Coolant mixing with gas in the intake

[UHHOHH1212]

So after rebuilding the head and putting new gaskets on the engine fired up and quickly died, would not restart. After a short time of cranking i looked past the carb and noticed alot of fluid in the intake. It has a fuel smell but not that strong and when it was drained had a green tint. I also noticed some coolant leaking past the gasket and dripping down the motor. It is the ford 460 head which has ports for coolant on both ends but the intake manifold does not have those ports as it has hoses for coolant. The only gasket i could find had openings for the ports on the head. Is there a different gasket that closes off those ports? Could i epoxy those ports closed on the head as they are not needed? 1986 mercruiser 170

 

[UHHOHH1212]

Going to close the ports with high temp epoxy. It doesn't stop the coolant from circulating anywhere else so I figure why not. If anyone has any insight on what the "correct way" is I would appreciate it

 

[Bt Doctur]

? There is no reason to do anything like that, nothing spec in the manual about it, You are using the correct gasket?

 

[Bt Doctur]

 

[Bt Doctur]

The A/F in the intake is the bigger problem. Is the intake cracked , the head gasket leaking or the intake valve allowing A/F into the cylinder and then into the intake itself

 

[hemi rt]

Is the thermostat housing part of the intake? If it is then you can not block the ports or you will not get any flow to the thermostat, if water is getting into the manifold then either there is a crack in the manifold or even possibly the wrong intake for the engine and not sealing properly to the heads.

 

[Bt Doctur]

the 170 is the bastard child of mercruiser. the exaust manifold had the t-stat in it

 

[achris]

Looking at the intake manifold, it has coolant hoses and, therefore, coolant running through it. Is it at all possible the manifold is corroded/cracked internally?



It also has a cooler tray on the bottom. Before closing up any ports, I'd be pulling the manifold off and having a really good look at it....

Just saying...

Chris..........

 

[Bt Doctur]

Dont even see ports to close off, there is no coolant passage in the intake system of the head

 

[UHHOHH1212]

I included 2 photos from the repair manual as reference. The head has an opening at each end and a square opening in the center that are all for circulating coolant on certain intakes, mostly automotive. I couldn't find a front view of the intake but it does not have those coolant ports because it is cooled by the hoses that connect to it. The correct gasket i believe has those ports covered but i was not able to find that gasket and bought an automotive gasket that does have those ports open. So my though was since those ports are useless to my engine and are only there for intakes that are cooled by those ports that it should be harmless to seal them off as it would have basically the same effect as having the correct gasket which closes them off. The intake has no cracks, i could see the coolant leaking past the gasket and dripping down the motor so im sure it was leaking into the ports. The picture above i believe is the 4bbl intake which is a similar design but mine is one solid piece with the part #7 assembly and the 2 coolant hoses on each side and no pan or what looks to be a plug on the top #2

 

[UHHOHH1212]

Before rebuilding the head it looked like the previous owner had either closed off the ports or there was build up from the correct gasket closing them off and when i was cleaning it all up i opened the ports back up because it just looked like corrosion. So prior to me cleaning out those ports the intake sealed to the head and there where no leaks, thats why im thinking of just closing them back up as i couldnt find the correct gasket that closes off those ports

 

[Bt Doctur]

guess you didnt check ebay or iboats

 

[Bt Doctur]

felpro

 

[achris]

OK, call me crazy... But why not just use the right gasket? It's still available (from any Merc dealer), part number 27-70905, and it's less than $10....

Chris.......

 

[achris]

felpro

That's a V8 set... OP has a '470'.....

 

[UHHOHH1212]

Bt doctor that felpro gasket is what I got which has the openings at the 3 ports. Achris, i was having trouble finding the right gasket as there are differences throughout the years on the 170/470 so I looked it up by the Ford 460 head, the part number you listed though does look like the right one

 

[achris]

If you have the engine serial number, that will definitely nail it... But I did check, and it's the same gasket right from the start of the '470' engines, regardless of 2 or 4 bbl carb.

Chris.........

 

[Scott Danforth]

this is a case where you need the Mercruiser intake gasket and the Mercruiser head gasket. this motor is probably the only time where the Felpro route isnt better.

BTW, nice upgrade is to use an Edelbrock aluminum head and drill the big hole for the 90 degree elbow