Which cam (standard)

[autox]

Well after blowing one engine up, melting 2 pistons on its replacement (1.3 head on 1.4 block) i have finally found a decent setup.

1.4 block, 1.4 MPI head, 1.3SR inlet, 1.4SR cam running on the pierburg carb. I was talking to one of the autox guys who said that the cam from the 1.4MPI engine might be better than the 1.4SR? what do you recon, bearing in mind that the 1.4SR cam already has the stuff for the mechanical fuel pump.

the setup above got me another 2nd place but want a bit extra for that elusive 1st :)

and i'm also going to put a 4.18 FD (currently 3.94) in my f10CR box, should help a bit off the mark :)

please not all parts must be standard so no aftermarket cams allowed.

cheers

Michael

[Snowface]

i would have thought the 1.4sr cam is better then the sri. It is designed for a carb'd engine for starters.

The setup you got is about the best you can possibly get from a 1.4 with pierburg.

Can you have head work done to the sri head?

The 4.18fd will help. even more so on a cr box.

Lightening the flywheel may make the engine a bit more revvy.

Would be v. interesting to see a r/r graph or even a 1/4 mile time. (comared to the 1.3 and 1.4sr's)

[autox]

thats what i thought with the cam, so thats what i went for. Just one of the guys said it lifts more or something. Think i might just stick with it. the last time i played about the head dept it ended up in tears (well 2 holes in me pistons)

unfortunatly need to stick with the standard carb and cant lighten the flywheel.

yeah, i cant wait to see what it's like with the 4.18fd in my cr box, should help a bit as it is all 2nd/3rd gear.

cant believe how much time i have got spare when i dont blow the engine up :)

[Aragorn]

well compare the cams then?

measure the lobes etc

[Paul]

the 1300 inlet wont fit the 1400 sri head will it, or did i miss something? :?

[Aragorn]

ports are close but not perfect

ideally metal needs added to the 1300 manifolds bottom edges to make it round

its nowhere near the 1400 carb head, but its almost there with the 1400sri head

[S_Gault]

use a 1.6 gte cam.

oh.. i might even have one lying about

[Paul]

something i picked up, from racing standard engines.

Get the cam carrier machined down very slightly at one side, so its wonky if u know what i mean.

This will use the edge of the cam lobe, and the followers sit on the lifters, and are flexible to move to adjust to the new angle. This will give a slightly higher lift, and you should get away with it, as they never usually measure the cam carrier, if they do, its only with a tape measure and they wouldnt realise....

Paul

[Stuart]

lmao iffy idea. but can see how it would work.

[Aragorn]

surely if u do it at one edge only the lifters on the other side would run normally and the ones at the side you machined would be sitting much further down?

i'd imagine it would just cause massive wear untill it was flat again or summat broke

[day]

he is talkin bout 1 side, not one edge right? like if you stood infront of the car there would be some skimmed from the furthest or nearest side or the rocker housing

[Paul]

thats the one

[Aragorn]

erm well surely all thats gonna do is rotate the cam a small amount forward or backwards?

same as retarding it or advancing it with a vernier?

[Paul]

Im saying if you stand infront of the car, look at the left side of it, skim a bit down from that side, but so the right side stays original height, it will give you a very slightly better performance, not much but all helps when racing standard engines.

[Aragorn]

i cant see how

in the same way as regridning the base profile of a cam increases lift, making the base profile larger by running the cam at a funny angle will reduce lift as the rockers will be further away during the valves closed state

and it will cause massive wear on the lobes / rockers as the cam will be running on the edge of each lobe rather than the entire lobe as a flat

[Paul]

I've never done it, just be told it works, and im sure it would.

[S_Gault]

machining of cam carrier is a common mod on racing engines to alter the rocker ratio to change the amount of valvel lift.

But it must be done stragiht.. the above is mad.. you machine it like that the cam sits at an angle and the belt wanders.

i think you maybe picked your engine build er up wrong here and misquoted him

Steven