6 replies to this topic

[Austin mini 30]

My mates 850cc mini (1977) is needing a new head gasket. can someone link me to the correct one on minispares please? that would be great.

 

Should anything else be replaced whilst the head is off?

 

Cheers Angus

[Cooperman]

GUG702506HG

[liirge]

When the head is off it is a very good idea to take stock of it an look for wear in any parts.

Before the below, make sure you inspect the head to make sure it hasn't banana'd, check for cracks between the valves, and check the block for any cracks between the bores. 

If this was me I would do the following:

 

1. inspect and check valves as necessary

2. Regrind valves

3. Replace valve stem oil seals

5. Check valve springs aren't worn/not full height. 

6. Check and clean the thermostat (drop in a boiling hot mug see if it opens) 

7. Remove all the gunk in the thermostat housing. 

8. Check and clean heater valve

 

9. Replace following gaskets: Inlet/Exhaust, Thermostat housing, Head gasket, rocker cover gasket, heater valve.

 

Something to note. 

a. make sure you are careful when cleaning the mating surfaces, getting grime into the combustion chambers can shorten the life of your engine. 

b. Some people say clean the carbon off the pistons, research this and make an informed decision before you do or don't do this.  

Edited by liirge, 23 February 2015 - 08:06 PM.

[Austin mini 30]

When the head is off it is a very good idea to take stock of it an look for wear in any parts.

Before the below, make sure you inspect the head to make sure it hasn't banana'd, check for cracks between the valves, and check the block for any cracks between the bores. 

If this was me I would do the following:

 

1. inspect and check valves as necessary

2. Regrind valves

3. Replace valve stem oil seals

5. Check valve springs aren't worn/not full height. 

6. Check and clean the thermostat (drop in a boiling hot mug see if it opens) 

7. Remove all the gunk in the thermostat housing. 

8. Check and clean heater valve

 

9. Replace following gaskets: Inlet/Exhaust, Thermostat housing, Head gasket, rocker cover gasket, heater valve.

 

Something to note. 

a. make sure you are careful when cleaning the mating surfaces, getting grime into the combustion chambers can shorten the life of your engine. 

b. Some people say clean the carbon off the pistons, research this and make an informed decision before you do or don't do this.  

 

GUG702506HG

Great thanks guys thats really really helpful!! brilliant.

 

Also, whilst im here, below the radiator side of the car, there is an big oil leak. is this from the seal on the timing chain cover round the pully? where else would it come from?

 

cheers Angus

[Cooperman]

The oil leak will be either the pulley seal or the timing chain cover gasket.

You will need to remove the radiator, take off the pulley (lock the flywheel by removing the starter motor to do this), take off the timing chain cover and fit new seal and gasket. You have to change the gasket after you remove the cover to fit the new oil seal. Take care not to over-tighten the timing cover bolts and do use a sealant on both sides of the gasket.

[Austin mini 30]

am i being  stupid or do 850cc minis not have any valve stem oil seals?

[Cooperman]

All A-Series engines have valve stem oil seals.

Very early cars have a simple O-ring on the valve stem, but later cars have to 'cap' type seal. originally BMC/A-R/Rover fitted them to all 8 valves, but later when they were short of profits they decided to fit them only to the inlet valves.

Of course, the engine will run without stem seals, but it will burn a lot of oil.