Another engine failure

[ice445]

Came across this regarding Cyls 4 & 8 on the Coyotes (no year specified):

I don't have any other info than what we see in that image clip...

Based on other threads and similar Coyote failures documented, it seems there is a heat problem with cyl 4 and 8, regardless if the vehicle is on Nitro, a tune or forced induction.

My opinion on it is that the CHT is close enough to #8 to get a good idea of what's going on back there. I don't know if the mod helps or not, but max fan profile is 223F, so if you can keep the car below that threshold at all times, it's unlikely that your back cylinders will fail. Detonation being a unique case. The power pack tunes add a lot of torque down low where the water pump flow rate is relatively low. I can see hot spotting happening with that situation on a hot day. CHT wouldn't tell the whole story in that case necessarily.

Sponsored

 

[GT 550]

The power pack tunes add a lot of torque down low where the water pump flow rate is relatively low. I can see hot spotting happening with that situation on a hot day. CHT wouldn't tell the whole story in that case necessarily.

Good point. A high pressure water pump might be the optimum solution, hot spotting is ignored too much in terms of prevalence and consequence. Coyote wouldn't be the first engine to have hot spot issues when pushed.

Not saying the crossovers don't work but if the water pump isn't up to it their benefit could be compromised.

 

[Dfeeds]

I'd agree, especially looking at the upper quench space between the top of the piston and the valves. It got real hot. Seems that 91 just wasn't cutting it.

I wouldn't think so, especially if you're tracking it. 93 is prominent in my area but when I have to use 91 the car runs noticeably worse. It misses terribly at idle and occasionally will nearly stall out completely when starting it up. It hesitates a lot under 4k and going to redline feels feels a bit flat. All issues that I don't have with 93. This is just street driving so I'd imagine tracking it would just exacerbate the issue.

I've fiddled around with e85, sunoco race fuel, and off the shelf octane boosters. 94/95 octane seems to be the sweet spot for the fp tune. I've only done a little bit of logging but around 94/95 is when I don't notice any hesitation and my SOTP doesn't notice any difference going any higher. But, again, I don't track it so going higher may benefit you.

 

[sk47]

Hello; I went back to the first post in this thread. The OP was driving on the streets with the only engine mod being a Ford supplied tune. Best I can recall this was not a GT350 or GT500. A 2017 GT.

So it has been my understanding a V8 GT will run on 87 octane gas. I checked on this during my recent search for a base GT. Not sire if the Ford tune changes the octane requirement. I think the OP was running 91 octane if memory serves.

The #8 and maybe #4 cylinders maybe only get coolant after it is already hot from passing thru other parts of the engine. So if the engine is being pushed it could be at an upper limit of temperature in #8 and 91 octane might allow some preignition?

Are the fixes to run 93 octane and get better cooling?

 

[luc]

Hello; I went back to the first post in this thread. The OP was driving on the streets with the only engine mod being a Ford supplied tune. Best I can recall this was not a GT350 or GT500. A 2017 GT.

So it has been my understanding a V8 GT will run on 87 octane gas. I checked on this during my recent search for a base GT. Not sire if the Ford tune changes the octane requirement. I think the OP was running 91 octane if memory serves.

The #8 and maybe #4 cylinders maybe only get coolant after it is already hot from passing thru other parts of the engine. So if the engine is being pushed it could be at an upper limit of temperature in #8 and 91 octane might allow some preignition?

Are the fixes to run 93 octane and get better cooling?

The tune requires 91 octane and I was on on a very special type of street with only 1 way traffic

 

[sk47]

The tune requires 91 octane and I was on on a very special type of street with only 1 way traffic

Hello; OK, I am not going to get on you for running the car hard. I am trying to learn about the engines in a GT. More so if there is a way to protect and engine from what may be a common weakness. I have been shopping for a base GT. I do not think I will ever get a tune. I will not run it on a track, but I may wring it out from time to time. In another thread the answer for some seems to be an extended warranty so they have peace of mind.

Guess I am wondering what, if anything, you may do once the engine is fixed/replaced? Better cooling perhaps? Maybe no tune or a tune which does not push the engine into a more risky state.

Not sure when prices and availability will get back to normal, so it may be a while before I get a new GT.

 

[GT Pony]

Hello; OK, I am not going to get on you for running the car hard. I am trying to learn about the engines in a GT. More so if there is a way to protect and engine from what may be a common weakness. I have been shopping for a base GT. I do not think I will ever get a tune. I will not run it on a track, but I may wring it out from time to time. In another thread the answer for some seems to be an extended warranty so they have peace of mind.

Has this problem actually happened on bone stock GTs that are never ran hard on a race track and just driven fast for short periods on public roads ??

 

[ice445]

Has this problem actually happened on bone stock GTs that are never ran hard on a race track and just driven fast for short periods on public roads ??

Well, my CHT goes into the 230's if I climbing a mountain pass in summer, lol. Base radiator sucks at altitude. I'm replacing it with the PP radiator.

 

[sk47]

Has this problem actually happened on bone stock GTs that are never ran hard on a race track and just driven fast for short periods on public roads ??

Hello; I do not know. Finding out is why I asked. I get that some push the cars to whatever the limit is. Such is fine, but not what I plan to do. I can do some spirited driving and may approach the redline from time to time. I do not know if I am overthinking it for a street car.

 

[luc]

Hello; I do not know. Finding out is why I asked. I get that some push the cars to whatever the limit is. Such is fine, but not what I plan to do. I can do some spirited driving and may approach the redline from time to time. I do not know if I am overthinking it for a street car.

You are for a street only car....

 

[sk47]

You are for a street only car....

Hello; Yes. No road track and no drag racing.

Sponsored