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-   -   Westerbeke - no start post inj. pump rebuild. (http://www.sailnet.com/forums/diesel/87874-westerbeke-no-start-post-inj-pump-rebuild.html)

Down2TheC 05-27-2012 02:17 PM

Westerbeke - no start post inj. pump rebuild.
 
Calling all Diesel guru's.

We just had the injection pump and injectors rebuilt and everything went back together without major incident. We're trying to get her running in the cradle but no joy as of yet.

Things we know:
1. Bleeding process went as indicated. We have fuel at the injectors. We went through the process several times for lack of other activities.
2. Oil is new and looking fine
3. The old "WD40 in the intake" routine got her to rumble a couple times but today yields nothing.
4. Exhaust is pushing the water out normally during cranking.

Here are the suspects in my mind:
1. I know of no way to independently verify that the injectors are firing. But the WD40 should turn the engine regardless of their operation.
2. Excessive blow-by. The WD40 should have the cylinder walls well lubricated and I find it hard to believe that after 32 years, the compression fails the same year I rebuild the injection pump. She was running fine last season. Just had the leak from the injection pump and the white smoke.
3. Crank speed. Seemed low initially but once she lubricated it now seems nominal to me. Starter batt was freshly charged each day and I have a pretty good ear for this engine after 30 years. I don't think it's too slow. We've had WD40 kick her over with a slower crank.

So any suggestions are welcome. If anyone has troubleshooting tests or things to check on, let me know. I'd be very interested in ways to test compression or injector firing.

Thanks, MJC
*Note: We used the Skipper's WD40 bleed method a couple times in a pinch but have suspended it's use for the past couple years after getting opinions from diesel pros.

jrd22 05-27-2012 02:43 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
Not familiar with Westerbeke but generally you'll have to set the injector timing after having the pump rebuilt.

dabnis 05-27-2012 03:32 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
If it was running fine before the re-builds, maybe:

1. The pump was not properly re-built
2. The injectors were not properly re-built
3. The timing is way off

Let us know what you find,

Paul T

sigmasailor 05-27-2012 03:57 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
An easy way to verify the injectors deliver fuel is leave them out of the cylinder with HP line connected. Do keep away from the jet of fuel; this will harm you when you touch it.

CarelessNavigator 05-27-2012 04:01 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
How about a little history on the engine. Why did you get the pump and injectors rebuilt were there any other running problems when it last ran or any other evidence for us to help you diagnose your problem?

As John said, timing if it can be set is the first thing that comes to mind. Compression would be next but, you mentioned slow cranking speed. Engine rpm during cranking should be approximately 250 rpm if it is significantly slower you need to find out why. It shouldn't be hard to believe that compression would drop to the point of being hard to start or needing a starting aid to help get her going it's 32 years old that's pretty damn old for an engine especially if it is original and slow cranking along with.

Diesel fuel autoignition temp is approximately 600 deg yours may depending on which grade fuel you have but your compression would have to be above 300 psi for autoignition (that's actually pretty low). Cylinder temperature rises 2 deg for every 1 psi of compression. So, slow crank speed and/or low compression will will not generate enough heat during the compression stroke and cause an engine to be very hard to start.

Always check the easy stuff first and NEVER assume. Gather more evidence.

CarelessNavigator 05-27-2012 04:17 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
Quote:

Originally Posted by sigmasailor (Post 876242)
An easy way to verify the injectors deliver fuel is leave them out of the cylinder with HP line connected. Do keep away from the jet of fuel; this will harm you when you touch it.

Not to criticize, but that is a horrible idea.

If you bend the injector lines enough to do what you are saying you risk kinking the injector lines creating reduction in pressure and volume which could lead to reduced participation or an outright misfire, improper atomization of fuel causing the injector to clog then washing the cylinder down.


http://images.wikia.com/southpark/images/d/d6/49a.jpg
Bending injector lines is bad kids UH MMMMKay

sigmasailor 05-27-2012 04:51 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
Quote:

Originally Posted by CarelessNavigator (Post 876245)
Not to criticize, but that is a horrible idea.

If you bend the injector lines enough to do what you are saying you risk kinking the injector lines creating reduction in pressure and volume which could lead to reduced participation or an outright misfire, improper atomization of fuel causing the injector to clog then washing the cylinder down.


http://images.wikia.com/southpark/images/d/d6/49a.jpg
Bending injector lines is bad kids UH MMMMKay

Normally there is some clever way to connect everything without bending fuel lines. It's quick and easy and will narrow down on the problem. I should have pointed out not to bend the fuel lines.

Down2TheC 05-27-2012 06:21 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
Thanks for all the quick traffic.

Only way I could see connecting the injector outside of the head would be to not have the return line hooked up so it would be sideways maybe. I'll take a peek to see if it's feasible. As long as I can catch fuel spewing from both ends, I guess it would be a good (albeit slightly scary) unit test of the injector rebuild.

History...
The W50 is a 1981 with low hours. Our Tartan 37 does daysailing mostly with a few cruises to the MI side of the lake. (We're in IL.) The past few season she started accumulating fuel in the sump at an increasing pace. Last season it got bad enough to find the source. The cutoff control on the injection pump was dripping at the stem. So I pulled it this Spring, had it rebuilt, and everyone said that with 32 years in service, might as well rebuild the injectors while I'm at it. So the shop did both. Other than some white smoke which I assume was a product of the injection pump, the engine was performing excellent throughout.

Timing on the W50 is a matter of 2 degrees play in the pump mount. I lost the scoring on the pump casing because I didn't know that the shop was going to put it through paint. But I matched the position using photos taken prior to disassembling. Other T37 owners claim that no timing available will make the engine not run. Only major smoke and maybe rough. Plus she'd run on WD40 with the timing off. So I don't think that's it, though I'm running out of things to do so I may try a twist if nothing else presents itself.

If nothing else works by Tuesday, I may have to bring in the pros ($$$) to get a compression test. Speaking of which... Could the injector mounting gear be an issue? Could we lose all compression because the shop gave me the wrong size internal washers or something? Mine has a copper ring over the injector nut and a crushable heatshield at the tip.

dabnis 05-27-2012 07:19 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
If you are getting fuel leakage or spray when loosening the pipe fitting the pump may be OK? Should get quite a bit if you loosen it a turn or two. Perhaps the injectors were set at too high a pressure rating and will not pass the fuel, or enough of it? Easy enough to take them back to the shop for checking. If it runs on WD-40 the compression is probably serviceable. You could put soap bubbles around the injector connections to see if there is air leakage around the connections, but that is probably a stretch. Possibly debris got into the lines when disconnected from the pump and is now plugging the injector tips? Probably another stretch. Maybe remove and blow out the lines? Maybe take both the pump and the injectors back to the shop for checking?

Paul T

Down2TheC 05-27-2012 08:50 PM

Re: Westerbeke - no start post inj. pump rebuild.
 
All good theories. But doesn't explain why it won't fire on WD40.

How about this... All symptoms point to loss of compression. What if the shop gave me the wrong copper washers that go around the nozzle nut on the injectors. That could explain weak to no compression in all 4 cyls. Shooting some soapy water around the base of the injectors and cranking should lead to bubbles if air is escaping at the base of each.

I'll have to check with my T37 forum and see if our injectors actually had those think copper washers. That's the only thing I didn't take a picture of as I broke things down. The injectors were and afterthought and didn't seem very complex so I just popped them out and delivered them to the shop. Can't recall what was on them when I popped them out. They do have that crushable heat shield at the tip.


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