Wonderboy's Metro XFi Revival

[Wonderboy]

Continued from the saga of acquiring this car earlier this summer...

I've entered terra incognita and ripped apart my very first engine. It didn't take that long and was pretty easy. Here's what the aftermath looks like:

Here's the head. Actually doesn't look too bad from what I've seen.

Pistons - also not bad looking. Typical carbon buildup. No scoring on the sides. I ran my finger up the side of each cylinder before removing the pistons; there was no evident wear, no lip around the top where the head gasket rests that would indicate the need for replacement pistons / re-bore.

Tidy.


The only issue I saw was a minor leak in the 3rd cylinder exhaust gasket - it looked like some exhaust had been bleeding over a little, but not crossing into the next pipe of the manifold. It could've even been a matter of not tightening the nearby bolt tightly enough or correctly. I plan on replacing the head gasket (duh), the water pump, the intake and exhaust gaskets, the rod bearings, the main bearings, and the rings. Anyone know what thrust bearings are / if I should get them as well? While I have it open, I figure I should try to find a 1.3l swift 5th gear or at least put bigger tires on it. If Darin finds someone to do a taller 5th gear on the cheap, I'll take this opportunity to ask him nicely to get me something to put here:

I'll pay if it's not an exorbitant amount. If it is... well, you pay

Any suggestions on more stuff to replace while it's cracked open are welcome, this is not just documenting the process because this is my first engine rebuild.

[Frank Lee]

Thrust bearing is part of one of the mains.

[SVOboy]

Neat pile of junk you got going there. Keep up the good work!

[MetroMPG]

Originally Posted by Wonderboy

While I have it open, I figure I should try to find a 1.3l swift 5th gear or at least put bigger tires on it. If Darin finds someone to do a taller 5th gear on the cheap, I'll take this opportunity to ask him nicely to get me something to put here:

The gear ratios are all the same on the Metroid transmissions; only the final drives are different. So there's nothing else I'm aware of that's a simple plug 'n' play for that 5th gear location.

I'll let you know what I learn from my machinist friend about modding/adapting a new 5th set.

[Funny]

Impressive! I haven't broken down an engine before, short of one and two cylinder lawn mowers and snow blowers. I look forward to more posts! Remember to re-hone the cylinders when you replace the rings, otherwise you may not have them seat properly. Good luck!

[Wonderboy]

Update:

Dropped off the head to get reground and a valve job today. I asked if they could/would make custom gears (taller 5th gear anyone? Darin?). Unfortunately the answer was no. I asked the guy who was doing the job if I could watch what he did and show me what the job entails when he got around to doing my head. At first he looked at me kind of weird (this is usually a speed shop where they do work on stock cars and old custom hot rods and I handed him a sewing machine to work on), but I forgot to get the valve gaskets from my car and he followed me out and saw my batcar. I explained all the ecomodding stuff to him, about the FE runs, how old school gearheads, racers, and antique car people were starting to get into the efficiency stuff. He got a gleam in his eye and seemed much more willing to let me come watch him work, and told me he'd call me up if he didn't have a bunch of other work going on at the same time.

[user removed]

Have your machinist check the cylinder bores for excess taper if there is any ridge you can feel at the top of each cylinder.

If you replace the rings and the cylinder bores have too much taper the new rings will break and you will be doing the same job twice.

The old rings wear as the taper is created. The new rings will not have the wear pattern and will be jammed against the ridge just below the top of each cylinder bore.

If the machinist thinks the taper is excessive, I would highly recommend having the block bored and new pistons and rings installed.

I would not do hone a re ring jobs in my shop. Had a piston that had been in an engine that was honed and re ringed and when the rings broke, it burned a part of the side of the piston away.

If you want to be cheap then have the ridge removed (at the top of each cylinder) and check your ring end gap using the old rings and pistons. If it is within specs, you should be OK.

I just could not afford to take the chance with a customers car. If the ridge was very slight or non existent I would just leave the pistons and rings alone. If the engine was using a significant amount of oil then we bored the cylinders and used new pistons and rings that were oversized to match the new bore diameter.

regards
Mech

[chuckm]

As far as what a thrust bearing is, I can help you. Whether you should replace yours or not, I don't know. I suspect that you should.
A thrust bearing is a thin bearing surface, usually residing around a shaft and between a fixed and rotating surface. See examples in this link.
THRUST and other BEARINGS at MSCDirect.com
Some use ball or roller bearings, others are simply a piece of self-lubricating bronze.

[Wonderboy]

@chuckm: I bought all new bearings, including thrust. I still haven't looked at where they go, but I'm sure I'll be able to find it seeing as I've got the new ones to compare.

@Mech:
Thank you for this advice. I checked with my finger and there didn't seem to be any lip even detectable. You're saying I sould have the machinist have a quick look with calipers? And if my old rings seem to be in alright shape, don't put new ones in? I've never actually thought of that, how they already have their little grove in the cylinder wall that new ones would theoretically have to "dig" their own groove (so to speak - this isn't anything on a visible level we're talking about here). Would you advise keeping the old rings in if I or the machinist have no reason to believe they have any faults, or was that just a frugal suggestion and if I bought new ones (I did) should I put them in?

I really appreciate your advice.

Will

[user removed]

If you know enough of the history of the engine to know it was not using a significant amount of oil then it may be OK to use the old rings. The key is the end gap of the rings when they are installed in the engine. There are minimum and maximum dimensions.

No detectable ridge, at the top of the cylinder, is a very good sign that the ring to cylinder wall tolerances would be good.

Slip the top ring (after you carefully remove it from the piston) into the cylinder. Use the same piston (inverted) to push it down so it (the ring by itself) sits evenly in the cylinder, from the top. Take a feeler gauge and measure the gap where the ends of the ring meet. That is your end gap dimension. There should be specifications for the end gap,something like 14 thousandths (but check for the proper spec) If yours is within the allowable tolerances, especially towards the minimum, the wear is minimal.

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Most important, you must know this without a doubt

If the engine did not burn oil (if you can verify that) and if it did not run hot (also if verifiable) then you should not have a problem. An overheated engine can cause the rings to loose their spring tension and not seal properly, even if they look fine.

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The greatest amount of wear in the cylinder walls will be at 90 degrees to the piston pin location. The piston pins line up with the length of the block, so the greatest wear will be on the sides (if that makes any sense). This is because the pistons suffer the greatest side (same point where the skirts extend from the bottom of the piston) loads when the connecting rod is turning the crankshaft in response to combustion pressure.

Also you want to check the top of the block to make sure it is flat, as well as the mating face (bottom) of the cylinder head. This will ensure you do not prematurely encounter a head gasket leak after all the time and effort to put it back together.

If the head needs to be surfaced to get it flat, the amount of warp-age needs to be minimal. or you could have to surface both sides of the head and use cam tower shims to get the tolerance between the crankshaft and camshaft back to its original specs.

While you have it apart I would have the intake manifold chemically cleaned to get the goop out of the EGR passageways. It wouldn't be a bad idea to have everything cleaned professionally.

The machinist is a key component in your eventual success. He can give you invaluable advice on what to make sure you have done to get the max life out of the engine.

Show him the pistons, main bearings, etc, and get his opinion on whether yopu really need them or not. On the other hand beware of those who will sell you stuff you don't need.

Many here who are more familiar with the 1.0 engine you are working on can give you more specific advice, and there is a world of info on the net.

My best advice is to take your time and research the best info. Knowledge is your best insurance of not having to do a repeat, and when she is purring like a new motor the thrill is priceless.

Take pictures of things before you tear them apart to help you get it back together correctly since it is your first rebuild.

The thrust bearing is usually one of the main bearings. It sees pressure when you push the clutch pedal down and the throw out bearing presses on the pressure plate. That same force is trying to push the crankshaft out of the front of the engine. The thrust bearing face will always point to the flywheel end of the engine.

regards
Mech