ThePinkPanther
28-09-2016, 12:27 PM
Hi Guys,
This is a repost of a problem I had about 18 months ago and in spite of some really great help from Ausfish, it could never be solved!
I'll try to be as brief as possible...................
1996 Whittley Cruisemaster powered by a 1995 Ford Windsor 351 V8 inboard with the usual mix of some Volvo Penta Parts in the accessories such as cooling manifolds, stern drive, exhaust risers etc.
For no real reason it started to overheat ON THE PORT SIDE ONLY. Coincident with this was the discovery of a small cylinder head crack in the STBD HEAD.
The weirdest aspect of the temp issue was that when I trimmed the bow UP, the temp also increased markedly. Trim the bow DOWN and down came the temp! Cruise along with zero trimming and the temp stayed down forever.
OK, jumping ahead somewhat I employed a "marine mechanic" who I know can do good work to rebuild the motor from the ground up as being some 20 plus years old it was in need of some serious work. To say he cocked it up 1000% would be the understatement of the year, I won't even go into it here but after discovering he hadn't tightened the PORT cylinder head down correctly, it soon filled the bores with water, seized and I had to pull the whole thing apart and rebuild it again.
If I do say so myself it came up very well and runs like a new motor but ...................... the temperature problem is still there! I feared it would be as I never discovered one single thing during the rebuild that I could say would cause the overheating.
So what was down from ground up was:
1. New impellor and check the intake holes were not blogged
2. New bellows, universals and intake seawater pipe
3. Complete overhaul of the RAW water intake pump
4. Replace all inlet pipes to the manifolds
5. New thermostat
6. New cylinder heads, manifolds, exhaust risers, gaskets, seals etc. etc.
7. The entire motor received new pistons, rings, rebore, valves and all the other stuff you would expect
8. The inflow of water to both manifolds is "huge" and unrestricted
9. Not a sign of a water leak anywhere
10. New Dizzy and retimed, new plug leads, coil and most anything you could think of.
But back in the water and whilst it performs beautifully it is back to the same old trick again with the overheating on the PORT side.
I have an IR Temperature sensor that I use to check temperatures and it confirms what the gauge and my hand both feel, very hot on PORT side. The max temp limit reached is about 80C and whilst this is not far away from the normal limit I can't see why it should be so. The STBD side runs a good 30 C below the PORT side.
And it is still the BOW up/down action that triggers the temp increase! Leave it alone and it is a happy motor.
I have back pressured water down the intake pipe rear of the RAW pump and it pours out of the ten intake holes on the lower gearbox. There is oodles of salt water being pumped into the motor on both sides. If I pull off one pipe you could put a fire out with it it is so strong!
So why does this BOW lifting movement cause such an instantaneous and rapid increase of the temp? It doesn't muck around and peaks within about 10-15 seconds as the BOW rises. The actual angle that the 10 intake holes in the lower leg increase by is pretty minimal and I just can't see the water flow into them being affected in the slightest as the BOW only goes up by about 10 degrees max!
So I and lots of other smart guys are pretty well lost! I've had some very clever guys ponder this problem and we are not even close to an answer!
My apologies for the above explanation if it is a bit hard to follow but it is pretty difficult to get everything in the right order and with the fact so much has been tried to correct it!
In summary, drop it in the water, leave the trim alone and she runs like a new boat all day long. Blip the trim up a few degrees and it cooks the PORT side! Bloody amazing!
Many thanks guys!
This is a repost of a problem I had about 18 months ago and in spite of some really great help from Ausfish, it could never be solved!
I'll try to be as brief as possible...................
1996 Whittley Cruisemaster powered by a 1995 Ford Windsor 351 V8 inboard with the usual mix of some Volvo Penta Parts in the accessories such as cooling manifolds, stern drive, exhaust risers etc.
For no real reason it started to overheat ON THE PORT SIDE ONLY. Coincident with this was the discovery of a small cylinder head crack in the STBD HEAD.
The weirdest aspect of the temp issue was that when I trimmed the bow UP, the temp also increased markedly. Trim the bow DOWN and down came the temp! Cruise along with zero trimming and the temp stayed down forever.
OK, jumping ahead somewhat I employed a "marine mechanic" who I know can do good work to rebuild the motor from the ground up as being some 20 plus years old it was in need of some serious work. To say he cocked it up 1000% would be the understatement of the year, I won't even go into it here but after discovering he hadn't tightened the PORT cylinder head down correctly, it soon filled the bores with water, seized and I had to pull the whole thing apart and rebuild it again.
If I do say so myself it came up very well and runs like a new motor but ...................... the temperature problem is still there! I feared it would be as I never discovered one single thing during the rebuild that I could say would cause the overheating.
So what was down from ground up was:
1. New impellor and check the intake holes were not blogged
2. New bellows, universals and intake seawater pipe
3. Complete overhaul of the RAW water intake pump
4. Replace all inlet pipes to the manifolds
5. New thermostat
6. New cylinder heads, manifolds, exhaust risers, gaskets, seals etc. etc.
7. The entire motor received new pistons, rings, rebore, valves and all the other stuff you would expect
8. The inflow of water to both manifolds is "huge" and unrestricted
9. Not a sign of a water leak anywhere
10. New Dizzy and retimed, new plug leads, coil and most anything you could think of.
But back in the water and whilst it performs beautifully it is back to the same old trick again with the overheating on the PORT side.
I have an IR Temperature sensor that I use to check temperatures and it confirms what the gauge and my hand both feel, very hot on PORT side. The max temp limit reached is about 80C and whilst this is not far away from the normal limit I can't see why it should be so. The STBD side runs a good 30 C below the PORT side.
And it is still the BOW up/down action that triggers the temp increase! Leave it alone and it is a happy motor.
I have back pressured water down the intake pipe rear of the RAW pump and it pours out of the ten intake holes on the lower gearbox. There is oodles of salt water being pumped into the motor on both sides. If I pull off one pipe you could put a fire out with it it is so strong!
So why does this BOW lifting movement cause such an instantaneous and rapid increase of the temp? It doesn't muck around and peaks within about 10-15 seconds as the BOW rises. The actual angle that the 10 intake holes in the lower leg increase by is pretty minimal and I just can't see the water flow into them being affected in the slightest as the BOW only goes up by about 10 degrees max!
So I and lots of other smart guys are pretty well lost! I've had some very clever guys ponder this problem and we are not even close to an answer!
My apologies for the above explanation if it is a bit hard to follow but it is pretty difficult to get everything in the right order and with the fact so much has been tried to correct it!
In summary, drop it in the water, leave the trim alone and she runs like a new boat all day long. Blip the trim up a few degrees and it cooks the PORT side! Bloody amazing!
Many thanks guys!