I got my engine build a few months ago and can't get rid of this rattle. It happens at 2500 rpms and above. BUT, it only rattles when the engine is transitioning from a positive load to a negative load. Like if your on the freeway and you let off the throttle. Or when I'm shifting gears it happens right at the same time you'd hear a BOV on an FI car. I've tried a stethoscope and can't track it down. It sounds like it coming from inside the engine.
My last hope is maybe it's one of the chain tensioners. I used the old ones. If I rev the engine with no load on it, in neutral, it will only make the noise when it's cold. Also, if I make it rattle purposely for more then a few seconds, it seems to get a hair louder/worse. I've been driving it like this for about 2k miles and it's not getting any worse, which makes me believe it's not a bearing. Because they are all new. It also seems to rattle more when at a lower rpm, 2500-3500, rather then at higher rpms 5-6K so maybe that's because the oil pressure is higher? BTW, I did a full rebuild, only kept my block, crank, bare heads, and front acc stuff.
I guess I just want a little reassurance before I take the front off the engine and waste my time that this is what it could be. My builder thought it may be a pully bearing because he said the rattle sounds faster then the rpms are. But they all spun fine when I took the belt off.
I'd like to figure this out before I go make a bunch of dyno runs and get it tuned. I've been trying to keep it under 5k or so because of this. TIA
My last hope is maybe it's one of the chain tensioners. I used the old ones. If I rev the engine with no load on it, in neutral, it will only make the noise when it's cold. Also, if I make it rattle purposely for more then a few seconds, it seems to get a hair louder/worse. I've been driving it like this for about 2k miles and it's not getting any worse, which makes me believe it's not a bearing. Because they are all new. It also seems to rattle more when at a lower rpm, 2500-3500, rather then at higher rpms 5-6K so maybe that's because the oil pressure is higher? BTW, I did a full rebuild, only kept my block, crank, bare heads, and front acc stuff.
I guess I just want a little reassurance before I take the front off the engine and waste my time that this is what it could be. My builder thought it may be a pully bearing because he said the rattle sounds faster then the rpms are. But they all spun fine when I took the belt off.
I'd like to figure this out before I go make a bunch of dyno runs and get it tuned. I've been trying to keep it under 5k or so because of this. TIA
