Need some ideas on what happened

[jet1]

8.7:1 on E85?

Rebuild that thing with 10:1 or more. Or switch to gasoline.

20 psi boost is why the e85 for periods of wot up ton 30 min. I would love to run gasoline trust me.

[jet1]

I just got thru spending 3 weeks on dyno with a 540BBC with 8-71 blower on fuel injection on pump E85. Pulled pump fuel from 7 different pumps and varied from 51% to 77% as Ethanol. Spent much time tuning to not only making live but run for power. Had to put static ratio aat 9.1 and that is calculated down to top ring. Combustion chamber is "softened", which helped. Is 20% over driven(presently) but run higher. Dynamic is as high as 12.?. If we pulled timing back too far, egt temp was waaay waay out of control. You better do all u can to widen the tuning window..
reed

The e85 being used has been tested to be e85. Good to know on the timing egt monster change.

[jet1]

Ok so now I am looking at the valve springs. They are a pac 1243 240 closed and 560 over the nose. The spring itself is 140 grams with steel retainer and stainless valve. I am not really a fan of the springs and I really cannot tell you why. I like either the comp cams dual conical or the psi 1575 ml.
Just so you don’t have to read the whole post the application is.
260 ci ls based engine
Twin 60 mm turbos
8.7:1 comp
Mast 225 cc small bore heads
Solid roller 244/248 115lc .662/.662 at the valve.
Extreme endurance, 30 min wot at 6800-7400.

[HaxbySpeed]

I've never built that small of an LS based engine, but based on your induction I would suspect that cam is a bit bigger then optimal. Are you finding the rpm you're targeting the most efficient with how your pump is set up? Who spec'd the cam? It may be worth talking to a couple different cam guys. As far as the low compression, it can actually make the egt tuning window smaller. It seems to be a trend that it's harder to control the egts on lower compression stuff, at least in my experience. Luckily, e85 is incredibly forgiving on timing, and afr. Don't get caught up in what it "should" want for afr and timing, and just tune until the engine is happy.
If I was building that engine it would probably be 10 to 1. For endurance applications 2 minutes is no different then 30 mins. It's just heat management after that. Not saying your approach won't work. But I would definitely give the cam specs a bit more research. There's a bunch of factors that will determine optimal timing, but I suspect it will want more then what you'd think. Go slow on the next session and do a few more short steady state pulls before you let er rip. I'm happy to look at any datalogs, or send you some different base maps from turbo and boosted e85 stuff to look at if it helps at all. Cheers

[Turborick]

Ok so now I am looking at the valve springs. They are a pac 1243 240 closed and 560 over the nose. The spring itself is 140 grams with steel retainer and stainless valve. I am not really a fan of the springs and I really cannot tell you why. I like either the comp cams dual conical or the psi 1575 ml.
Just so you don’t have to read the whole post the application is.
260 ci ls based engine
Twin 60 mm turbos
8.7:1 comp
Mast 225 cc small bore heads
Solid roller 244/248 115lc .662/.662 at the valve.
Extreme endurance, 30 min wot at 6800-7400.

I run a turbo 259 inch small block Chevy in a land speed application where our runs take approximately 90 seconds.
I run the 1343 PAC on the intakes and 1344 PAC on the exhaust we turn the motor 10,000 RPM. And have had pretty good life with the springs

[jet1]

I've never built that small of an LS based engine, but based on your induction I would suspect that cam is a bit bigger then optimal. Are you finding the rpm you're targeting the most efficient with how your pump is set up? Who spec'd the cam? It may be worth talking to a couple different cam guys. As far as the low compression, it can actually make the egt tuning window smaller. It seems to be a trend that it's harder to control the egts on lower compression stuff, at least in my experience. Luckily, e85 is incredibly forgiving on timing, and afr. Don't get caught up in what it "should" want for afr and timing, and just tune until the engine is happy.
If I was building that engine it would probably be 10 to 1. For endurance applications 2 minutes is no different then 30 mins. It's just heat management after that. Not saying your approach won't work. But I would definitely give the cam specs a bit more research. There's a bunch of factors that will determine optimal timing, but I suspect it will want more then what you'd think. Go slow on the next session and do a few more short steady state pulls before you let er rip. I'm happy to look at any datalogs, or send you some different base maps from turbo and boosted e85 stuff to look at if it helps at all. Cheers

I agree that the cam may be a bit much on it. our intended operating redline is 7400. with how the jet boats work we find that they perform the best when run the tq pk at or close to our operating redline. The cam is prob 4deg too much dur and is maybe something I should look at.
Good info regarding tuning window and low comp ratio. One of the reasons for the low comp is that we are maybe going to try to run it on 100 octane if the boost is low enough and we still get enough power. Right now it's making 850 hp at 12 lb boost. Our goal being 1000 hp.

[jet1]

Ok so now I am looking at the valve springs. They are a pac 1243 240 closed and 560 over the nose. The spring itself is 140 grams with steel retainer and stainless valve. I am not really a fan of the springs and I really cannot tell you why. I like either the comp cams dual conical or the psi 1575 ml.
Just so you don’t have to read the whole post the application is.
260 ci ls based engine
Twin 60 mm turbos
8.7:1 comp
Mast 225 cc small bore heads
Solid roller 244/248 115lc .662/.662 at the valve.
Extreme endurance, 30 min wot at 6800-7400.

I run a turbo 259 inch small block Chevy in a land speed application where our runs take approximately 90 seconds.
I run the 1343 PAC on the intakes and 1344 PAC on the exhaust we turn the motor 10,000 RPM. And have had pretty good life with the springs

Very interesting. the springs I have decided on are very close to what you are running on the exhaust but are way lighter at 111 gr vs 143. Are you running ti intake valves? I am running Stainless as i have had issues trying to run Ti before.

[ptuomov]

Sorry I got called out to work. Anyhow i will try and give as much info as i can.
This thing is a 258 ci ls based engine 244/248 115 lc .660 lift.8.7:1 comp, Holley high ram with Mast small bore cathedral port 225 cc heads, twin 60 mm turbos with water to air intercooler.
AFR 11.7
Holley dominator fuel injection
coolant temps 150
ign timing 22 deg
sustained rpm test 7200 rpm at a power level of 800 hp and 11 psi boost for 2 min with resulting burnt exhaust valves and sparkplugs on #7 and #4.
zero damage to pistons,head or cylinder walls. As mentioned we are wondering if it doesnt have enough water flow from the meziere 12 volt water pump through #10 lines.

I am beginning to believe that timing could be the issue and maybe the water flow a bit. At 7200 this thing hasn"t even hit the tq peak yet and in my experience it seems that low timing tends to flatten out the tq peak some giving it more over rev but less peak plus really timing is the only thing would explain super hot ex valves and plugs but not burnt pistons or head gaskets.Specifically the water pump not making enough pressure to move enough water through the #10 lines and be able to create 10- 15 psi pressure in the block to keep hot spots from boiling.

Ran eng analyser software on it and it is looking for 35-36 degrees also timing.

I don’t know the firing order here, but are #4 and #7 the two best filling cylinders that are neither 90-degree nor 180-degree exhaust blowdown interference victims? If i’m guessing the firing order and cylinder numbering correct, I think those are the cylinders. Humoring my guess for a bit, how’s the cylinder specific fuel trim set up for those two cylinders?

[jet1]

Sorry I got called out to work. Anyhow i will try and give as much info as i can.
This thing is a 258 ci ls based engine 244/248 115 lc .660 lift.8.7:1 comp, Holley high ram with Mast small bore cathedral port 225 cc heads, twin 60 mm turbos with water to air intercooler.
AFR 11.7
Holley dominator fuel injection
coolant temps 150
ign timing 22 deg
sustained rpm test 7200 rpm at a power level of 800 hp and 11 psi boost for 2 min with resulting burnt exhaust valves and sparkplugs on #7 and #4.
zero damage to pistons,head or cylinder walls. As mentioned we are wondering if it doesnt have enough water flow from the meziere 12 volt water pump through #10 lines.

I am beginning to believe that timing could be the issue and maybe the water flow a bit. At 7200 this thing hasn"t even hit the tq peak yet and in my experience it seems that low timing tends to flatten out the tq peak some giving it more over rev but less peak plus really timing is the only thing would explain super hot ex valves and plugs but not burnt pistons or head gaskets.Specifically the water pump not making enough pressure to move enough water through the #10 lines and be able to create 10- 15 psi pressure in the block to keep hot spots from boiling.

Ran eng analyser software on it and it is looking for 35-36 degrees also timing.

I don’t know the firing order here, but are #4 and #7 the two best filling cylinders that are neither 90-degree nor 180-degree exhaust blowdown interference victims? If i’m guessing the firing order and cylinder numbering correct, I think those are the cylinders. Humoring my guess for a bit, how’s the cylinder specific fuel trim set up for those two cylinders?

Honestly at this point it is not that I know of. have only done some preliminary dyno runs before we noticed the valve issues.

[ptuomov]

Is the fuel injector system port injection or throttle body injection? Is there a cylinder specific fuel table in case it’s a port injection system? What do the exhaust manifolds look like, are they water cooled log manifolds?

[MadBill]

I'd say it's a virtual certainty that the valve is sticking in the guide, for whatever reason. I'd just open up the clearance a half thous and if that works, forget about why and just carry on. If it doesn't, resume tearing out your hair.

[jet1]

I'd say it's a virtual certainty that the valve is sticking in the guide, for whatever reason. I'd just open up the clearance a half thous and if that works, forget about why and just carry on. If it doesn't, resume tearing out your hair.

ok because I don't have any hair.lol

[jet1]

Is the fuel injector system port injection or throttle body injection? Is there a cylinder specific fuel table in case it’s a port injection system? What do the exhaust manifolds look like, are they water cooled log manifolds?

It is a Holley dominator port fuel injection with water jacketed headers.

[Newold1]

Just curious. Is this engine in a river runner aluminum hull Hamilton jet drive?

[jet1]

IMG_3430.jpg

Just curious. Is this engine in a river runner aluminum hull Hamilton jet drive?

IMG_3700.jpg