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never said I wanted to do that myself. Im actually in the middle of swapping the motor in my daily e36 due to a blown head gasket. NOT FUN. Screw german engineering.
Originally Posted by codrus
I dropped your numbers into my valve shim spreadsheet. All the gaps are too small right now, but if you swap shims around you can probably get by with only needing to buy 4 or 5 new ones. They're $7 each from Mazdacomp, dunno what they cost at a dealer.
(I recommend double-checking the specs & measurement numbers before buying stuff)
--Ian
THANKS IAN! Question, what is "slop", and shim min and max (where did you get these numbers from?), lastly, "available shims" I have no shims less than 3.xxxx, soooo r u saying I need to decrease by .2 for example? I was just gonna subtract the spec clearance from my clearance and add that number to shim size.
Last edited by icantlearn; 04-06-2018 at 07:48 PM.
THANKS IAN! Question, what is "slop", and shim min and max (where did you get these numbers from?), lastly, "available shims" I have no shims less than 3.xxxx, soooo r u saying I need to decrease by .2 for example? I was just gonna subtract the spec clearance from my clearance and add that number to shim size.
shim min/max is the calculated minimum/maximum shim size that will bring the valve gap to being within the factory spec. Essentially:
measured shim + measured gap == total gap.
shim max == total gap - minimum spec gap
shim min == total gap - maximum spec gap
"available shims" are the sizes that Mazda has for sale.
To use the spreadsheet, you pick a shim size for a given valve (between the calculated "min" and "max" values) and add it to the appropriate cell ("new shim"). It then calculates the "new gap", and "slop" tells you how much larger than the minimum that new gap is. If you're aiming to get everything to the minimum spec, then you want all of the "slop" values to be as low as possible. Assume that you can re-use all of the shims that are currently in there, so spend a bit of time shuffling them around in software to fix as many valves as possible, then pick sizes out of "available shims" list to fill in the others. Then you can order those, put them in, and measure it to see how close you got it.
Some people argue that for a turbo track motor you should be increasing the minimum gap from the factory number. Doesn't seem to have been an issue for me, though.
I dropped your numbers into my valve shim spreadsheet. All the gaps are too small right now, but if you swap shims around you can probably get by with only needing to buy 4 or 5 new ones. They're $7 each from Mazdacomp, dunno what they cost at a dealer.
(I recommend double-checking the specs & measurement numbers before buying stuff)
--Ian
I was going to get back to setting up my 1.8 head over the next few weeks, and was going to make a spreadsheet just like this. You saved me a lot of work, thanks! (sorry for the thread-jack, MiataMan)
I gave my machinist my clearances before the work, he said that if it needed to be changed he would do it included for what I had already paid. You should at least ask how much to adjust some of the clearances. The correct shims would be good too though, as usual Ian always has helpful information.
I gave my machinist my clearances before the work, he said that if it needed to be changed he would do it included for what I had already paid. You should at least ask how much to adjust some of the clearances. The correct shims would be good too though, as usual Ian always has helpful information.
bit too late for that. I ll just do it the hard way. Not a huge deal, I have time to kill before valve springs arrive.
So you're aiming for the minimum size shim everywhere to get the maximum sized gap?
Your list has a few cases in which you're actually slightly over the maximum gap, and has you buying 12 shims. In theory you could get away with 10 if you're willing to have some on the smaller end of the spec range.
Yes. There are 2 that are slightly over. I caught that earlier and fixed one of them. The other one I can’t do anything about. It’s still in spec within a hundredth. I figure it being over by a few thou isn’t the end of the world. If anything it will heat up into spec range.
Yes. There are 2 that are slightly over. I caught that earlier and fixed one of them. The other one I can’t do anything about. It’s still in spec within a hundredth. I figure it being over by a few thou isn’t the end of the world. If anything it will heat up into spec range.
Excessive lash is hard on valve seats and the back face of the valve. The cam profile has portions designed to take up lash and to move the valve on/off the seat safely. Too much lash means these events don’t happen at the right place in the cam profile. The Mazda cold spec range already takes into account that clearances will change at operating temperature, so out of spec is out of spec.
I understand but im not sure 5 thou of a mm is enough to cause serious issues. spec range just goes to hundredths. So idk how crucial it is. But I made some changes anyways. The blue are shims I can reuse for the intake side. Red are shims I can reuse for exhaust side. Black are shims have to buy.
Brown Santa came. He left me things for the motor. Shims, gaskets, etc.
I also went to Santa Sav. Where I obtained more things for the motor (brake fluid not for motor heh). Ur looking at a trigger wheel for supermiata damper, gates racing timing belt, ARP head studs, and supertech valve springs.
Upon opening the blue box, I was surprised to see new retainers and those other things in there. I thought I was just gonna get springs....cool.
Such springs....much wow.
Also, question, is this rubber thing on the right way? Nobody seems to show online.
BTW, when you put them on, you need to use both the stock thin washer thing as well as the Supertech spacer. I put them all on without the stock one then had to take it apart and do it over again.
Not sure how many head jobs you've done, but there's this amazing trick to getting your valve keepers seated. Basically, do this:
1) start your valve keepers on the top of your valve. They'll align and seat flush with the spring retainer and the tip of the valve stem just with finger pressure
2) slip in a heavy Ziploc bag between your spring compressor and the spring retainer
3) compress the spring
The plastic bag gets trapped by the spring compressor and pushes in the valve keepers. Since it's plastic, it can deform and wiggle as needed. it will stretch out little dimples in the bag, so you might burn through a couple bags doing the whole head. Sometimes you'll have better luck doubling up the bag to get more tension out of it. Here's a link with a couple pics I shot of me doing this process. It's amazingly fast and easy compared to any other technique I've ever tried.
04-06-2018, 07:17 PM
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