Lets talk about cams

[StanTheMan]

There has been a few discussions in various threads about cams. Lets not soil other current threads

lets keep it in one place

Cams are serious choice. Its a black art for most of us including me.So many things to consider not just duration lift
It is all about what you want to achieve. and for us mere mortals trying to get our heads around it. sure for some of us ist just a cam 1 or 2 steps up from standard to get a bit more go.

Yes you can go to the pro's & throw money at them. & most likely will make the choice & result a better one.

Billet or regrinds

what are we trying to achieve. what is the best individual choice. what have you currently got & what can you achieve with what you have. Or what do you need to do do to achieve the result you want.

some good information in some threads.
This one is old but has some serious info in it. Cost is prolly out of date a bit but the rest is relevant
viewtopic.php?f=29&t=48320

about B6 engines
viewtopic.php?f=29&t=72221

cams.... bit old but very relevant. Obviously the group buy is not happening any more
viewtopic.php?f=29&t=17675


what do you need to do to get the best out of your cams or what are you willing to do and make the appropriate choice of cam.
appropriate compression
appropriate air flow intake & exhaust
Exchaust frequencys & back pressure
upgrading Valve-train, when is it required
ECU tune.
Turbo or N/A application

[NitroDann]

Im going to put it bluntly. Im willing to help people decide when they want ACTUAL gains.

In my experience most people who are chasing cams want another thing to brag about at EOMM.

In my experience most people will not choose anything which has worthwhile gains, additionally the only way these things work is if the parts match. Its like a recipe, just because bacon chocolate and lasagne all taste good doesnt mean you can just blend them to get a masterpiece. Again, very few are willing to look past "hektik jdm muffler brah, thats so in right now" and pick parts which will complement each other.

Im way more than happy to help those who are willing to help themselves, however.

Dann

[hks_kansei]

I'd also suggest the best option to get what you want is to speak with your cam grinder and talk with them about what you want from the cams.

You can speak to them about stuff like how well it needs to idle, what RPM range you want the power at, what current/future mods the engine has etc.

[Magpie]

^^^ What He said ^^^

[StanTheMan]

here is just some random info that you may consider when changing cams

Compression.
If your going for bigger cams you want to make sure your current compression in the old donger is acceptable.
Standard compression for a B6 on start cranking is 195 psi
Recommended rebuild is below 132psi
a friend suggested not to bother putting cams in if the compression is below 150 psi. I know thats subjective, that's probably more relevant to my own situation.

9mm lift will clear the pistons
any more than 10mm lift may make your engine an interference engine. It was suggested to me to make sure I have valve clearnce with a 10mm lift by the make of the cams.That would perhaps also be relevant weather or not the head has been reduced or not.also tha fact that the valves have 2,5 mm lift at TDC for those particular cams

Your valves. Are they the standard ones. Are they big enough as not to compess to maximum with maximum lift and stop dead before maximum lift is concerned
are your valves old and worn out. How far are you going with your rev limiter. Will your stock valves start dancing at 9000 RPM ( thats just talking )

all the above things are going through my head currently plus more. None of it is law. That's just what I've read on the net.If you disagree say so. But please explain why so all of us can learn.

[NitroDann]

Talk to a cam expert?

ƒü¢k that brah, heaps of the boys on facebook have cams, they all said get some Poncams, said they are the sickest.



In addition to piston clearances many large lift cams need the head ground or machined so that the cams can rotate within it without hitting lifter bores.

Dann

[StanTheMan]

Im going to put it bluntly. Im willing to help people decide when they want ACTUAL gains.

In my experience most people who are chasing cams want another thing to brag about at EOMM.

In my experience most people will not choose anything which has worthwhile gains, additionally the only way these things work is if the parts match. Its like a recipe, just because bacon chocolate and lasagne all taste good doesnt mean you can just blend them to get a masterpiece. Again, very few are willing to look past "hektik jdm muffler brah, thats so in right now" and pick parts which will complement each other.

Im way more than happy to help those who are willing to help themselves, however.

Dann

Overlord Dan,

let me assure you that's my aim. I cant say that for everyone though. My aim was to get acrross the fact that it is a recepe. And every recipe varies.

[StanTheMan]

Talk to a cam expert?


In addition to piston clearances many large lift cams need the head ground or machined so that the cams can rotate within it without hitting lifter bores.

Dann

In my case that's actually been done. Awesome point regardless. Interesting point though, does anyone know at what point this needs to be considered?

[Magpie]

You can also modify the base circle as well as the ramp angles on the cams. CAM profile dictates the power band that you want the engine to run in.

Why aren't you including in the discussion the valve train as well, the choice of valves/springs also dictate the cam choice.

It is a recipe that is highly modified to suit the individual.

[hks_kansei]

Talk to a cam expert?

ƒü¢k that brah, heaps of the boys on facebook have cams, they all said get some Poncams, said they are the sickest.

I wonder how many of those kids have also not bothered to lube the cams and break them in properly as well?

[StanTheMan]

with brand new cams you get the lube along with it.
on re grinds you would probably get it as well.
on 2nd hand ones where would you get the correct lube?

[StanTheMan]

You can also modify the base circle as well as the ramp angles on the cams. CAM profile dictates the power band that you want the engine to run in.

Why aren't you including in the discussion the valve train as well, the choice of valves/springs also dictate the cam choice.

It is a recipe that is highly modified to suit the individual.

This discussion is about anything to make the correct choice with cams & things which immediately affect choice. Different size valves to increase air flow. valve material & seats to cope with extra heat of E85. Please be my guest.
Personally In my case, It is, what can I do with what I have. Will not change valves as I have restraints on what I can do. If I did change valves & change to high compression pistons......I would have gone to Dan & say Dan Overlord.....please insert BP SVT 1.8 with turbo....instead.

[hks_kansei]

with brand new cams you get the lube along with it.
on re grinds you would probably get it as well.
on 2nd hand ones where would you get the correct lube?

It's just regular engine assembly lube, you can get tubes of it at most auto shops.

Alternatively you can make do with a thick grease, or even just a good thick oil.

The proper stuff is better though, since it stays stuck long enough for the oil etc to start lubricating properly.

[NitroDann]

E85 is less heat

[StanTheMan]

right .....There you go.

I read that someone changed their valve seats to cope with E85. The way I understood it is that it was because it runs hotter. I also would like this thread to be accurate since I'm hardly an expert.Only know what I read. rightly or wrongly. I must admit I didn't cross check that either. which is my own fault.