Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

[shackmaninc]

Hello all I need some advice.
I recently replaced my head gaskets on a fairly new engine rebuild (20 hrs.) The port side head gasket was blown. Middle two cylinders were blown and eating coolant. Closed loop cooling system btw.

Upon start and test run today with a new thermostat 160 degree. I had my heat gun at the ready everything was just dandy manifolds were both at about 140-160 and both heads were at the same 140-160 (a bit colder at the rear of the engine) and the block at 140ish. My worries are with the intake manifold. Both front and rear of the manifold were about 130 -140 but right in the middle where it looks like there are another set of ports the temperature was a blazing 300 at the end of my 10 minute test run. I was running the engine on muffs and was at idle for 5 min. and then up at about 1500rpm for the last five.

I really can't recall if those are water ports or not, but I just don't feel it should be that high. The paint even has been burnt off right on those ports. I am thinking that maybe this has something to do with the head gasket failing right in between those two cylinders.

I would appreciate any help or input you guys have. I just don't want to go out and have the same thing happen if it is something that is bad.

Thanks for your help

 

[wrench 3]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

These are exhaust ports for the intake manifold heater and will get quite hot.

 

[Walt T]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

SSHHHHhhh Wrench, shoulda told him "You DID check the intake bearing, right?"

Well, I would have laughed.

 

[wrench 3]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

SSHHHHhhh Wrench, shoulda told him "You DID check the intake bearing, right?"

Well, I would have laughed.

Hey, not every body can be a mechanic. Good thing, or I wouldn't have any work.

 

[shackmaninc]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

hardy har har
Thanks for the input wrench. I will admit I do not know all that much but have held my own so far. Is the purpose of those ports to get the manifold up to temperature quicker? And so in your opinion 300 + degrees is not uncommon for those ports to reach? Thanks

 

[Lou C]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

There is an exhaust crossover under that area but no part of a marine inboard should ever get that hot. Mine gets to 130 at most in the area where the thermostatic spring for the choke is on the intake manifold.
Your manifolds are hot too, on the water hose they should be closer to 100* or so. Look for restrictions in the exhaust and make sure the raw water pump is not worn and the heat exchanger is not clogged. You had a rebuild last 20 hrs and it blew the head gaskets? Something is obviously wrong and if you don't find it you will blow another set or worse.

 

[wrench 3]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

The purpose of the manifold heater is to stop the carburator from getting to cold. Even at 70'f temperatures the pressure drop through the venturi can lower temps below freezing.
I may have read your first post wrong. Thought you had 20hrs since doing head gaskets. As with any failure you need to fix the cause not just repair the symptom. It worries me that you did not mention checking the heads for warpage.
The temps Lou gave you sound right for no load but could be a lot hotter if it's been running under load.

 

[Lou C]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Thats right, the temps I listed are no load temps on the water hose on land. Even in the water after running on plane, the manifolds on my boat at the hottest part are 130 and they cool off to about 100 after idling for like 5-10 minutes. The area where the choke thermo spring sits not more than 155-160 after running. IF its hitting 300 something is VERY VERY WRONG...Most of that intake is water cooled....either the hot exhaust is not getting OUT....or the cooling water is not getting IN...in any case it needs to be fixed right away...

Imagine if the manifold right under the carb was cookin' at 300*F, it may boil the gas in the carb, LOL....in fact....that's what we used to call vapor lock back in the day....but thats running a much hotter automotive 195* stat, the 160* stat should never let it get anywhere near that hot....

 

[Fun Times]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

But right in the middle where it looks like there are another set of ports the temperature was a blazing 300 degrees.

This kind of sounds like you may have used the incorrect intake manifold gaskets. Do you recall if both the gaskets had an opening in the center area? The correct ones would have an opening.

300 degrees is excessive.

 

[wrench 3]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Hay Lou, thanks for keeping me thinking. I never used an inferred thermometer to get actual readings. But you make a lot of sense. Cars will often burn the paint off of that part of the manifold but boats usually don't, because they don't have a heat riser valve to force the exhaust through the intake. The only thing that comes to mind is a messed up exhaust flap, but I'm not even sure what the GLs use. I'll look in the manual tomorrow. Regardless, if the exhaust is restricted on one side, that exhaust riser should be cooler than the other one.
BTW the only water in the intake is from the thermostat to the front port on each head. the rear ports are blocked off by the manifold.

 

[wrench 3]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

This kind of sounds like you may have used the incorrect intake manifold gaskets. Do you recall if both the gaskets had an opening in the center area? The correct ones would have an opening.

I checked the intake gaskets that Sierra list for that engine and they do have port openings in the center.

 

[shackmaninc]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Thanks so much for the ideas guys. I will try to address everything.

LOU C
I took off both exhaust elbows and neither of them looked like they had blocked passages ( I bought brand new manifolds with the rebuild) . There are no flappers in the exhaust. I also took apart the raw water pump and everything looked perfect with no noticeable wear (also replaced that at time of rebuild).
Good thinking with the heat exchanger being clogged. I will check that, I feel that enough water is coming out and the water is not boiling hot it seems to be just right like it is flowing at the correct rate. maybe about 130-140* when coming out ( just a guess)
When you say the water hose should be about 100. Are you talking about the hose exiting the water heater and feeding the manifolds. BTW I have a half cooling system. The manifolds are cooled by fresh water still.

Wrench

I did check for warpage on the side with the blown head gasket and could not even find a thou. I did not check the block though.
I have an Edlebrock 1409 carb with the electric choke on the side. Also A duel plane intake, do not know what model at this point.

Lou
Would you consider running at 1500 rpm on land being under load? I always considered under load when it is actually pushing some weight, moving some water, and making me happy lol

Fun times
I was thinking this as well, I did try and save some money and went with an automotive victor reinz gasket kit. I assumed it was ok being that I am running with a closed system. I will pull the intake tomorrow. Even if they were closed wouldn't that keep the hot exhaust from entering the manifold in the first place? I am still a little in the dark as to the plumbing of that intake manifold if not all manifolds.

Thanks again I really appreciate it

 

[jeffnick]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

This is normal.

 

[gbeltran]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Thats right, the temps I listed are no load temps on the water hose on land. Even in the water after running on plane, the manifolds on my boat at the hottest part are 130 and they cool off to about 100 after idling for like 5-10 minutes. The area where the choke thermo spring sits not more than 155-160 after running. IF its hitting 300 something is VERY VERY WRONG...Most of that intake is water cooled....either the hot exhaust is not getting OUT....or the cooling water is not getting IN...in any case it needs to be fixed right away...

Imagine if the manifold right under the carb was cookin' at 300*F, it may boil the gas in the carb, LOL....in fact....that's what we used to call vapor lock back in the day....but thats running a much hotter automotive 195* stat, the 160* stat should never let it get anywhere near that hot....

Actually, the intake is not water cooled. The only place water goes is up front where the thermostat and hoses go, simply because it's a convenient place to tie the two sides together. I've never measured the crossover for temp, but it's going to be a lot hotter than the thermostat temp. The picture Jeff posted is normally what I see, that crossover gets pretty hot.

 

[gbeltran]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Did you buy the correct gaskets? Or just use some automotive ones? They usually have a stainless piece with a small hole in it where the crossover goes so to restrict the amount of exhaust that can pass thru the crossover.

 

[Lou C]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

The last comment about the gasket for marine use limiting the amount of exhaust gas crossing over may be it. No way should the intake right under the carb be 300*, it will boil the gas into a vapor. Mine does not get hotter than 160. Barely hot enough to make the choke open all the way.

 

[shackmaninc]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

 

[shackmaninc]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Attached a picture of what the old gasket that I replaced looked like. It has a pretty big hole in it. Another picture shows the carburetor and the port with paint burnt off. And the other shows the engine and cooling system plumbing. Does everything look ok as far as the plumbing goes?
I ran the engine again today and same thing. Right on that port it is 300 - 330 but all around it even right next to it the temp is in the mid to low 100's .

I did use an automotive gasket and am not sure of the size of the hole. Yet some of the replies have said that normally the hole is open. So I am not too sure on what to do. I am hesitant to take the manifold back off and check. I might just take it out and keep a close eye on everything while taking it easy. ?? What do you guys think?

 

[Maclin]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Looks pretty normal to me.

 

[shackmaninc]

Re: Volvo penta 570a ccheyv 350 intake manifold too hot HELP please!

Alright then I have got some mixed replies. But have decided to run it how it is. I did some research on vapor lock and that seems to have nothing to do with the temperature of the manifold but to do with the temperature of the fuel lines themselves and being that they are plenty far away from the manifold, I do not think I ned to worry about them. I will continue to keep a close eye on temp and coolant levels.

Thank you to everyone for all of your input!