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cylinder honing still showing; still see cross hatch marks after 30,000 miles
Topic Started: Jan 22 2012, 08:08 PM (2,964 Views)
geosedan
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I rebuilt my 1996 1.3L engine about 30,000 miles ago. I reused the pistons and put on a set of standard rings from ebay because the cylinders were still good enough and yea I used a cheap head gasket from ebay. Well I am getting bubbles in the coolant so I figured the head gasked is leaking. I pulled the head and I still can see the cross hatch marks on the cylinder walls. It's not just a few marks that haven't been polished out yet, the entire cylinder walls are still cross hatched. The cylinder walls are not as rough as when I honed them but there are no polished spots where there are no cross-hatch marks. I can feel the marks with my fingernail. It still burns about a quart of oil every 2000 miles or so. I didn't take a compression reading, I guess I should have. So much for using ebay parts I guess. So now I'm putting on a fel-pro head gasket. I was wondering since I have the head off if I should just pull the pan and put another set of rings on the pistons and let the new rings finish polishing out the cylinder walls without honing any more. Anybody have any opinion about if I should do this? If I do this does anybody have a favorite brand of rings? Thanks
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jeremy_nash


If you are going to pull the pistons to re ring it, there is no reason not to hone it. cover your crank with towels and tape, then have at it. Oreilly auto parts has bar style hones on the loan a tool program.
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clarkdw


Before you pull the pistons and rering it. Check the cylinder bores for size. Measure for taper and out of round. If it is out then there is no sense putting another set of rings in a bad hole. Still seeing the cross hatch is not a bad thing. It just means that there is still some opportunity for the rings to seal up. What oil and or additives did you put in at break-in time?

What kind of compression numbers do you have? Edit: I see you didn't do a check.

If it was mine, I think I would put a new head gasket on and try it. The oil burning will do one of three things.
1) It will get better and/or you will find that it is a small leak somewhere else and problem is gone.
2) It will stay the same and you will have to add a quart every 2k miles.
3) It will get significantly worse and you will have to do something about it.

I know where my money would go. :beer
Edited by clarkdw, Jan 22 2012, 08:35 PM.
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dayle1960
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Fastest Hampster EVER

Oversized cylinder wall bore from PO and standard sized rings from your rebuild ?

If it were me, I wouldn't get too excited about the cross hatching. I would start thinking about miking the cylinder bores.
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rmcelwee
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I would have done the same thing as you (did a half way engine rebuild to save money) but if you are having to go in again it is time to think about spending some money to get it done the correct way (rebore, oversized pistons/rings).
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geosedan
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I coated the cylinders with break in lube when I rebuilt it. I just used regular oil in it not synthetic. I guess I will just put the head gasket on and see if the rings continue to seat. When I rebuilt it there was enough left of the cylinders to put in standard rings but if I have to hone it again there may not be enough left. I wish I had taken a compression check before I took it apart I'll just chalk that up to a lesson learned for next time. If it continues to burn less and less oil as it has been then eventually I'll figure the rings have seated and I'll switch to synthetic oil.
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gerrygrit
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If you were getting bubbles in your coolant then you may not
have gotten a "TRUE" reading on whichever cylinder was leaking even
if you had done the compression test.....
May have shown that it was worse that it really is.......

Just saying.......... :hmm
Edited by gerrygrit, Jan 23 2012, 09:46 PM.
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geosedan
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I put in the head gasket and everything has been fine for about 5 months now. When I tightened the cylinder head in 20 foot pound increments something went "snap", it sounded like something cracked to me but after 4 months now everything seems fine. Thad cracking sound sure made me sweat at the time though!
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Coche Blanco
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Troll Certified

Did you lube the headbolts before you installed them?
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geosedan
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Yea I lubed the headbolts and the head is hoding for about 4 months now.
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Shinrin
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The problem with reusing headbolts isn't them not holding, it's them breaking off when you go to remove them. That said, they do kind of pop or click when you torque them down.
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dwilly99
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is it stilll burning 1qt every 2k
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davegran
Old Fart w/Wrenches

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What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ... How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ?? Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??
From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into the cylinder surface, to seal the combustion pressure as well as possible.

The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !! If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again

On the Dyno:
Warm the engine up completely !!
Do Three 1/2 Throttle runs from
40% - 60% of your engine's max rpm

Do Three 3/4 Throttle runs from
40% - 80% of your engine's max rpm

Do Three Full Throttle runs from
30% - 100% of your engine's max rpm
Go For It !!

On the Street:
Warm the engine up completely:
Because of the wind resistance, you don't need to use higher gears like you would on a dyno machine. The main thing is to load the engine by opening the throttle hard in 2nd, 3rd and 4th gear.

The best method is to alternate between short bursts of hard acceleration and deceleration. You don't have to go over 65 mph / 104 kph to properly load the rings. Also, make sure that you're not being followed by another car when you decelerate, most drivers won't expect that you'll suddenly slow down, and we don't want anyone to get hit from behind !!

The biggest problem with breaking your engine in on the street (besides police) is if you drive the car on the freeway (too little throttle = not enough pressure on the rings) or if you get stuck in slow city traffic. For the first 200 miles or so, get out into the country where you can vary the speed more and run it through the gears !

Be Safe On The Street !
Watch your speed ! When you're not used to the handling of a new vehicle, you should accelerate only on the straightaways, then slow down extra early for the turns. Remember that both hard acceleration and hard engine braking (deceleration) are equally important during the break in process.

Whaddaya think? :hmm
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JoeBob
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Why you Mutt!

If everything else was working OK, just put on a new head gasket. Make sure the head is not warped, and valves look OK.

2000 miles/quart of oil? The owner's manual for my '65 Mercury Comet said 1000 miles to a quart of oil was within acceptable limits. I wouldn't worry about 2000 miles/quart. It's a heck of a lot better than the 30 miles/quart my first Corvair got...
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