Volvo Penta D8 550 stbd exhaust temperature @ 1020F, port at 770F

Sailor999

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Oct 13, 2021
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Hello, I am new to this forum so please forgive my etiquette mistakes.

I noticed that my engine display shows the starboard exhaust temperature sensor @1020F vs 770F on port at about 80% of power. All other engine parameters were nearly identical on both sides, within normal. and no errors were recorded. I know that the error detection system works as they are displayed liberally on benign occasions.

Questions:
- what is the allowable exhaust exhaust temperature? (could not find the limits anywhere)
- what could cause it and is that something critical to fix right away?

I just ordered an IR temperature meter to check the external temperature on both sides of the exhaust. Any other suggestions would be appreciated.

Thank you!
 

alldodge

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My guess is the sensor may be the problem, thinking other things would show up.

The IR gun will help identify if there is an issue. Might swap the sensor to see if it moves to the other motor
 

Sailor999

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My guess is the sensor may be the problem, thinking other things would show up.

The IR gun will help identify if there is an issue. Might swap the sensor to see if it moves to the other motor
Thank you alldodge. I will try your suggestion when I am next on the way. Any thoughts what that temperature should be? Not listed in the spec or operating manual.
 

alldodge

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Don't know for sure. If probe is right after the turbo then 1000 degrees or more would be right. If itsin the muffler then less because of water mix. Who knows the one reading 700 might be the problem. Just depends where the probe is located
 

chris.olson

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Hello, I am new to this forum so please forgive my etiquette mistakes.

I noticed that my engine display shows the starboard exhaust temperature sensor @1020F vs 770F on port at about 80% of power.

For future reference, EGT is a matter of duty cycle. 1,000F is maximum continuous. 1,100 F is 5 minutes max. 1,200 F is 2 minutes max. 1,300F is 30 seconds max. The pyrometer probe is just ahead of the turbocharger turbine inlet. It will be 200-300 degrees cooler on the turbine outlet due to what a turbocharger does - it converts exhaust heat into mechanical power to run a compressor. A pyro probe placed after the turbocharger turbine is totally useless.

Exceeding the limits will cause damage to the turbine wheel in your turbocharger. Unless you have replaced the turbine wheel with a special ceramic coated wheel, which is very expensive (to the tune of around $10,000) and not likely.

Most common cause of excessive EGT is over-fueling. If it runs consistently high have somebody with the proper equipment check the max fuel rate to make sure the engine is not being over-fueled. Over-fueling produces more power, but diesel fuel burns very hot and pouring too much fuel on the fire will damage not only your turbocharger, but also exhaust valves.
 
Last edited:

Sailor999

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Joined
Oct 13, 2021
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For future reference, EGT is a matter of duty cycle. 1,000F is maximum continuous. 1,100 F is 5 minutes max. 1,200 F is 2 minutes max. 1,300F is 30 seconds max. The pyrometer probe is just ahead of the turbocharger turbine inlet. It will be 200-300 degrees cooler on the turbine outlet due to what a turbocharger does - it converts exhaust heat into mechanical power to run a compressor. A pyro probe placed after the turbocharger turbine is totally useless.

Exceeding the limits will cause damage to the turbine wheel in your turbocharger. Unless you have replaced the turbine wheel with a special ceramic coated wheel, which is very expensive (to the tune of around $10,000) and not likely.

Most common cause of excessive EGT is over-fueling. If it runs consistently high have somebody with the proper equipment check the max fuel rate to make sure the engine is not being over-fueled. Over-fueling produces more power, but diesel fuel burns very hot and pouring too much fuel on the fire will damage not only your turbocharger, but also exhaust valves.
Chris,
Thank you for a comprehensive answer. I have also noticed that that starboard engine shows consistently more power (on the engine power gauge) than port engine at the same RPM. The difference increases with RPM. I have a Volvo mechanic visit scheduled on Monday and will share the finding.
 
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