After 15 months finally got a motor

[kinger]

Well its not normal for the tune brand we run, but there is a lot of fried engines and cracked heads from deto with the brand of tunes the OP was running. Not only Yamaha engines but a rash of 900t's as well. Most don't seem to talk of it publicly which I just don't understand. I know a few here have tried to warn people like Turboflash, but he's in the minority. Most seem to protect the tuner and not speak about it.

There is a reason "our tune guy" refuses to turn down the knock sensitivity! I will never switch tuners because of it, also because he did the testing and development on the knock detection and perfected it on the 998 with knock ears on the engine dyno like Delphi or GM would do in the automobile world while developing engine platforms to verify the proper frequency and noise levels.

I'm glad Yamaha stepped to the plate for an new engine for the OP, they certainly didn't have to do that to cover a tuners inadequacies in developing a proper knock system on a tuned sled, but they did. Speaks volumes for the company Yamaha is. Some of the other OEM's would have told him to pound sand.

There is nothing so far that has been determined to be the cause of these motors failing relating to the tune. The first one was a cracked head which they think is a casting error in some '17s, the 2nd one they think was an assembly error (dealer assembled 2nd motor inhouse) where the head loosened up and took out the gasket. No signs of any deto in either motor.

Yamaha does have to prove the tune took it out and they couldn't so they are standing by it, very good company, just took way to long.

Also first one was 270 tune, 2nd was 240 mild tune that is pretty much bullet proof and peak boost levels were not even over stock on the print out because I hadn't even got to run it hard before I noticed it was taking coolant again in the oil. I am not saying I like PEFI or will ever deal with them again but evidence is evidence and there is no deto or hot spot like what @Turboflash posted pictures of, looks to be just a case of the worst possible luck strung together in a rare series of events.

 

[Turboflash]

There is nothing so far that has been determined to be the cause of these motors failing relating to the tune. The first one was a cracked head which they think is a casting error in some '17s, the 2nd one they think was an assembly error (dealer assembled 2nd motor inhouse) where the head loosened up and took out the gasket. No signs of any deto in either motor.

Yamaha does have to prove the tune took it out and they couldn't so they are standing by it, very good company, just took way to long.

Also first one was 270 tune, 2nd was 240 mild tune that is pretty much bullet proof and peak boost levels were not even over stock on the print out because I hadn't even got to run it hard before I noticed it was taking coolant again in the oil. I am not saying I like PEFI or will ever deal with them again but evidence is evidence and there is no deto or hot spot like what @Turboflash posted pictures of, looks to be just a case of the worst possible luck strung together in a rare series of events.

My first head was cracked and replaced under warranty no questions asked (with 280 tune in it). Sled had only a couple hundred miles on it - lots of coolant in the oil! Head crack was on left-side core plug boss at about 3 o'clock. See pics.
These core plugs are pipe thread (NOT what I would do. I would use a machine thread and orings to seal). The farther the plug is tightened into the head, the more outward pressure is exerted against the cast aluminum boss. Go too far and it cracks. So either it's an assemble error (too much torque on plug OR it's a casting defect in the head.

 

[NYTurbo]

Lots of bad heads on the 998.

 

[Turboflash]

Lots of bad heads on the 998.

From my tiny perspective, I've only seen or heard of a few (maybe 3?), not many. Maybe you've seen more? But, it is a reality for a few. Cat HQ was told (by my dealer) that my engine did not have the stock tune in it. They were not concerned about that; they told him to warranty it and he did. Did they know already that there was an issue?
IDK how many are/were cracked. All I know is more than just my one. When I read or hear of guys saying they have unexplained coolant in their oil; or they have to add coolant every now and then, or their coolant overflow tank is empty, I can't help but wonder if their head is similarly cracked. IF everything is sealed and right, you should not have to add coolant to these 998s even for a whole season. I got a new head under warranty; I moved all the valves (with new seals); re-shimmed the valves, re-assembled engine and now, 3 years later all is still perfect with engine (running with 300+ HP tune). All I can surmise is the original head was cracked during original assembly and leaked from the 1st time the engine was assembled. IMO, the design choice to use a pipe thread was destined for problems. I would have chosen a straight machined thread using a silicone or teflon o-ring to seal the plug to not put outward pressure on the cast plug boss.
For those who do have to add coolant from time to time, either there is a leak somewhere, or (if they have a big tune) the head gasket is leaking. I can say after last season running 300HP tune, I never had to add coolant, ever. From rebuilding many of these 998s, I have seen many with evidence the head has been "moving". It was evident from "blurred" sealing lines on the block and/or head. Those with head studs show very distinct, clear, sharp sealing lines. I prefer to tell my customers that if they are going to run more than about 12 lbs of boost, they should install ARP head studs. When I installed my new head, I installed ARP head studs. NEVER have had to add coolant after that. Tells me, the stock head bolts do not provide enough clamp force to keep head from moving on block (at 12+ lbs of boost).

 

[Upstater57]

From my tiny perspective, I've only seen or heard of a few (maybe 3?), not many. Maybe you've seen more? But, it is a reality for a few. Cat HQ was told (by my dealer) that my engine did not have the stock tune in it. They were not concerned about that; they told him to warranty it and he did. Did they know already that there was an issue?
IDK how many are/were cracked. All I know is more than just my one. When I read or hear of guys saying they have unexplained coolant in their oil; or they have to add coolant every now and then, or their coolant overflow tank is empty, I can't help but wonder if their head is similarly cracked. IF everything is sealed and right, you should not have to add coolant to these 998s even for a whole season. I got a new head under warranty; I moved all the valves (with new seals); re-shimmed the valves, re-assembled engine and now, 3 years later all is still perfect with engine (running with 300+ HP tune). All I can surmise is the original head was cracked during original assembly and leaked from the 1st time the engine was assembled. IMO, the design choice to use a pipe thread was destined for problems. I would have chosen a straight machined thread using a silicone or teflon o-ring to seal the plug to not put outward pressure on the cast plug boss.
For those who do have to add coolant from time to time, either there is a leak somewhere, or (if they have a big tune) the head gasket is leaking. I can say after last season running 300HP tune, I never had to add coolant, ever. From rebuilding many of these 998s, I have seen many with evidence the head has been "moving". It was evident from "blurred" sealing lines on the block and/or head. Those with head studs show very distinct, clear, sharp sealing lines. I prefer to tell my customers that if they are going to run more than about 12 lbs of boost, they should install ARP head studs. When I installed my new head, I installed ARP head studs. NEVER have had to add coolant after that. Tells me, the stock head bolts do not provide enough clamp force to keep head from moving on block (at 12+ lbs of boost).

I cannot imagine adding a 50% increase in power and NOT have some issues somewhere. Head studs should be standard after 240HP just for safety.

 

[NYTurbo]

240 is not even close to requiring head studs, anything over 300 hp would be my cut off point. As long as I had the knock protection from GAP.

 

[Upstater57]

I am an old 1100 guy. I am not as trusting in the 998 as I am in the Suzuki anvil motor. You may be right but head studs are cheap insurance.

 

[Turboflash]

240 is not even close to requiring head studs, anything over 300 hp would be my cut off point. As long as I had the knock protection from GAP.

FWIW - Ulmer Racing I believe recommends head studs in anything over like 250. Speedwerx insists on them at 250 or more.
I've seen multiple 998s with even 240 tunes that show head has been "moving". Gaskets show same. Engines with studs the gaskets and head shows clear precise sealing lines - no movement of head.

 

[Upstater57]

Fortifying engines, syspensions, drive trains, and clutches should be common sense when boosting a 200hp product to 240, 270, or even 300 hp and then hooking it hard to the snow or ice. Nothing was engineered by cat or yamaha for those boosted numbers. I see guys plug in a big boost then complain after stuff pukes or breaks. Big horse power will find the next weak link and show you where it is. High performance machines need high performance owners. If guys can't live with that, they should buy them stock and leave them that way. Even then, stuff breaks. LOL

 

[NYTurbo]

FWIW - Ulmer Racing I believe recommends head studs in anything over like 250. Speedwerx insists on them at 250 or more.
I've seen multiple 998s with even 240 tunes that show head has been "moving". Gaskets show same. Engines with studs the gaskets and head shows clear precise sealing lines - no movement of head.

Sure, and possibly a lot of this head movement is from blowing belts at full throttle . Head studs are not a bad idea but properly tuned, properly aligned clutches, and proper knock control goes a long way .

 

[NYTurbo]

I am an old 1100 guy. I am not as trusting in the 998 as I am in the Suzuki anvil motor. You may be right but head studs are cheap insurance.

1100 is definitely a well built motor

 

[Turboflash]

I cannot imagine adding a 50% increase in power and NOT have some issues somewhere. Head studs should be standard after 240HP just for safety.

Agree. Designed for 190HP; not a wonder why something might/will go south at 300HP (with no changes to compensate).

 

[Upstater57]

My 1100 is at 300hp at 28.9 pounds of boost @ 8000 rpms. It's a thumper. It has head studs of course. The mod stock turbo under the hood could be tuned to run in the mid to high 30's for boost. I would not tune past where it is without beefing up the internals.

 

[kinger]

 

[kinger]

Picked it up today, and...it wont start. Lovely...

Dead battery. Gotta love it!