knocking sound from the new replaced engine

Asked by Sep 08, 2015 at 03:39 PM about the 1991 Nissan 300ZX 2 Dr STD Hatchback

Question type: Maintenance & Repair

I just replaced the engine in my 91 Nissan 300zx. When I started the car it mad
a loud noise. Sounds like a machine gun going off. What is wrong with the
engine. By the way the engine is aJDM.

4 Answers


could be anything>>>even a belt.

you may need to tighten your exuast headers?


carbon is in the combustion chamber, the engine was having its first life, then it sat. the carbon deposits dried, flaked, etc. You start it again in a different car, after sitting and you hear the dislodged deposits. Combustion chamber cleaner, an exhaust management shop system for the smoke and voila. This is normally diagnosed by the engine installer or builder if the heads stayed on and chambers were not cleaned prior to install. The operation is best performed professionally.


Did you put oil in it?

1 of 1 people found this helpful.

Your Answer


Looking for a Used 300ZX in your area?

CarGurus has 119 nationwide 300ZX listings starting at $3,995.


Nissan 300ZX Experts

  • #1
    Tom Demyan
  • #2
    Jamie Staples
  • #3
View All

Related Models For Sale

Used Nissan 240SX
10 listings
Used Ford Mustang
291 Great Deals out of 38,369 listings starting at $1,995
Used Toyota Supra
52 listings
Used Chevrolet Corvette
86 Great Deals out of 15,794 listings starting at $4,500
Used Chevrolet Camaro
242 Great Deals out of 30,118 listings starting at $4,980
Used Nissan Skyline
10 listings
Used Mitsubishi Lancer Evolution
8 Great Deals out of 528 listings starting at $14,000
Used Mazda RX-7
60 listings
Used BMW 3 Series
963 Great Deals out of 33,201 listings starting at $1,000

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.