I have a few questions. on a 3.1 v6

Okay #1 cylnder had low compression 75 PSI. I checked the valves and they look good when I removed the head. Dont seem to be burnt nothing missing.

I purchased a set of stock rings. From reading Looks like a ball hone would be the best to hone the cylinder and then installed the new rings.

I have never hones a cylinder before. Can you take me through the steps.


How do you measure the ring gap on the cylinder.

Is there anything else I need to do on this evelution.

 

I'm assuming you've pulled the engine from the bay and it's up on a stand now eh?

First off, 75psi doesn't sound like rings, they don't just "go". I'd be looking for another possibility. Head gasket or... Well, valves..

But anyway, this is how i'd re-ring it:

You'll need to remove the pistons (remember which is which!) and remove the crank and set them aside.

A ball hone is very expensive, I just used the other style, it has 3 square-ish stones on it and it's spring loaded. Will work in any 2-6" cylinder, so i'm pretty much covered.

Buy a piston ring expander and compressor for your size engine. I used the compressor that's a one size fits all collar, it's a pain to use, but it works. If you can't find a tapered ring compressor for your engine then go for this.

I prefer a cordless drill, they have better speed control than my cheap $25 electric one. Your call. I used a few liters of diesel fuel as lube, ATF is apparently a bit better.
I did this solo, but it's easier if you get a helper. Get them to pour the lube down the cylinder SLOWLY, while you hone it. Spin the tool slowly, and move while it's honing. Remember you're trying to get a 45* angle crosshatch for best ring seating.

Buy new iron rings, NOT moly faced. The moly ones seat well to a bored and honed engine, but if your bores aren't perfectly cylindrical apparently plain-jane iron ones seal better. Besides, they're cheaper, and this is just a V6.

Then wash the cylinder well, use dishsoap and water, and a scrub brush. Clean it and dry it. When you spray it with WD-40 and wipe it with a paper towel the towel should come out clean (well, covered in WD-40, but no grey dust)

 

Engine is out

Prior to pulling the engine I squirted spray can lub down the cyl and the compression did not go up. But it was not regular engine oil. That why I am thinking to replaced the rings on number 1.

I pulled the head and there was no apparant damaged to the valves. Told it was possible a burnt valve. But nothing look wrong. I have agood set of heads from another motor.

I applied compressed air to the cyl at TDC. I got air out the intake and a small amount out the oil filler opening.
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Also a friedn suggested of honing the cyl up side down

 

This screams intake valve. It's still really strange that only one cylinder would have it's rings fail.

Hone it upside down?!? That's a new one on me... I can't see it making any difference though.

 

SO if it was you what would you do??

 

Take the heads to a shop and have them go through them - "valve job", it's typically called.

Rent a ball hone if you don't have one. Just run it up and down quickly a couple of times in each cylinder, with the cylinder walls oiled before you start. You aren't trying to remove material, you just want to "break the glaze". The result should be a "cross hatch" pattern with about 20-25 degree angles in the lines (one set of lines produced when the hone goes down the cylinder, the other as it comes back up - http://www.energetics.com/recips06/P...s/Bolander.pdf , page 13 & 23). This helps the rings "break in" more easily when you start it up again, and also retains a very thin film of oil on the cylinder to help the rings seal and not wear when running. You need a pretty good drill motor to run the ball hone, the typical homeowner 1/4" drill (especially a cordless drill) isn't going to cut it.

You don't have to hone it upside down, but you do need to thoroughly wash it after you're done.

 

Yea, i'd bring the heads to a machine shop and tell them you had only 75psi of cranking pressure on cylinder 1, and a leakdown showed some leakage up through the intake.
Tell them to do a valve job, but also make sure you let them know you want their opinion if the intake valve seat was bad enough to give you that kind of reading. If they do the valve job and tell you "they were all a little rough, no one worse than the other", or something along those lines, then go ahead and hone the cylinders. If they tell you that #1's seats were bad and would have leaked - then skip the hone job - IMHO.

Is there a lot of difference in the final outcome when using a ball hone vs a stone type hone Five7?
I'm not sure who would rent out a ball hone, at least in my neck of the woods...

 

More likely that it was past TDC during or after the overlap period.

 

okay the head is going to the shop tomorrow. I am going to see if they would check it. With out a valve job. I have two good heads that I could put on.

 

Could also be a cracked head. I like the slightly open valve theory, too.

The ball hones are quick and clean. You don't have to worry about going in or out too far while they are running.

 

machine shop said that in their opinion its not the rings the valves were not sealing. So I am going to start assemble the engine put the engine back today. And swap the motors this weekend