EGT on my 480CE saved the day??

[Steve Lewis]

Tony, Rob and the forum in general, I just re-read the article “Boost, EGT and Horsepower” and I think I have my answer but I am going to ask anyway.  First the operating context.  Yesterday(Saturday) we left the dock and were headed to our favorite swimming hole on the North side of Kelley’s Island on Lake Erie.  We did our usual multi-stage warm up.  Start the engines just before loosing dock lines then a 5-7min no wake run at 750rpm where EGT is 300F, normal baseline value.  Once we clear the inlet we throttle up to hull speed.  1140rpm and EGT increases to ~500F, normal baseline value.  Once our oil pressure gets below 50 on the analog gauges we throttle up to 2229-2280 depending on conditions.  Saturday was a 2240 day and EGT was 750port 725strdb, normal as usual.  We were running for about 10mins and I constantly scan the gauges for Voltage, Oil Press, Coolant Temp, RPM and EGT.  Port EGT jumped to 1000F.  I did not hear or feel anything.  We immediately throttled back to Hull speed 1140rpm and EGT temps returned to normal 500F for that RPM.   We ran at hull speed for a bit and cleared some traffic and then we throttled up again to see if we got the same reading.  I advanced the throttles and the Port EGT went way high very fast.  So I backed off immediately.  Scratching my head at this point.  We continued at hull speed to our swimming location, set the anchor and opened the engine hatch to let some heat out before I went down to take a look.  I was focused on the EGT gauges so I did not turn around to look for dark smoke.  I did not think to ask my wife to look for dark smoke. 

I was going through different options in my head.  I could swap the probes from one engine to the other and see if the problem followed.  That would have lead me to believe that there was an issue in the port probe/wire/gauge system.  We just had a new VHF installed so there might have been some issues there with wires getting messed around behind the dash………

The engine compartment was not hot so I went down and started checking things.  Probes looked fine, nothing out of place with the wires.  I do not have an IR gun(will be buying one soon) so I did the ole hand check on some components and found things to be safe to the touch.  I touched the Turbo Air Tube(the tube that comes out of the Turbo and goes into the Aftercooler) and it moved.  One of the Constant Torque clamps on the rubber boot that joins the Turbo to the Tube had broken and the boot was loose and moved easily to the touch. Low/No Boost!  is my thinking. I guess here is the question for confirmation.  Based on the article, it appears that the lack of boost could/would lead to a direct increase in EGT?  Is this a valid conclusion?  I will be ordering some clamps for the spares bin on the boat.  I will also call my local Diesel Mechanic as he might have one that I can buy quickly and install.  I am expecting that when I get the Turbo Air Tube sealed tight again the EGT will come back down to normal.  Am I on the right track or am I missing something?

Attached Pic shows the broken clamp but I had re-seated the rubber boot before I took the pic.  It was loose and moved easily to the touch.

We ran 1000rpm back to home dock once we were done swimming etc., so less than hull speed and EGT was 400F on both at 1000RPM.

Thank you in advance for your responses.

2 users thanked author for this post.

Woo, 1969Roamer46

Topic

[Steve Lewis]

Tony,

Both of my risers are the Doomed to fail type.  Both port and starboard have been off the turbos twice in the last 3 seasons and I have personally looked at the exhaust side of both turbos and they are not showing any signs of ingesting water.  Fresh water boat and it is on my list to replace them but at this point in time I am going to run with them, as they are in “good nick”.   My Eyes are wide open on this item.

Steve

[Tony Athens]

Exhaust Riser

Curious —this riser belongs to who?

 

 

[Craig Rutledge]

Thanks for the info and pics Steve I appreciate your experience and input I think I’ll follow in your wake on quite a few of these upgrades ! I’ll post a few progress pics when I get to the reassembly phase . Enjoy Your Weekend 

[Steve Lewis]

Some items of interest

CR,

I have attached the engine drawings, pic egt02 is of the starboard engine probe location. 

We have a spare parts collection.  We have belts, fuel and oil filters, impellers and extraction tool, clamps and the latest addition being ignition mag switches.  We had one go bad on us in Mackinaw City.  Port engine would not start.  Press the start button and you get nothing.  Short the mag switch terminals and the engine cranked and fired.  We ended up wiring a work around until we could order 2 of them.  Replaced them both and have 1 in the spares bin.  We take a 2 week trip each summer and we find another random part to put on the spares list each time. 

[Steve Lewis]

CR,

We installed the probe on the exhaust flange at the turbine out.  Had to have a mechanic remove the plug but I installed the probe.  I had the wires run from the upper dash to the engine compartment when we had the electronics replaced.  

<br />1/8 npt is the size.  I am on my iPad right now so when I get on my computer I will post a few things and pics you might find helpful.  We still have the factory Hytorq props but they are now 23×25.  They are 4 blade.  Prop shop is Class 1 spec. <br /><br />

at 2250 we are burning 30gph.  We should be burning 30 at 2300 but I am ok with being a touch over in heavy cruise trim.  We will carry a max of 300gallons of fuel along with all our cruising stuff.   Our speed at 2250 is a range of 22.5 to 24 mph depending on conditions. <br /><br />

egt is stable at 750s/725p when on plane.   500 at hull speed which is 1140rpm and 300 at idle.   Coolant temps are stable at 159p/165s when on plane and 156 when off plane. <br /><br />

more later

[Craig Rutledge]

Hi Steve that exact same clamp broke on my port engine and it is what has sent me down the path of parts and maintenance. Unfortunately we had no EGT gauges and I don’t know how long or how hot we were running with it . All hoses and clamps in the works ! Was planning on smx pyro boost and exhaust temp gauges just curious where u installed probe and wether u used 1/4” or 1/8”  npt fitting I see they offer both on site . Thanks

[Steve Lewis]

Closing this one out…..

I caught covid on a business trip so I had to sit out 2 weekends of prime late season boating……..  I replaced the clamp last weekend.  Top Tip – when trying to get the whole turbo air pipe complex back on, wipe dish soap on the outer diameter of the metal pipe flares and the inside lip of the rubber boots.  That helps the rubber boot get over the lip of the piping without deforming.  Learned that one the hard way.  Fought with it way too long before asking for help.  My local guy texted back a one word answer to my plea for help “dishsoap”.  Simple yet effective.

We ran the boat yesterday and EGT’s are back to normal.  We ran the boat over to the storage facility basin.  Another season in the books.  We are FINALLY getting new heads for our 480CE’s this off season.  New SMX water pumps as well.  I still need to order those.

Once this is all complete, our boat will be “Seaboard Style”, as Rob puts it.

Cheers!

[Tony Athens]

Break a clamp on a boost hose and that is exactly what happens.. Glad you saw it..

 

 

3 users thanked author for this post.

Woo, 1969Roamer46, Steve Lewis

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