shailoche

I am wondering: Has anyone here rebuilt their engine and swapped the camshafts out with new exhaust and/or intake cams?

I have seen some posts about swapping the intake cam with the exhaust cam to make some more power...however I did not find any current discussion on swapping cams altogether. In the Honda world a cam swap is relatively commonplace especially with the single cam engines. So, does anybody here have different cams...and why?

I am rebuilding the engine from scratch. Overbore, bigger valves, low compression forged pistons, forged rods, and ARP throughout. I want to get the most strength as possible on the block and while I am at it I was thinking about replacing the cams for more aggressive timing for exhaust...I know cam gears can adjust timing but I really want to see what you guys think about replacing the cams and leaving the cam gears alone.

???

Rafa

iTrader: (22)

Forewarning; I'm mechanically challenged. I was at the shop today and asked my mechanic this precise question. By coincidence, the brother of the shop's owner (who owns a Honda himself) made a remark about the fact that in the case of Miatas that wasn't possible because of the camshaft sensor.

I asked because in a recent thread started by M2CupCar (Rob) about Fidanza gears, another forum member (Patsmx5) happened to mention that option. I had never heard that before so I asked at the shop today.

I want to know the answer to that myself.

FWIW, a simple solution in the Miata world is to buy a 99/01 head. This is the best bang for the buck that I know of.

sixshooter

iTrader: (12)

There are cams available from Webcams and others, but most of the guys running turbos are doing so on the stock cams. But yes, I believe there are a few around that do.

From my understanding, the cams are not as big a hindrance as the head ports. This is why several here have swapped for the better flowing '99 or '00 year model head, with positive results.

If you found cams that were optimized for a turbo car, I'm sure they would show benefit as well. But some of the aftermarket large cams are not ideal for turbos.

shailoche

So you are saying...and I am really reading into what you posted...that it would be better to spend the money on the head and using stock cams? Head work would ultimately make better since than fooling around with the CAMS.

I like that. Good information. But if anyone else has any advice on the CAM question please let me know.

sixshooter

iTrader: (12)

I was about to add something, but I realized I don't even know what motor you have. You are supposed to put your car info in your "signature" so it shows up under your posts. That eliminates confusion and bad advice. Miatas have at least 4 generations of engines out now.

18psi

iTrader: (76)

what they are saying is that the 99-00 head has the best flow. It will be much better/easier for you to just swap in a stock (or ported) 99-00 head and use its stock 99-00 cams. cheaper than cams too

shailoche

I don't have the car right now. I am building the engine separate from the car. It is a 1.8 Liter block out of a '99 miata. I am going to have it bored to 1995cc. In the process of the build I am going to swap everything in that I can to make it as strong as possible.

Then, once the motor is done, I will find the body to fit it to.

This is my logic...engine is most important to the overall performance of the car and since most want to swap in a 1.8 anyway I figured start with the engine and then go from there.

Does that make sense?

Saml01

iTrader: (9)

Its like getting the shoe first and looking for the leg later.

dc2696

iTrader: (2)

3mm over bore is pushing the BP. I've heard of people having issues at that bore with boost.

Most, myself included, run 2mm over ob boosted motors.

What are you intending on doing with the car once its built?(Motorsports wise)

-Dean

shailoche

It is sorta like getting a show first and then finding a leg...but it is how I approached my Del Sol build and that turned out Ok.

I am looking into autox but really it is mostly just for me. I like to build and tinker so my goal is to make good reliable power and make it last. So, whether or not I end up racing in auto x or something else really hasn't made me reconsider my approach.

I guess there are some rules that apply to the types and sizes of motors for certain racing scenarios so maybe I should consider that before punching out the block.

NA6C-Guy

iTrader: (1)

Doesnt Web offer both turbo grind and custom grind for the BP? Unless you have done everything else you can possibly do, I dont see cams being worth while. Im going to agree with the 99-00 head swap. Probably cheaper, and will yeild more power than a cam swap on an NA head. Plus most cams that have more lift will possibly run into valve float issues. Not sure what the specs are for the valvetrain really, never looked into it. So if that were the case, on top of $500-$600 for a set of cams, you would need valve springs and retainers for probably another $400, and if you are going that far, you might as well have the head worked on a bit, get some backcut stock valves or aftermarket valves... so you are looking at probably $1500+ for maybe an extra 5-10whp. When you could just swap a 99-00 head and gain the same or more for probably half, depending on what you can find in your area or online.

I also like the "turn up the boost 1psi" answer that Im sure someone will post eventually. Its free and will give you more power.

Rafa

iTrader: (22)

Aren't the 99 and newer engine blocks aluminum? If that is the case and I was in your shoes (meaning overboring it so much) I would've gone with a late NA 1.8L engine. Just my 2 cents but, as usual, I could be wrong.

skidude

iTrader: (3)

I'm pretty sure they're all iron blocks with aluminum heads.

dc2696

iTrader: (2)

[QUOTE=shailoche;380627]I don't have the car right now. I am building the engine separate from the car. It is a 1.8 Liter block out of a '99 miata. QUOTE]

First off everyone giving headswap advice, READ.

Secondly if I was you I would look into some other guys builds and see what they are running and how much power they are making before you make any more decisions.

Hot_Wheels

iTrader: (12)

i plan on running the 99 head with mazda GTX cams, now i dont care about the cam sensor working or not, i would like to utilize the cam sensor with the gtx cams if possible but i guess i will cross that bridge when i get there. but my point is for the power gains a set of GTX cams are what the FWD guys are running and with good suceses, but i dont know about it working with the cam sensor or not.

gospeed81

iTrader: (51)

I thought with a turbo it was better, and easier, to just get the adjustable cam gears, and dial them out on the dyno.

Someone had a thread about that recently.

NA6C-Guy

iTrader: (1)

Oh, well he has a '99 head already. You typically dont see people with those heads asking for what cam they can swap. I say leave it alone.

sixshooter

iTrader: (12)

What are the specs of the GTX cams? Is there a difference in lift or duration or both between them and the '99 cams?

Or are you just saying you are going to use them because someone else has done it and you really don't have a clue what you are doing? I ask because I have a Puerto Rican friend here locally that is behaving similarly.

magnamx-5

iTrader: (7)

omfg chaos. ok shailoche u have a nice big bore miata motor and on of the best heads power wise.
Most 2L miatas do not bore the full 2 liters i know sucks. But they still turn major rpms with the offered stroker crank from flying miata. Take that throw in some beefy rods if and some billet oilpump gears and barring detonation u will be as solid as 99% of the high boost turbos we have out to date and be able to run as many rpms as you like. There just aren't alot of good things cam wise out there for us so we just tweak our LSA abit and work on our valves springs, port work etc. And then proceed to shoves metric fucktons of boost in. Also FWIW grab a 6 speed and a set of 3.9's or even 3.6's if you wanna autocross and make more than say 300 whp or so u will thank me later cause u didnt breack **** and you could actualy keep traction.

dc2696

iTrader: (2)

Again I wouldn't punch it out to 3mm if you want a strong reliable motor and I def wouldn't stroke it if your going to boost it.

Stroking kills your rpms and if your going to boost it, it really isn't a nessicary mod imo.

Bang it out to 1929cc's and throw some internals and an oil pump in and boost the **** out of it.

I agree with magna on the 6speed, I'm going to see how 375whp handles a oem 90 5speed and my guess is not good lol.

-Dean