Custom/Hybrid Billet engines blowing up??

Christian_83

Christian_83

Xscream
Location
Denmark
Ive read about 3 billet SS engines blowing up lately. Does anyone in here know if they all are cauesd by faiing or outworn wrist pin bearings? I know 2 of the cases, the owners posted pictures of the engines that looked allmost identical, after the blow up.
Have other guys have the same problem with stroker engines?
I dont wanna start a bashing/trashing thread here, but just being curious.
 
S

Seanc

Location
Seattle wa
these billet stroker motors are not your run of the mill sea doo engine from the factory. the stress on all the parts is much much higher. to avoid a VERY costly repair on my 850 4 mil stroker. i replace my pistons, rings, and wrist pin bearings at a minimum of once a season.
 
yamanube

yamanube

This Is The Way
Staff member
Location
Mandalor
Seanc said:
these billet stroker motors are not your run of the mill sea doo engine from the factory. the stress on all the parts is much much higher. to avoid a VERY costly repair on my 850 4 mil stroker. i replace my pistons, rings, and wrist pin bearings at a minimum of once a season.
Click to expand...

Minimum?!? How long is a WA season?
 
snowxr

snowxr

V watch your daughters V
Location
Waterford, MI
Seadoo wrist pin bearings are a good alternative, but they are not a replacement for proper service intervals. Seadoo's RXX race couch called for wrist pin bearing replacement after only 24hrs of use due to piston weight and high RPM's.
 
Superjetjim

Superjetjim

X-
I would speculate that poorly designed/functioning/setup ignitions causing backfires and or low grade oil cause most issues with wrist pin bearings..
 
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Q

QJS

X-
Location
GONE
A few people seem to want to blame ignitions/ backfires but how do you explain the ones without backfires? I have seen hoods lifted off old 550,s and even a nose cone blown off one without damage to the wrist pin bearing. The type of backfire you are referring to is due to unburned fuel in the exhaust, for the backfire to take place the flame front has to have access to this fuel ie the exhaust port would be open or part open and the energy would go straight out of the exhaust often taking out a waterbox or hose. Even if the piston were on its way up and only partly closing the exhaust port when the backfire occurred it would have to be strong enough to put the engine into reverse before unduly stressing the wrist pin bearing, but I used to get this very thing happen to me on a superjet all the time years ago running an old ignition I won't name and the engine frequently went into reverse BUT STILL NO WRIST PIN BEARING DAMAGE. What sort of forces do you think exist on these bearings at 7000 rpm?
I said it before somewhere......Look at the country of origin of the bearings Wiseco use. I throw all aftermarket bearings in the garbage and use OEM. This is based on experience not speculation.
Chris.
 
kx454

kx454

Location
Sweet Valley, pa
Seanc said:
these billet stroker motors are not your run of the mill sea doo engine from the factory. the stress on all the parts is much much higher. to avoid a VERY costly repair on my 850 4 mil stroker. i replace my pistons, rings, and wrist pin bearings at a minimum of once a season.
Click to expand...

Not necessarily, if those strokers are pump gas motors on stock ignitions they are not being stressed more than a sea doo that has a 12 year old kid holding it wide open from cold start until dark....
 
Superjetjim

Superjetjim

X-
Had a backfire/missfire on my DASA last week caused by bad timing (MSD Flywheel had moved on woodruff key - my fault). But the miss fire stopped to motor dead when cranking with a sound like a rod had gone through the block. Dread to think of the load on the wrist pin bearings. It also turned a PFP water box into a football!

Not sure where you get the impression this is aimed at any particular brand of ignition?

Agree none OEM Jap bearings are junk!
 
Q

QJS

X-
Location
GONE
And presumably your wrist pin bearings are still in one piece? This is exactly the point I am making. Did I say this was aimed at a particular brand of ignition?
Chris.
 
Superjetjim

Superjetjim

X-
QJS said:
And presumably your wrist pin bearings are still in one piece? This is exactly the point I am making. Did I say this was aimed at a particular brand of ignition?
Chris.
Click to expand...

Yes after a single back fire they seem fine, my point is based on this occcuring frequently a failure would be more likely due to the massive forces this exhibited. Another point is the ever growing piston size using the same wrist pins?
 
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kevbo

kevbo

Location
dfw
Superjetjim said:
Yes after a single back fire they seem fine, my point is based on this occcuring frequently a failure would be more likely due to the massive forces this exhibited. Another point is the ever growing piston size using the same wrist pins?
Click to expand...

Try turning down the compression, timing, and rev limit to pump gas levels.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
For starters, it doesn't come with wrist pin bearings that this thread is talking about.
 
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