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post #68 of (permalink) Old 06-11-2019, 09:41 AM Thread Starter
Canadian Spider
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Join Date: Jun 2017
Location: Toronto, Canada
Posts: 135
Quote:
Originally Posted by 65Sprint View Post
Reading through your thread, it looks like you replaced the head but I did not see any mention of performance oriented changes. Is that correct? Is there a reason you would expect the carburetor jetting to be incorrect? I recently saw a temperature increase of 20 degrees F after significant engine changes and before increasing the idle jet size. This was during the 30 minute cam break-in process. I am running emissions Dellortos (DHLA 40L) and changed from 57 to 65 idle jets, which brought the temperature back down to 180 degrees (and eliminated spit back).
The cylinder head is from Centerline. They offer a plain head and a performance one. This is the plain head, but Centerline told me it does have some mild improvements over stock. The cams are original.

"Centerline’s remanufactured cylinder heads will put the ZING back in your Alfa! Each head is meticulously inspected for cracks and other damage. Those that pass are treated to all new valves, manganese-bronze valve guides, teflon seals on intake and exhaust guides, and our performance valve springs. A careful multi-angle valve job is performed to ensure peak airflow and performance, and each head is resurfaced for optimum head gasket sealing."

I don't know much about carbs. I removed the carbs from my car, took them to a reputable rebuilder and asked them to rebuild them for an Alfa 2L. When he handed them back, he said they'd run but would need fine tuning. It's been my understanding that carbs should always be jetted to the specific engine they're mounted on, which can only be done after installation. But I've heard conflicting opinions so I'm not sure if that's true. I have not (yet) had any such tuning performed.

And I *am* getting some spitback!

Could carb tuning be the cause here? The first carb specialist I called said no way, but I don't know what to believe anymore.

1976 Spider
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