stevieturbo

Have you removed the pistons ? How do they look ?

At the minute it sounds like a badly tuned engine that has melted pistons ....but kept on running flat out and then blew all the oil out of the engine via the breathers then ******* the rest of the engine as there is no oil.

I really cant see this being the fault of the rings.

Huffa

Pistons are perfect other than seized on pins,no broken rings

stevieturbo

How is the crankcase breather system configured ?

Huffa

It just has the two breathers, one on each rocker cover up on bout foot high stacks

stevieturbo

And all the oil got blown out these breathers ? Or do these not go to some sort of catch can ?

Huffa

That's correct, no catch can, just extended the breathers up high. A guy I know runs a LS1 twin turbo in race boat. He tried the catch can thing and found that the extended breathers worked the best and dosent ever have an issue

stevieturbo

So you've no real way of knowing if the oil got threw out these ?

Or would there be visible signs of oil getting spewed out ?

Not sure I'd trust what you've done without some sort of can, although in theory it probably should be ok assuming everything else with the engine was good.

But when the engine appears to have died from lack of oil....where did that oil go ?

Huffa

So there was visible signs of oil thrown out breathers. Oil all over the rear of boat in and out. There was still plenty of oil in the engine, still close to full on dipstick so cant have been that much thrown out, probably looked worse than what there was actually. But the fact remains there is a starvation problem, so is it a lack of supply via the pump or oil been held up by crankcase pressure?

stevieturbo

I can see no conditions, scenario, whatever where crankcase pressure could hold oil out of the oil pan.

Huffa

Cool, thats good to know then.

Huffa

Getting keen to get another 5.3 going, just ordered a HV oil pump, got a Compcams custom ground camshaft, new LS7 style lifters, thinking about installing an oil accumulator for the engine as still not really sure why it starved of oil and spun the centre main with best part of 9 litres of oil in sump and cooler, any more suggestions?

OkieDave

I lost thrust BRG due to drive line pushing on crank in my Jetboat. It seized. One of many failures for LS powered jet boats for me.

SethU

Put your oil cooler in a place that will require the shortest and straightest hose runs. A step up in hose size to/from the oil cooler can only be good. Run as few fittings in that run as you can, especially angle fittings and eliminate any 90º fittings if at all possible. Absolutely no kinks in in the hose, not even marginally, almost, or not quite kinked.

However, that's all good practice stuff. I suspect the failure was a clearance issue. Something was on the tight side. I agree with OkieDave, probably your thrust clearance or driveline pushing the crank forward. For sure, double check that you're not bottomed out in the splined end of the yoke and that it slides in and out smoothly without binding.

Good to hear you're back at it! Best of luck.

-Seth-

Huffa

Thanks Seth. Yep just collected the next 5.3 this arvo. Got all the bits to do the upgrades, but time is not on my side. Will get new HV oil pump in tomorrow hopefully, but am thinking about leaving heads and cam until a later date as got a race in a months time. Do you think the stock springs will handle 7psi boost? I have a good set in my other heads, but just don't want to change it all at this time, would have to get another tune and so on. By memory from previous reading the stock springs are ok up to about 7 or 8 psi aren't they?

stevieturbo

Springs would depend on cam, boost usage etc etc.

For sustained high rpm use....good springs are cheap insurance.

Huffa

Stock 5.3 cam, same as what I ran in the last engine. 5300rpm flat out

stevieturbo

It probably would be ok....but given they are so easy to change and cheap. I'd be doing it anyway

Huffa

Ok, so is there any reason why I cant change my heads over to my set with good springs, install arp head studs and also install the new lifters but not change the cam at this stage? New lifters-old cam. Just not going to get time to re-tune with new cam, opens up can of worms on a short time frame. Cam can be swapped out easily at later date and heads could stay on

stevieturbo

You can do many things. But I would never advise pushing an engine hard without knowing the tuning is safe/good.

SethU

You can run the first set of heads on the current engine... If you're certain the 1st set are free of any foreign debris. I would. There's no good reason to swap the springs over, unless there's something better or more desirable about the heads on the new engine. ie. cleaner, better valve face and/or seat condition, deck quality, etc.


"Arvo"... had to google that one. LOL