Port & Polish and head work for 16V cars, benefits?
03-13-2003, 05:01 AM
#16
Burning Brakes
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Greg,
Thanks for your answer - The reason I asked was, that I years ago had problem with my M28.11/12 CIS engine (1980 S Euro 10:1)
To make a long story short:
1. Discovered scratch in cylinder #4 due to broken piston rings and ring lanes
2. Bought a new block with piston in Germany - Its shows up that the pistons in this was for M28.21/22 (1984-1986 S Euro 10.5:1)
3. The heads had been planned before, and they need planning again, so I adjusted the compaction ratio to 10,5:1 by removing (milled/grinding) material from the combustion room in the heads, and everything was carefully calculated and the surface made smooth - The engine run well until I (after app. 15,000 km) on a long/fast (220+km/h) trip to Belgium via Germany suddenly damage the engine - Piston #4 burnt and most of the rings in the other pistons was broken
4. Contacted the Porsche factory regarding boring of the new block - Recommended company Tailacker, Stuttgart
5. Took the block to Tailacker, Stuttgart, who bored cylinder # 4 and #8 to +1 mm oversize (98 mmØ) and honed and installed new piston rings on the remaining (They had telephone contact to the Porsche factory regarding the question only to bore 2 cylinders)
6. Reduced the compaction ratio to 10:1 (also taking into account the bigger bore of cylinder #4 and #8) - Carefully checked the CIS system for delivery amount and pressure and some pressure valves and WUR was changed - Devek oil baffle installed - The engine run well, but then 'the same story repeated' - During a long fat trip to Le Mans via Germany (220 + km/h) suddenly blue smoke - The piston rings and ring lanes broken on piston #3, #4 and #8, and the 'new' block is scrap
7. I 'gave-up' regarding the old engine and bought my 1984 S2 donor car from Switzerland and took all goodies from this. (Such car are extremely cheap in Switzerland compared to Denmark and most of them are in very good condition)
The old engine is now hanging as monument in my small Porsche workshop
BUT, I never found 'THE REAL CLEAR ANSWER' - Therefore when I saw you comments regarding REDSPOTS, I though maybe that's 'the answer'
PS: The only thing I didn't check during the 2 engine overhaul was the seat for the thermostat (the 1980 model do not have the rubber seal) and the alu seat is not looking too good! But the car was not running hot
Thanks for your answer - The reason I asked was, that I years ago had problem with my M28.11/12 CIS engine (1980 S Euro 10:1)
To make a long story short:
1. Discovered scratch in cylinder #4 due to broken piston rings and ring lanes
2. Bought a new block with piston in Germany - Its shows up that the pistons in this was for M28.21/22 (1984-1986 S Euro 10.5:1)
3. The heads had been planned before, and they need planning again, so I adjusted the compaction ratio to 10,5:1 by removing (milled/grinding) material from the combustion room in the heads, and everything was carefully calculated and the surface made smooth - The engine run well until I (after app. 15,000 km) on a long/fast (220+km/h) trip to Belgium via Germany suddenly damage the engine - Piston #4 burnt and most of the rings in the other pistons was broken
4. Contacted the Porsche factory regarding boring of the new block - Recommended company Tailacker, Stuttgart
5. Took the block to Tailacker, Stuttgart, who bored cylinder # 4 and #8 to +1 mm oversize (98 mmØ) and honed and installed new piston rings on the remaining (They had telephone contact to the Porsche factory regarding the question only to bore 2 cylinders)
6. Reduced the compaction ratio to 10:1 (also taking into account the bigger bore of cylinder #4 and #8) - Carefully checked the CIS system for delivery amount and pressure and some pressure valves and WUR was changed - Devek oil baffle installed - The engine run well, but then 'the same story repeated' - During a long fat trip to Le Mans via Germany (220 + km/h) suddenly blue smoke - The piston rings and ring lanes broken on piston #3, #4 and #8, and the 'new' block is scrap
7. I 'gave-up' regarding the old engine and bought my 1984 S2 donor car from Switzerland and took all goodies from this. (Such car are extremely cheap in Switzerland compared to Denmark and most of them are in very good condition)
The old engine is now hanging as monument in my small Porsche workshop
BUT, I never found 'THE REAL CLEAR ANSWER' - Therefore when I saw you comments regarding REDSPOTS, I though maybe that's 'the answer'
PS: The only thing I didn't check during the 2 engine overhaul was the seat for the thermostat (the 1980 model do not have the rubber seal) and the alu seat is not looking too good! But the car was not running hot
03-13-2003, 05:09 AM
#17
Erik, I'm sure you know this, detonation would do this, do you hear or feel anything on these trips? How much blowby did the engine have? You know oil mist getting past the rings and into the combustion chamber. Maybe oil getting pumped up by the lifters and sucked down worn intake guides?
Hope you have it sorted now.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
P.S It is when they polish the chamber that all machining marks are removed.
Hope you have it sorted now.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
P.S It is when they polish the chamber that all machining marks are removed.
03-13-2003, 06:22 AM
#18
Burning Brakes
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Greg,
You are really fast!
It was all new - The engine was up to almost new standard with new valve, valve guide, block, pistons, bearings, everything. I did not safe anything (except new heads and new thermostat house - the last I didn't discover) <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />
The aim was to get a good engine, up to new standard
Second time I installed the Devek baffle of the reason you said. (Oil driven detonations)
What did my ears said? Actually that's a sad story, it was both a long trip, and when happen I was co-driver, therefore I did not feel myself <img border="0" alt="[sleep]" title="" src="graemlins/sleep.gif" />
But for sure as you also said, that's due to detonation - But why?
You are really fast!
It was all new - The engine was up to almost new standard with new valve, valve guide, block, pistons, bearings, everything. I did not safe anything (except new heads and new thermostat house - the last I didn't discover) <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />
The aim was to get a good engine, up to new standard
Second time I installed the Devek baffle of the reason you said. (Oil driven detonations)
What did my ears said? Actually that's a sad story, it was both a long trip, and when happen I was co-driver, therefore I did not feel myself <img border="0" alt="[sleep]" title="" src="graemlins/sleep.gif" />
But for sure as you also said, that's due to detonation - But why?
03-13-2003, 06:36 AM
#19
Did the car blow smoke or have excessive oil comsumption? Sometimes you can have an engine that has good compression rings and bad oil control rings. Just trying to throw up ideas Erik. <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" />
03-13-2003, 07:03 AM
#20
Burning Brakes
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Greg,
You are still fast -
No smoke and excessive oil consumption - Actually after second repair (before damage) I sent the car to a Porsche garage and also to the Bosch dealer's garage for check and they found all Ok.
We are looking for some ghost - But if you catch it, I will pay you a good dinner ..... when you come to Denmark! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
You are still fast -
No smoke and excessive oil consumption - Actually after second repair (before damage) I sent the car to a Porsche garage and also to the Bosch dealer's garage for check and they found all Ok.
We are looking for some ghost - But if you catch it, I will pay you a good dinner ..... when you come to Denmark! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
03-13-2003, 09:17 AM
#21
Racer
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Greg Gray - do you have the address or e-mail of the guy om Melborn who can hone out my Euro intakes for a good price and grind out that restriction by the injectors? The price in the US is $600. Thanks
