Cold engine knock

[losh1971]

I mentioned in my build thread that the rattle is a balance shaft. I spoke to the mech who did the work and he was bummed about not removing the cog now. I think he was relieved I didn't push him for a year down to do the former.
I spoke to him about trying a 15w oil instead of 20w. I wonder if it's worth trying a 15w next oil change in 7k? He seemed to think it's not a bad idea.

 

[Immortality]

Balance shaft rattle is annoying but it's not going to do any damage. On the ecotec they added an oil feed to the rear balance shaft bearing to stop this problem (crap getting into the needle roller bearing).

 

[losh1971]

Balance shaft rattle is annoying but it's not going to do any damage. On the ecotec they added an oil feed to the rear balance shaft bearing to stop this problem (crap getting into the needle roller bearing).

Is it worth going lighter oil? It quietens down after a bit. I was thinking the thinner oil my get in quicker and not be as loud and less time making the noise. Both sets of crank bearings are new. But cam bearings are not so wouldn't want low oil pressure to them. I currently run 20w.

 

[Immortality]

Tasmania isn't so hot so a thinner oil shouldn't adversely effect the motor. Try running some nylon lifter free, it works like an engine flush but doesn't thin out the oil so it may help to get the crap out. The big issue with the balance shaft bearings is that they as splash lubricated only so basically the rear needle roller bearing doesn't see stuff all oil. Generally speaking a needle roller doesn't need stuff all oil however in a sealed motor where hot gasses rise to the top carrying any contaminants from the running engine with them unfortunately that is exactly where the **** seems to accumulate.

Worst case scenario for the cost of a couple of gaskets and a few hours work you could disconnect the balance shaft if the issue doesn't resolve itself.

 

[losh1971]

Balance shaft disconnected and the BS knock has has gone. Now i have a light knock for about 3 minutes after starting. It sounds like it's coming from up high. But since rattles and knock noises travel it could be down lower. I'd like to figure out if I can sort it when the heads come off?
Does it sound like lifters? Can I assume if it was cam bearings they will continue to knock and not become quiet after a few mins? Lastly can any of the cam bearings be replaced when the heads come off? I understand it's engine out to replace the back one and that it requires specialist equipment.

 

[Immortality]

What oil are you running and have you tried the Nulon Lifter Free?

No, cam bearings are an engine out deal.

 

[losh1971]

Gulf Western 15/40 Semi. with a Wix filter. I was running straight mineral 20/50 in what ever brand I could get on a decent special. Plan is to replace the lifters when the heads come off. I have used Nulon Free Up two or three times in as many years. That being the case with cam bearings it would mean full rebuild as the engine overhaulers would want to do a lot more than press in cam bearings, which makes sense.

I might add the noise you hear for a few minutes can be heard from down low, if you get down by the sill and have a listen, so definitely demonstrates just how much rattles travel and pin pointing them can be tricky.

Shame about the cost of Buick parts though. I can buy full kits for a 304 50%-60% cheaper than I can for my V6.

 

[losh1971]

Had a listen to the knock/rattle this eve after the ute sat for an hour or so. I could here the noise from the top but it only lasted 15 seconds. Anyone know if this is lifter bleed? And is it just a matter of replacing the lifters to correct lifter bleed?