Smokey Ford Sabre 250 - Page 3

gohelm · 16 September 2012, 16:01

My money is on fuel timing as doggypaddle suggested - do you have a long history on the engine? It was rather recently overhauled? Is there a chance somebody tried to improve performance on the jet maybe?

I had a yanmar 4lh on a HJ which smoked like a panicking Sioux Chief during battle. this turned out to be partly because the engine had been tweaked to work optimal (in somebodies opinion at least) with the jet (higher revs) and we solved the grey smoke part on that engine by tweaking back the timing on the fuelpump. So if somebody tweaked yours for the same reason ... It may give some direction on where things are wrong(actually yanmar allowed higher revs on this engine when coupled to a jet than to a propeller, at least so they told me when adressing some other jet/ engine issues).
If it is not that or injectors i have some fears you may end up with some disassembly work this winter!

Rokraider · 16 September 2012, 17:24

Just the propshaft bolts and mounts to undo and then the search begins for something that is tall enough to lift the engine out, with the Rib on its trailer. I don't think the forktruck (Eager Beaver)will lift high enough. Will find out tomorrow. I am happy that I have made the decision to go this route, at least I can sort out the odd oil leak whilst it is out and give the engine a paint up, as well as clean all the gunge out of the bilges and give the engine bay a spruce up. I will have all the intercoolers and heat exchangers checked whilst it is out, I don't want to be doing all this lot again. As I have been going round it, I have noticed lots of little jobs that needed doing that were a real pain to get at, with the engine in place.

Rokraider · 17 September 2012, 17:56

Engine is out and sitting on its high tech engine stand. So much easier to work on!
Found some other odds and sods that need attention, now that I can get to everything. Plan is to do the repairs and get it running properly on the stand before putting it back in the boat. looking at the pump, it appears to be fully retarded on its slots, so chances are that the pump timing is out.

Rokraider · 18 September 2012, 17:20

Discovered the cause of a driveline vibration that had been perplexing me today, took the propshaft off and found the large nut that holds the flange onto the jet drive was loose.
Hopefully the mainshaft hasn't been to badly mauled, wont know until I get it out tomorrow. The previous owner had all this apart to have the impeller overhauled, so obviously didn't tighten it properly. Wonder what else I am going to find?

Rokraider · 22 September 2012, 17:31

Stripped the head out today. After giving all the valves a couple of laps with fine paste, surprised to see such bad pitting on both inlet as well as exhaust valves. Not much carbon build up and the guides are all good, as are the valves. The inserts in the head don't look particularly well done, with quite a large lip protruding in the middle of the chamber beside the injector hole. No 1 exhaust has quite a large chunk missing from the inner face of the seat (first pic) . interesting to see what has caused this, the fact that there was no air cleaner, other than a bellmouth with a bit of mesh across it, wont have helped. Any sand that got into the engine box, will have got sucked straight in. I think I might have a new set of inserts fitted and blended in to remove the sharp edges.

doggypaddle · 28 September 2012, 12:33

propshaft falling off, dodgy valve seats....I think I would whip the pistons out as well, measure/hone the bores while you have the chance in-case that was "overlooked" too
also a good opportunity to replace the big end shells if they show any wear and also all the Rod bolts, last thing you want if its running right is to find a leg out of bed for the sake of a set of rod bolts

They should be cheap i guess Ford D series/Cargo 08-14 ones the same?

Rokraider · 29 September 2012, 17:08

I have come to the same conclusion. If everything is good then the worse case would be a set of shells, seals,conrod bolts, rings and a light hone. It had good oil pressure before, so am not expecting to find any issues with the bottom end.

I am also going to put some timing marks on the front crank pulley that are clearly visible, so when it is back in the bilges, if I want to check the timing, it will be much easier.

Temptation is to upgrade the bores and liners to the later Cargo turbo spec, which would raise the compression some. Problem is I am not sure how well they will cope cranked up to 250 BHP.
I need to do some more homework before going much further.

m chappelow · 29 September 2012, 17:21

Is there a cold start lever on the pump that's not adjusted right or not tripping back proper .

Rokraider · 29 September 2012, 20:34

It does have a push knob on the side of the pump for cold starting, but that appears to be working properly and pops in and out ok. I never use it. The pump is being given an overhaul anyway and I have asked for a list of faults found.
I am considering fitting a heater system on the intake manifold to help with cold starting whilst it is all accessible. The Mazda 3.5 turbo diesel (which is based on a Perkins) has a very neat heater element that fits into the mouth of the intake manifold and is very efficient.

Rokraider · 30 September 2012, 17:38

Pistons out. Bores look good as do the pistons. Going to take the block and pistons in for a light hone and measure before re asembling with some new parts. Signs of oil contamination in the shells, but the crank looks ok at this point. Wont know for sure until i get it out. Now need to make a puller to get the crank pulley off.

doggypaddle · 01 October 2012, 19:21

Quote:

Originally Posted by m chappelow

Is there a cold start lever on the pump that's not adjusted right or not tripping back proper .

that wouldn't cause the smoke that this engine had,
we had one on the cargo and it was cable operated, if you yanked the cable when driving along you just got loads more power and a big cloud of dense black smoke

I will put my money on the problems with this motor being timing and valve seals.

doggypaddle · 01 October 2012, 19:26

Quote:

Originally Posted by Rokraider

It does have a push knob on the side of the pump for cold starting, but that appears to be working properly and pops in and out ok. I never use it. The pump is being given an overhaul anyway and I have asked for a list of faults found.
I am considering fitting a heater system on the intake manifold to help with cold starting whilst it is all accessible. The Mazda 3.5 turbo diesel (which is based on a Perkins) has a very neat heater element that fits into the mouth of the intake manifold and is very efficient.

I wouldn't of thought you really need it, if the timings retarded it won't start very well.
Our cargo would start first time it hit compression in normal winter weather. Even one day when it was -16c it started after cranking for about 5 seconds......and that was a 12 volt system.
i would see what its like once its running well first.

doggypaddle · 01 October 2012, 19:32

Quote:It had good oil pressure before, so am not expecting to find any issues with the bottom end.

I used to think that till my 2.8 isuzu developed a tick, that turned to a tap, then a rattle and ultimately a knock, over my 30 mile commute.
next morning when cold the knock was gone so i went for a drive, soon as the oil warmed up it started knocking again, when ticking over it had 35psi oil pressure. when i stripped out it the only white metal on no3 big end was the size of 1/2 pence piece

. I reckon it was about 20 miles away from a "leg out of bed"

Rokraider · 05 October 2012, 17:04

A bit more progress. The report back on the pump states that No 5 was delivering virtually no fuel at idle, but worked better when opened up, which would explain it only running on 5 cylinders at idle. The pump is currently being rebuilt with new innards, bearings seals etc with a smoke box modification that wont make any odds at idle, but should give me more accurate control of the fuel delivery as the turbo boost kicks in. Hopefully it will run a bit cleaner in the mid and upper ranges, without sacrificing power.

The head had a .005" warp , so the valve inserts have been reground, the block face and manifold face have been given a minimal skim to get them flat. It has been pressure tested and all is looking good on that front.

I have pulled the pistons out and visually it doesn't look bad, however there is some light etching at the point wear the ring wear stops, nothing much ,but the start of a little corrosion. Water maybe? The big end shells have light wear top and bottom, which makes me wonder if the con rod big end has ovalled slightly. Going to get them checked as well. Will finish stripping the last of the block out and will then take the block, crank, pistons and rods in to be measured and if all is well, give the bores a very light hone and rebuild it with new rings, shells, bolts, seals etc

I can't believe the size of the secondary oil pump that feeds the oil squirter rail that is located beneath the crank and squirts oil onto the underside of each piston crown (additional cooling to compensate for the turbo). It is simply massive! I would like to be able to look inside the engine whilst that is going on.

I am also looking at doing a modern turbo upgrade, as the old one is past its best and technology has moved on since this layout was designed.

I should hopefully should have all my answers by the end of next week.

doggypaddle · 05 October 2012, 18:05

A more modern smaller waste-gated turbo may well generate more boost in the mid range, and with extra fuel to go with that boost(with the compensator opening the rack earlier) you will make more torque. you will not get any more power at the top end though unless the rack stop is opened up too.
I would be very careful of this, many engines of this era had the turbo sized so that the boost built up after what would the max torque point of a normally aspirated identical engine.
This had the effect of reducing smoke at the top rpm range where the engine was getting a bit asthmatic, and also flattening the Torque curve and saving the engine from excessive strain.
If you get loads of boost from low RPM and the fuel to go with it it may well overload the bottom end of the engine which was originally normally aspirated.
Another consideration with your boost compensator is that without over fuelling slightly in the low RPM range under load you may not generate enough boost to operate the boost capsule, the excess fuel and black smoke puts a lot of heat into the exhaust which spools the turbo up quicker. as does retarding the pump timing.
a great example of this was my old perkins 500 in my landrover with the compensator set as intended boost would build slowly after 2000RPM. with the off boost fuel stop adjusted in so it was a bit smokey at 1000RPM it would whoosh up to 15PSI boost by 1500RPM.
Personally I don't mind a little bit of black smoke at the bottom end if it makes the engine a bit more lively

Your engine should be spot on when put back together even with the old turbo.

BTW poor fuel delivery on one cylinder is probably from shit passing through the element, give your tank and filters a good steam out!!

doggypaddle · 05 October 2012, 18:10

Quote:

Originally Posted by Rokraider

I can't believe the size of the secondary oil pump that feeds the oil squirter rail that is located beneath the crank and squirts oil onto the underside of each piston crown (additional cooling to compensate for the turbo). It is simply massive! I would like to be able to look inside the engine whilst that is going on.

Direct injection innit....all the fire goes on in the piston so they need lots of cooling with oil from below. All the heat goes into the head on an indirect injection engine and taken away directly by the coolant, which is why DI engines have bigger sumps oil coolers and take forever for the heater to warm up!!
combine a TDI engine with a drafty old landrover and a cold day, its time to get the thermals out

Rokraider · 05 October 2012, 19:23

I agree with your points above. I am considering going for the same size turbo,un waste gated with similar characteristics, but possibly water-cooled and with modern materials and design. I am not trying to make it a hotrod, just giving it a makeover with some modern benefits.

Rokraider · 06 October 2012, 19:02

Finished stripping the engine today, I can't believe how heavy everything is. The block and crank probably weighs the same as my BMW 3.0 turbo diesel engine complete!

Signs of oil contamination in the main bearings some light scratches on the journals, but hopefully will clean up.
Block, crank, cam, pistons and rods now ready to go to shop next week for measuring etc.
Decided to strip out the turbo intercooler and have a look. Glad I did, one end of the body is badly corroded and there is signs of corrosion inside the housing, presumably caused by raw water ingress. Someone has attempted to bodge it up with filler at some point. It really pisses me off when people bodge stuff, especially something that could destroy the engine.
So more money to be spent

Depending on the price of a new / good secondhand one, I may end up machining off the damaged end and having an insert fabricated that can be welded in and then machined to tolerance, effectively removing the corrosion.

doggypaddle · 07 October 2012, 17:18

That should be easy enough to build up with a Mig/Tig and machine back.
This is getting expensive isnt it

Rokraider · 07 October 2012, 18:34

Pending no other surprises, I am hoping to have change out of £3k to sort the engine and jet out. Not holding my breath though.

Stripped the raw water pump out today. Found 2 of the impeller legs going the wrong way and the front cover that has a a raised shaped face to match the pump shape had been fitted in the wrong position. I couldn't turn the pump by hand.

Not much else left to strip down, so hopefully things will improve from here.