2003 4 tech wrong crank ?

[Mekanix]

About to go buy a 2003 GTX that was rebuilt but would not start.
They say its a new crank and full rebuild but through some troubleshooting they determined that the timing was off 20 degrees.
Ok... Looking at part numbers, the 2002-5 super and non supercharged cranks and encoder wheels are the same part numbers. unless i missed something.

Says it won't start and backfires. Haven't looked at it yet but looking for advice.

What cranks for the 155 for what ever years change the ignition timing pin on the crank gear that would cause this ?


Thanks.

 

[mikidymac]

Sounds like you and Rezistor have the same issue, Look a couple posts below yours.

 

[Mekanix]

 

[Mekanix]

Yup

 

[Rezister]

Its the same machine! I went to pick it up, but it turned out to be a 03, not an 05. I didn't bring it home

 

[Sportster-2001-951C-Stock]

This can't be as easy as it looks, the encoder wheels can't be rotated xx degrees or swapped?

 

[Mekanix]

Its the same machine! I went to pick it up, but it turned out to be a 03, not an 05. I didn't bring it home

Really? That's funny! Where are you located ? While i was there, the calls and messages were non stop.
I ended up chatting with the guy for about 3 hours and thought it all through before I bought it
Looking into it a little deeper I'm just going to do it right and replace the crank I think.
All the other parts I'm just starting to source now. It will live again! and I plan on possibly keeping it unless something amazing comes along. I do like these early 4 tech's for some reason.

So the story is: Guy bought a crank and connecting rod kit on ebay from a local rebuilder CVtech. They are like our version of SBT engine wise.
In the fine print of the ad it said 2005 seadoo 1503 215 and 255 engines only. So the crank is pinned like the image on the left and unfortunately I don't think i can re index the pickup wheel so that it matches the one on the right. Look at the balance shaft mark on the bottom and look at the bolt holes. The place I need to index will be off by half a hole. I could just set the pin at between 12 and 13 teeth like the picture and then drill the other holes and have them elongated. I know one local repair guy to hooked it up to his computer and determined it was off timing and he had a story where someone else had attempted the same thing and it resulted in so many backfires that it damaged main bearings and resulted in a rebuild.

 

[Mekanix]

This can't be as easy as it looks, the encoder wheels can't be rotated xx degrees or swapped?

Look at the mark and look how far the first bolt hole is.

Each tooth off is 9 degrees. So it would be1 tooth off. The gear has 40 teeth and the pin looks to be supposed to be between 12 and 13 So somewhere between 108 and 117 degrees but not in the middle. so I could be way off. Unless I can change the timing in buds???

 

[ski-d00]

A new hole can be drilled in the encoder and it runs fine. It ends up being like a degree or two off but the ECU is constantly adjusting the timing so it runs perfectly. Have done it quite a few times.

Timing can't be changed in BUDS, ECU self adjusts for minor adjustments.

 

[Mekanix]

I thought it would be 9 degrees off still just moving it two holes so i was looking at elongating ththe other holes as well to get it perfect

 

[ski-d00]

The first one I did I ovaled out the 6 mounting holes, then drilled the pin hole in the exact location. Can't remember the exact degree location but thought it was just a couple degrees. The next one, after I talked to few people who said timing will self adjust, I kept the mounting holes as is and drilled the hole to line up with the pin and it ran perfectly. Have done a few more since then and always runs perfectly. Still feels wrong to me not to be exact but have been servicing one I did for about 10 years and still runs perfectly.

 

[Mekanix]

Well that might be the direction I go then
Cheaper than a $700 crank!
I did have a plan to degree the wheel properly and drill it precisely.

 

[ski-d00]

No need to be precise. Drill the hole and go.

I tore one down a year two ago that had the pin hole already redrilled so pretty common knowledge now. Wouldn't be surprised if sbt were building them that way.

 

[Mekanix]

The guys at sbt were the first to tell me about the differences between cranks. That picture is from their site. Thanks for the reassurance.

 

[Mekanix]

Looking at this closer before I get to tear it apart. I have a good 2006 mag cover and sensor. Can I just swap that on and not touch the timing ? Will all the ports line up ? Just looking at pics I'd say yes but I bet there will be a bolt that is off a bit. Just curious...

Also what are ththe weak points of the 2003 engine that were addressed later on ?
I hear valves, timing chain, mag bolts... and that's about all I've read or found so far.

 

[ski-d00]

Yes, that will work. The only reason for the pin position change was the mag sensor position change.

I don't think there was any real weak point on the 2003 4tec motor. The engine was designed very well for 155 and 185 hp. The BRP engineers did realize the added hp of the 185 didn't work on the plastic pump that year so that was changed to aluminum in 2004. I see very few dropped valves here in the midwest. With proper winterization and maintenance, it happens at less than 1% for this area from what I've seen. I'm sure saltwater environments are much worse since this failure revolves around the rusting and micro cracking. When they went to the 215 hp and higher rpms, very rare failures became more common even rod failure where it blows out the side of the block. Timing chain failures were common when they switched suppliers around 2011. Mag bolts were fine until the hp and rpm but was fixed when they went to stretch bolts.

 

[Mekanix]

Should i go with the stretch bolt kit ? Or is it necessary ?

 

[Sportster-2001-951C-Stock]

If the holes don't line up you can try these special order bolts:

 

[Mekanix]

But do they come in stretch ?
Actually the second one exists! For camber adjustments on struts.

I did buy the stretch bolt kit for 20$cad so why not do it as right as I can.
Thinking of it, I get why they changed the crank and what I'm going to do is pretty straight forward. Just havent decided drill or use my spare mag housing. Have to check the two sensors to make sure the impedance is the same.

Then again in the back of my head I love thinking of things. If it's really just about 120 degrees off why couldnt I take say cylinder 1 injector and coil plugs and move it to #2 and #2 stuff to #3 and #3 stuff to number 1.

Essentially I'm fixing a 3 phase issue. Similar to electrical motors. Only reason I think it wouldn't work would be the cam sensor. I'm not sure what it picks up but assuming it would know something is wrong.
Dont mind me I just like thinking out loud

 

[Sportster-2001-951C-Stock]

I like the idea of moving the injectors and plug wires/coils around if the math says it's possible. 360/3 is 120

 

[Mekanix]

Still 7 degrees off mechanically but most people say it works anyways.
Just trying to figure out If the cam sensor knows which cylinder is which or it's still just 3 phase but half freequency of the crank.

 

[Sportster-2001-951C-Stock]

Unobtanium has infinite stretch and the clamping force remains constant. This means over torquing is impossible. We used to fax that bolt chart to the machine shop when something came back out of spec. They would send us this drawing with a list of questions in response.

 

[ski-d00]

The stretch bolts are better but I don't think I've ever seen a mag bolt failure on a 130 or a 155 motor.

 

[Sportster-2001-951C-Stock]

Still 7 degrees off mechanically but most people say it works anyways.
Just trying to figure out If the cam sensor knows which cylinder is which or it's still just 3 phase but half freequency of the crank.

There's only a single sensor and just one reluctor? There are no fuel injection systems I know of that only use a single sensor, there has to be a #1 reference. Unless a 3 cyl doesn't require it for some reason I don't know of.

 

[Mekanix]

The encoder wheel has two teeth missing so I'm guessing thats how it knows. But on the cam I haven't found what it reads yet.