2003 4 tech wrong crank ?

[Sportster-2001-951C-Stock]

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.

The cam rotates half the speed of the crank and without a double reference crank TDC compression stroke cannot be determined. So all the references begin with the crank, it's not necessary to have a cam sensor b.c if you know where the crank #1 TDC compression stroke is, you don't care where the cam is b/c you alreadt know where the compression stroke is..

7* of ignition advance will make a huge difference in a marine engine unless Rotax was extremely conservative. It'll either be a pig or faster than other 4-tecs, but I'd be afraid of knock count going through the roof if it was advanced that much.

 

[Mekanix]

From what I found, the cam sprocket has one pin and that is the trigger. So I'm still not sure what that represents but maybe its tdc #3 cyl. Which would now be tdc #1 according to the crank. Hmmm this makes me think it wouldn't work just by swapping the electrical around...
The 7 ish degrees in this case would be retarded. But I have read in a few forums that on top end the ecu pushes ignition timing to knock and then backs off. But no one knows if there is enough room to make up 7 degrees. Otherwise people say they turn up the idle a bit and just deal with weaker bottom end but normal top end.
I would like my bottom end and midrange though

 

[Sportster-2001-951C-Stock]

From what I found, the cam sprocket has one pin and that is the trigger.

So there are two position sensors, one on the crank and another on the cam?

If others tell you it works, it probably does as they describe.

The injection event is important as well, my guess is the 4-tec fires injectors sequentially. Some V8 injection systems batch fire injectors while intake valves are closed others sequential fire each injector separately as the intake valve opens. The timing of the injection makes a difference, but especially if it's sequential I think.

The earliest (1985 ?) sequential V6 I knew of, injection was triggered off a converted distributor (you could turn this thing to play with injection timing) and if it was 180 out the engine ran like a turd. Of course some people made this mistake, set the crank at #1 TDC and stabbed the injection sensor not paying attention if this was the exhaust or intake stroke.

Spark can occur at normal xx degrees BTDC and then again on the exhaust stroke, it's up to the engineer but why fire twice if it's unnecessary?

 

[Mekanix]

Found out some more news. P.O reused all stretch bolts
So this will be a complete teardown and rebuild.
I'm sure there are a few gaskets I can save. Like the oil pump and mag covers.
Curious, what about the head gasket ?
It has only been crushed and not run. I'm going to replace it but I'm wondering if people have reused head gaskets like this before ?

 

[Sportster-2001-951C-Stock]

Get a new head gasket, IMO.

 

[Mekanix]

Oh yeah I will!

 

[Sportster-2001-951C-Stock]

Oh yeah I will!

The only head gasket I've ever re-used was on a lawn mower. It worked out fine.

I was rebuilding a flathead V8 and failed to torque the head properly, it was wheezing water at startup. I torqued the head properly without replacing the gasket and it's been fine since.

 

[Mekanix]

Wsm vs oem for head gaskets ?
I've used wsm in the last 4 tech build I did and it withstood 215 hp
I think it will be ok in the 155. But are there any differences in quality I'm not aware of ?

 

[Sportster-2001-951C-Stock]

Somebody must make the gasket for WSM like Detroit Gasket or Fel-Pro, surely they know what they're doing. Maybe it's the same gasket as a Yugo? (lol, kidding!)

I wouldn't know about the 4-tec specifically but curious, are they stainless by chance?

 

[Mekanix]

Not sure, but seems like it.
I know with typical fiber gaskets there is definitely a difference from oem to other brands but did t know about this one.

 

[Sportster-2001-951C-Stock]

Most real marine gaskets are stainless, automotive gaskets corrode too easily thus won't last decades, (maybe).

My big block Olds Jet has automotive gaskets on it, they've been fine for a couple decades but it doesn't get a lot of time on it b/c it's a garage queen.

When I do a head swap on someone elses boat, I use aftermarket marine gaskets, they're stainless like the OEM gasket.

 

[Sportster-2001-951C-Stock]

And yes it's true there are different strategies employed in head gasket technology, quite right. Aluminum head on iron block, iron head on aluminum block, iron/iron aluminum/alumunum, bla, bla...

The goal is to maintain the seal as the head walks around the deck as both heats and cools at different rates, there's quite a bit to it and they go on and on for hours seems like. Some gasket manufacturers are perhaps more adventurous than others that stick to old-school ways, (aluminum blocks have been around a long time) the demands are always manufacturer driven so those guys designing gaskets for the OEM's are always a few steps ahead, seems like.

But I'm not hot for change just for the sake of change, I don't care for the nylon carrier with silicone o-ring inserts I've seen weeping antifreeze on intake manifolds. Truth is, it's probably the silicone I despise but the OEM silicone intake manifold gasket isn't compatible with the organic acids in the OEM antifreeze, according to the application charts.