Head pressure test

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Carlo
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Head pressure test

Post by Carlo » Sun Feb 08, 2015 5:51 pm

Hello Everyone

The water pump failed in my bongo and she overheated.

After this she has been starting lumpy with lots of white smoke, and not picking up on revs for at least 10 seconds from start up, this along with water disappearing from the tank with no leaks visible has led me to believe that the head gasket has gone, and possibly the head cracked.

So i have taken the head off (following the fact sheets from the members area).

Please can somone tell me where the best place to have the head pressure checked would be? I am from Somerton in Somerset.

Thanks

Carl
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Northern Bongolow
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Re: Head pressure test

Post by Northern Bongolow » Sun Feb 08, 2015 7:32 pm

they usually seem to crack around the exhaust valves on either cylinder no 2 or 3, is there any visible signs. they tend to go behind the valve seat up towards the stem seal so are hard to spot, you usually get one discoloured valve etc.

pressure testing does appear to be a little inconclusive especially if done cold, hot test sometimes shows it up.

put a straight edge along the rocker shaft bearings first, as ive seen them lift in the centre and snap the cam into 3 pieces when they over heat, then they are just scrap.
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Simon Jones
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Re: Head pressure test

Post by Simon Jones » Sun Feb 08, 2015 7:48 pm

I took mine to Bellhill Garage at Norton St Philip who have a place that can pressure test at close to operating temperature. They can also supply you with the oil feed pipe that you ought to change as part of the preparation for refitting the head. Have a search for my posts on 'decking the block' for further info.

When you refit the head (current or new one) don't forget you'll need new head bolts and cambelt kit. Good luck.
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haydn callow
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Re: Head pressure test

Post by haydn callow » Mon Feb 09, 2015 12:51 pm

Somerton!! So am I, ADS Bristol are good, pressure tests are often misleading with these heads, almost certainly cracked I'm afraid....
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
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haydn callow
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Re: Head pressure test

Post by haydn callow » Mon Feb 09, 2015 12:54 pm

Examine the area around the exhaust valves....fine brown lines are a give away.
Where in Somerton are you??? I'm Behind Berry by the bus stop nearest the Fire station.
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
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Carlo
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Re: Head pressure test

Post by Carlo » Mon Feb 09, 2015 1:48 pm

Thank you all for your reply, the head dose not seem to have any damage from heat at all, also with a precision edge the head has not warped.

To Hayden, we are at St Cleers Way. I cannot see any brown lines on the head. I will post some pictures on here when i can upload them.

Thanks

Carl
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haydn callow
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Re: Head pressure test

Post by haydn callow » Mon Feb 09, 2015 7:41 pm

Our Jo who now runs the Bongo Low Coolant alarm business lives near there.
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
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Carlo
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Re: Head pressure test

Post by Carlo » Thu Feb 12, 2015 6:04 pm

Image
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Carlo
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Re: Head pressure test

Post by Carlo » Thu Feb 12, 2015 6:09 pm

Thanks again to everyone. We have got the head back on and she is driving a dream, much better than when we first bought her, and so far has lost no water (must purchase a low coolant alarm from hayden)

Now all i need to do is drill and tap the exhaust manifold bolt that i sheared off, and cure the leak in the fuel injection pump (which i am not looking forward too as i have large hands)

Carl
Bob
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Re: Head pressure test

Post by Bob » Thu Feb 12, 2015 6:25 pm

Sound job. :D
Take a torch, toilet roll, and tea bags.

https://m.youtube.com/watch?v=hcF9JSxkUSE
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