Should I cam my m20?

[Stoner Sam23]

So my 89 325is aproaching the 250k so i decided i wanted to swap the engine and build my own 2.7 seta. I got the bottom end from a 88 528e with 100k, cleaned and rebuilt it. stumbled along a craigslist ad for a deer struck 89 325is with a new cylender head bought it for $500. great buy! friend will most likely start a project thread on it. we estimate the head has about 20k on it becuase the timing belt snaped and the car only has 146k. and it is very shiny :D

I dont know much about this cyl head?? it is non bmw. where the marks 885 should be it has AMC. Does anyone have any info on these? are they any good?

So I need this car as a DD but i still want some power out of it. would love to make 200hp or something close. what are the cam options for this type build?

[jaycheetwood]

There is no reason not to. cams are cheap and easy to do.

Just get some over sized valve eccentrics from Ireland Engin. and get a 272 or 284 cam.

[Stoner Sam23]

I'm not sure I like the idea of a reground cam but it is cheap... how is Ireland eng stuff compared to schrick? And I am curious of the current cam specs.

[Sagaris]

As far as I am concerned a cam should be done only after a proper port and polish job.

A larger cam puts more stress on valve springs and rocker arms.
Being on a budget, I love the idea of saving hundreds of dollars by staying stock and not having to replace valve springs, eccentrics, and if you want peace of mind; rocker arms. Instead I will be applying that money where it is needed ( new sway bars, misc. interior pieces, LSD, new tires).


But if you are not on any particular budget then have at it

[nando]

regrinds = yuck

regrind from IE = double yuck

just IMO, of course

[nando]

As far as I am concerned a cam should be done only after a proper port and polish job.

A larger cam puts more stress on valve springs and rocker arms.
Being on a budget, I love the idea of saving hundreds of dollars by staying stock and not having to replace valve springs, eccentrics, and if you want peace of mind; rocker arms. Instead I will be applying that money where it is needed ( new sway bars, misc. interior pieces, LSD, new tires).


But if you are not on any particular budget then have at it

if you are rebuilding the engine you should probably replace the cam, rockers, springs and shafts anyway. Usually by the time the head needs rebuilt, the lobes of the cam have some pretty serious grooves in them.

[dark89e30]

I dont know much about this cyl head?? it is non bmw. where the marks 885 should be it has AMC. Does anyone have any info on these? are they any good?

The AMC heads are great. Really nice, better than stock, spanish castings.

[Stoner Sam23]

The AMC heads are great. Really nice, better than stock, spanish castings.

Thankyou someone noticed that this is a relatively new head. It shouldn't have much problem if I slip in a hotter cam. And a built n/a stroker could use the higher lift. I have heard port and polish does little for a 885 head.

[jaycheetwood]

1. I dont see anything wrong with a properly done regrind from some where reputable.
2. Valve eccentrics are like a few bucks for the set.
3. If you are rebuilding the head then there is no reason not to.

If you are going to post things about why this or that is bad. Please provide factual data. Not being a dick just trying to figure out if its all opinion or if there is any real truth to this.

thank you.

[nando]

the cam lift and advertised duration of a regrind may be similar to a new cam from schrick or catcams, but that doesn't mean the actual profile, duration at low lifts, duration at peak lift, etc. will be the same.

Add in the extra weight of the eccentrics, whatever effect they have on the rocker ratio, the fact that you've ground off the hardened surface of the cam (yes I realize it's re-treated, but it won't be the same), and then there being less overall sufrace area (faster wear) from the smaller base circle, and really having no idea what the true specs are (lift at .050", valve lift, overlap), it's gamble that is unlikely to pay off.

I would take a new stock B25 cam over a regrind, any day.

as far as a port not being worth it on an 885 head, that is total nonsense. you shouldn't be polishing anything regardless.

[jaycheetwood]

^ Thats all I was looking for. Thank you for the info.

[Stoner Sam23]

Ok that is good info but lets get off the regrinds here. How about some new billets?

[nando]

I bought a new billet once

they still sent me a regrind..

I just don't think you are saving anything there. If you want a performance increase, you want a cam from somebody reputable. If you just want your engine to perform a little better on a budget, get a new stock cam as your lobes probably have 1/16" grooves in them by now.

[Stoner Sam23]

I bought a new billet once

they still sent me a regrind..

I just don't think you are saving anything there. If you want a performance increase, you want a cam from somebody reputable. If you just want your engine to perform a little better on a budget, get a new stock cam as your lobes probably have 1/16" grooves in them by now.

Groves After 20k? And who's cam would you suggest?

[digger]

regrinds are ok if they give give you a cam card telling you the actual specs of it (which certain places don't). Porting the head is not neccesary and you don't normally see much improvement over stock 885 compared to other brands which benefit alot. There are obviously improvements to be made if done properly but it wouldn't be high on my list for a budget build.

Schrick and Catcam make good cams.