Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Mercruiser 140 HP 3 Litre
Hi all,
I have a Mercruiser 140 HP 3 Litre engine in my Fletcher, approx 1988 vintage. Due to the engine water pump failing I think that I have cooked the head. Does anyone know if this engine was used in any Vauxhall / Bedford vehicles, so that I can find a head? The other thing that crossed my mind was fitting a diesel if doing this engine up would cost too much. Lancing marine does a kit to fit the Ford 1.8 diesel onto the Mercruiser outdrive. I happen to have a good Turbocharged 1.8 in an old Sierra, which I am told you could get 80 Horsepower out of with a bit of tweaking. Has anyone had experience of doing this? All advice gladly accepted!! TIA Barleycorn. |
#2
|
|||
|
|||
Mercruiser 140 HP 3 Litre
On Fri, 18 Jun 2004 20:21:34 GMT, "Barleycorn"
wrote: Hi all, I have a Mercruiser 140 HP 3 Litre engine in my Fletcher, approx 1988 vintage. Due to the engine water pump failing I think that I have cooked the head. Does anyone know if this engine was used in any Vauxhall / Bedford vehicles, so that I can find a head? The other thing that crossed my mind was fitting a diesel if doing this engine up would cost too much. Lancing marine does a kit to fit the Ford 1.8 diesel onto the Mercruiser outdrive. I happen to have a good Turbocharged 1.8 in an old Sierra, which I am told you could get 80 Horsepower out of with a bit of tweaking. Has anyone had experience of doing this? All advice gladly accepted!! TIA Barleycorn. Hi Barleycorn The head on this engine is cast iron and doesn't warp very easily, but even if the engine pump fails, you still have quite a bit of circulation from the leg pump. Did the engine actually overheat? if not, its likely little damage was done unless you were really pushing it. The engine is the old General Motors unit used in American pick-ups et al, and there are quite a few spares available, but the only heads I have replaced were due to poor maintenance where valves and head gaskets have failed. Suggest you carry out a compression test before going to the expense of replacement parts and let us know the results, plus any other details that made you consider a failed head. HTH John |
#3
|
|||
|
|||
Mercruiser 140 HP 3 Litre
Hi Barleycorn The head on this engine is cast iron and doesn't warp very easily, but even if the engine pump fails, you still have quite a bit of circulation from the leg pump. Did the engine actually overheat? if not, its likely little damage was done unless you were really pushing it. The engine is the old General Motors unit used in American pick-ups et al, and there are quite a few spares available, but the only heads I have replaced were due to poor maintenance where valves and head gaskets have failed. Suggest you carry out a compression test before going to the expense of replacement parts and let us know the results, plus any other details that made you consider a failed head. HTH John Hello John, Thanks for your help. When I started the boat for the first time in the spring I noticed that it was 'breathing' heavily, especially on tick over. When I took her out last week the engine ran very rough, on three cylinders a lot of the time. Also I noticed the temperature gauge going right up to the red, and then coming down to normal, every couple of minutes. I put this down to the thermostat playing up perhaps. Also she was a bitch to start when hot. We usually cruise at about 3000 revs when out, too tight to buy the petrol! When I got her home and put the bellows on to wash the engine through I noticed a rattle in the water pump. I pulled the plug leads off, and found that the cylinder farthest away from the water pump was not firing. (Swapped sparking plugs, but still same cylinder). I did a compression test, and cold this cylinder was 130, while the other 3 were 150. After a squirt of oil in the bores this one went up to 150, while the others went to 170. Also the oil has gone milky. From all this I assumed the head gasket may be the problem. I have removed the head, but the gasket was perfect. However from the rust in the head / valves on the poor cylinder it shows that it has not been running. The bore is a little marked, I did wonder about stuck / broken piston rings? On removal of the water pump I found that the impeller has worked loose on the shaft. The reason that I suspected the head was that I imagined that perhaps the farthest end of the head was starved of water due to the engine pumps failure, and created a 'hot spot', perhaps cracking it, thus letting water in the oil, and causing the poor compression. Having said all that, I am more used to diesel engines in tractors, so I am really grasping in the dark. I have found a firm locally who will pressure test the head, and can treat it with some sort of Teflon coating if it leaks, but how this would stand up to sea water I am not sure. They do not like welding cast iron. They charge £45 for the test, so I am just going to improvise with a metal plate, some bungs, and an airline to see if I can find a leak first. If I am in trouble, I have found a 2 1/2 litre Mercruiser engine with a new head for sale. Do you think that they are interchangeable? Many thanks again for your help, Barleycorn. |
#4
|
|||
|
|||
Mercruiser 140 HP 3 Litre
Next chapter in the Mercruiser saga, if anyone is interested!!
I think that I have traced the problem to a rusted out manifold water jacket. There is a hole through to the end exhaust port, and I expect when it gets hot it lets water in the adjacent inlet port. Better start looking for a secondhand manifold. Nearly $500 on the Mercruiser parts.com website, which usually means the same in pounds by the time we are ripped off over here. Anyone got a siezed up 3 litre Mercruiser sitting out in the shed?!! Cheers, Barleycorn. |
#5
|
|||
|
|||
Mercruiser 140 HP 3 Litre
On Sat, 19 Jun 2004 09:07:01 GMT, "Barleycorn"
wrote: Hi Barleycorn The head on this engine is cast iron and doesn't warp very easily, but even if the engine pump fails, you still have quite a bit of circulation from the leg pump. Did the engine actually overheat? if not, its likely little damage was done unless you were really pushing it. The engine is the old General Motors unit used in American pick-ups et al, and there are quite a few spares available, but the only heads I have replaced were due to poor maintenance where valves and head gaskets have failed. Suggest you carry out a compression test before going to the expense of replacement parts and let us know the results, plus any other details that made you consider a failed head. HTH John Hello John, Thanks for your help. When I started the boat for the first time in the spring I noticed that it was 'breathing' heavily, especially on tick over. When I took her out last week the engine ran very rough, on three cylinders a lot of the time. Also I noticed the temperature gauge going right up to the red, and then coming down to normal, every couple of minutes. I put this down to the thermostat playing up perhaps. Also she was a bitch to start when hot. We usually cruise at about 3000 revs when out, too tight to buy the petrol! When I got her home and put the bellows on to wash the engine through I noticed a rattle in the water pump. I pulled the plug leads off, and found that the cylinder farthest away from the water pump was not firing. (Swapped sparking plugs, but still same cylinder). I did a compression test, and cold this cylinder was 130, while the other 3 were 150. After a squirt of oil in the bores this one went up to 150, while the others went to 170. Also the oil has gone milky. From all this I assumed the head gasket may be the problem. I have removed the head, but the gasket was perfect. However from the rust in the head / valves on the poor cylinder it shows that it has not been running. The bore is a little marked, I did wonder about stuck / broken piston rings? On removal of the water pump I found that the impeller has worked loose on the shaft. The reason that I suspected the head was that I imagined that perhaps the farthest end of the head was starved of water due to the engine pumps failure, and created a 'hot spot', perhaps cracking it, thus letting water in the oil, and causing the poor compression. Having said all that, I am more used to diesel engines in tractors, so I am really grasping in the dark. I have found a firm locally who will pressure test the head, and can treat it with some sort of Teflon coating if it leaks, but how this would stand up to sea water I am not sure. They do not like welding cast iron. They charge £45 for the test, so I am just going to improvise with a metal plate, some bungs, and an airline to see if I can find a leak first. If I am in trouble, I have found a 2 1/2 litre Mercruiser engine with a new head for sale. Do you think that they are interchangeable? Many thanks again for your help, Barleycorn. Hi again barleycorn, OK so you seem to have done the 'good' things, lets take it one step at a time. When you laid up the boat at the end of the last season did you oil fog the combustion chambers? failure to do this can result in stuck rings and lead to excessive breathing from the crancase vent, it will also give the low compression reading ( although not that bad at cold, a good pressure warm with throttle wide open is usually about 150 psi). I assume the milky oil is in the cylinder being tested and not the sump, either way water is definately getting into that particular cylinder. As its No4 cyl. which sits lowest in the boat during normal running, it is possible that due not firing the cylinder is causing a partial vacuum within the exhaust manifold and sucking water back from the discharge and into the cylinder. Too much hose pressure while flushing with the muffs can cause the same thing to happen. I have managed to get home with broken pump belt with just the pressure from the leg pump with no damage, but I was being careful. It is highly possible that if the cooling system wasn't adequately inhibited upon laying the boat up severe corrosion can damage the head and exhaust manifold especially if used in salt water conditions. you can check the manifold off the head with some home made bungs and a hose pipe, water should only be discharged from the overboard/exhaust outlet, if any comes out of the head/ manifold ports there is a breach within the manifold. This is where I would put my money on a crack or corrosion hole between the water way and inlet valve porton the manifold of No4 cylinder. The head and block can only really be checked properly by leak testing. I'm not sure about the 2.5 head, never had one, but if it is the same you could have problems with compression ratios Look hard at the manifold. John |
#6
|
|||
|
|||
Mercruiser 140 HP 3 Litre
" Better start looking for a secondhand manifold. Nearly $500 on the Mercruiser parts.com website, which usually means the same in pounds by the time we are ripped off over here. try ebay, there are some biggish us dealers that will ship to uk. |
#7
|
|||
|
|||
Mercruiser 140 HP 3 Litre
"Tom" m3cbzATmapctDOTcom wrote in message . .. " Better start looking for a secondhand manifold. Nearly $500 on the Mercruiser parts.com website, which usually means the same in pounds by the time we are ripped off over here. try ebay, there are some biggish us dealers that will ship to uk. Thanks, good idea. My local freindly Mercruiser dealer wants £500 + VAT for a manifold and elbow. But he can't give any discount because the margins are so slim on parts. There must be a bull in the next field, as I can't half smell some s**t!!! Barleycorn. |
#8
|
|||
|
|||
Mercruiser 140 HP 3 Litre
On Sun, 20 Jun 2004 08:52:18 GMT, "Barleycorn"
wrote: Next chapter in the Mercruiser saga, if anyone is interested!! I think that I have traced the problem to a rusted out manifold water jacket. There is a hole through to the end exhaust port, and I expect when it gets hot it lets water in the adjacent inlet port. Better start looking for a secondhand manifold. Nearly $500 on the Mercruiser parts.com website, which usually means the same in pounds by the time we are ripped off over here. Anyone got a siezed up 3 litre Mercruiser sitting out in the shed?!! Cheers, Barleycorn. I seem to recall paying about $250 for a new manifold, six bolt, rochester carb model from the states, had to pay the import duty and vat so it was about the same in £'s. Looking at the catalog the 2.5L engine has the same manifold listed, so how about that other engine you had a chance of? Meanwhile I'll keep my eyes open, we get the odd motor in with a blown bottom end that has some suitable spares available, and I'll try to find some more suppliers but I usually use www.sierramarine.com . HTH John |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Question about older Mercruiser inboard | General | |||
Question about older Mercruiser inboard | General | |||
Mercruiser 3.0 litre help needed. | General | |||
? Mercruiser oil vs synethic oil | General |