Warm winter = New Piston Rings

S

snopax

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Dec 24, 2009
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Age
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Location
Wisconsin
Well I was going to put it off another season, but my compression is just hitting 120 so time for new rings. Since the weather is warm and no site of snow for a week or two I might as well. Can anyone point me towards a guide on how to do this. Anything specific I should know? Any common pitfalls? From what I gather, the procedure is as follows:

Remove domes
Remove cylinder jugs
Clean
Inspect jugs for damage
If Crosshatch still visible
Scuff with Red Scotchbright pad
If No Cross Hatch
Use 3 Stone hone tool and hone crosshatch

Clean bottom block mating surface and replace gasket

Remove old rings from piston
Set new rings in place and center on locating nub (any special tools needed?)

Lube Jug with engine assembly oil
Compress rings by hand and place jug over piston

Repeat x 2

Reinstall Domes and gaskets

Fill tank with 50:1 convential mix and break in (how long is break in?)
 
all sounds good,but I wouldn't pre mix the gas in the tank,you will create a lean condition.Just make sure if your removed any oil lines..to bleed it again.I just bleed my oil lines after a re-build.Start her up,pull choke wide open by hand for a couple of minutes.That will give it a boost of oil everywhere and the smoke will be nasty but at least you will know the oil is getting in there.Then break her in for a few hours and pin it...After some 400 miles already on my rebuilt 700..compression number are coming up...131/127/129
 
I recommend putting a new cross hatch in if the previous one went more than 200 miles. You can usually see the cross hatch on most newer engines even with many miles on them. However the edges that help the rings set are gone in a couple hundred miles and need to be recreated by honing.
 
I would just wash the cyl and scrub them with a scothbrite pad, they are nikasil plated cylinders. The coating isnt very thick but its extremely hard. All the plated cylinders I have seen still had crosshatching and cleaned up nicely with a scothbrite pad. Depending on the hone you use you risk the chance of catching a port and potentially ruining the cylinder. You just want to deglaze the cyl you dont want to remove any material. The nikasil is only .002-.004" thick, that doesnt leave you much room for error. If the crosshatching is worn down the cylinder may measure out of spec and need to be replated.
 
snopax said:
After break in, near 150
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No,,,not nearly that high unless someone cut a bunch off the heads. Youd need race fuel with 150lbs of compression. any 2000-02 srx in tip top shape would be right at 125-130ish on the high side.

compression readings vary ALOT with the guage used because of the differnt length hoses and thread adaptors used. All those things change the volume adding to the area(lowers reading), with a direct hole mount guage youd see 130-132 possibly and still be accurate, higher then that the engines not stock!
 
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