Julian Xavier

Thanks, that explains it.

Got another opportunity to get down to the boat. I don't suspect the timing chain but I did want to remove and clean the timing chain cover regardless due to the large amount of rust and grime that I just couldn't get to easily. Used an impact gun to get that nut off of the crank pulley mine happened to be 1-5/16" FYI. Here are some images and a video of the timing chain, the tensioner seems like it's got a lighter spring than I expected however being on the slack side I'm not sure it matters. For my motorcycle I usually measure chain wear as the distance pin to pin. I'll have a look in the manual to see if there is a spec but if someone already has the figure or another method for checking I would appreciate the assist. I turned the motor over until the pips lined up, seems close enough to me. Thoughts? https://photos.app.goo.gl/YQymfJM63G8owv336 I'm taking the pulleys and the timing chain cover to sand blast them, replace the oil seal and gasket ect. I plan on scraping the rust and old gasket off the motor. All of the bolts are getting replaced, they all seemed pretty tired and corroded. On a different note, does anyone happen to know what the threads/fittings are for the injector pipes? Are they 1/4 bsp or some other designation?

I struggled with that, eventually I did find the specs for resistance and pressure/temp range. Ultimately I just ordered new senders and gages as matched sets. The temperature guage came as a complete kit whereas the Seastar oil temp guage called for a type C sensor (0-80 psi 240-33ohms) so I found the appropriate sender and purchased it separately. It proved difficult for me to find an oil guage sold with a sender. It's a problem I've run into frequently with this motor. Auto parts vendors always want to know vehicle specifics to source parts. Give them specs and measurements... good luck. I've had some luck with parts such as the alternator providing info on vehicles such as the 74 MG MGB that were fitted with the BMC 1.5 Petrol motor.

Ah! I'll have to look him up. I live in Boulder Creek not too far away we were evacuated during the fires, I hope your cousins home was left intact. COVID restrictions put a bit of a damper on meeting new folks at the moment. And to your point, yes the climate is very moderate here, another reason why the starting issues trouble me. I am hoping that the timing truly takes care of it. though to get more adjustment out of the injection pump it looks as though it would require bending the injector pipes. Another option would be to increase the speed of the starter. Very subjective but it sounds like it's turning over just fine as is. Earlier the state of the battery cables was asked after, they are all brand new. I bought brand new 4/0 wires, short as possible and made all of the connections myself with solder in the terminal ends. I could have gone heavier on the wire gage but I seriously doubt that's my limiting factor. It's an option to bump up the starter voltage but I am weary of destroying the starter output gear. All that said I made my adjustment earlier in the week and had to wait for a cool motor to see if the starting has improved. Might get back out to the boat this afternoon.

Hopefully unrelated but my oil pressure gage stopped reading somewhere along the line, I suspect it was just the sender (when I measured it it came out to 153kohms with the engine off). I've ordered a replacement and shut the engine off, I don't like running it without being able to keep an eye on the oil pressure. The new sender is on it's way with a 1/8NPT thread, anyone happen to know what the threads are in the motor? It looks to be 1/4NPT or 1/4BSP. While I was at it I ordered a new temp gage and sender, it bothers me that even after running in gear for up to an hour the temp generally hangs out around 120-140F. The 82C thermostat is on its way as well, it is currently fitted with the 72C, though I wouldn't expect this to make a difference after a sufficient amount of run time.

Tony, yes I checked both. The strainer had a couple of Small splinters I could not identify. They could have been metal or portions of gasket or even carbon. The second component seemed clean but I noticed a of bit resistance while reinstalling it.

The fuel is likely two years old, however I do add Stabil diesel treatment to it every 6 months. That said I can swap out for fresh diesel to see if it makes a difference. I have used starting fluid (with ether) and that works like a charm, but I would like to find a different solution as so many people caution against it, plus It seems to me it shouldn't need it with the compression I'm getting.

It seems like this motor will be in great condition once I figure out the timing or whatever else is causing me issues on cold starts. I'm looking forward to getting it squared away so I can clean up and paint the motor.

That's excellent Rob! What did you use to establish the proper angle between the master spline and the timing notch that you have on the outer disc? I see in the manual some mention of 208 deg but really not sure what that means. 208 degrees from the master spline? Also according to the figures discussed for the compression it seems that my engine is doing just fine on that front. I really have no idea how the mechanic I called previously could have come up with values as low as 220psi when this is what I read: Anyhow, I checked the oil strainer to the skew, seemed clean and clear. I ran the compression test above. The motor still had a hard start but once she runs that's it, I will have to have a friend along next time I cannot see the exhaust smoke from inside the engine compartment. Whilst running I rotated the injection pump (CW seemed to slow the revs, CCW sped them up). Ultimately I rotated the pump very slightly CCW and it seems to run faster for the given throttle input and perhaps smoother, very hard to tell though, the whole boat experiences significant vibration while the motors running and I'm not sure how much is normal for this motor. Next time I get out to the boat will be the real test. I will try to start cold (with the glow plugs), and see how it goes. If this still doesn't improve the starting I'm going to try changing the battery cables out to series and go for 24v on the starter, see if the extra oomf starts it up or burns my starter out, hoping for the former. It could be that the extra juice would get her going quicker, might be better for the motor than the endless cranking have had to do in the past.

This is what I have come up with based on the information in the manual, though I'm not certain about the placement of the notch. I'd be interested in making these for anyone that could benefit from the use of them, not looking to make a profit. Best case scenario these may be candidates for 3D printing, in which case I could simply make the file available, no shipping necessary.

Ok, I think I'll still try making one of those, unless this was the timing tool that you mentioned members might be interested in? Or is there yet another...

I've been doing a bit of digging trying to figure out the injection pump timing tool but I still haven't figured out what all the geometry would need to be. Has anyone already puzzled this out? Looks to me like perhaps this is another tool for establishing the master spline at 5 O'clock. If that's the case, and all that needs doing for a notch to be made opposite the master spline I should be able to make one. Anyone able to weigh in on the alignment of that notch? Also came across this Tempest version of the BMC 1.5 manual, seems like it has a lot of great info, additional drawings as well. https://drive.google.com/file/d/1_nglPfi5gnKQ_w9qtlc_gwAGM-NilaIn/view?usp=sharing

I have not but after all the information I'm getting here I'm pre pairing my tools in order to try all of these approaches. check the timing chain/tensioner, pressurize and listen for leaks, pull the skew gear + strainer. It will be a bit before I can make it to the boat but I’ll post my results.

Bizzard I have an adapter that should work. I will bring the compressor & give it a go with the leak down test. However I was able to test the gages at my shop today. The results suggest that if anything I have ~ 500 psi + on each cylinder. If accurate I doubt I have issues with rings or valves. Is 500 psi problematic? Could excess carbon buildup be responsible for that large of a reading?

I will do all the above, feel and visually inspect for wear. If I can figure out the necessary details to make one of those timing gages I would happily make one for my own use and make them available. I would probably just turn the shaft down and only worry about making the master spline (the large tooth) I believe but do not know that the valves are in good order, last I had them out they looked decent in terms of pitting etc. and I lapped them in by hand. I performed the valve clearance adjustment last week before the compression test (0.015") and triple checked them to be sure. I might ask my mechanic to come down and perform another compression test before I take the head off, but if it still comes back high (480 psi +) If low: I'll remove the head inspect the valves, maybe replace them or have them ground, seats cut, etc. inspect the cylinder wall for wear if high: I don't really know what to do here, pull the head anyways and check what's going on, clean out carbon if excess buildup is present count my blessings and leave well enough alone, try to address the cold start issues with the injectors and pump timing alone.

Ultimately it seems that if the compression is indeed low and I just have faulty values then it would be much more likely an issue with worn piston rings etc. If that's the case I'm I would be interested in honing the cylinders and fitting new rings but I understand that could well mean replacing: rod bearings rings crankshaft bearings (unless it can remain installed while removing the pistons) pistons themselves In the case that there is significant cylinder wear it could mean boring and purchasing oversized pistons + rings which means all the above with a considerable increase in expense. Anything else I'm missing?

This is the link to the nozzles I purchased from ASAP: https://www.asap-supplies.com/products/bmc-injector-nozzle-for-bmc1-5-thornycroft-90-engines-12h834-131121 As to the 11/64 drill for reaming I expect I used a larger drill as the glow plugs fit easily and the 5mm diameter heating element is larger than 11/64" (4.37mm) I can pull the crank pulley and check the timing chain and tensioner. As to the skew gear, is this the component that fits to the injection pump shaft to drive it from the motor? If so can replacements be sourced?

Sounds good, I'll post a photo of an injector once I get a chance to pull one. Can the atomizer washer be reused? This is why I have hesitated to pull them out until I have the replacement parts.

Thank you very much for the replies, I will attempt to answer the questions raised to the best that my memory serves: I reamed out the glow plug ports with the largest drill I could fit in the ports and turn by hand so as to try not to create metal shavings. The new GP has a 5mm thick element so I'm sure its a tight fit, I did not modify anything in the head past the threads. Unfortunately I don't have one of the old glow plugs for comparison. picture of the new GPs bellow As to how I managed to break of part of the top hat. I believe that at the time I had misunderstood and used a copper washer in the bottom rather than one of those stamped stainless steel atomizer washers and the copper turned out to be too thick. I have a picture describing where I've now placed the sealing washer and atomizing washer. The replacement nozzles were sourced from ASAP supplies and they are indeed the Pintaux nozzles clocked correctly with the pin. I have tried the trial and error method of timing in the past, will do again, just wasn't confident in my results. What do you look for other than a subjective "good" running sound when making this adjustment? Too bad the spill test method won't work for this pump that would have been a nice way to set the timing. I will have to take my gages and triple check them against my shop air to make sure those readings for compression weren't totally off. Difficult to do though as my compressor doesn't reach the same pressures needed, I've heard that pressure gages have a sweet spot for accuracy. Atomizer washer: Injector prior to cleaning and installing the new nozzle: Broken heat shield "top hat" : Replacement glow plug AC Delco 60G, If I recall the only modification to the head was milling down the face and tapping the M10 threads deeper. The glow plugs seal on the seat so the only depth that should matter is from the seat to the tip of the heating element: FWIW here is a short film including slow motion of the motor running, though this is prior to all the work done on the head: https://photos.app.goo.gl/c78kVrLPPhdhDduQ6

I've been doing some more digging around and found this topic of spill timing the injector pump. I have never felt confident with the injection pump timing so it sounds like another good place to start in conjunction with another compression test to confirm what I was finding before. If I understand right the procedure is to find 22 degrees before TDC and that should be the point at which the spill cuts off on that injector provided you remove some hardware (looks like some sort of check valve) from the injection pump coupling. There was also some mention of always rotating the pump and the crank pulley in the direction of normal operation to account for any backlash.

I have been reading posts in this forum since I obtained the boat back in 2011 and I greatly appreciate the information members here are willing to share. I've made it through most all of the BMC posts and still don't see anything that quite parallels what I'm experiencing so I would love to get some feedback and opinions. I was told by the previous owner that the boat runs 'perfect' so long as you leave the glowplugs on for 90 seconds before cranking. Even in the beginning it would eventually start up after holding the plugs several times for well over 90 seconds (ill advised I know, but I got away with it without any burst or broken plugs). Of course warm weather or restarting after the engine is warm is and always has been easy. Cold starts are now worse than when I first got the boat. Here is what I have done so far: replaced the injector nozzles (pop tested at 2000psi) cleaned the DPA pump and replaced all of the consumables available in the 'rebuild' kits injectors seemed to pop off fine with good spray patterns when run out of the motor but that's just my observation new thermostat (72c) cleaned out the tube stack in the bowman heat exchanger removed the head (had overtightened an injector and broke off the head of a heat shield) had it boiled out and checked for warping modified the head (GP ports) to accept ACDelco 60G glow plugs (someone had already done this previously the two rearmost cylinders so I wanted them to match ps. I am a machinist) lapped the valves by hand Had the starter motor rebuilt (rewound at the local starter/alternator shop) replaced the batteries and have two 12v in parallel for starting replaced the water pump replaced the fuel lift pump with a 12v electric pump Recently I have just been using starting fluid, the smallest amount possible, and it gets the motor going on the first crank and works great the rest of the day. Suspecting compression I had a mechanic come over and we found the compression (cold) to be 220,240,220,240 when I was hoping for 280 psi. He told me to try performing a valve adjustment and retesting. I did so (0.015"), bought my own compression tester and read, get ready for this, 480,480,490,480 ?. I thought I had a faulty gage so I borrowed another and retested at 490,500,485,500psi. Still starts hard, still runs fine after it gets going, by the way the starter sounds very strong. It's possible that both of my the latter gages were faulty and the readings were bogus but I'm not certain where to go from here. I am considering just ordering another head gasket so I can get in there, inspect for cylinder wear, check the carbon buildup, glow plug depth etc. Would also consider buying one of those injector sets off eBay for $135 (cheaper then sending them out) as perhaps they are calibrated better than I was able to do on my own. Trying figure this out, most of all I want to be able to start easier and rest easier knowing that I'm not just ignoring some deeper issue that's going to result in damage down the road. If necessary I'm willing to replace rings, bearings, bore, hone, whatever. But I'd like to only do what is necessary and I'm having difficulty figuring it out on this one. Here are some photos for reference: