tjk23

First off i have a FB with a 12A in it and the only mod done is the rats nest removal. Everything else on the car is stock. The car has just over 100k miles on it and I have owned it for 8 years. When I bought the car it had sat for over 1 year. Multiple vacuum leaks have been fixed and a carb rebuild. Since then the car ran great for about 6 years and then the engine started knocking. So I bought another car and my FB has been in storage for the past 2 years.

I now have a bit of time and money to play with so I would love to get the 7 back up and running.

The knocking would only occur under load at around 4k rpm. It was accompanied by a loss of power. The spark plugs still look good and the wires are connected correctly. The leading coil is almost brand new. I have a fresh fuel filter on the car and I only have about 5k miles on it since the carb rebuild.

I had a compression test done at a Mazda dealership shortly after I bought the car and he said the compression was great for a 7 that old. But I have not had another compression test done since the knocking problem.

Right now I'm looking for things to test to see if I can't find the problem. Any suggestions would be much appreciated.

Thanks in advance.

Kentetsu

Start with the ignition system. Pre-ignition (spark knock) is the most likely culprit, if you are lucky. Check the timing, and make sure that the plug wires are routed correctly.

The other possibility is a failing apex seal, which would mean a rebuild. So let's hope you find something in the ignition system instead.

Here's my thread related to my failing apex seal, if you want to check it out:
https://www.rx7club.com/1st-gen-archive-71/engine-signs-failing-rotary-engine-679328/

Hyper4mance2k

iTrader: (40)

if it ain't that it ounds like it might be a spun bearing or a cracked stationary gear either of those will allow the rotor to slop around and crash into the housings or iorns and cause a loud knocking sound..

craigcorx7

I would have to agree with Kentetsu.I don't know if your distributer has ever been out or not.My car did the same thing when accelerating hard.My distributer was off by one tooth.Good luck

7aull

iTrader: (2)

I just had a similar experience with my SA, also coming out of storage - ran fine when put away, but on resurrection: no power, engine (or some part thereof) making a metallic knocking sound when I tried to accelerate, esp above 4000rpm. Believe it or not, new plugs, cap and rotor fixed it!! (I bow to the Rotary Gods). Worth a shot-
Stu Aull
80GS
Alaska

tjk23

Ok, it seemed that the timing was my problem and the knocking has stoped.

But now I am getting a high pitched whine at about 3500 rpm. It seems to be coming from the water pump area. The water pump is still stock with over 100k miles on the car. But I also am only running 1 belt at the moment due to the removal of the air pump. Is it possible that my belt is just slipping on the water pump pulley? Or am I looking at buying a new water pump?