Diagnosis Please???

Technical questions and answers about the Mazda Bongo

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Mattylad

Repaired and heres what it was!!!

Post by Mattylad » Mon May 16, 2011 6:37 pm

Hello all,

For the benfit of anyone who is remotely interested in this thread I thought Id post on what actually happend to my beloved.

Turns out my cam shaft had completely sheared in two. In the words of Andy 'the bongo king' you were fu**ing lucky you didnt bend any valves.

Looks like the clips that hold the cam shaft in place were way tooo tight allowing no play.

Anyway, job all done for £200 with a 2nd hand very good nick cam shaft.

Thanks again for all your ideas guys but the prize goes to Mikeonb4c for getting the correct answer lol.
skater
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Re: Diagnosis Please???

Post by skater » Mon May 16, 2011 6:44 pm

If I'd known there was a prize I would have tried harder.
Sounds like you were very lucky indeed.
Seems a reasonable price to fix it too.
=D>
" it's not rocket surgery! "
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Northern Bongolow
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Re: Diagnosis Please???

Post by Northern Bongolow » Tue May 17, 2011 2:39 am

where abouts did the cam snap,was it at the oil hole on pedestal number 2. approx half/half.??
Mattylad

Re: Diagnosis Please???

Post by Mattylad » Tue May 17, 2011 10:57 am

I dont know much about these things but snapped right where the first clamp thing was that holds it in place, so about a fifth of the way down it.
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widdowson2008
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Re: Diagnosis Please???

Post by widdowson2008 » Tue May 17, 2011 12:22 pm

Mattylad wrote:I dont know much about these things but snapped right where the first clamp thing was that holds it in place, so about a fifth of the way down it.
Ady has seen this recently on another Bongo and is trying to see if it is broken at similar place. Can you identify where the shaft snapped from this pic? The numbers 1 to 5 are the cam shaft bearing pedestals.
Was yours bust at No.2? and if so, which side? toward No.1 or No.3? or AT the bearing pedestal?

Image
Last edited by widdowson2008 on Tue May 17, 2011 12:27 pm, edited 1 time in total.
Steve
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Re: Diagnosis Please???

Post by Doone » Tue May 17, 2011 12:25 pm

Steve, Allan has replced a few cams on Bongos. I'll ask him where they snapped and get back to you. :)
Allans Garage retired. Try PGS (Plymouth Garage Services) or Mayflower Auto Services Plymouth
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mikeonb4c
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Re: Repaired and heres what it was!!!

Post by mikeonb4c » Tue May 17, 2011 12:29 pm

Mattylad wrote:Hello all,

For the benfit of anyone who is remotely interested in this thread I thought Id post on what actually happend to my beloved.

Turns out my cam shaft had completely sheared in two. In the words of Andy 'the bongo king' you were fu**ing lucky you didnt bend any valves.

Looks like the clips that hold the cam shaft in place were way tooo tight allowing no play.

Anyway, job all done for £200 with a 2nd hand very good nick cam shaft.

Thanks again for all your ideas guys but the prize goes to Mikeonb4c for getting the correct answer lol.
Blimey - I never win anything :oops: :oops: :oops: :oops:

V. glad its sorted and that the £s wasn't too traumatic 8)
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widdowson2008
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Re: Diagnosis Please???

Post by widdowson2008 » Tue May 17, 2011 12:45 pm

Doone wrote:Steve, Allan has replced a few cams on Bongos. I'll ask him where they snapped and get back to you. :)
Thanks Lorna. I think I know what's in Adys mind here as to WHY the shaft snaps - may be wrong but I'll throw it in anyway.
If the head overheats it will possibly warp (bend) taking the pedestals with it, and if that happens, the shaft will try to bend also. But because the shaft is made of a different (stronger) material than the head, it can't bend and so it effectively gets trapped by the pedestals. Something has got to give.
Is this a load of c**p? Dunno.
Steve
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Re: Diagnosis Please???

Post by Northern Bongolow » Tue May 17, 2011 1:06 pm

=D> =D> . spot on steve. =D> =D>
Mattylad

Re: Diagnosis Please???

Post by Mattylad » Tue May 17, 2011 2:28 pm

Ady has seen this recently on another Bongo and is trying to see if it is broken at similar place. Can you identify where the shaft snapped from this pic? The numbers 1 to 5 are the cam shaft bearing pedestals.
Was yours bust at No.2? and if so, which side? toward No.1 or No.3? or AT the bearing pedestal?

Steve,

Its difficult to tell since he just brought the shaft through and sat in on the worktop. It looks like it would have been number two or four. the break was directly at the bearing pedestal as the bracket above was also cracked and broke up once removed.

Hope that makes sense.

Matty
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Re: Diagnosis Please???

Post by Doone » Tue May 17, 2011 3:02 pm

I asked Allan. :) These two had both snapped between the first and second bearing carriers. (Neither of them had over-heated.)
On one, it was found that the previous garage had made a mistake when fitting the cambelt. Fortunately for the customer, his previous garage settled the bill. =D>
The other one had no obvious fault or suspect history. It had done over 225,000 kms on the original cam, so it may have been due to wear and tear. That's not to say that all cams will snap at that mileage, it's just that this one had and there was no obvious cause. :)
Allans Garage retired. Try PGS (Plymouth Garage Services) or Mayflower Auto Services Plymouth
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widdowson2008
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Re: Diagnosis Please???

Post by widdowson2008 » Tue May 17, 2011 3:14 pm

Mattylad wrote:
Ady has seen this recently on another Bongo and is trying to see if it is broken at similar place. Can you identify where the shaft snapped from this pic? The numbers 1 to 5 are the cam shaft bearing pedestals.
Was yours bust at No.2? and if so, which side? toward No.1 or No.3? or AT the bearing pedestal?
.......... It looks like it would have been number two or four. the break was directly at the bearing pedestal as the bracket above was also cracked and broke up once removed.
Matty
Coolant in the head is from back to front, to it's picking up heat as it travels forward, making the front end theoretically the hottest. However, the head is air cooled(ish) all round, the front getting the biggest share of air cooling, so the hottest spot is probably a little back from the front.
This is more or less confirmed by the fact that faults in the head (from previous posts) seem to be between No.s 2 and 3 cylinders. So, from what you said (either 2 or 4 pedestal), I would lay a few quid on it being No.2. Any takers?
Hold that a minute - Lorna is back (beat me to it). Need to digest Allans info. :wink: ......................Had a shufty at Allans stuff and yep, at or around the same place.
Steve
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Re: Diagnosis Please???

Post by mikeonb4c » Tue May 17, 2011 3:49 pm

Did I read on here of one or two failures due to fitting old camshaft to new (poorly made) replacement head? Camshaft forced to run out of true, with inevitable result. :roll:
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Re: Diagnosis Please???

Post by skater » Tue May 17, 2011 4:24 pm

Anyone think there might be a performance increase with a new cam shaft compared to old ?

I guess you wouldn't notice.

But maybe.....
" it's not rocket surgery! "
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Re: Diagnosis Please???

Post by mikexgough » Tue May 17, 2011 8:54 pm

The owners of vehicles that use WL-T engines in hotter climates suffer camshaft breakages....it's quite common in those parts and they tend to opt to use 10/40 oils which seems to prevent breakages.....according to those owners....
I guess it's the owners call and yer pays yer money and all that......
Old Skool thinking and experience suggests that in some OHC engine a "thicker" oil tends to cling when the engine is shut off so it is still lubricated from start up.... as for the WL-T engine.... your choice but I know mine.
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