Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
The head is flat skimming the head will have no effect on the gasket thickness. The piston height above the deck is the only thing that needs to be considered.
Click image to enlarge
1st Jan 2021 12:43 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10359
Kviasen wrote:
If a head is scimmed 0,1mm the notches is reduced to 2 notches
If you skim the head, you increase gasket thickness to maintain the same compression ratio and gap between piston and valves
1st Jan 2021 1:21 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
This is correct where the combustion chamber is built into the head but on these engines the combustion chamber is built into the pistons and the head is flat the valves are also sunk into the head enough to cope with the maximum amount of skim.
1st Jan 2021 2:04 pm
Kviasen
Member Since: 24 Dec 2020
Location: Norway
Posts: 107
It is the valve clerance between piston and bottom of valves that has to be maintained even after skimming.
1st Jan 2021 2:29 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
The valves clearances are fine on these engines even when you skim the maximum amount from the head. Its also good practise to recut the valve seats and valves which also mitigate any issues
1st Jan 2021 2:41 pm
Kviasen
Member Since: 24 Dec 2020
Location: Norway
Posts: 107
Yes aja4x4 are perfectly right if you skim the head you should also get the valves and seats done at the same time the cost for that is marginal compeared to the cost for the whole operation.
1st Jan 2021 2:49 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10359
Interesting.
You wouldn’t reduce gasket thickness as well as a skin though ?
What would that achieve ?
1st Jan 2021 3:43 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
No i wouldnt alter the gasket thickness.
If your engine has the pistons protruding 0.6mm above the deck you would fit a 1.22mm gasket, this would mean that the piston would have 0.62mm clearance when the piston is at TDC.
If you skim the head the maximum 0.5mm the pistons will still protrude by 0.6mm and with the same 1.22mm gasket fitted the pistons will still have 0.62mm clearance.
This is only true for engines with flat cylinder heads where the pistons have a recessed combustion chamber.
If the pistons are flat and the combustion chambers are in the cylinder head, skimming the head will reduce the volume of the combustion chamber and you need to fit a thicker gasket to achieve the same compression ratio.
1st Jan 2021 4:25 pm
Jonmoore1970
Member Since: 19 Apr 2020
Location: Wokingham
Posts: 125
Pete K wrote:
Is the other bank gasket got the same number of notches ?
Has it got writing on the head ?
PM me your email address and I will send you manual with torque figures etc
Thanks
The other head has no writing and only one notch on the gasket.
1st Jan 2021 4:28 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10359
Jon.
So what you would want to do next is inspect the head closly for any signs of tracking between the round sooted area and the coolant water ways. (the holes with rust round them). This would show evidence of compression getting into the coolant system
Once you have done that, inspect the gasket for similar evidence.
It's not an easy thing to do. If you can't find a smoking gun, it could be the other head that has the problem. This is why I wanted you to look through the injector holes first, to try and see coolant.
If you are going to reuse that head, first you need to clean some of the oil off with petrol and paint brush, both sides.
Then you need to get the surface spotlessly clean. A red dish clearner maybe a suitable tool.
Once its all silver, you need to inspect again for any deep groves between the round compression area, and any of the holes close by. If there are, the head needs skimming.
Use a metal rule on the head surface to ensuire the head is flat and not warped.
Check the resistance of the glowplugs to ensure they are 1R. Otherwise now is the time to change them.
Then a final clean of the head with petrol to ensure it's spotless.
The engine block also needs cleaning, try not to get rubbish down the holes
1st Jan 2021 5:17 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10359
lynalldiscovery wrote:
Might be my eyesight, but looks like it has been blowing between them two cylinders?
.
Yes.
That may explain
"The car has injector timing codes of p020a, p020b, p020c.(cylinder 1,2,3. Off side)"
I would expect it to say ballance or offset
1st Jan 2021 5:42 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
I would pay to have the head skimmed and pressure tested, its worth the money to know you are putting good parts back on.
1st Jan 2021 5:53 pm
Jonmoore1970
Member Since: 19 Apr 2020
Location: Wokingham
Posts: 125
Waiting for parts now....
2nd Jan 2021 7:01 pm
Jonmoore1970
Member Since: 19 Apr 2020
Location: Wokingham
Posts: 125
quote="Pete K"]Jon.
So what you would want to do next is inspect the head closly for any signs of tracking between the round sooted area and the coolant water ways. (the holes with rust round them). This would show evidence of compression getting into the coolant system
Once you have done that, inspect the gasket for similar evidence.
It's not an easy thing to do. If you can't find a smoking gun, it could be the other head that has the problem. This is why I wanted you to look through the injector holes first, to try and see coolant.
If you are going to reuse that head, first you need to clean some of the oil off with petrol and paint brush, both sides.
Then you need to get the surface spotlessly clean. A red dish clearner maybe a suitable tool.
Once its all silver, you need to inspect again for any deep groves between the round compression area, and any of the holes close by. If there are, the head needs skimming.
Use a metal rule on the head surface to ensuire the head is flat and not warped.
Check the resistance of the glowplugs to ensure they are 1R. Otherwise now is the time to change them.
Then a final clean of the head with petrol to ensure it's spotless.
The engine block also needs cleaning, try not to get rubbish down the holes[/quote]
Good advise, I wish I’d seen the post first.
While I’m waiting for bits I will remove the injectors on the other head and crank by hand .... the head and the block seem dead straight to me, and I can see no indication of cracking in the head.
2nd Jan 2021 7:06 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10359
Blimy. Quicker worker
I see you loosened some bolts for the oil cooler. You had better order a new gasket or tighten them
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