1FZ-FE Rebuilt but have a Rod Noise when Cold Start (1 Viewer)

[at1992]

Hi,

I just do a master rebuild of the 1FZ-FE. The engine is rebuild with 0.25 clearance not standard.
I notice a BIG loud noise when cold start or when the truck is sitting for 3 to 4h. The Knock noise last for about 2 seconds! the times that RPM goes up and down when starting.

What is this noise? Sounds like a Rod Noise! but I replaced all the rod bearing during the rebuild.
What it can be? Piston Slap? Bad Tensioner?

It's killing me now, as I rebuild to get it of that noise and now its still there. What can be bad or cause that?

Thank you

A.

 

[tominboise]

Did you inspect or replace the timing chain and guides? That is a typical source of start up noise. What weigh motor oil are you using?

 

[at1992]

Did you inspect or replace the timing chain and guides? That is a typical source of start up noise. What weigh motor oil are you using?

The Shop replace the Timing Chain Guide. Can it be off or over tight?

 

[excessive]

The timing chain is fairly difficult to inspect , if you pop your valve cover off you can only see the top pulley. It's difficult to Check tension on. You can check the tensioner on the LH side of the engine , perhaps that should have been replaced .

 

[Pin_Head]

It is likely to be related to oil pressure building up, so it could be a lot of things including rods, mains, chain, oil pump and oil pump drive gear. If they didn't replace the timing chain cover it could be the oil pump drive gear. Use a stethoscope to localize the noise.

 

[TrickyT]

The timing chain can indeed be a source of noise on engine startup, especially in colder climates. The timing chain tensioner relies on oil pressure to properly tension the chain, and there is a small hole in the tensioner where the oil feeds in. On some rebuild threads I've read, guys will slightly enlarge the hole so that it presents less restriction to oil flow resulting in the chain getting tensioned more quickly on startup. I don't remember exactly where the hole is, but if you remove the chain tensioner it is pretty obvious. (See attached pages from FSM.)

 

[SmokingRocks]

mine gives a little 'Kaa clack' on initial start up with rotella 15w-40 after my rebuild. Stopped caring too much about it.

 

[half k cruiser]

Mine makes noise on startup, especially cold. Its been doing it for years now with no noticeable ill effect. I wouldn't be too worried about it. If it were a rod bearing you would continue to hear it after the initial startup.

 

[Kaninja]

I think this is just the 1FZ-FE startup sound. Every one I've been in has a clackity clack sound for a couple seconds after startup. Doesn't seem to effect anything.

 

[SmokingRocks]

I've heard you can go to a 5-30 or 5-20 mix to reduce the effect but personally I'll keep my zinc package