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post #16 of 35 (permalink) Old 02-18-2015, 03:54 PM
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My point is bad running can be many other things than low compression. Fuel, spark, etc.

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post #17 of 35 (permalink) Old 02-18-2015, 04:23 PM
Del
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Absolutely. Can be fouled plugs, bad rotor (burned) or cap (cracked or dirty inside). Those are the first things I look at.

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post #18 of 35 (permalink) Old 02-18-2015, 04:31 PM
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Quote:
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Don't forget to dribble a little oil into each cylinder when doing the compression check. If you don't do this, you can end up with low readings.
Whoa, whoa - You're right, dribbling in a little oil will raise the readings if worn rings are the culprit. So yes, that's a diagnostic: if compression is low without oil, comes up with oil, blame the rings.

However, that doesn't mean:

1) you should always dribble in some oil before measuring compression.

2) if the readings are high with oil, then everything is fine.

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post #19 of 35 (permalink) Old 02-18-2015, 07:41 PM
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I neglected to say anything about what it means if the readings do come up. I didn't say that the rings would be fine if they did come up as you imply I did in your second point. I think you misunderstood my comment, and just assumed that.

When I said, "If you don't do this, you can end up with low readings", I meant that it may be the case if the rings are worn, and it will result in those low readings.

It has been standard practice to use a little oil in the cylinder to see if that does happen. It is a check to see if the readings do come up, meaning that perhaps the compression rings are faulty; or if the values don't come up, valves are most likely dodgy.

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1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27

previously owned since 1964:

62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6

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post #20 of 35 (permalink) Old 02-20-2015, 06:09 AM
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As others have stated the running terrible is not caused by low compression in your case. 110 is not that low and they are even, so solve the other problems first. There are several tech articles about extreme wear in piston engines and the conclusion is that they can be run until the compression is so low they will no longer idle. I've seen engines run with numbers as low as 60 and once warmed up they run fine, of course they don't make the power they should.
If this was my engine I'd leave well enough alone and find the real culprit to poor running then only if I needed more power would I open the engine up.

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post #21 of 35 (permalink) Old 02-20-2015, 01:24 PM Thread Starter
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dang

i am bummed about this. i bought a new compression test kit. and the compression seems okay now.

i really just wanted to know why the car runs so bad, bad rings would of at least given me something instead of just throwing money at this stupid car.

first pic is cold the second is hot.

so....
rebuilt the carbs,

new distributor and coil

good compression

should i still check the cam timing?

this thing is too much
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post #22 of 35 (permalink) Old 02-20-2015, 01:43 PM
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Rebuilt carbs? I'm going guess the carbs are out of sync
New distributor, are you sure the timming is right?
It sounds like you have what you need, putting in new rings would be throwing money away.
Here is a good article on setting the carbs, Daves home page

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post #23 of 35 (permalink) Old 02-20-2015, 02:09 PM
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Which carbs are you using - the full model number?

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post #24 of 35 (permalink) Old 02-20-2015, 02:17 PM
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Maybe your cams are flat......

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post #25 of 35 (permalink) Old 02-20-2015, 04:09 PM
It would probably be useful to define what the motor is doing:
Hard starting?
Rough idle? Rough running at certain speeds? At All speeds?
Lacking power at certain points?
Backfire out exhaust?
Backfire out of intake?
Is it worse cold, hot or all the time?
Blue smoke?, white smoke? Black smoke? No smoke?
Water in oil? Oil in radiator? Oil leaks around the head?

I'm sure there are plenty of other maladies, these are just off the top of my head.

If you can make a youtube video and post it, it may help in the diagnosis.

Sounds like you just need some tweaking and not a lot of money. I know this is not a SPICA motor but I find it interesting when you are dialing in the FI pump that as you go the motor runs crappier and crappier until the final twist of the screw driver and then every thing falls in place and it runs fine. Unnerving in the process though...

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post #26 of 35 (permalink) Old 02-21-2015, 12:38 AM Thread Starter
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Quote:
Originally Posted by NMMilano View Post
Rebuilt carbs? I'm going guess the carbs are out of sync
New distributor, are you sure the timming is right?
It sounds like you have what you need, putting in new rings would be throwing money away.
Here is a good article on setting the carbs, Daves home page
carbs may indeed be out of sync. i need a sync tool and that link will be of great use, thanks

i believe the timing is right

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Originally Posted by alfaparticle View Post
Which carbs are you using - the full model number?
full number? i don't remember dcoe 40s xxxx....

Quote:
Originally Posted by 101/105guy View Post
Maybe your cams are flat......

interesting thought, i'll post some pics


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Originally Posted by gprocket View Post
It would probably be useful to define what the motor is doing:
Hard starting?
Rough idle? Rough running at certain speeds? At All speeds?
Lacking power at certain points?
Backfire out exhaust?
Backfire out of intake?
Is it worse cold, hot or all the time?
Blue smoke?, white smoke? Black smoke? No smoke?
Water in oil? Oil in radiator? Oil leaks around the head?

I'm sure there are plenty of other maladies, these are just off the top of my head.

If you can make a youtube video and post it, it may help in the diagnosis.

Sounds like you just need some tweaking and not a lot of money. I know this is not a SPICA motor but I find it interesting when you are dialing in the FI pump that as you go the motor runs crappier and crappier until the final twist of the screw driver and then every thing falls in place and it runs fine. Unnerving in the process though...
yes i should of said all this first, sorry

hard to start cold, rough idle, uneven idle, will go up then die down.

lacking power when you accelerate, also a large bog if you floor the gas pedal.

backfire out of intake, and i retarded the timing from the mark and it runs a little better.

no smoke, no leaks. here is a video of it running


thanks for the help everyone, and the shoulder to cry on
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post #27 of 35 (permalink) Old 02-21-2015, 12:15 PM
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I am joking about the cams, althou some here think all Alfa cams are worn.
This method of trouble-shooting is the least likely to get results as there are so many opinions to check.
On owner went on for a long while checking and replacing parts until he found that the exhaust pipe had been filled with acorns by an industrious squirel.
Do a proper trouble shooting method. System by system as a pro would do.

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post #28 of 35 (permalink) Old 02-23-2015, 02:43 PM Thread Starter
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okay, checked the cam timing marks. i am assuming these are them and they are on at TDC.

i ordered a carb sync tool, so the carbs may still be out of tune here but here are some videos of the car running, the idle gets really fast after the car has warmed up, but like i said, we will see after i re-sync the carbs



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post #29 of 35 (permalink) Old 02-23-2015, 03:34 PM
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Have you checked for air leaks in the rubber carbie mounts?
This will definitely make the car run like a dog when everything else appears ok.

Wazza.

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post #30 of 35 (permalink) Old 02-23-2015, 09:56 PM Thread Starter
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Quote:
Originally Posted by GTVMk1 View Post
Have you checked for air leaks in the rubber carbie mounts?
This will definitely make the car run like a dog when everything else appears ok.

Wazza.
i did a visual check before reinstalling the carbs. they seemed good, but i did not take them off the car to inspect. is there a way to test them? how do they come off?
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