Thread: Knocking noise

Well I'm the third owner that I know of. Previous 2 are friends of mine. I helped the first one put it in his car. And knowing him I'm sure he dogged it. 2nd owner drives like a grandma. He knows this and we make fun of him for it. (some of you southeast guys know who im talkin about lol) but both are knowledgeable car guys and wouldn't do anything stupid to it. Not sure where the engine was ordered from though. Need to find that out. Might give some background insight into this.

A lot of the tuners/builders out here swear mobile 1 is bad. I belive because of a low zinc content

ok so i had my dad start it and hold it at 3k rpm while i pulled each plug wire one at a time. the knocking noise never stopped. i did notice on two of em when i plugged em back in the rpms stayed about the same. when i plugged the other two, the rpms shot up where dad was tryin to keep it at 3k. from the front of the car the knocking is loud but dad said it sounds really loud under the car as well. not sure if it is because its just really loud or what. pullys are all tight and like i said the lifters all look ok. anything else i can check to help rule one thing or another out?

how about a video?

uploading one to photobucket now

A lot of the road racing guys out here in NASA AZ run Mobil 1 15w50 and have no problems whatsoever, especially in the AZ extreme heat. I've been running the 15w50 all racing season, 8K redline with 3-4 20 min hard sessions not one problem whatsoever. The car serves as a daily at times, no clatter at startup and runs and idles as good as the day I put the JDM DE in 3 years ago. The ONLY two Mobil options worth putting in any car IMO are the 15w50 and the 0w40. The other Mobile 1 options I wouldn't use even if I got them for free. On the BITOG forums and the 350Z forums there is discussion on the Mobil 1 blends and their reformulation issues. The only two formulas they mentioned even worth using are the 0w40 & 15w50 blends.

this is actually the quietest it has been since all this started. which isnt a good thing cause its hard to hear lol. towards the end of the video about 0:48 you can really hear it good. but like i said, normally it has been much louder than that.

hmmm, its kinda hard to say exactly.. at times it really sounds like rod knock, at times it doesn't.. I have had my alternator adjuster bolt come loose and cause that very sound! but then i've heard bad passenger motor mounts make a similar sound..

first thing first, check every motor mount bolt, alternator bolts, crossmember bolts ECT.

ok might have to wait till wed to jack it up and start going over everything. one thing i did notice is as i was driving it home, i could really feel the knocking in the stick. def have to check out the shift linkage too.

Yeah doesn't matter what oil you have if you're 2 quarts low and revving to near 8K, you are asking for major problems. Especially since our oil capacity is 3 5/8 quarts. Doesn't leave any margin for error. Time to replace rod bearings. Check your crank for damage and if you have any you may have to replace it. You might want to figure out what caused you to lose a couple of quarts in the first place while you are at it. Good luck.