Super Eta, budget stroker...

[Sean]

Ok,

I'm beginning to compile the parts to do my stroker. My I Head is at the machine shop for cleaning and resurfacing.

I've been considering having my head shaved just a tad.

Here's the thing. I know that this is a budget stroker, I'm just doing it because I can. I know the compression ratio is far from ideal, but it will yield better results then just a normal Super Eta.

Here's my question to you guys.

If I were to shave my head, how much could I shave it WITHOUT risking warping the head? And, if it's such a small amount, would it even make a big difference?

ALSO - I'm considering removing my entire bottom end, maybe the whole engine - since I have the resources and know what to do now. If I do that, how much could I deck the block to raise the compression a tad and add a bit more performance? And, if I did this, should I even bother to risk shaving the head at all?

Right to the point, if I remove the whole engine, how much should I deck off the block and/or shave off the head? And, if I don't remove the engine, how much could I safely shave from the head? Ultimately - what's the best route to go if I want to raise the compression just a tad? And - is it even worth the effort - will the change in compression even be noticed?


I know I ramble, but I was hoping to find out quick. I wasn't sure of how much should be taken off to raise the compression, and was wondering what you all had to say about that...

Also, real quick - would the stock head gasket work the best, or are there recommended alternatives?

Thanks!

-Sean

[nando]

shaving has nothing to do with warping your head.

what I would do is collect the parts for a 325i intake and exhaust. buy a cam (I have a 325i cam for sale and dual valve springs if you're interested), have the oil journals drilled for the cam etc. leave the head alone otherwise, have it surfaced if you need to. there is no reason to shave it unless it's warped. it already has the larger valves etc, it just needs the cam and i intake. then you need the software from a 325i for the increased redline etc. that's pretty much it!

I would stay away from decking the block or messing with your compression, for one you can throw the cam timing off if you go too far and you could also cause pinging and other desired effects. the real way to gain compression is with custom pistons, but you're trying to do this cheap.

KISS, you're building a budget stroker, no need to touch the bottom end unless there's problems with it. the most I would do was replace the seals. the head is relatively easy to remove and replace so I'd leave it at that. good luck!

p.s. stock headgasket is just fine

[Sean]

Well, shaving and decking were the ways I thought were possible to be used to raise compression.

My plan all along was to just have my I head resurfaced, and put everything together. Then it dawned on me - could I deck the block and/or shave the head JUST A LITTLE? Like, just enough to raise compression and not offset the timing at all?

However, here's what I was essentially getting at. If I deck/shave just enough to NOT effect timing - would that have any noticeable effect on performance?

I'm still deciding on whether or not I want to bother removing my bottom end. When I think about it now, I don't really want to bother. Which in turn means, I'm considering just leaving my compression alone and not screwing with it. But, I am still intersted to know if there's any way to raise compression a noticeable amount without offsetting the timing?

However, I do want to put in a new oil pan gasket, since I'll be putting in new engine mounts. How long do the Oil PUMPS on these cars usually last? Would it be a good idea to put in a new oil pump too?

Just to point this out - I have EVERYTHING I need for this budget stroker - including the 325i ECU, throttle body, etc... - I was just wondering if I should bother trying to raise compression...

Thanks for the reply!


Real quick - I was looking at head gaskets - what's the difference between a head gasket SET? and the non-set one? It's about a $45-$50 difference, so I was just wondering.

[modifiede30]

you can get compression up to 9.5:1 if you shave the block & head, without causing timing issues. go stock minimums on the head, and ~.05" on the block. Seems like a small amount, but the combo will work. I'll look for the exact numbers tonight...

[Sean]

you can get compression up to 9.5:1 if you shave the block & head, without causing timing issues. go stock minimums on the head, and ~.05" on the block. Seems like a small amount, but the combo will work. I'll look for the exact numbers tonight...

Hmm, that does seem VERY tempting...

What could I get without decking the block? After thinking about it, it'd be nice to just leave my block in there, but I could remove it if it would make that big of a difference.

How much of a performance difference are we talking? Like 5 hp?

Thanks for the reply!

[modifiede30]

The difference in HP is very minimal, but it greatly depends on what the engien is being built for and any future plans. If you're going to tb the car, leave it, if you're going to race it, go for max compression. If its a daily, you'll likley be pretty happy leaving it alone.

[Sean]

The difference in HP is very minimal, but it greatly depends on what the engien is being built for and any future plans. If you're going to tb the car, leave it, if you're going to race it, go for max compression. If its a daily, you'll likley be pretty happy leaving it alone.

Here's my idea. I wanna do the stroker because I have the parts and REALLY want the revs. I need the car to get my thru college, 4 years of use at autocrosses for fun, hopefully driving schools each year at Octoberfest, and maybe driving schools in between.

After college I am planning on getting an S50 into the car, and getting rid of the M20 altogether.

So, I basically wanna find a good medium here, and have some fun with what I got in the meantime.

I just started this post because I was wondering what my options were in terms of raising compression and if it was a good idea or not. I know getting custom pistons is a better way, but it's not the route I want to go.

Basically, if I shave the head a good amount, what can I get? And, the other question was, if I shaved both, what could I get - and you answered that one already.

Your input is greatly appreciated!

[nando]

the head gasket set comes with all the upper end gaskets you need to remove and reinstall the head. the cheaper version is only the headgasket.

[modifiede30]

Given the cost to shave, the use you have for the engine, and the benefits, I'd just leave it alone unless you have a need to shave the head for another reason. Just make sure everything is solid, bottom end and head.

[Sean]

Given the cost to shave, the use you have for the engine, and the benefits, I'd just leave it alone unless you have a need to shave the head for another reason. Just make sure everything is solid, bottom end and head.

Ok, that's real good advice. :) You're probably right too. I'll ask how much it would cost at this shop I took my head, just cause I'm wondering. lol What's a good way to make sure everything's solid? Run a quick compression test? Any other methods? (mainly for the bottom end)

Nando - so, basically - the headgasket set comes with: Head gasket, valve cover gasket, rocker shaft end caps...what else is there?

Thanks for all the helpful information!

[modifiede30]

Without taking the bottom end out, the only way to do a good check is to do a compression test, and check the cylinder walls once you have the head off. If you can get the oil pan off, would also be good to make sure there is no play in the rod or main bearings. Depending on mileage, I'd probably say replace the oil pump while you're in there.

The head gasket set should also include the intake, exhaust, water pump, and a few other gaskets for water pipes, and new valve seals. Can't think of what else it comes with but I think a few other seals, like the cam seal and o-ring.

[nando]

head gasket set comes with the headgasket (duh), exhaust manifold gaskets (including for the downpipes) intake gaskets and valve stem seals. I don't think they come with anything else, at least the set I had didn't. water pump gasket etc was all extra. but I have so many extra parts now I don't really need a full set. :P

[modifiede30]

I have a new headgasket set at home that's not yet opened. I'll take a look and let you know for sure (as well as wear I got mine from). I believe it was only about $68 from Eurasion (black forest).

[Sean]

Should I get the set? I was just gonna get everything seperately (all I was gonna get: headgakset, intake, exhaust and rocker shaft plugs). Should I put in new valve stem seals? How hard are those to install?

Also, real quick - I called the machine shop today, my head is a little warped. So, he's going to shave it for me, and get rid of the warping. Should I have it shaved a little more than needed (like, a little below the max), since I'm shaving anyway, or just do what I need to do to get rid of the warping?

[nando]

installing new valve stem seals requires compressing the springs and removing the valves, it's not too hard with the right tool (I got a $20 compressor from sears that worked like magic). I would definetly replace them while you have them out.