Overheating issue - conglomeration motor.

[Numlaar]

Don't know if this is relevant or not, but basically have a 5 in one motor that works to be roughly a 1978 175hp.

New rings, bearings, in good block, best 2 heads i had, etc.

Put it all together, ran fine on muffs, took it to lake, and its overheating on port (left) side only. This particular block never ran hot before, and heads came from a freshwater engine, cleanest i have ever seen.

Ran it about 5 mins trying to do the varying RPM to break in the rings, and it started to heat seize. (I have installed individual temp gauges in each head, starboard was 145, port hit 190 before i shut it down and could hear it start to knock/seize). I do believe, however, I shut it down in time without doing any major damage. Let it cool down, and it fires right back up. Pulled the plugs and they are clean, no water (milk) or piston breakdown debris.

So the only thing I can think of is the head gasket didnt seat on this side???
questions:
1. What are the possible causes of a one side only overheat?
2. If it is the head gasket, is it possible for it to blow in a way to make it overheat, but NOT get water in the cylinder??

Any suggestions would be welcome at this point. If i can't resolve this, im ditching the boat, motor and trailer at this point, im over it.

 

[sutor623]

Re: Overheating issue - conglomeration motor.

Does this motor have dual thermostats?

 

[Numlaar]

Re: Overheating issue - conglomeration motor.

Does this motor have dual thermostats?

Yes V-6, one in each head, and both are brand new, along with new poppets.

 

[itsaboattime]

Re: Overheating issue - conglomeration motor.

This may sound like a dumb question but, did you put new water deflectors in when you assembled the powerhead?

 

[Numlaar]

Re: Overheating issue - conglomeration motor.

This may sound like a dumb question but, did you put new water deflectors in when you assembled the powerhead?

Not dumb at all, and actually I did not. I assume you are talking about the rubber things in around the cylinder bores... The original ones were all there, and seemed ok. So I left them alone.

This particular block (and engine) was running fine, nice and cool on both sides, it had just ran lean (carb issue) and burned a piston, hence the rebuild, so I didn't think it was necessary to change them. Now after re-assembly the left side is running hot.

 

[itsaboattime]

Re: Overheating issue - conglomeration motor.

On my 110 v4 the starboard(right) side runs a little warmer than the port side. From all accounts that is normal. Other than water deflectors, I can't think of why the port(left) bank would be hotter.
I am going on the assumption that the left bank sits lower, like on my V4, than the right bank. And should actually run cooler. I am going to say you have a restriction someplace.
I hate to say it but I would pull the head and swap out the deflectors and maybe blow some compressed air down the water passages to try and clear them.
But you said this block had always ran cool.
I'm at a loss. Sorry brother.

 

[sutor623]

Re: Overheating issue - conglomeration motor.

He could also pull the thermostat just to make sure that the stat isnt clogged or getting stuck. I have bought brand spankin new faulty thermostats!!!

 

[pn]

Re: Overheating issue - conglomeration motor.

i recently purchashed new thermostats off ebay, for a 120 v4 and testing them in water proved that all four open at different temperatures. I would switch out the port for the starboard, and see if the head temp flips too. If you have the bullet type, you can take the thermostats apart as well by putting a small screwdriver in the bullet top and unscrewing. good luck

 

[sutor623]

Re: Overheating issue - conglomeration motor.

i recently purchashed new thermostats off ebay, for a 120 v4 and testing them in water proved that all four open at different temperatures.

That sucks man.

 

[Numlaar]

Re: Overheating issue - conglomeration motor.

On my 110 v4 the starboard(right) side runs a little warmer than the port side. From all accounts that is normal. Other than water deflectors, I can't think of why the port(left) bank would be hotter.
I am going on the assumption that the left bank sits lower, like on my V4, than the right bank. And should actually run cooler. I am going to say you have a restriction someplace.
I hate to say it but I would pull the head and swap out the deflectors and maybe blow some compressed air down the water passages to try and clear them.
But you said this block had always ran cool.
I'm at a loss. Sorry brother.

Yeah I am at a loss too... hence me being here. I didn't really think about the t-stats because they are new... I will pull em both and do a hot water test and see what happens, then go from there.

I really don't think there is a blockage.. as I said this engine ran very cool and great for the last year, and was a freshwater only motor so very little buildup... I may go ahead and re-pull the port head as well to see what it looks like. I will let u guys know.

Thanks

 

[sutor623]

Re: Overheating issue - conglomeration motor.

Yeah I am at a loss too... hence me being here. I didn't really think about the t-stats because they are new... I will pull em both and do a hot water test and see what happens, then go from there.

I really don't think there is a blockage.. as I said this engine ran very cool and great for the last year, and was a freshwater only motor so very little buildup... I may go ahead and re-pull the port head as well to see what it looks like. I will let u guys know.

Thanks

Well def. check the stats before you pull the head!