Help and advice needed on the Tipo 16v engine build

Road-race engines and ancillaries - general discussion
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Kerem1967
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Help and advice needed on the Tipo 16v engine build

Post by Kerem1967 » June 13th, 2020, 4:59 pm

Dear Friends,

We have a Fiat131 with a Tipo/Tempra 16v engine in the workshop. Although I have built some Fiat ohv pushrod and Sohc engines, I have not built a Fiat 16v engine before. Therefore, I need some general build advice and also specific information regarding the performance camshafts for this particular engine type.

Currently, I have not fully dismantled the engine and the owner does not know what is inside. The engine was running on twin 45 DCOEs.

So far, I have noticed that there are 2 Colombo Bariani camshafts in the engine but unfortunately I could not find the technical information of these profiles which I will need during the blueprint and the build. ( or I will have to find the Lobe Centerline by measuring but I still need the cam data at least for the correct clearances )

Inlet cam part nr. 16.109.276 S ( 10.9 mm lift and 276 degrees )

Exhaust cam part nr. 16.101.262 S (10.1 mm lift and 262 degrees )

One simple question here is; do these engines ever have exhaust cam timing @ TDC more than the inlet side ? ( I guess not but the current cams timed like that !! )

My other findings are; the exhaust cam has an adjustable vernier but the inlet cam doesn’t have one.

The engine normally has 2 balance shafts but this particular engine doesn’t have the balance shafts fitted. So, the timing belt runs thru a cylinder head mounted belt tensioner only. The belt width is 17.30 mm

Shall I be able succesfully built this engine without the balance shafts as I have found.

As I have mentioned, I don’t know what I am going to see in the engine. Cylinder head’s inlet ports give me a clue that the head might have been worked.

Regards,

Kerem
GC_90

Guy Croft
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Re: Help and advice needed on the Tipo 16v engine build

Post by Guy Croft » July 1st, 2020, 2:16 pm

Kerem hi

you should use the production Fiat cambelt!

The cams are street version. Don't worry about the actual open/close degrees just time them up with full lift eg:

full 110 deg both
or
108 inlet 110 ex
or
106 inlet 108 ex

you need to be careful with valve to piston clearances. 110 will give the most clearance.

Set the running clearances cold at 0.016" inlet and 0.018 ex cold +/- 0.002"

If you want a cam timing data sheet written by me send me an email to guy@gcre.uk

G
Guy Croft, owner

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