What are cam followers

[Mikey16vClio]

Whats their job? How do they cause tappty noise or wear? Thanx

 

[BenR]

they follow the cam lobes, placed inbetween cam and the tip of the valve stem.

Hydraulic ones just allow automatic valve clearance settings, so no need for shims.

When they wear they cause a tappetty noise as the tip gets hammered and stays depressed or it becomes loose leading to larger gaps and the tap.

 

[Embro2002]

mine are tapping a bit would I just need to replace the followers? Anyone know how the hydraulic ones work and allow automatic valve clearance settings? what is the alternative to hydraulic? what will my 16v have? (my mates nicked my Haynes manual)

 

[BenR]

your 16V has hydraulic tappets, switching to solid tappets will mean the use of shims to set the clearances during the rebuild, and its an annoying time consuming process.........

Sorry forgot, hydraulic tappets are simply a piston in cylinder. They get pumped up with oil at all times. As the cam depresses on the follower the piston moves up untill the bleed hole is covered and no more oil is squeesed out, thus oil is incompressable and force is put into the valve, until this bleed hole is coved, no force is put on teh valve tip.

 

[Mikey16vClio]

If u have a performance cam fitted u should always get new followers so ive read.

Is fitting easy when replacing the cam and how much are the followers? Thanx

PS: Should u keep the revs above 2k after fitting for the first start-up for 20mins?

 

[BenR]

WHen fitting a new cam its best ot get new followers as not to score or damage the new cam.

Fitting followers is a matter of droppin them in a hole, and a whoel set is about 120 quid from Ren so cheaper elsewhere. they usually come with a cam kit.

When running in a cam you have to keep enough rpm not to put too much load on the nose fo the cam as max loadings occur at low rpm, so about 3000rpm with LOTS of cam lube all over the shop.

 

[Mikey16vClio]

Nice 1

So switch ignition on and immediatly rev to over 2.5k ish for 20 mins?

 

[BenR]

thats the way to do it......

they key is finding the perfect speed where the tip isnt overly loaded from low rpm, and the base ramps and flanks from overloadign at high rpm....so 2500rpm is about right.......

but 2 mins gets boring, so a brick does a nice job, just stand by it so it doesnt speed up or slow down.....