Fiat TC 8V cylinder head & inlet options - Big valves with big ports or small?
Posted: December 28th, 2016, 7:08 pm
Hi all,
I need some advice regarding cylinder heads that I have and my best overall options.
I currently have a 105TC head as far as i know (casting No 4460623) with 43.5mm inlet valves but with fairly small inlet ports, 41mmX33mm measured at the gasket face.
I also have an 1800 head (casting No 4277590) with standard 41.5mm inlet valves but featuring much larger inlet ports (45.5mmx36.5mm).
My understanding for best results would be to use the 1800 head but with the larger 43.5mm valves fitted - am I correct? Also is it possible to fit the larger valves by having the valve seats re-cut to suit or are more modifications required?
The bottom end is an 1800 currently fitted with standard flat top pistons although I may consider domed pistons assuming there will not be valve to piston clearance issues when using the larger valves, assuming of course that I actually can use these.
The 105TC? head has been mildly ported (photo of combustion chamber area attached for info) - in your opinion has the modifier gone about this the right way and should I look to replicate this with the 1800 head if I use it?
My second question although relevant to this concerns my choice of inlet manifold. I have available a well ported factory waffle manifold with matching 40IDF's and all the necessary distributor parts to swap from block mount to head mount distributor. Also I have a 131 type IDF manifold which is made by a well known aftermarket company and allows the fitment of the standard block mounted distributor. This manifold has longer inlet runners than the standard waffle item which I'm thinking will produce more torque? Has anyone any info regarding these manifolds and how they perform against each other? I deliberately have not named the aftermarket manufacturer but will do if acceptable to GC?
The engine will be used in a full weight 124 saloon purely as a fun road car and will be a pretty mild spec. Basically an 1800 with hopefully a large port/large valve flowed head, 40IDFs, good inlet manifold and a tubular exhaust manifold, possibly fast road cams and higher than standard compression subject to advice of those in the know.
As always any advice or thoughts are most welcome, positive or negative.
Lee.
I need some advice regarding cylinder heads that I have and my best overall options.
I currently have a 105TC head as far as i know (casting No 4460623) with 43.5mm inlet valves but with fairly small inlet ports, 41mmX33mm measured at the gasket face.
I also have an 1800 head (casting No 4277590) with standard 41.5mm inlet valves but featuring much larger inlet ports (45.5mmx36.5mm).
My understanding for best results would be to use the 1800 head but with the larger 43.5mm valves fitted - am I correct? Also is it possible to fit the larger valves by having the valve seats re-cut to suit or are more modifications required?
The bottom end is an 1800 currently fitted with standard flat top pistons although I may consider domed pistons assuming there will not be valve to piston clearance issues when using the larger valves, assuming of course that I actually can use these.
The 105TC? head has been mildly ported (photo of combustion chamber area attached for info) - in your opinion has the modifier gone about this the right way and should I look to replicate this with the 1800 head if I use it?
My second question although relevant to this concerns my choice of inlet manifold. I have available a well ported factory waffle manifold with matching 40IDF's and all the necessary distributor parts to swap from block mount to head mount distributor. Also I have a 131 type IDF manifold which is made by a well known aftermarket company and allows the fitment of the standard block mounted distributor. This manifold has longer inlet runners than the standard waffle item which I'm thinking will produce more torque? Has anyone any info regarding these manifolds and how they perform against each other? I deliberately have not named the aftermarket manufacturer but will do if acceptable to GC?
The engine will be used in a full weight 124 saloon purely as a fun road car and will be a pretty mild spec. Basically an 1800 with hopefully a large port/large valve flowed head, 40IDFs, good inlet manifold and a tubular exhaust manifold, possibly fast road cams and higher than standard compression subject to advice of those in the know.
As always any advice or thoughts are most welcome, positive or negative.
Lee.