Seized Motor?

[squinn8810]

Today I started the break in procedure for a 4.6 I have been working on about a year now. On first start up, it was slower to start than what I would consider normal, but started within 5 seconds. I did 5 minutes of the varying rpm then wanted to see if it would idle briefly. It died, when trying to start up again it cranks very slowly for two to three turns then stops. The battery and starter are both new. It seemed to run well for the first 5 minutes unlike if the CPS was oriented poorly.

Is this a normal behavior for new strokers or does it sound like this thing is close to seizing already?

[Cheromaniac]

Pull the plugs and try turning the crank bolt manually with a breaker bar to see how much resistance there is.

[squinn8810]

It was hard to tell if it was more resistance than normal with all the accessories on it. It started up cold and idled well until it warmed up and same as before, died. Slow crank until no crank immediate following. It did seem like the upper radiator hose was abnormally hot...temp gauge never went above 210. Is it likely that it could overheat within the span of a few minutes causing it to seize?

This is the second time i've put the thing together. The first time rod bearing number 3 was the issue. I attributed this to finding that two pieces from inside the timing chain cover had been sent around/through the block and the fact that the wear was located right at the oil galley of the journal. I guess it'll have to come out again to see what went wrong this time.

[len1xj]

I would tear it down and inspect everything you can think of. when you put it back together again you are confident that it is mechanically sound .
Reset the ECU. If you put larger injectors' in it will run ruff for a little while until it learns the engine is getting more fuel then it should.
good luck

[squinn8810]

Tore it apart…rod bearing number 3 giving me my issue again. Going to call the machine shop and see if they can take a look at the crankshaft.

IMG_5515.jpeg

[dwg86]

It looks like the bearing was starved for oil. I’d definitely have the crank checked.

[dwg86]

I’d also check the oil galley in the block that feeds the main that feeds the #3 rod. It should be #3 main. Just a shot in the dark, but maybe it’s partially clogged with something, and has enough oil to feed the main but not the rod bearing. Might as well have it all checked…not just the crank.

[dwg86]

[attachment=0]IMG_7446.png[/attachment
Check the number 2 cam bearing to make sure it’s installed correctly. It looks like the #3 main gets its oil from the #2 cam bearing.

[squinn8810]

[attachment=0]IMG_7446.png[/attachment
Check the number 2 cam bearing to make sure it’s installed correctly. It looks like the #3 main gets its oil from the #2 cam bearing.

That’s a good suggestion, I’ll have a look and see what I find. The machine shop cleared out the oil galleys but they pressed in new camshaft bearings when they cleaned up the crankshaft from the first failure. This time they asked to look at the connecting rod to see if that’s where my trouble is coming from.

[dwg86]

Let us know what you find.

[squinn8810]

It ended up being my error...switched the caps of rods 3 and 4 around. Dumb. Good news, however, I'm about 300 miles into the break in after putting it back together and so far my only issues I think are related to tuning. Waiting for the larger throttle body to come in before I get it tuned at the shop.