Newly rebuilt engine with pac man inside.

[m411b]

1994 Ranger 4.0 OHV. It literally sounds like pac man. The high pitch chirp chirp chirp chirp pac man makes when he's going around the board.

Rod? Main?

Anyone have any ideas? I think it's a rod bearing.

Thanks

 

[m411b]

MODS - can you move this to the 4.0 forum please?

 

[RangerFabWorks]

As you wish!

 

[Dirtman]

Remove the belt(s) and start the engine for a minute. If the noise is still there you can at least rule out one of the drive belt accessories as the culprit.

 

[m411b]

Done did. Not the belt.

I've put a scope on it and it sounds like it's coming from the bottom end. The chirp is in tune with the RPM's of the engine. But goes away after idle.

It just sits there - chirp, chirp, chirp, chirp, chirp. I used 5w30 with Lucas break in additive. Wondering if 5w30 is too thin for this engine. The book calls for 5w20 unbelievably.

I've checked everything external. The ballancer is fine, the belt is fine, the pulleys are fine. Only other thing I can think it too be is a rod bearing. Excellent oil pressure too and zero cooling issues.

Clearances were fine when checked with plastigage on both the rods and mains. The only thing I didn't check and I always miss for some stupid reason is cam and crank end play. It's never caused a problem, though and I can't see that causing this sound. I haven't pulled spark plug wires yet. Wanted to see if anyone else had this problem on a fresh rebuild first.

Literally pac man...

 

[Dirtman]

Pac man said "wocka wocka wocka" not "chirp chirp chirp" btw... lol.

No idea just giving you a free bump.

 

[m411b]

I just pulled the wires and no change.

BUT - I added some honey oil and the noise got quieter. I think 5w20/30 is too thin for this engine. I'm gonna change it out to 10w30 and go from there.

I'll report back with my findings.

Thanks so much

ETA: Laughing my ass of about Pacman. I think it sounds like chirp chirp chirp. My wife said "it's wocka wocka wocka." I was outside listening to the engine and came in to them playing Pacman and it sounded exactly the same.

 

[m411b]

I figured it out - I think. It has nothing to do with oil viscosity.

I had air still in the engine. Drove it 40 miles last night at highway speed to see what would happen and when I stopped to listen to the engine, it sounded like an engine on it's last leg from over heating. We all know that sound.

Apparently the thermostat wasn't opening and it trapped a ton of air inside. Took the thermostat out and made a gasket for the housing. Started up with no chirp chirp chirp and no more air in the engine. I noticed an immediate difference.

My best guess is the trapped air was somehow making the chirp chirp chirp noise. Really hope I didn't F up this new engine and heads. Don't think I did, but only time will tell.

If you think you have air in your engine or if your gauge fluctuates, take the thermostat out and let the cooling system do it's work. My gauge was holding steady where it always has, so I assumed it was good until I squeezed the upper hose and felt the water in there boiling. I knew immediately there was a cooling issue.

Thanks for the space, TRS and thanks for the replies that made me think harder on what was going on.

 

[Ranger850]

Pac man said "wocka wocka wocka" not "chirp chirp chirp" btw... lol.
No idea just giving you a free bump.

"Wocka wocka wocka" was said by this guy

According to the innerweb, Pac Man says -"Waka waka waka"

 

[Curious Hound]

"Wocka wocka wocka" was said by this guy
View attachment 27070
According to the innerweb, Pac Man says -"Waka waka waka"

Tomato/tomoto
Wocka/Waka

At least it's not chirp.


Some thermostats have a tiny hole in their flange with a little "jiggle thingy" that, as I understand it, is to let air pass through when the valve is closed. When I get a thermostat without the jiggler thingy I drill a 1/16" hole there before installing the thermostat. Don't know if that's good or bad. But it seems to work for me.

 

[Dirtman]

Fozzie said "wocka wocka" not "wocka wocka wocka"

 

[m411b]

My thermostat has the hole in it and I specifically put the hole at the 12 o'clock position. There's actually a cut out in the hole in the intake at the 12 o'clock position for the hole in the thermostat.

I'm gonna put that same thermostat in some boiling water tomorrow to make sure it is actually bad before ditching it. If it's good, it's good. But it sure was making it nearly impossible to let air escape for some reason.

I ran the truck tonight again for another 40 miles and it was a totally different beast. No thermostat and it hasn't sucked any water out of the reservoir. So I'm thinking no more air.

I think I'm gonna drive on it a couple more days and then add the thermostat back in and cycle in antifreeze. Then call it a day.

 

[Ranger850]

Fozzie said "wocka wocka" not "wocka wocka wocka"

I guess I got carried away with the "wocka"s

 

[Curious Hound]

Let’s just wocka way from this one.