Sad engine drama...

Sad engine drama...

Joined: September 10th, 2007, 8:05 pm

May 2nd, 2008, 5:35 pm #1

Hi all, as the heading suggests i think this is a sad one.
After a lot of speculation a few months ago i sent my engine block off to be honed out and new rings installed.This was done and i was able to rebuild. All went well, installed the carb today after posting on here about a minor worry, all set to go. Well it would not start. So I done all the checks, Starter was fine, petrol ok, ect. ect. After all this still no joy. So I done a dry compression test.
Cyl 1: 90psi Cyl 2: 100psi Cyl 3: 90psi Cyl 4: 100psi.
So I thought it might be the valves (new ones from Matt) Ground in by the same mechanic who honed the block. Well when i took the cambox lid off I found that I now have Gas/petrol in the oil.
Correct me if I`m wrong, but i believe that the gas/petrol is bypassing the piston rings. Does anyone have any other explanation to this bad experience.
Last edited by JerryLawrence on May 2nd, 2008, 5:55 pm, edited 1 time in total.
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Ed
Ed

May 2nd, 2008, 5:48 pm #2

Ohhh, have I so been here before. Now you are saying you have petrol in the oil. Petrol is gas right? That I can't help you with, but if you somehow have coolant in the oil that you see mixing in, that could be that you used the wrong gasked in the thermo housing. The water gets into the EGR port and leaks into the oil.

Ed
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Joined: September 10th, 2007, 8:05 pm

May 2nd, 2008, 5:54 pm #3

Sorry forgot its gas in the USA. I`ll edit.
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Ed
Ed

May 2nd, 2008, 6:04 pm #4

Wow, how can you see that the gas is mixing? Never seen that one. My advice does not apply.

Ed
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htf
Joined: May 5th, 2001, 4:29 pm

May 2nd, 2008, 6:22 pm #5

Hi all, as the heading suggests i think this is a sad one.
After a lot of speculation a few months ago i sent my engine block off to be honed out and new rings installed.This was done and i was able to rebuild. All went well, installed the carb today after posting on here about a minor worry, all set to go. Well it would not start. So I done all the checks, Starter was fine, petrol ok, ect. ect. After all this still no joy. So I done a dry compression test.
Cyl 1: 90psi Cyl 2: 100psi Cyl 3: 90psi Cyl 4: 100psi.
So I thought it might be the valves (new ones from Matt) Ground in by the same mechanic who honed the block. Well when i took the cambox lid off I found that I now have Gas/petrol in the oil.
Correct me if I`m wrong, but i believe that the gas/petrol is bypassing the piston rings. Does anyone have any other explanation to this bad experience.
I think compression readings are not exact before you break in the engine.
Let the rings set in and check again.
Also' low compression doesn't mean the engine wont start. It may not be a good performer, but should start.
Check spark at plugs
Check timing - an often culprit
Do you see fuel squirting down the carb when you actuate the acceleration pump?
Dump a bit of fuel down the carb, not much.
Use a strong battery, or a charger. The engine has to spin fast if compression is low.
And how can you see fuel in the oil anyhow?
Last, and most important, you must be in a positive mood every time you crank the engine.



HaXD
Herzel, in Israel

WhiteX
The late Green '85 X1/9
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Jerry
Jerry

May 2nd, 2008, 6:23 pm #6

Wow, how can you see that the gas is mixing? Never seen that one. My advice does not apply.

Ed
Damn.
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Jerry
Jerry

May 2nd, 2008, 6:27 pm #7

I think compression readings are not exact before you break in the engine.
Let the rings set in and check again.
Also' low compression doesn't mean the engine wont start. It may not be a good performer, but should start.
Check spark at plugs
Check timing - an often culprit
Do you see fuel squirting down the carb when you actuate the acceleration pump?
Dump a bit of fuel down the carb, not much.
Use a strong battery, or a charger. The engine has to spin fast if compression is low.
And how can you see fuel in the oil anyhow?
Last, and most important, you must be in a positive mood every time you crank the engine.



HaXD
Herzel, in Israel

WhiteX
The late Green '85 X1/9
I`ve tried all that you have suggested but no luck. After spending so much time and money on my X and not even driven it yet, i find it hard to stay positive. But this X will start and run even if it kills me.
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Joined: December 17th, 2007, 2:00 am

May 2nd, 2008, 6:35 pm #8

Hi all, as the heading suggests i think this is a sad one.
After a lot of speculation a few months ago i sent my engine block off to be honed out and new rings installed.This was done and i was able to rebuild. All went well, installed the carb today after posting on here about a minor worry, all set to go. Well it would not start. So I done all the checks, Starter was fine, petrol ok, ect. ect. After all this still no joy. So I done a dry compression test.
Cyl 1: 90psi Cyl 2: 100psi Cyl 3: 90psi Cyl 4: 100psi.
So I thought it might be the valves (new ones from Matt) Ground in by the same mechanic who honed the block. Well when i took the cambox lid off I found that I now have Gas/petrol in the oil.
Correct me if I`m wrong, but i believe that the gas/petrol is bypassing the piston rings. Does anyone have any other explanation to this bad experience.
Hi. It is very possible that if you have been cranking quite a bit to get it started that the gas is bypassing the rings and going into the crankcase. I would think this would be normal especially after a rebuild before the rings had a chance to seal. Once you get it running, you will want to change the oil. I have had this happen before on ATV's. If you keep trying to start it, gas is flowing at the same rate, but has no where to go, but down.

As for it not starting, are the cam and crank marks all aligned? Is the cam out possible 180 degrees (I learned that the hard way) - if it is it will backfire through the carb.

Rob
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Damonfg
Damonfg

May 2nd, 2008, 6:49 pm #9

Hi all, as the heading suggests i think this is a sad one.
After a lot of speculation a few months ago i sent my engine block off to be honed out and new rings installed.This was done and i was able to rebuild. All went well, installed the carb today after posting on here about a minor worry, all set to go. Well it would not start. So I done all the checks, Starter was fine, petrol ok, ect. ect. After all this still no joy. So I done a dry compression test.
Cyl 1: 90psi Cyl 2: 100psi Cyl 3: 90psi Cyl 4: 100psi.
So I thought it might be the valves (new ones from Matt) Ground in by the same mechanic who honed the block. Well when i took the cambox lid off I found that I now have Gas/petrol in the oil.
Correct me if I`m wrong, but i believe that the gas/petrol is bypassing the piston rings. Does anyone have any other explanation to this bad experience.
I wouldn't be worried yet. Lots of cranking and not firing can put some gas into the oil.

The GOOD news is that if you don't run it with the now-thinned oil, there's really little risk of damage. Enough cranking to mix gas into the oil would also be enough to get plenty of almost-oil throughout all of the bearings.

If you want to play it safe, drain the oil and refill with freh oil.


The compression numbers should not be alarming for a new assembly where nothing has yet bedded in. Check that the cam and crank are properly timed. If they are out by a little bit, you can get abnormally low compression readings.


Have you monkeyed with the carb since taking the engine apart? If not it should fire right up.

Does it sound like it's trying to start? If not, possibly no spark?

Did you set the rotation of the distributor relative to the crank TDC, with the rotor pointing to #4 (that's usually the reason for a no-start on a new engine)

Post some details as to what you have tried and we can have it running in short order.

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///Mike
///Mike

May 2nd, 2008, 7:05 pm #10

Hi all, as the heading suggests i think this is a sad one.
After a lot of speculation a few months ago i sent my engine block off to be honed out and new rings installed.This was done and i was able to rebuild. All went well, installed the carb today after posting on here about a minor worry, all set to go. Well it would not start. So I done all the checks, Starter was fine, petrol ok, ect. ect. After all this still no joy. So I done a dry compression test.
Cyl 1: 90psi Cyl 2: 100psi Cyl 3: 90psi Cyl 4: 100psi.
So I thought it might be the valves (new ones from Matt) Ground in by the same mechanic who honed the block. Well when i took the cambox lid off I found that I now have Gas/petrol in the oil.
Correct me if I`m wrong, but i believe that the gas/petrol is bypassing the piston rings. Does anyone have any other explanation to this bad experience.
That motor should run so go back to square one and check the basics, cam and ignition timing; valve clearances; spark *at the plugs*; fuel supply, etc. Test everything, assume nothing. For example, the reason I emphasize checking spark at the plugs themselves is that I've seen plenty of used plugs go bad after being out of a motor for a while. So don't assume that the plugs are sparking just because they're getting fire....

As to fuel in the oil, bypassing the unseated rings is the most likely explaination. But if you're running a mechanical fuel pump there's another possibility-- the diaphram in the pump may have cracked, allowing fuel to leak out of the pump and into the block. There's a weep hole on the pump that's supposed to allow the fuel to leak to the outside of the motor but I've seen bad pumps contaminate the oil on more than one X1/9. One reason to suspect this might be the case is that it occurs most often when the pump has been left dry (like while the engine is apart for a rebuild) because the diaphram will become brittle when it dries out, rendering it very prone to cracking.

Bottom line, if you have any reason to suspect that you're not getting adequate fuel supply to the carb you may well have a bad pump.

And as Rob said, change that oil the minute you get it running to avoid engine damage due to poor lubrication.

Once you get it broken in do another compression test and compare the numbers to those you'll find in the archives here. Hopefully you'll have a happy surprise. Check this link for info on engine breakin: http://www.mototuneusa.com/break_in_secrets.htm

HTH,

Mike

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