This Can't Be Good...

[mike7a10]

Rebuilt engine last year. 2 weeks ago I tuned up engine and it ran great. During tune up I found very very fine metal shavings/filings on the inside of the distributor cap. Cleaned it and put on new cap, points, condenser and rotor. Ran super good.

This weekend I had a sudden and rapid shut down with some shaking and some backfiring. Checked timing and it seemed OK. Pulled fuel lines and the new mechanical fuel pump is not sucking gas to carb.

Additionally when I sprayed starting fluid into the carb I got nothing. It just cranks. I have good spark at the coil and at the spark plugs. BUT...when I started moving the distributor around trying to retard and advance the timing (at different settings) I am getting a strange knocking sound. SEATOW skipper and wife said it sounded like a backfire coming out of the exhaust. I heard it but typically a backfire comes from the carb area...this sounded like it was internal. The main thing is that the engine absolutely would not fire up even using starting fluid which is really strange.

Since the camshaft runs the fuel pump and the timing I am having a bad feeling that this may be related to the distributer (shavings/filings). I am guessing that some slop has been occurring in the distributor shaft causing the rotor to scrape some fine metal filings off of the contacts.

Has anyone run into a similar situation? I cannot find a similar thread. I am hoping it is only the fuel pump....here are my thoughts on troubleshooting:

1. The fuel pump has failed and needs to be replaced
2. The distributor has gone bad and needs to be replaced
3. The camshaft has crapped out and a major repair is needed

OK guys...please put on your thinking caps on this one. I just spent over $2500 last year rebuilding. I did not replace the distributor at that time. The fuel pump and sediment bowl were changed out just after the rebuild. Any advice/experience you may have will certainly be looked at and appreciated!

Mike

S/V Plan Sea
Punta Gorda, FL

[Loki9]

Maybe the springs on the centrifugal timing advance broke? Take out the plate that holds the points in the distributor and check underneath.

Also check your compression on each cylinder, maybe a broken valve spring?

[ILikeRust]

I second the suggestion to take a good, hard look at the advance mechanism in your distributor. If you found some metal shavings in there, it sounds like something self-destructed under the cap.

Also take a good look at the rotor and up under the cap - make sure all the contacts look good.

[Al Schober]

Also agree the problem is spark. I like using the spray to get a quick diagnosis of fuel vs spark. A compression check is quick and easy to verify the third leg of the tripod is still there!

[CalebD]

Failed oil pressure sensor causing fuel pump to shut off?

[TomG]

Failed oil pressure sensor causing fuel pump to shut off?

I think he said he has a mechanical fuel pump, so I think the OPSS isn't an issue here.

That your SeaTow folks said it sounded like it was "backfiring" out of the exhaust makes me think the spark is occuring well late in the sequence, i.e. the spark is happening just as the exhaust valve is opening. This would support Loki and Rust's assertion of a possible timing issue, related to the centrifugal advance or distributor.

[Carl-T705]

Mike , I'll go with number 2. Before pulling the distributor bring it around to number 1 firing position. That way when you go back with a "new distributor" it will make it a lot easier and less prone to a screw-up. Also doing it this way will let you see if the cam is indeed turning. Don't be too concerned about the backfire, spraying starting fluid in a hot engine will ignite without spark , that is why they warn against it.

[jhwelch]

I had the "metal shaving" problem last year (I think what you are finding is a fine mist of graphite from the rotor contacts) and after replacing the distributor the problem went away. This fine layer of graphite causes short circuits inside the distributor cap, so you will experience poor (or no) running conditions unless you wipe it out.

Don and Ken did not think a distributor could get "wobbly" and go bad that way but apparently in my case it did.

-Jonathan

[mike7a10]

Thanks everyone. I will not be able to look at the engine until Friday. After thinking about your comments I am pretty sure the issue is a distributer failure of some sort. Mainly as the timing seemed to go haywire instantly.

Any other thoughts are welcome!

I will check Friday to see what is going on here...


Mike

[Marian Claire]

How did you check for fuel flow, cranking or using the hand primer? If it pumps by hand but not by cranking that could point to some internal problem. Have you tried the thumb/compression test? If something has snapped internally would you have 0 or very low compression??? This is on the edge of my knowledge so if I am wrong with this let me know. Dan S/V Marian Claire

[mike7a10]

Marian Claire: I pulled the fuel line to the sediment bowl and later pulled the copper tube running between the fuel pump and carb. Gas was not being sucked up by the fuel pump but when I spun the engine I saw that the fuel pump was actually pumping out (what little gas was left in the fuel pump). I have plenty of gas in the fuel tank.

I did not have time to check for compression but at this time I am fairly sure I have compression due to the "backfire" noise that the SeaTow skipper noted. I believe this is a build up of internal pressure that is being expelled.

However I will be checking this Friday and I will definitely spin the engine and do a quick compression check.

I am hoping this is only a distributor change out and not a damaged camshaft. I will know more once I can pull the distributor and look at the gears at the base of distributor shaft...keeping my fingers crossed.

Mike

[ILikeRust]

I am still betting it's something inside the distributor. I bet you won't even have to pull and replace the distributor - maybe just replace a few of the components. Don't go pulling the distro out until you take a good look at what's going on under the cap. Look carefully at the underside of the cap, the rotor, the points, the mounting plate, and then the advance mechanism.

[Bold Rascal]

Bill's right

Don't go pulling that distibutor just yet and if you decide to pull it. Make sure your engine is at TDC first and confirm that the rotor is pointing directly away from the block. Check your plug wires as well for proper routing.

So you did a tune up and it ran super good and then suddenly this past weekend it was backfiring/ stalling and your new fuel pump wasn't sending fuel to your carb?

Solve or confirm you have proper spark at the proper time. Engine at TDC, rotor @ 9:00 o'clock pointing away from block. Spark plug wires properly routed. Confirm good spark. If you have all that THEN start looking at your fuel system.

[Marian Claire]

Mike thanks for the info. I am not discounting the timing/distributor possibility. Your test with starting fluid sure point to a no spark, timing or no compression issue. But if you are not getting fuel we also need to know why. Plugged pickup, clogged filter, closed valve, bad squeeze bulb??? Warning: I have the electric pump so I am not that familiar with the mechanical pump. I think the fact that the pump is moving during cranking is good but I would still try to manually work the pump. A simple and quick test but you can test things in the order you see fit. Was the raw water intake closed during all this cranking? Is it possible the plugs got flooded with water after the shut down? Dan S/V Marian Claire

[mike7a10]

All good advice. I am definitely going to give the distributor a good once over before I pull it and I appreciate the reminders about the position of the rotor, etc. I will be marking and at TDC.

BUT...with the fine metal filings (it looks like silver powder) floating around in the distributor cap I am still inclined to think I have wobble in the distributor shaft. I am going to first vacuum all of that out and really clean it good. Reset the cap, etc. and see if I can get it to kick off. If she runs I will feel much better. If I get nothing then I will pull to see if the distributor gears have sheared or broken and see if it has jumped the timing. That fine metal powder may have set off a mini electrical "storm" inside of the cap!

As to the mechanical fuel pump it is activated by a small push bar that hits one of the cams that causes the pump to work. It is a very good sign to me that it was showing pumping action as I feel the camshaft may be OK. But I simply will not know until I pull (or have to pull) the distributor.

I closed the seacock once it spun a few times without kicking over. There should not be any water in the block as I know not to do that!

Thanks again everyone for the advice. It really is appreciated. Here's hoping for a simple fix!

Mike