after I had my top end rebuilt my big ends went (grrr) - kinda funny now but wasn't at the time !
instead of using spanners etc on crank pully you can leave the car in 4the gear
and by pushing the car back and forward its much easier to find TDC
make sure the car is not started BTW
leak down test are the best way without pulling thr engine down to check the condtion inside the engine
I've just found a ready made adaptor for your air line here
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