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2.0 Rebuild

I'm planning to rebuild the top end of my stock 2.0. The engine only has 64,000 miles on it, but it sat in a garage for 17+ years. 2 cylinders have only 110 lbs of compression, the other 2 have 120. In addition, my oil is dark shortly after changing it. My guess is that the cylinder walls got rusty/pitted over time.

If I do the rebuild, should I use 94, or 96mm cylinders? Stock or euro, etc.? I've never torn an engine down or anything. Am I correct in assuming I should have 150lbs on all cylinders? I would like to continue to use the orig Djet setup, so I realize that limits my options. Also my checklist includes: cylinder/piston kit, gasket kit, heads to machine shop for inspection. What am I missing? I couldn't find a tech article on this. Thanks in advance.

Brian
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Old 03-14-2005, 02:50 PM
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If you check the manuals, down to 110 PSI is allowed.

You can do a top end rebuild by having the heads redone, having the cylinders honed to clean them up, and re-ringing the pistons. Or you can have your current cylinders torque-plate honed out to 96mm (supposed to be better quality and more stable than the current batch of iron 96es) and get 96mm pistons to use with them. Re-doing the heads is probably mandatory regardless...

Note that it is possible that this will place extra stress on the bottom end of the motor; sometimes that causes a bottom-end failure shortly after the top-end rebuild.

If you don't want to modify your D-jet at all, then go with European-spec 94mm (stock 2.0) pistons and cylinders. Going up to 96mm will likely require some tinkering. Do not get a more aggressive cam grind--even the "FI compatible" ones generally requires a fair amount of tweaking, some knowledge of the way the MPS works, and some dyno time to get right.

If you're comfortable doing the tweaking, then the Web #73 grind should work well.

You can probably run up to about 8.5:1 compression on CA's "super"-grade fuel with the stock cam. That's a bit beyond the Euro-spec setup, but easy to get to by flycutting the heads slightly. (But measure all the pertinent volumes, because they may have already been cut or the manufacturing tolerances may have stacked up in one direction!) Small changes in the geometry can cause good-sized swings in compression ratio.

Any time you split the crankcase, you should get a new cam. There seem to be issues with some lifters and some cams nowadays; I can't tell you how to tell ahead of time if your lifters will definitely eat your cam or definitely not. There are $$$$ ceramic lifters and $$ coatings, but they may be a bit hard to come by and are expensive regardless.

Don't forget to get your crank inspected, cleaned, and micro-polished. And get your rods checked and very possibly re-sized.

Umm, can't think of more off the top of my head.

--DD
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Old 03-14-2005, 04:10 PM
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Won't you even try starting the engine first before considering a rebuild, and all the $$$ that will entail? I mean, it's only got 64K on it; the engine might not be as bad as you think. Mind you, this is assuming that it's still in the car (you didn't indicate otherwise).

Me? I would:
  • Do an oil change
  • Get a fresh battery on-board
  • Flush out the fuel lines & install new fuel filter
  • Have some new spark plugs in-hand
  • New air filter
  • Purge & bleed the brakes
After doing all the above (and whatever else others might suggest), remove the old plugs and crank the starter to get the oil circulating & pressure to build up in the block. By then the fuel pump should have pressurized the FI system.

Now comes the Act of Faith: install the plugs (please, DON'T cross-thread them, or you'll be in a world-o-hurt) and wires, whisper a short, reverant prayer, and give her a crank. I've seen garage queens that have sat longer bark, pop, and shake themselves to life, none the worst for wear.

Again, only if it were me ...


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Old 03-14-2005, 04:27 PM
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Quote:
Or you can have your current cylinders torque-plate honed out to 96mm (supposed to be better quality and more stable than the current batch of iron 96es)
Thanks Dave.

Is this something most good machine shops can accomplish?

BTW, have you actually experienced the bottom end failure you describe?
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Old 03-14-2005, 05:37 PM
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I'm with rouser. I got mine for $600 no title, rats nest in the engine compartment, had to pour gas down the intake to get it to turn over. $30 in fluids, filter, and plugs later and I drove it for the summer. Its compression was 95, 95, 93, 105. I'm rebuilding it now, but wanted to make sure it was a fun car first!!

Good luck either way
Old 03-14-2005, 08:35 PM
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Quote:
Originally posted by bpgreer
Is [torque-plate honing of cylinders] something most good machine shops can accomplish?

BTW, have you actually experienced the bottom end failure you describe?
Any machine shop can bore your cylinders. Good ones have a special jig (I have heard it called a "torque plate") that they set the cylinders up in. Rimco can do the job for you, but their prices have gone up in the past year. Call them first. There are other machine shops that have the facility as well, but I don't remember any other names off the top of my head.

The only bottom-end failure I have personally experienced is excessive end-float, requiring align-bore to fix. I have heard reports of what I described above; we have pics of a massive catastrophic bottom-end failure in the Tech Articles section (look for "Rendezvous with a dropped valve seat"). I don't know what your odds are of having the bottom end fail on you if you just freshen up the top end; probably rather low with the relatively-low mileage on the bottom end of your motor. The odds of a massive catastrophic failure (see the pics) are even lower.

--DD
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Old 03-15-2005, 08:28 AM
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Cool. Thanks again Dave. Right now the 96mm option seems to be the most appealing. I will probably have my orig cylinders honed out as you suggest. Do you know of a good source for the 96mm pistons? It doesn't look like pp carries them, and some other sites only sell as set. Thanks.

Brian
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Old 03-15-2005, 04:32 PM
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Make sure you have done the compression test correctly. First time I did one I didn't block open the intake all the way and the readings were about 120-125. Reran the test and saw 135 (+ or - maybe 3) psi all around, which is considered plenty good, I think. I've never heard of a 914 with 150 psi.
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Old 03-15-2005, 07:07 PM
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Thanks Scott. I'm actually planning on testing it all again before I pull it. My added concern comes from the dark brown my oil turns shortly after a change. Since it doesn't sound like I'm doing any kind of irreversible damage to my motor, I will likely run it for a while as is while deciding where to go from here. BTW, 150 is what someone stated as the proper psi, but that could be off a bit. 135 all around would make me very happy. If the engine hadn't sat idle for so many years, I don't think I would be having this problem. Of course the sitting around did do wonders for my interior

Brian
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Old 03-15-2005, 09:42 PM
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