Loud/deep knock when revving the motor

[B1B Keven]

Made me cringe and turn my head when I was revving the motor at the carb.

Mains?

Motor only makes about 25 or 30 psi oil pressure. Less at idle.

[NiftyFifty]

Mains typically knock when it warms up, rods will knock from the moment it starts usually, but either way...it's time to drop the pan and start investigating.

[Don Coatney]

Quite possible a wrist pin knock. Rod or main knock would have close to zero oil pressure.

[B1B Keven]

35 minutes ago, 4mula-dlx said:

Mains typically knock when it warms up, rods will knock from the moment it starts usually, but either way...it's time to drop the pan and start investigating.

Thanks and yes it is.

[NiftyFifty]

The rod bearing in my Massey tractor knocks...oil pressure is 30-40lbs, it's not always related to oil pressure, I even changed all the bearings because I wasn't sure what I was going to find when I opened it up....lasted an hour...little better oil pressure, and back to knocking all the time.

[B1B Keven]

Timing adjustment and nearly all the noise is gone. Might need a valve adjustment.

[NiftyFifty]

if it was knocking at idle I'm amazed it ran if the timing was that far advanced...but valves tick that should never "knock" lol

 

oh...and timing too far is "pinging" not knocking...lmao

Edited July 30, 2017 by 4mula-dlx

[wallytoo]

7 hours ago, 4mula-dlx said:

if it was knocking at idle I'm amazed it ran if the timing was that far advanced...but valves tick that should never "knock" lol

 

oh...and timing too far is "pinging" not knocking...lmao

ridiculing someone for asking for opinions of others about possible sources of noise type, and their reporting of specific tasks to eliminate the noise, is not particularly helpful.  lmao.

[NiftyFifty]

I was refering to the correct name for the right sounds in a joking manner...and did my duty for helping in previous posts as well....but thanks for all your help in this thread 

[wallytoo]

51 minutes ago, 4mula-dlx said:

I was refering to the correct name for the right sounds in a joking manner...and did my duty for helping in previous posts as well....but thanks for all your help in this thread 

if the only help i can offer is to ridicule a non expert in automotive technical terms, i'd prefer to remain silent.

[B1B Keven]

It's OK guys. At my age I just ignore most things. lmao. I just hate the people that post for the sake of posting without bringing anything to the tread. Now some poor owner doing a 'search' will have to wade through this crap.

I know the difference between knocking and pinging. I learned that in auto shop 40 years ago.

This knocking noise made me cringe when I revved it, wasn't a pinging noise.

Still has a slight noise, I might get away with a valve adjustment.

[Don Coatney]

If (when the engine is running and knocking) you remove one spark plug wire at a time and the knocking subsides you will know what cylinder is the culprit.

[wallytoo]

1 hour ago, B1B Keven said:

This knocking noise made me cringe when I revved it, wasn't a pinging noise.

Still has a slight noise, I might get away with a valve adjustment.

if it makes you feel any better, my 237 has had a rod bearing knock for several years.  it is the number 2 rod bearing, and i replaced it twice.  the first time with the same size insert as on the other 5, the second time with a slightly oversize insert.  in both cases, the knock went away for about 250 miles, but has returned.  either i'll pull the engine and take the crank to a machine shop to regrind the rod journals, or i'll wait for the engine to put a rod through the side of the block and pull the engine and replace it with the 251 spare i have sitting on a crate in the garage.

 

in all, i've put nearly 1,200 miles on it with the knock.

Edited July 30, 2017 by wallytoo

[NiftyFifty]

2 hours ago, B1B Keven said:

It's OK guys. At my age I just ignore most things. lmao. I just hate the people that post for the sake of posting without bringing anything to the tread. Now some poor owner doing a 'search' will have to wade through this crap.

I know the difference between knocking and pinging. I learned that in auto shop 40 years ago.

This knocking noise made me cringe when I revved it, wasn't a pinging noise.

Still has a slight noise, I might get away with a valve adjustment.

You'll have to explain to me then how you made a true "knock" go away with a timing change?  Only thing I can imagine is you either advanced or retarded the timing so far that it's now limiting the actual combustion and taking strain off the actual culprit, which sounds like a bearing is shot.  Try driving it before you adjust the valves, if you just adjust out the noise, you may be doing the same thing, losing compression off the bad spot to make the noise go away.

[B1B Keven]

LOL. Keep posting. This is hilarious.

[NiftyFifty]

I'm serious, but you keep on doing what your doing...I'm done helping those that can't be

[dpollo]

Twice now I have had engines which developed profound knocks  which turned out to be loose flywheels.    

You have never heard anything quite like it !      It goes away if you put your foot on the clutch.