Cold Start Piston Slap/Knocking?

[Perovich]

I'm trying to wrap my head around this. I just got my FJ60 winter-ready (rebuilt front axle, new fluids in differentials, t-case/trans w/ equalizer hose, etc.) after sitting for around 6 months. Got everything buttoned up and tuned in on the carb and have been issue-free for the last week or so.

Then fast-forward to this morning, after our first night below freezing, and the LandCruiser sounds like it has a rod knock for the first 1-2 seconds on start up. Loud, rhythmic knocking not unlike a rod knock then goes away immediately and doesn't come back unless the truck has been brought back down to ambient outside temperature.

The knock goes away immediately and doesn't re-occur with higher RPMs. I'm getting about 65-70 PSI oil pressure cold, and around 32 PSI once fully warmed up at idle. The engine also has about 750 miles on a rebuild, so I'm hesitant to blame carbon knock or condemn rod or main bearings prematurely. I had the same noise in my 5.3, but those were hydraulic lifters and these... aren't.

Which leaves me with maybe piston slap, from a clearance issue? Any other ideas of what I can look at?
I'll try and get a video of it once it's cooled down again.

 

[Homey55]

I have the same noise you are describing. I have about 4k on my rebuild. I will be curious to see what others say. My hunch is fuel or oil pump noise but it's gone by the time I get out of the truck and look under the hood.

 

[OSS]

Use 10w-30 or 5w-30 synthetic oil. See how it starts with that.

 

[Homey55]

Not on a fresh rebuild!

 

[OSS]

There's an oiling problem.

 

[Homey55]

Could be, but if you put synthetic oil in a fresh rebuild then you risk oil leaks and improper break-in.

 

[Perovich]

Broke the engine in running conventional 10w-30 high zinc formula from the engine builder. Changed out and switched with 15w-40 Rotella T and Lucas Zinc additive.

Changed out again at 250 miles, changed again with Rotella T and Zinc.

So far I haven't been able to replicate it. We'll see in the morning!

 

[morganism]

Just posted this article on the "too hot" post here, i would be tempted to go back down to 10-30 till break-in year is done.

do you have a 180 or 190 thermostat? the 60s run cooler with a 190 (and better mileage too)

Low Temp Thermostats: What’s the Advantage?

 

[Imesseditup]

I'm trying to wrap my head around this. I just got my FJ60 winter-ready (rebuilt front axle, new fluids in differentials, t-case/trans w/ equalizer hose, etc.) after sitting for around 6 months. Got everything buttoned up and tuned in on the carb and have been issue-free for the last week or so.

Then fast-forward to this morning, after our first night below freezing, and the LandCruiser sounds like it has a rod knock for the first 1-2 seconds on start up. Loud, rhythmic knocking not unlike a rod knock then goes away immediately and doesn't come back unless the truck has been brought back down to ambient outside temperature.

The knock goes away immediately and doesn't re-occur with higher RPMs. I'm getting about 65-70 PSI oil pressure cold, and around 32 PSI once fully warmed up at idle. The engine also has about 750 miles on a rebuild, so I'm hesitant to blame carbon knock or condemn rod or main bearings prematurely. I had the same noise in my 5.3, but those were hydraulic lifters and these... aren't.

Which leaves me with maybe piston slap, from a clearance issue? Any other ideas of what I can look at?
I'll try and get a video of it once it's cooled down again.

I have the same issue with my 62. Did you ever determine the source of this sound?

 

[dogfishlake]

That 15-40 might be to heavy for winter I agree on dropping down to a thinner oil. Just my .02. I can't imagine it would be a bad idea to keep pouring the zinc to it. It is obviously great for the cam but wondering if it would protect the "dry" crankshaft a bit on startup too?

 

[SteveH]

If you sense the problem is lack of oil pressure at startup, you might try a different oil filter (in case yours has a problem with the drainback valve). Easy to screw off the old and screw on a new/diff one without changing the oil. Then add back whatever was trapped (or not trapped ) in the filter.

 

[Dr. John]

I've had the same issue for years. Different wt oils, different filters, good oil pressure. Tapping is gone within 1-2 minutes of startup. I'm down to piston slap, sticking lifter, or maybe an ex manifold leak. I'll Have the manifold off soon for a Sniper conversion, so I'll check for a leak then. 120K on complete oem parts rebuild and consumes almost no oil, so I'll live with it.

 

[Imesseditup]

Hopefully this link works. This is the sound that my 62 makes up on start-up and only lasts for a few seconds. No other issues that I have seen or heard. Only does it when the engine is cold.

 

[WILLD420]

I think you are hearing loose engine parts until oil takes up the clearances. Sounds a lot like sloppy rockers to me. Depending on ambient temps you should run thinner oil. Don't buy into the zinc argument too much. There's a lot of b.s. floating around about it.

MOTOR OIL ENGINEERING TEST DATA

Some say this guy is full of crap. I'm having great luck with the higher end of his oil recommendations. Also, motorcraft filters have a very good anti drain back valve. Some of the Wix filters have been having issues lately. I wouldn't run a free Fram anymore.

You could have piston slap but it usually takes several minutes to go away.

 

[dogfishlake]

Definitely sounds like valvtrain rattle. I don't think that is from the crank, and piston slap would last likely minutes until they warm up.

 

[Dr. John]

+2 on lifter/valvetrain.

 

[Imesseditup]

Definitely sounds like valvtrain rattle. I don't think that is from the crank, and piston slap would last likely minutes until they warm up.

Ok. Thanks for the input. This leads me to a few additional questions. Is this causing damage? How do I verify if it is valve train noise and how difficult is it to correct that issue? It never gets any worse but it sure does bug me every day.

 

[dogfishlake]

Well, I suppose it would be a good idea to make sure all looks good, like pull the valve cover and check and maybe the lifter cover on the side. Going lighter on oil might get it gone but not sure. I really don't think it's hurting much like it is but checking it over would be good assurance. The 80 series smacks like that because the chain tensioner is flat til pressure comes up. It drives me nuts but it is normal.

 

[dogfishlake]

I have a Kat's magnetic heater I use on my oil pan in the winter. I like the idea of the oil getting up to the top quicker.

Might help your rattle out.

 

[Imesseditup]

Thanks for the input, guys. Will let you know how it goes.