Rattling under the hood, help me diagnose!

[JasonG]

Don't know honda engines well but was thinking clutch bearing and detonation.
Someotherdave has it right.
If noise#1 is detonation, be careful, it can destroy am engine quickly.
Don't ask how I know that.....

[Ecky]

Originally Posted by JasonG

Don't know honda engines well but was thinking clutch bearing and detonation.
Someotherdave has it right.
If noise#1 is detonation, be careful, it can destroy am engine quickly.
Don't ask how I know that.....

Thanks, I'll see if pulling timing makes it go away. I recently set the timing with a light but I really don't know for certain if the pulley on the crank (where the timing marks are) is the one that was supposed to come with this engine, so it's very possible that I'm advanced.

Originally Posted by some_other_dave

Noise #1 sounds a little like detonation ("pinging"). Which in my non-Honda, sounded kind of like a "spitting rattle" noise, not a metallic "ping". If your engine is on the edge of detonation, moderate loads and medium RPMs and warm temperatures would be the most common times for it to happen.

I suppose I didn't suspect detonation as my understanding was that it would most likely occur when cylinder pressure was highest and burn was leanest - ie WoT before the computer begins enrichment. I suppose I need to read up on detonation.

[Ecky]

It was dark and the timing belt has a cover, but I think my tensioner came apart. Timing belt is slack.

Looks like I can get a used head for around $75 if it comes to that. Crossing my fingers that there are no bent valves, and I just need a new belt.

If I pull the head off just to look at the valves, do I definitely need to replace the head gasket?

[some_other_dave]

If you disturb the joint between the head and the block, you will need to replace the gasket.

Removing the head counts as "disturbing the joint".

Sorry to hear about the belt.

-soD

[Ecky]

Started taking the timing belt off and I tore up a 1/2" to 3/8" adapter with my 30" breaker on the crank pulley bolt.



Pulled it apart, here's the culprit. Looks like it almost ripped in a second place too. If the last mechanic I had work on my car did what he said he did, that belt was only 40k miles + 3 years old.

[some_other_dave]

Don't use a 3/8" socket on the crank pulley bolt. You need a 1/2" drive socket. And a good way to hold the crank from moving, like a screwdriver jammed in the flywheel teeth or some such.

Or use a really good air hammer/impact wrench on it. That puppy is on TIGHT!

-soD

[Ecky]

Originally Posted by some_other_dave

Don't use a 3/8" socket on the crank pulley bolt. You need a 1/2" drive socket. And a good way to hold the crank from moving, like a screwdriver jammed in the flywheel teeth or some such.

Or use a really good air hammer/impact wrench on it. That puppy is on TIGHT!

-soD

Yeah, pulley bolt came out with a proper socket, had to remove it in order to get to the belt. I bought the proper tool for holding the crank still when I ordered the new belt (and it got here first), but I still ended up standing on the end of my 30" breaker bar before it budged. New belt should be here tomorrow.

[Ecky]

All's well that ends well. Installed the new belt, water pump, tensioner and reassembled, and it started right up. I haven't done a compression test but if there is any valve damage, it's minor.