998 engine rebuild

[sideshowBob]

Hey that’s not original clutch, very nice

Primary clutch is a 102C I had laying around with weights and spring from my 1975 JD 340S. All stuff I had in my parts supply.
I have set the center to center and spacing to run an 8DN belt as well...it all works amazingly well.

 

[Big_Phil]

I guess this post is a lesson on which tune not to run. 5000 miles is barely broken in on these engines. There is no issue with the cooling systems on these sleds running only 280hp.

 

[Mototown]

I wouldn't run anything other than hurricane or TD tunes ...

 

[justinator]

I wouldn't run anything other than hurricane or TD tunes ...

Deto, sorry I meant to say ditto. Bad jokes aside, I agree. The knock system has proven to work and the gap flasher datalogging etc is easy to use and priced fairly. All wins in my book

 

[Turboflash]

@Turboflash any picts of the swain tech pistons? What are you hoping is the temp reduction the slug will see?

Pic shows what domes look like after Swaintech Gold Armor Ceramic coating. The piston to cylinder clearance is very tight (.0015 - .002") so you can't put any of their low-friction coatings on skirts as those coatings build to about .001 - .0015" thickness per side.
They (Swaintech) says ceramic coating will reduce piston temps about 30%.

 

[Turboflash]

Just FYI - I am rebuilding another PEFI 998 (TCat). 6,500 miles on Stage 3 PEFI. Owner was not aware of damage but fiber-optic camera inspection showed the story (coupled with he was having to take weight out of primary to get it to RPM correctly). Center cylinder down about 45 psi in compression. All 3 pistons have deto with damage to head and top of cylinder bore too. Both will need to be repaired (strip bore plating from cylinder bore, weld, machine, re-plate bore); head- weld repair combustion chamber intake side, machine).
Interesting! After talking to Millennium Technologies, they have a dedicated line to repair 998 engines!!! They told me they have 20 staged for repair right now! Head and block with detonation erosion! They told me they have them from all 3 major tune companies! They said there are many more 998s "out there" that have damage that owners are not aware of. Their top technical guru says 17 psi boost flashes are not 91 octane safe from anyone!
FYI - head repairs run about $300-$400. Block repairs run about $600. New head is about $700 and new block is about $2200.

 

[Todd Beenen]

Thanks for the info Flash,

 

[DMCTurbo]

Just FYI - I am rebuilding another PEFI 998 (TCat). 6,500 miles on Stage 3 PEFI. Owner was not aware of damage but fiber-optic camera inspection showed the story (coupled with he was having to take weight out of primary to get it to RPM correctly). Center cylinder down about 45 psi in compression. All 3 pistons have deto with damage to head and top of cylinder bore too. Both will need to be repaired (strip bore plating from cylinder bore, weld, machine, re-plate bore); head- weld repair combustion chamber intake side, machine).
Interesting! After talking to Millennium Technologies, they have a dedicated line to repair 998 engines!!! They told me they have 20 staged for repair right now! Head and block with detonation erosion! They told me they have them from all 3 major tune companies! They said there are many more 998s "out there" that have damage that owners are not aware of. Their top technical guru says 17 psi boost flashes are not 91 octane safe from anyone!
FYI - head repairs run about $300-$400. Block repairs run about $600. New head is about $700 and new block is about $2200.

Thanks for the info. I always run 93 when running 17lbs just to be safe.

 

[Todd Beenen]

I guess this post is a lesson not to jump to conclusions and place the blame on the tune supplier. Now bring back the Sazuk twin please.

 

[KnappAttack]

I guess this post is a lesson not to jump to conclusions and place the blame on the tune supplier. Now bring back the Sazuk twin please.

The Suzuki twin is no better. In fact it’s less reliable with less HP. And to clarify it is a majority of one tune supplier. And even that one tune supplier is having problems with their lower 250 HP tune on pump fuel.

Everyone wants big power, but no one wants to put the octane in the tank. Even 93 octane is not enough for some of the tunes claiming to be safe on 91. This I why I tell people I love the 240 tune so much. The 900t guys will go thru the same thing. The greed will get ya if you don’t understand boost, octane, temperatures and know when your outta fuel or injectors. DATA LOGGING IS ESSENTIAL!

 

[Todd Beenen]

The Suzuki twin is no better. In fact it’s less reliable with less HP. And to clarify it is a majority of one tune supplier. And even that one tune supplier is having problems with their lower 250 HP tune on pump fuel.

Everyone wants big power, but no one wants to put the octane in the tank. Even 93 octane is not enough for some of the tunes claiming to be safe on 91. This I why I tell people I love the 240 tune so much. The 900t guys will go thru the same thing. The greed will get ya if you don’t understand boost, octane, temperatures and know when your outta fuel or injectors. DATA LOGGING IS ESSENTIAL!

sounds like all 3 are having trouble, who’s 250 tune is having trouble, please elaborate.

 

[STAIN]

This is not good news. I wonder what the tuners have to say?

 

[Crossfire12]

What is the safe boost ? 16 psi and less if running proper 91oct?

 

[justinator]

Theres no way to say for sure what boost level is safe for 91 all the time. Too many factors come into play......snow conditions causing extra engine load , hotter IAT's, aggressive clutch setups, minor boost leaks etc. Low boost tunes (15-15.5 psi) or less I would guess arent gonna be too fussy but only way to know is to datalog. I cant imagine spending money on tunes and hardware and clutching and spending time on testing different setups etc but not spending the extra for the datalogging. Real time info, no guessing about adequate fuel, no staring at a dash trying to watch rpms while clutching a 250/275/300hp + sled. All the data you need at your fingertips. No assuming your sleds happy with your gas choices because you dont see a knock light but in reality its pulling 1-2 degrees of timing just about every time your on it and you dont know. worth every penny all day every day.

 

[Fast]

I run these scratchers and leave the down 100% of the time. I ran them 2 seasons so far and they are still good to go. I haven't overheated at all in 2 seasons with temps always in the 170's

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