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Why so much carbon on top of the piston on a newly rebuilt engine? It's an Alfa Romeo, get into it man.

Reminds me of the often repeated story about 2 Alfa Romeo owners, both loved their cars but in different ways; 1 guy, lets say a New Zealander used to wash and polish his Alfa every weekend, and attended to every need of the car and drove it very carefully; the other guy, lets say an Australian, cleaned his car once every 3 months and drove the living snot out of it and just loved it.

They bumped into each other in a international Alfa club meet and the Australian commented "I've had this current Alfa for 6 years now, never given any trouble whatsoever"; the New Zealander was shocked, and stated "really we have the same model, and yet mine is always in the shop getting tuned and attended. I love the car but ..."

Point of the story; Alfa mechanicals NEED to be used and used properly. Puttering around being ever so careful will result in an unreliable Alfa. Don't believe me; my father used to be a service manager for an Alfa Romeo dealership; the first thing the Alfa mechanics would do before they tuned or serviced any Alfa would be to take them for a thorough blast ... they loved their job!
Pete
 
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Discussion Starter #22
I drive the car a lot and pretty hard not sure what you are saying?
 

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I drive the car a lot and pretty hard not sure what you are saying?
Oh, cool. Wonder what's causing the carbon on top of the pistons then?

Admittedly the last engine, I had recently driven, that I pulled apart was a race engine, thus spotless. Don't get carbon build up when wide open throttle all the time :)
Pete
 

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Discussion Starter #24
I havent rebuilt that many motors in my life but ive never seen carbon free pistons when ive opened something up
 

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Is oil still pooling in your intake runners? A quick check of the system would be to swab out the intakes with a paper towel and take the car out for a jaunt with the air cleaner back on .. 10-20 miles of brisk driving .. then revisit the intake runners.... there should be some oil but not dripping wet. Cleaning? OVS. If it's only been in place a couple thous miles . I wouldn't suspect it needs a rinse. It's not dirty oil that clogs any OVS.. It's the rust and crud of the container itself.
 

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Discussion Starter #26
I'll do that check. I have the airbox on and off all the time and have never noticed more than a very light film. Those are the runners you are asking about correct, not post throttle plate?
 

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Discussion Starter #28
Where in the system should I be seeing oil, besides the small line to the sump? Should the large line at the bottom of OVS to airbox show a slick coating of oil?
 

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Do ensure that the small dia oil return hose is not clogged or restricted. In the 164, as an example, that line runs from the OVS to the top of the oil pump, and can get clogged to some extent at that point. Yours is different, but still...
 

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Do ensure that the small dia oil return hose is not clogged or restricted. In the 164, as an example, that line runs from the OVS to the top of the oil pump, and can get clogged to some extent at that point. Yours is different, but still...
That is part of my instructions on my NEW OVS Kit
 

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Discussion Starter #32
Is there such a thing as too little oil in the recovery circuit? The hose leading from the valve cover feels entirely dry. The intake runners on the throttle bodies and airbox are similar. I blew out the line to the dipstick and got just a trace amount of oil maybe the equivalent of if you filled up the cap of a quart of oil. The same is true if I put my pinky in the large outlet on the bottom of the OVS. It certainly does not come out wet there are trace amounts and I can smell oil but that’s about it

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Discussion Starter #33
Well this doesn’t exactly compute. I could have sworn when I bought this new dipstick I checked the measurements however looking now at the dipstick carrier tube it is nowhere near 8 cm. I always save my old parts but I’m unable to put my hands on the original dipstick and suppose I have no way to confirm it was in fact correct to begin with. Can someone with a known good dipstick check this measurement from the bottom of the collar to the maximum Mark? The one from classic alfa is 240 mm.



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Is there such a thing as too little oil in the recovery circuit? The hose leading from the valve cover feels entirely dry. The intake runners on the throttle bodies and airbox are similar. I blew out the line to the dipstick and got just a trace amount of oil maybe the equivalent of if you filled up the cap of a quart of oil. The same is true if I put my pinky in the large outlet on the bottom of the OVS. It certainly does not come out wet there are trace amounts and I can smell oil but that’s about it

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I'm going to go out on a limb.. Technically this an impossibility unless A) the port from the cam cover is blocked or B) you have a road draft tube from the crank case , typically on the rear of the engine venting the sump pressure undr the car.like the cars in the 60's.. Just my gut on what I see... or don't see.
 

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Discussion Starter #36
I'm going to go out on a limb.. Technically this an impossibility unless A) the port from the cam cover is blocked or B) you have a road draft tube from the crank case , typically on the rear of the engine venting the sump pressure undr the car.like the cars in the 60's.. Just my gut on what I see... or don't see.
What mistakes could I have made that would have the gasses venting elsewhere? Would the potentially significant leakage from cyl 1 explain this?
 

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I don't think you have a problem. So unless you are venting elsewhere, relax and enjoy the car. It is a rebuilt engine so shouldn't be pumping combustion pressure into the crankcase.

Btw the only time I've seen fumes out of a crankcase breather was with my Sud race engine. Turned out the cylinder walls were too thin and she was flexing away ... and cracked one cylinder bore. Replacement block from a 33 was sourced.

Btw2, I think I was told to tune with air cleaner off with carbs, that means crankcase breather on my '71 GTV is open to the atmosphere, but maybe there is a valve in the air cleaner housing ... ?????

Pete
 

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Discussion Starter #39
What are people looking for with the clear cam breather hose? Can I simply run the motor at speed on / off throttle while stationary and feel with my palm for gas pressure at the breather outlet?
 
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