Engine Knock getting worse BJ-40 (1 Viewer)

[Max Wilder]

Hi, I have a B engine BJ-40, 1979.

The engine has made a distinctive knocking sound for a while, but I just moved from Arkansas (low altitude) to Idaho (higher altitude) and the knock is worse. I'll let you watch this video and draw your own conclusions:

(I happen to have a camera and microphone)

Engine Knock?.mov - YouTube

I'm planning to have it checked out by a diesel shop, but I need to find a shop that will look at it first and in the mean time I thought I could consult with you folks.

Thanks in advance!

 

[Capitalguy]

Have you checked your exhaust system for leaks, broken hangers or exhaust pipes rubbing or resting on something? Mine made a similar noise, my exhaust was resting against my slider, I pried it away and the noise was gone.

 

[Biche]

My HJ60 done the same thing last year, my neighbour who's working on heavy machinery (drilling) and own a couple of diesel trucks told me that is a normal knock for an old diesel and that I could check valve clearance and head to try to pin point the issue. But the knock mysteriously gone...

 

[Biche]

And here's the link to my original question: https://forum.ih8mud.com/diesel-tech-24-volts-systems/511479-strange-sound-engine-bay.html

 

[lostmarbles]

To my ear, your engine sounds exactly the same as mine.

1979 BJ40 cruiser with reconditioned injectors - YouTube

In other words, I don't think you have any problem there.

 

[Max Wilder]

Thanks for the replies, another consideration is the fact that it only has about 50,000 miles on it.

 

[roscoFJ73]

Its when they are knocking under load you have a problem. What tyoe of oil do you have in there? Too thin an oil and they can be a bit rattley

 

[Max Wilder]

I use RotellaT 15W-40, what oil would you recommend?

 

[roscoFJ73]

I use RotellaT 15W-40, what oil would you recommend?

That should be fine but in really hot weather I prefer something a bit thicker 20-50

 

[lostmarbles]

From my experience, pre-1981 B engines have more "diesel knock" than most other Toyota diesels.

I think it is because of their higher compression ratio (21:1 for the BJ40 B compared to 20:1 for the BJ42 3B) and more-importantly the different injection timing (10 degrees BTDC for the BJ40 B compared to 14 degrees BTDC for the BJ42 3B).



PS. Wow. 50,000 miles is low. That engine is probably in pristine condition!

 

[magnus_heydoc]

my 40 sounds exactly the same as that. It's annoying. I also have a 62 series with a 3B in it and it sounds great, tight and no annoying knocks.
aaron

 

[Max Wilder]

Thanks for the help and info. Unfortunately now the alternator quit

 

[roscoFJ73]

Where did this one come from, see its left hand drive. 12v or 24v?

 

[Max Wilder]

It's 24v and came from Belize.

 

[lostmarbles]

Thanks for the help and info. Unfortunately now the alternator quit

Probably just worn brushes ... (even though 50,000 miles is a little bit early for that).

My original alternator is still going well but I did put new brushes and a new front bearing in it at some stage.

Make sure no-one welds on your cruiser without taking precautions to protect it though.