Volvo AQ130 installed new head from B20 car engine problem with cooling

[Krle]

Old Volvo AQ130 B20 from the seventies had problem with cooling and the head end up with the hole letting sea in the cilinders. I tried to find good head from the same marine engine but it seems that all the heads from the B20 are in very similar bad condition due to the sea water going through it for all these years. So I found B20 engine from Volvo 144 old car which was running. We took off the head and we prepared it to fit it and it is on the engine now.

Problem we have now is, we think that there is no proper flow inside the head. The temperature seems ok, but the difference (by touch) between the exhaust manifold and the thermostat cover is big. Thermostat cover seems hot.

Big question I want to ask is:
Is there any difference between the automotive B20 head and the volvo penta marine B20 head?

We are now thinking that car version (closed cooling system) is having different circulation inside the head. Is it?

The only difference we found is that the temperature sensor was on the opposite side, and there is one hole we had to make for the water to go in through the tube which is than covered with cover of the thermostat. Several more holes we had to close also, the ones we saw that are different on the old head.

Any idea? What did we do wrong? Has anybody else tried to fit automotive engine head on the AQ130?

 

[diesel1960]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

Yes ,you can bolted automotive B20 head and vice verse.I have done this before(always use marine head gasket)
Your problem is in raw water cooling system.
These engines had always overheating problems.
Check older posts related to AQ130 overheating.

 

[Krle]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

thanks for the info about the head. I would not stand another head removal
We plan to examine the path of the water circulation and I expect to find something in the filter or something around the pumps. impeler is good and cold. we do not have thermostat in the system.

 

[captmello]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

It doesn't help to run without a thermostat, so I would put one in. Those cooling systems are prone to leaking air on the intake side of the raw water pump, pull the hose off the fitting at the outdrive, right bellow the ujoint bellows. the fitting and gasket are notorious for leaking, but only when the boat is on plane. when the boat slows, the fitting goes under water and the temps go back to normal.

How hot is the manifold? can you touch it for a second or two, or is it much hotter than that? I don't see how comparing the thermostat housing to the manifold temp is relevent, especially with no thermostat in the motor.

Welcome to iboats, btw.

 

[diesel1960]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

For engine components temperature tests I using laser thermometer ,it's handy tool ,they go around $30-50 now.
I ran my AQ130 at 180*F,taken on the top of the head.

 

[Krle]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

everything I explained happens in idle, we still did not load the engine by putting it in gear until we get proper cooling of the system. the intake of raw water is ok, we had this issue and solved it this winter

so, we start the engine and it takes some minutes to come into the working temperature (it is always green on the temperature gauge, right in the middle). temperature sensor in this head (automobile) is on the back (opposite from the thermostat cover).
I touch by hand and I can feel that the part where impeler is is cold and also the complete exhaust manifold is cold. what is hot is copper tubes going out from the manifold and also the brass cover of the thermostat. You can not leave a finger on it for a second. I compare the temperature following the path that water is going. Maybe I use wrong words pardon by English. It seems to me that we are cooling the exhaust manifold and something is blocking the flow to the head.

are you really shure that missing of the thermostat could prvent the flow? I am aware that the temperature is not controled by it, but could it really cause prolems in flow of the cooling water?

It doesn't help to run without a thermostat, so I would put one in. Those cooling systems are prone to leaking air on the intake side of the raw water pump, pull the hose off the fitting at the outdrive, right bellow the ujoint bellows. the fitting and gasket are notorious for leaking, but only when the boat is on plane. when the boat slows, the fitting goes under water and the temps go back to normal.

How hot is the manifold? can you touch it for a second or two, or is it much hotter than that? I don't see how comparing the thermostat housing to the manifold temp is relevent, especially with no thermostat in the motor.

Welcome to iboats, btw.

thnx

 

[Krle]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

For engine components temperature tests I using laser thermometer ,it's handy tool ,they go around $30-50 now.
I ran my AQ130 at 180*F,taken on the top of the head.

thnx for the info I'll have that value in mind on Monday when we plan to measure th temperature with the IR thermometer.

 

[diesel1960]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

With help of my son (big Volvo cars fan) I find out that some of the automotive engine heads have smaller coolant passages .
If you give me complete number -stamped on your donor head ,we will tell you if is small passages or marine ,larger.
Check this link-you will find all info there.
http://www.v-performance.com/articles/volvo_b20_head_identification.html

 

[Krle]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

still having problems when running in the gear it goes overheating. After it gets in the red I get it in idle and cool it with high Rpm. After that when I put it in gear it again goes but slowly again overheats. I think that there is flow in he circulating system but something is on the way. Tomorrow I will try to check the incoming hose from the sea water with pressure. Everything else is checked. Any comment or idea?

 

[diesel1960]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling

still having problems when running in the gear it goes overheating. After it gets in the red I get it in idle and cool it with high Rpm. After that when I put it in gear it again goes but slowly again overheats. I think that there is flow in he circulating system but something is on the way. Tomorrow I will try to check the incoming hose from the sea water with pressure. Everything else is checked. Any comment or idea?

Looks like you have water restricted only when the boat is moving,must be a problem in your outdrive water pick-up.

 

[Waffu Chief]

Re: Volvo AQ130 installed new head from B20 car engine problem with cooling



Looks like you have water restricted only when the boat is moving,must be a problem in your outdrive water pick-up.

One of the biggest problems is the years of rust scale build up within the heads and engine block. I have recently changed aq130 engines with a serviceable 2nd hand engine. On inspecting the water ways I could see flakes of rust in all the water ways which I put a water hose on and was surprised by the amount of rubbish that came out of both. I then took a drill to the ports that had closed up and again flushed through with water, as I moved the block and head around even more scale came out. On further inspection of the head I noticed there were four more ports to one side that had blocked holes, these I ran a a small drill through realising there were infact two holes in each of these ports. I am in the process of rebuilding.