Hammering noise from engine!! Please help.

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playnotwork
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Hammering noise from engine!! Please help.

Post by playnotwork » Sat Apr 15, 2017 11:03 pm

evening
have had exactly the same noise on my bongo after suspected hydrolock in feb. Pulled head and found crack in cylinder 3 and bore looked undamaged. replaced head but noise still there. compression down to 295 in cylinder 3, 460 in the rest. now missing on cylinder 3 so smoke.
Feel only option left is bent conrod but really don't want to pull head. Could it be bearing.
Cost of replacement engine would effectively mean spares or repairs.
Any help appreciated she has not been used for 2 months
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Sat Apr 15, 2017 11:21 pm

https://youtu.be/zqpUmBXA28w
any ideas appreciated
Bongolia
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Re: Hammering noise from engine!! Please help.

Post by Bongolia » Sun Apr 16, 2017 1:54 am

That doesnt sound like an end to me.
Did the piston heights look OK when you had the head off?
Was it a full head or bare, new or S/H?
Does the compression pump up on cyl 3 when cranking a few times?
Are the valve clearances ok?
Does the smoke clear when held up on a steady fast idle?
And does the engine smooth out?
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Sun Apr 16, 2017 11:26 am

sorry if hijacking a thread
This is what i thinks has happened ( please correct me if incorrect)
Since buying the bongo 4 years ago the coolant level has always dropped a small amount. Managed this by fitting a low coolant alarm. One feb evening the alarm sounded. So i topped up, but beeing unable to see overfilled the tank. Drove the van 5 miles and left overnight. In the cold and freezing morning, I tried to start the van.
The motor did turn over but sounded very lazy. I thought the batteries may be on the way out. On the second attempt the van did start easily but the rattlr noise began istantly from then. Drove home about 5 miles. The noise is louder when the vechile is under load. Engine occasionally seems to mis-fire
Checked tappets all ok.
Thought it could be injector noise so cracked all injectors, noise stayed constant.
Listened to rattle seems to nbe top end.
Compression tested through glow plugs rseults 460,460,300,460.
Decided to remove head and found a crack between the valves in cylinder 3.
Cylinders looked ok with no scouring on the bore so assumed bottom end ok.
did not turn over engine as did not want to upset the timing
Reconditioned head, new gaskets and new bolts purchased
Reassembled and started with anticipation.
The same noise still present, but now i have grey smoke coming from the exhaust, sounds like not firing on 1 cylinder
Removed auxillary belts to eliminate water pump, air conditioning and alternator, still exactly the same.
Did a compression test Results 460,460,295,460 ( is 295 to low to ignite diesel but 300 ok ?)
definate mis-fire that does not smooth out on fast idle

Only options left to pull head (again!) looking at conrod, piston rings, wrist pin, big end. but could be non of these.
No tax Mot or insurance on the van now and getting presure of the wife.
Any ideas appreciated
rita
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Re: Hammering noise from engine!! Please help.

Post by rita » Sun Apr 16, 2017 11:55 am

playnotwork When you said "did not turn over engine as did not want to upset the timing"

As soon as you remove the cylinder head and fit a replacement you have "upset " the valve timing. I would check the timing .

Good Luck.
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Sun Apr 16, 2017 12:16 pm

timing is ok
cam pulley and injector marls align.
rita
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Re: Hammering noise from engine!! Please help.

Post by rita » Sun Apr 16, 2017 1:10 pm

That's good, I would recheck the valve clearances especially No3 .

It would also be worthwhile checking for Back pressure.

Good luck.
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Sun Apr 16, 2017 2:50 pm

valve clearances checked ok 0.004 and 0.006
should i not be more concerned in the lack of compression in cylinder 3 with 2 different heads. I was thinking a bent conrod would produces reduces compression.
it has been suggested that it could be the starter ring on the gearbox but nit really sure what this is?
what do you mean by back pressure
rita
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Re: Hammering noise from engine!! Please help.

Post by rita » Sun Apr 16, 2017 5:39 pm

It could also be a problem with piston or rings on N03 cylinder, IE the compression leaking past the rings into the Crankcase .

Alas all this should have been checked when the head was removed, but might be worthwhile removing the oil filler cap when engine is fairly warm and checking for excess pressure / gasses.


Good Luck.
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Sun Apr 16, 2017 6:04 pm

Do you have to remove engine to remove Conrod piston etc. If that is definitely the noise Will have another go. Just want to make sure it is that before i pull begin
Bongolia
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Re: Hammering noise from engine!! Please help.

Post by Bongolia » Mon Apr 17, 2017 2:21 pm

Did you need to swop over the valves and cam?
What makes you feel its no1 thats got the miss?
Will the compression on no3 rise if you crank over around ten turns?
rita
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Hammering noise from engine!! Please help.

Post by rita » Mon Apr 17, 2017 2:47 pm

Bongolia wrote:Did you need to swop over the valves and cam?
What makes you feel its no1 thats got the miss?
Will the compression on no3 rise if you crank over around ten turns?
I think they mean that its only firing on Three cylinders IE 1 cylinder not firing ?. "sounds like not firing on 1 cylinder"
playnotwork
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Re: Hammering noise from engine!! Please help.

Post by playnotwork » Mon Apr 17, 2017 7:38 pm

compression does not rise when cranking over.
thinks its all about cylinder 3
cant get sump off removed bolts can see underneath, wont budge. what am i missing
Bongolia
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Re: Hammering noise from engine!! Please help.

Post by Bongolia » Mon Apr 17, 2017 11:38 pm

Leaving aside the low compression issue for the moment.
If you swop an injector from the misfiring cylinder with one from a firing cylinder does the misfire stay on the original misfiring cylinder?
Did you have to transfer the valves from the cracked cylinder head to the replacement head or did it come fitted?
Why are you removong the sump at this point?
You will not be able to acertain piston damage from there.
Bongolia
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Re: Hammering noise from engine!! Please help.

Post by Bongolia » Tue Apr 18, 2017 10:22 am

rita wrote:
Bongolia wrote:Did you need to swop over the valves and cam?
What makes you feel its no1 thats got the miss?
Will the compression on no3 rise if you crank over around ten turns?
I think they mean that its only firing on Three cylinders IE 1 cylinder not firing ?. "sounds like not firing on 1 cylinder"
Yup, my bad.
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