nasty knock, any ideas?

[ThomasLRNL]

All,

i rebuilt this engine and paired it up to my gearbox. however, im hearing a knock. All bearings in the engine are new and have maybe max 5 minutes of runtime on them. I did feel/seem to have a slight gearbox knock from before when i put this engine in. this leads me more towards it being a gearbox knock. but i would like to hear opinions of more knowledgable people.

 

[saxavordian]

12:15 to Exeter train leaving Landy platform 2

 

[ThomasLRNL]

12:15 to Exeter train leaving Landy platform 2

xD its a bit of a train rn yes

 

[Wildefalcon]

If it's in neutral, then can't be gearbox? Check valves first. I'd look at the dizzy, then the cam gear. Couldn't see from the video, is there oil coming through the rocker shaft?

 

[ThomasLRNL]

If it's in neutral, then can't be gearbox? Check valves first. I'd look at the dizzy, then the cam gear. Couldn't see from the video, is there oil coming through the rocker shaft?

input shaft of the gearbox is always turning no…? i thought maybe its something there.

dizzy and cam gear what should i look for when inspecting those exactly? valves should be set correctly. yes oil coming through the rocker shaft and ive always had excellent pressure as well.

 

[Wildefalcon]

It's hard to tell from a video. Get a stick/rod mechanics stethoscope to isolate the knock.

Sounds cam shaft speed, not crank shaft speed.

 

[kermit_rr]

I'm going to go with a dead big end just on one piston

 

[ThomasLRNL]

It's hard to tell from a video. Get a stick/rod mechanics stethoscope to isolate the knock.

Sounds cam shaft speed, not crank shaft speed.

yep agree

 

[ThomasLRNL]

I'm going to go with a dead big end just on one piston

weird though, since i redid all of them

 

[steve2286w]

I counted about 15 knocks in 5 seconds that’s 180 per minute
Assume tickover speed about 720rpm, so cam speed is 360rpm
Does it sound noiser with ear to air intake
After rebuilding my 200di I had a regular clonk like that , turned out I stuffed a rag into tdi intake manifold to stop filings going in , on running the engine it got sucked into an inlet port and stopped air getting into cylinder
Compression pressure was only 90psi on that cylinder with gases being forced back out of air filter leading to knock noise
May be worth a check, also feel the gbox if you think it’s that

 

[kermit_rr]

It did seem to be in time with the valves opening