Is there a downside to (Reground Camshaft)

[tinkerputzer]

The 272 is much better suited for a dd with stock bottom end. The 285 would pull like a freight train up top but feel like a turd down low. One of the easiest traps to fall into is over camming. Bigger is not always better.

[essi1553]

The 272 is much better suited for a dd with stock bottom end. The 285 would pull like a freight train up top but feel like a turd down low. One of the easiest traps to fall into is over camming. Bigger is not always better.

When you say things like this is just makes me want the 285 more, I am not concerned with drag stripping the car. I only care about above say 3k, and reliability. I'm considering reducing the Diff to a 3.25LSD, simply because detest the shitty mpg when doing 80+. I enjoy the car once it's moving, and wouldn't a cam gear help reduce the "lag" you speak of?

[digger]

i will never say no improving the head since there are certainly gains to be had even on a stock car no matter what people say. An engine with a bigger cam will like a better head every day of the week if it is done by competent head porter.

VAC should be able to show what flow gains you are getting for your $$$ even though flow numbers arent the be all and end all

A schrick 272 or a cheaper regrind if it is above your budget is a solid choice on a lower 8.8:1 CR engine. the european 9.7:1 engine could tolerate a slightly bigger duration without as much detriment.

i would pay attention to the piston to head clearance to get that right (0.040" to 0.050") and you can skim the head in conjunction with this to also bump the CR but you cant gain much CR and you dont want to take too much off a head that has a fair bit of $$ invested.

you'll want an adjustable cam gear aswell and be mindful of piston to valve clearance

[essi1553]

Thanks for all the insight, im actually taking notes. Glad to know this now, im going to look into the PNP megasquirt at $800, which seems out of reach. The cam is the more interesting issue since its the same price either way. I hope eventually to:

Intake and exhaust, headers, chip (I really would like to avoid standalone), and many more suspension tweaks, bushing replacements. If im going to go standalone, im buying ITB's first. I don't care how rational it is, I just want to scare the shit out of people.

[tinkerputzer]

When you say things like this is just makes me want the 285 more, I am not concerned with drag stripping the car. I only care about above say 3k, and reliability. I'm considering reducing the Diff to a 3.25LSD, simply because detest the shitty mpg when doing 80+. I enjoy the car once it's moving, and wouldn't a cam gear help reduce the "lag" you speak of?

I'm not saying the 285 won't work on a stock bottom end. I was just trying to say you won't feel any power increase until say above 4500 rpm and below that it will probably feel more weak than the stock motor with stock cam. For a dd car you want broadness not something peaky.

Taller gearing will make an overcammed engine seam even weaker. You would want to go shorter gearing.

As for engine management if you plan on doing lot's of different mods to you engine your going to want the ability to retune to take advantage of them. There is no one size fits all tune. I recommend megasquirt if you are half way computer savvy. After seeing all the headaches people are having with miller i'm so happy i went that route.

An adjustable cam gear is a pretty much a requirement for any custom m20 if you want to get the most out of your setup and yes advancing the cam can increase low end.

[redlightpete]

You'll almost surely need to cut more valve clearance into the pistons with anything bigger than a 272. If you're keeping the bottom end stock, this may be an issue.

[essi1553]

I'm not saying the 285 won't work on a stock bottom end. I was just trying to say you won't feel any power increase until say above 4500 rpm and below that it will probably feel more weak than the stock motor with stock cam. For a dd car you want broadness not something peaky.

Taller gearing will make an overcammed engine seam even weaker. You would want to go shorter gearing.

As for engine management if you plan on doing lot's of different mods to you engine your going to want the ability to retune to take advantage of them. There is no one size fits all tune. I recommend megasquirt if you are half way computer savvy. After seeing all the headaches people are having with miller i'm so happy i went that route.

An adjustable cam gear is a pretty much a requirement for any custom m20 if you want to get the most out of your setup and yes advancing the cam can increase low end.

Thanks for breaking it down in laymans terms for me, this post really helped. Truth be told, im going longer gearing don't care how slow it makes the car, I do a lot of highway driving, and maintaining 80 mph kills the mpg with the 3.73 thats in there.

I'm pretty computer savvy, I just know nothing about duty cycles, A/F ratio, etc. I'm sure I could work the program, I just wouldn't know what any of it means, and/or if I was damaging the car in the process.