Operating TEmp Questions

R

rkirkwo1

Cadet
Joined
Mar 31, 2006
Messages
9
Background Info

twin 115 V4 flatbacks, running on muffs for about 15 - 20 min.

Stats / relief valves / springs replaced 2 years ago. Water passage in thermostat housing block slightly enlarged, small v notchs (x2 each) filed in edges of relief valves (previosuly had issue with air entrapment causing overheat at initial shakedown @ seasonal start.)

Water pumps / impellers replaced @ begining of last season on both.

Temp measured with laser guided infrared thermomter

Port Engine
- Reman'd block approx 100hrs
- Compression 105ish on all cylinders
- Good Spark on all cyclinders
- Port block / head temps approx 108
- Starboard block / head approx. 128

Starboard Engine

- Reman'd block approx 50hrs
- Compression 120ish on all cylinders
- Good Spark on all cyclinders
- Port block / head temps approx 115
- Starboard block / head approx. 125
- Water pressure / tell tale a little stronger as compared to port motor

Questions
Are they both running a little to cold?
What are the implications of running in this condition? (I dread the thermostat pulling routine and re-assembly!)?
Does the starboard bank typically run hotter?
What could be the potential cause of the 20 degree delta between sides on port motor?
 
Texasmark

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,782
Re: Operating TEmp Questions

Possibly your variances are caused by where you measured your temps since surface emissivity has an effect on your reading and the temperature of the cylinder head is not uniform necessarily, and changes when the stats open.

The engine to engine variance could be anything, but higher compression and friction from a tighter engine could contribute to the higher temp readings on the Starboard engine. Course by 50 hours, you'd think things were pretty slicked up.

I have access to two Mercs. One runs a 120F stat (opening temp) and the other, a V6, runs a pair of 143 stats. Don't know what yours runs. Not knowing that, nor how long your engines were running when tested makes it hard to second guess the problem if any. I have about convinced myself that the stats are necessary as is a warm engine for proper engine life, emission, and efficiency.

Being a V4 one bank sits higher than the other; on Merc it's the starboard bank . The higher bank could run hotter if any air is trapped in there or circulation is reduced by the flow going out the Port stat (on the Merc setup where the stats are at the very top of the heads) when it opens. At your temps however, I doubt either stat (if you have two) has had time to open.

Best I can do.

Mark
 
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