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Burnt Exhaust Valve(s); Rings bad as well?
Topic Started: Apr 22 2011, 10:23 AM (6,901 Views)
rmorman
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Hello all!
I've been surfing the forum and thanks to the "how To" section I was able to diagnose that I have likely 2 bad exhaust valves (and maybe rings). I have attached pictures of the results from my compression test. This is on a 1995 Metro.

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Here is a photo of the 3 plugs (300 miles on spark plugs). #1 looks bad!
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Cyl 1 Dry 34psi
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Cyl 1 Wet 37psi
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Cyl 2 Dry 173psi
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Cyl 2 Wet 194psi
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Cyl 3 Dry 91psi
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Cyl 3 Wet 91psi
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On a side note, I used a tool for measuring 2 stroke oil for getting a teaspoon of oil in the cyl

OK, I believe I have a valve job in my future. Do I also have a ring job? 2 of the cylinders change only marginally or not at all from the dry to wet test. Isn't that a sign of bad rings???

This car is my daily driver. I'd like to do as much of the repair work as I can. I'd also like to get it done quickly as my backup vehicle gets 14mpg and I drive 70miles a day. Even in this poor of shape, the metro still gets better mpg than the truck.
1) How many parts can I "pre-order" before I open it up to save down time?
2) What are the chances that valves, guides and seals will be ALL that the heads need???
3) How will I know if I need "oversized" valves?
4) How will I know for sure if I need rings?
5) Can I pre-order rings or will I need to see if I need to punch out the cylinders?
6) Looking through this forum, I've seen a few links for ordering parts online. For what I need, what would be the best "one stop shoppping?"

I believe I've also seen I should invest in stainless valves. What else should I be concerned with?

Thanks for all your help!
Russ
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mcmancuso
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Bad rings is usually indicated by a BIG change between dry and wet, as the oil seals the rings and increases wet compression. Low compression in both dry and wet is indicative of a bad valve.

If you do the head and not the rings, you're going to be doing another head job in a year or two, the rings are usually gone or close if its burnt an exhaust valve badly. Typically the head is fine, just drop/lap new valves and seals in, clean the lifters really well and head is done. Also install a new cam seal(comes in kit) and distributor O ring (rubber washer 15/16" ID, 1/8" thick)

You won't need oversize valves, those are really just performance mods.

Usually all that's needed is a good hone on the cylinders, they don't wear badly on these cars. Personally, I'd recommend this:
http://cgi.ebay.com/ebaymotors/6-93-95-Geo-Metro-1-0L-3CYL-New-Engine-Rebuild-Kit-G10-_W0QQcmdZViewItemQQhashZitem3a54b42e56QQitemZ250529197654QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
$233 full rebuild kit, additionally pick up a felpro head gasket, the kit comes with one, but it has the small oil holes, the felpro is usually made right. Pick up some valves, the SS ones from 3tech are the best, but you can pick up some normal ones on ebay for ~$5 ea.

Grab a felpro head gasket at advance auto using this coupon, link: $35 off $85
And also pick up some plugs/wires/dist cap/rotor whatever else you'll need for the rebuild to get to $85 :D

I'd also recommend copper gasket spray (pick it up at advance auto) and put it on both sides of all gaskets including the head gasket, never had a gasket that was sprayed leak on me :D You'll also need some RTV either red or ultra black for the oil pan, and on the outside mating surface of the cam/crank seals.
Edited by mcmancuso, Apr 22 2011, 10:49 AM.
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rmorman
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mcmancuso,
Thanks for the help. I'll do a complete rebuild I think.

After thinking about it all day yesterday, I wonder if it might actually be quicker to find a boneyard 1995 1L and rebuild it while I limp the current motor on the back roads? As it still get better MPG than the truck. Downside is the $$$ buying a 2nd motor. My big concern was if I could order the rebuild kit ahead of time for when I start the project. If I read correctly, the answer is, Yes I can. Then I might be able to rebuild my motor on a long weekend.

From start to finish, how long would it take to do a complete for the first time? I can take the engine out of my Monte Carlo in 2 hrs with my eyes closed, but never done one of these!

If I read the enhine removal "how to" right, you should pull motor and tranny at same time as it is easier??

Either way, I've seen there are pleanty of "How To" pages here.

Any other "tips" for a 1st timer????

Thanks a lot!
Russ
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GeoStalker
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"Chicks dig me and guys think I'm cool."

The only time I'd recommend taking the engine/tranny out for a rebuild is if you have to weld the frame horns in addition to the rebuild, and you need easier assess. You can do the top end and bottom end rebuild with the engine remaining in the car.
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rmorman
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90metro,
Frame wise, everything is solid. Glad to hear I can leave the motor in the car to do the rebuild. I'm gonna order everything Monday. Thanks a bunch!
Russ
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rmorman
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OK,
I'm sitting in front of the laptop ordering parts this morning. Normally, would I need to replace the valve guides? I see them for sale on 3tech's web site. I don't think they come in the rebuild kit from e-bay. I don't mind spending the money, but only if you would generally need them.

Russ
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mcmancuso
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In my experience I have not needed to replace the guides, the seals yes, but not guides. I think most people do not replace them, unless a valve is wobbly in its guide.
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rmorman
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Got my rebuild kit ordered on e-bay. Getting the stainless exhaust valves from 3tech later today/tomorrow.

Another question (s).... I drive 70 miles/day at 60-70mph. While I got it apart, I thought about going with the economy cam and +6 gear. With my highway driving should I just stick with the stock cam and gear?

Seems like 95% of the folks here LOVE 3tech's stuff, and I have spent the last 2 hrs reading posts on the economy cam and sproket. The question is if it is worth it considering my highway driving?

Russ
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bogs
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Duct tape heals all wounds

Actually, 3tech himself would be probably best able to answer that one. Pm him the question, in case he misses it here.
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Coche Blanco
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I'd go stock cam if most your driving was at that speed. Economy cam doesn't help all that much for highway driving.
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rmorman
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Rebuild kit will be here on Friday. Going to try to do the rebuild over the weekend of May 6th. I have had a heck of a time contacting 3tech for the valves. If I can't get ahold of him (he must be really busy this time of year) is there another reputable company I can get the stainless valves for a fair price from?

With shipping (isn't he from ONT) time, I'm getting close to a deadline to have them here on time.

Thanks!
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rmorman
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Funny thing.... I no more than sent the last post and 3tech got back to me.... Nevermind! :D
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rmorman
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bogs
Apr 25 2011, 11:28 AM
Actually, 3tech himself would be probably best able to answer that one. Pm him the question, in case he misses it here.
Bogs,
Here is what I heard from 3tech when I asked him what combo of cam and timing gear to go with:
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Probably the +6 on your stock cam would work best.
Once you rebuild the head, and start removing material to reface, you lose some timing, then make it up with a sprockt. On a stock motor, the +6 would be my choice

Anybody used a +6 timing gear with a stock cam? SHOULDN'T lower the power band too low for my highway driving.
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Coche Blanco
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Your power band is up near 5,500 rpms or something. It won't lower it too much.
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mcmancuso
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you can get SS valves from partsdinosaur.com I believe.
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