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Discussion Starter #1
What can be done to keep them down?
Heads have signs of heat, oil is cooking under piston.
1550 * EGTs from 5500-6000.
Iron Eagle 345, no intercooler, 8psi, 900hp. 150* intake temp. low 12AFR cruising. Low 11`s @WOT
13,000# heavy boat .

I thought about giving it more fuel. ( Northstar engine after 20 seconds of WOT goes to 10.0 AFR to cool piston)
Water injection.
Intercooler?




 

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Discussion Starter #4
Ignition timing is based on MAP input. Basically 30* at 4000.. progressive to 35* 6000.
Scott I thought about piston oilers, both motor are at machine shop now waiting their turn so this would be the time however with the spring oilers eating up volume and pressure I`m not sure dry sump could supply enough oil to feed both. Schumann pumps are already bought.
 

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Some guy
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Ignition timing is based on MAP input. Basically 30* at 4000.. progressive to 35* 6000.
Scott I thought about piston oilers, both motor are at machine shop now waiting their turn so this would be the time however with the spring oilers eating up volume and pressure I`m not sure dry sump could supply enough oil to feed both. Schumann pumps are already bought.
So you don't think that 35 degrees of timing is making your heat with 8psi and no intercooler and a 13,000 lb boat?
 

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Discussion Starter #6
Not sure what you mean. I have large chambers (134cc) It likes 35*
The more timing I give it the lower the EGTs ( I understand etgs and combustion temps isn`t the same)
You saying too much timing , boost and no intercooler is the issue?

I`d agree with that. I`m trying to figure out how to lower it in it`s current state.
water injection, lower the boost , intercooler..????
 

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Highaboosta
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I would be more concerned about the intake air temps than the EGT's on gas.

I never found any useful tuning information from using EGT's because EGT's are highest at stoich.
To pull a number out of the air and say that's high is a guess.
My setup runs 1550 EGT at a part throttle cruising speed under vacuum. Doesn't hurt a thing.
It burns clean and the plugs last for years.
 

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Discussion Starter #9
hard to find much info about piston oilers, anyone have experience about how much pressure they eat?
 

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I have experience. We built a turbo piece for Washington University Engineering students back in the early 90's. (maybe 89 or 90) Drilled oilers.
Let me ask you a question. What is your concern? Discoloration? Oil temps?
Way back in the day.... the discoloration was a sign of cylinder temps. IF you weren't cooking oil, you weren't making much power.
Fast forward 30 years..
Again, what is the concern..... or goal?
That is normal blown gas stuff.
Wags
 

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steelcomp was here
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hard to find much info about piston oilers, anyone have experience about how much pressure they eat?
I've run piston oilers and T&D rockers with spring oilers and not seen any oil pressure issues with a wet sump and Melling M77HV pump.
What Wags said...
 

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Discussion Starter #12
Wags, it boils down to reliability.
Bought this boat 3 years ago and it has been nothing but issues, from both drives being shot to the leaking headers and fuel tanks and beyond.

The motors were fresh at that time but had many leaks, used oil, lots of blow by, wrong plugs, terrible valvetrain set up etc...
I`ve been making things right and now I`m down to the last piece that I haven`t touched. The short blocks.

This is a pleasure boat and I`d like to get a few seasons out of it without having to spend most of my day in the bilge or missing weekends in a very short season. I`d like to do everything possible to keep detonation/heat down and be able to run if I want to.
Running it at WOT for a few miles without issues would be fantastic!

I`ve got 4 motors in my garage , mine and a friends. His pistons after 100 hours look brand new on the bottom.
His is a lighter boat by 3000lbs and his 468s make a 800hp. No intercooler 6psi Dart 308`s.

Maybe I need to get a set of intercoolers but this thing has me drained at the current time $$$ (gas tanks, interior, exhaust last year, 2 rebuilds, bottom work etc this year)
So I`d like to spend my money wisely and get the best bang for my buck cause everything I do is times 2.

Maybe the burned oil is not an issue...





It`s for the children!:wink2:


 

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IMO... you are worrying about a total NON issue.
IF the oil cooking bothers you, spraying oil on the bottom of the piston may help a little. You still have the heat in the piston.

HOWEVER, coating the piston tops will stop the heat transfer into the piston, this will stop oil cooking on bottom.
AND, you are not reinventing the wheel.

Spraying oil is way less common... PLUS, at 5000 rpm do you really think that oil is going where it is aimed, or just making more windage??

Wags
 

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Discussion Starter #14
Running extended times at max TQ and load is an issue to me. Heat soak and high temps are an issue in an endurance engine. At 3500 I`m already pushing 4psi. Load is high.
Piston oilers have been proven to work, many manufacturers use them today as do almost all modern Diesels.
Coatings reflect more heat in the chamber and don`t allow it to be transferred to the cooling system doing the exact opposite to what I`m trying to prevent.

Seems like you guys have a little clique here.. Guess I should get a lake boat and maybe then I`ll get some replies.
Thanx for the input, I`ll see my self out.


.
 

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Discussion Starter #15
I've run piston oilers and T&D rockers with spring oilers and not seen any oil pressure issues with a wet sump and Melling M77HV pump.
What Wags said...
My spring oilers with the same Melling pump dropped my pressure about 10psi. Spring a leak in a line and pressure goes down, that`s just simple Physics.
Thanx for your input.
 

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steelcomp was here
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My spring oilers with the same Melling pump dropped my pressure about 10psi. Spring a leak in a line and pressure goes down, that`s just simple Physics.
Thanx for your input.
Depends on the leak and the pump. If the pump has the capacity to maintain the volume, then there shouldn't be a drop in pressure. If you have a lot of bearing clearance, lifter clearance, oil cooler lines, etc. and your pump is close to maxed out already, then yes...you'll probably see a drop in pressure.
 

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steelcomp was here
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Running extended times at max TQ and load is an issue to me. Heat soak and high temps are an issue in an endurance engine. At 3500 I`m already pushing 4psi. Load is high.
Piston oilers have been proven to work, many manufacturers use them today as do almost all modern Diesels.
Coatings reflect more heat in the chamber and don`t allow it to be transferred to the cooling system doing the exact opposite to what I`m trying to prevent.

Seems like you guys have a little clique here.. Guess I should get a lake boat and maybe then I`ll get some replies.
Thanx for the input, I`ll see my self out.


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Thermal coating pistons is very common in endurance builds, especially blower engines. We do it all the time. It's inexpensive and it works. You have an unlimited supply of cold water for your engine cooling. BB Chevy chambers by design are huge and have a LOT of surface area. This means a lot of heat transfer capacity and the added heat reflected back into the chamber from a coated piston is not an issue. You'll make more power. Coating the piston will also help keep oil temps under control.
 

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Sure, piston oilers are common in diesels. Think of the rpm a diesel turns vs what you are turning. I just think, for your app, coating is easy, and proven.
I didn't mean to piss you off. Most guys don't have experience with oilers, coatings, etc.
I do. I built a few demo derby pieces, (7000 to 8000dollar pieces) coated tons of stuff. They will run half of forever with radiator compromised.
Wags
 
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