Just another question

[fiat218]

I have a 2.0 in my 79 . Dual carbs, I guess I'm not sure the size at this moment
But I do have marks ignition on it,so it will have hot spark
I'm wondering if I add a hotter cam, now I got no idea what this engine has,so I'm going to assume nothing ok
If I was to add a cam for better performance,what would be the best route,
Thanks

[So Cal Mark]

depends on the compression ratio of the engine and how you're going to use it. Both are important questions when picking a camshaft

[fiat218]

Ok thanks,I will do some checking when I get it running again,as far as using it! More power,little lumpy sound

[BEEK]

static compression ratio is the issue with big cams. the reason you need to raise compression to use big cams is the valves open sooner and close later. this builds less dynamic compression. in simple terms, it takes more compression ratio for the engine to see the same compression ratio because of the camshaft. most all modern engines use around 10-1 compression, with modern camshaft designs and knock sensors and fuel injection, this survives real well. fiat uses a stock camshaft that would be considered a performance upgrade in most modern engines. looking at specifications only. mainly duration.

[fiat218]

Ok back to the compression
All 4 cylinder are 152 all read out the same,
I suppose now I need to know what cams are in this to see if I can swap out for better.or what
Reading what beek wrote. I need better compression?

[timinator]

Ok back to the compression
All 4 cylinder are 152 all read out the same,

What procedure did you use to take your compression readings? Did you do a leak down test? Did you verify your cam timing with a dial gauge? 93 octane pump gas generally can support 175psi hot engine cranking compression with the throttle plates held wide open. If you delay full advanced timing until after peak torque you can add a safety factor to the 175psi. You might find your 1979 engine will show greater improvement with a good performance valve job, fresh rings and hone, and a good carb tune than with a change of cam. After the engine is in top shape and still lacking in performance would be a good time to go cam shopping.

[fiat218]

Ok back to the compression
All 4 cylinder are 152 all read out the same,

What procedure did you use to take your compression readings? Did you do a leak down test? Did you verify your cam timing with a dial gauge? 93 octane pump gas generally can support 175psi hot engine cranking compression with the throttle plates held wide open. If you delay full advanced timing until after peak torque you can add a safety factor to the 175psi. You might find your 1979 engine will show greater improvement with a good performance valve job, fresh rings and hone, and a good carb tune than with a change of cam. After the engine is in top shape and still lacking in performance would be a good time to go cam shopping.

I did none of the above, just used a plain old pressure gauge read out,stuck it in the plug hole and cranked it over
I guess there lot more to this then just adding a bigger cam
I know what needs to be done now. Thanks

[wizard124]

When i owned my '71 coupe, i rebuilt that 1608 with US stock compression, hotter street cams, and obtained the European version twin Webers. I dont remember the specs or Weber model. i stayed with the stock compression based on a recommendation of an outboard mechanic ( the only engine mechanic i knew ).

Big mistake! He didnt know Fiats. That engine ran nice but didnt perform like i hoped. Had i installed 9.8:1 pistons like the Europe models ran........110hp! How sweet it could have been!

[BEEK]

8.0-1 compression with stock cams fort sake of explanation makes 150lbs of compression when tested, 9.8-1 compression with stock cams makes 180lbs of compression when tested, 9.8-1 compression pistons make 150lbs of cranking compression with big cams. understand the dynamics?

[fiat218]

8.0-1 compression with stock cams fort sake of explanation makes 150lbs of compression when tested, 9.8-1 compression with stock cams makes 180lbs of compression when tested, 9.8-1 compression pistons make 150lbs of cranking compression with big cams. understand the dynamics?

Hm, what are you sayin ? That I got a stock cam?
So I could have stock cams or 9.8.1 compression pistons?
Thanks

[BEEK]

no, i was using fictitious numbers for reasons of comparison.

[fiat218]

no, i was using fictitious numbers for reasons of comparison.

Ok, I understand sora