V6 wont start after cam belt change

[teenmal]

Just checked the TSOBBT and found this from williefixit......

From williefixit.

However for the benefit of others who may find this discussion in the future, I can report that after the installation of 24 new hydraulic tappets (from Japan) the Bongo is running well and we had it back before Christmas, after a stay of 9 weeks with the Bongo specialist.

[teenmal]

Found the full story if it is of use to anybody ..

http://igmaynard.co.uk/bongo/forum/view ... ilit=japan

[foxuke]

What are hydraulic lash adjusters?

No news. Mark has been working though the various thoughts etc should get an update tomorrow for you all

[teenmal]

What are hydraulic lash adjusters?

No news. Mark has been working though the various thoughts etc should get an update tomorrow for you all

It would appear that the HLAs are ok as I have just noticed this report from Simon Jones.

"The hydraulic lifter are functioning and valves seen to be operating. When the cylinders are pressurised there is no sign of leakage into inlet & exhaust manifolds, or getting past the rings. Unfortunately, the option of tow start is not feasible as its an auto. My V6 can left standing for over 3 months & it will start fine so there is nothing to suggest the lifters should require re-priming.

[Simon Jones]

There's definitely fuel getting in through the inlet valves as the plugs have been seen to be wet with petrol when removed. They've spun it over with the nearside cam cover removed and everything appeared to be going up and down as expected. The pressure test they did on the cylinders did not pick up any air escaping into inlet or exhaust manifolds as would be expected with valves stuck open.

[Transporterman]

Looks like just about everything's been covered but how about induction? A hand over a big intake pipe as close as possible to the manifold should produce a huge vacuum you can really feel even on cranking only.

Years ago before fuel injection was common, certain Vauxhall carburettor inlet manifolds used to collapse internally causing non-start. I can't see any thing like that with this one because it looks like the manifold is in two separate halves so you would expect some life at least. I have even seen a big core plug popped out of an inlet manifold! The only other thing I can think of is the EGR stuck open but that would normally only cause running idling faults. Anyway, good luck guys, I'm retired these days but I feel your pain!

[rita]

What are hydraulic lash adjusters?

No news. Mark has been working though the various thoughts etc should get an update tomorrow for you all

It would appear that the HLAs are ok as I have just noticed this report from Simon Jones.

"The hydraulic lifter are functioning and valves seen to be operating. When the cylinders are pressurised there is no sign of leakage into inlet & exhaust manifolds, or getting past the rings. Unfortunately, the option of tow start is not feasible as its an auto. My V6 can left standing for over 3 months & it will start fine so there is nothing to suggest the lifters should require re-priming.

When you say "Pressurised" do you mean that they carried out Compression tests on all cylinders, if so do you know what the figures were.

[mikeWalsall]

.................... "Compression test has been done & this shows all cylinders are lower than expected at around 85 psi. This has been compared to a running Bongo which is around 100. It should be between 140 & 196 psi, so while it's very low, it's unlikely to have changed from when the engine was last running"...................

This is not text book .. just the way I generaly try to suss out the internals of an engine ..

As a rule of thumb (in a 4 stroke .. 2 strokes are different) .. I multiply the compression ratio (which I do not have for the Bongo) by atmospheric pressure (14.7psi) ..

So (say) a 10.1 C/R .. the compression should be around 140.7 psi .. generally in a mechanically internally well sealed engine ie: valves / rings / seals .. given that with carbon deposits the C/R usually increases slightly .. in this scenario a good compression should be 150psi plus ..

[Simon Jones]

When you say "Pressurised" do you mean that they carried out Compression tests on all cylinders, if so do you know what the figures were.

1) Compressed air fed into cylinder at point in compression cycle where all 4 valves are closed. The speed at which the pressure drops indicates the amount of leakage past the rings and valves. If one or more valves was not closed, air would be heard escaping into inlet or exhaust manifold. None was noted and the leakage past the rings was not considered excessive.

2) déjà vu

I would say that the compressions are too Low (dry test), you should get (with a good engine ) about 160/170 PSI.

Have you been able to remember what it was you were going to tell us the other week? I'm hoping you have spotted something that has been overlooked.

1) call Allan in Plymouth as he is one of the most knowledgeable guys when it comes to the V6.

I have a sneaky feeling what he is going to suggest.

[foxuke]

Hi All
Here is an update from Mark verbatim.
Seems promising to me.

Hi Andy right update I tried the thing with a timing light on Friday afternoon with the new battery on and it showed the ignition timing too be way out.
So have been racking my brains why it would be so far out its not enough like the dizzy was 180 degrees out which we can't do as it will not fit. But it was out a lot but then thinking about it the timing is meant too be checked at idle speed which is about 750rpm but cranking speed is about 200rpm so almost a quarter so it would be out so I don't see how this is going too help us.
I have now taken he whole front of the engine back apart and am going too check through everything we have done when changing the cam seals I have taken the cam wheels off and sat one on top the other too see if the location pegs and timing marks are the same and they are so it would not matter if you got them the wrong way round the only difference I can see is two of the wheels have a lip on the edge too stop the cam belt riding off the pulleys. This is were I am at. See attached pics.
I have also added a pic I have got from mazda parts center of the location of each cam wheel.

Photos can be seen here

http://s1148.photobucket.com/user/foxuk ... ent&page=1

[mikeWalsall]

Maybe mention to him that all V6 component part / illustrations are available..

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

http://lushprojects.com/bongopartsmk2/

[andyb36]

hi guys - I was talking to my brother in law - a 25 years a mechanic and works on most vehicles etc --- but hasn't a v6 petrol bongo.. as I may be getting one - ive told him to brush up on the v6,s and mentioned the woes your having with this one, he has asked if the v6 petrol engine has been put - or if any other vehicle uses the same engine

I must admit they are pretty good at that garage and I have never taken my bongo else where apart from the mot

its all pretty high tech in there - with computers everywhere and fault finding equipment - and the garage is meticulously kept clean etc

as you've all stated - if it was running previously and only the cam belt changed - it can only be something daft - missed

anyways - I am sorry I cant help - but my bro in law has asked the question - if anyone could kindly give an answer - I will get him more involved and see if he has any ideas

they are auto electricians

http://www.brcartronics.com/

cheers

andy

[Ian]

The only other vehicle that used the same engine was the early nineties Mazda 929 2.5 litre petrol. A very rare beast, but there is a workshop manual available.

[Simon Jones]

Here's what I'd do:

1) Get the battery fully charged up so it's got enough oomph to spin it over properly for a while.
2) Mark the position of the distributor. I know it's been off a few times but at least it can be got back to the previous position.
3) Loosen the clamp and move round a few degrees, tighten clamp & try to start it.
4) Continue until it reaches the end of the travel or the engine starts.
5) Repeat by rotating it the opposite direction until it gets to the other end stop.

[windywatson]

Just a thought, the distributors on these vehicles have a built in sensor that is used as part of the ignition timing system. Read somewhere on the forum that there was an issue with a V6 not running due to the failure of some internal sensor in the distributor. Remember the issue being resolved by the distributor being replaced. As the distributor has to be removed as part of the strip down to do the belt change, is it possible that the dizzy has developed a fault?
I'm just about to embark on the same job myself as cam seals started leaking. Whilst looking at suppliers for parts found AVA liesure, Mazdabongo.com do a Timing belt information sheet that gives full comprehensive details on belt change with a complete break down on how to do the job. This info is a real must if your going to do the job & worth a look to actually double check all of your work against.

Cheers