Help Selecting Buckets

i thought that was the difference between 02 and 03+ heads, with shimless buckets it didn't matter which bucket went where (i.e. you can just buy 16 shimless buckets), whereas with the 02 you had to remember where each one went and make sure the tolerances were correct.

i could be completely wrong tho

 

well, you're right about one part


there's a service manual page that describes this pretty easily of where to measure. measure the gap, add the valve lash (different for intake and exhaust DYI) and voila you have your bucket thickness.

I'm sure breel has it saved handy somewhere... I can't find it at the moment

 

No still have to measure regardless if has shims or not

 

figured. the only times i've had heads apart we've just put the buckets right back where they came from

 

yeah this is the correct way to do it, mostly. it's still a good idea to measure because they ARE wear items. if he's coming from an earlier shim head and wants to switch to no shims, he will need to measure

 

One suggestion....the heads must be torqued down to the block in order to measure the buckets correctly.

 

If you don't know all of this you shouldn't be rebuilding anything IMHO.

 

There is not a tq sequence. It's 2 tq sequences followed by specific turns.

 

please explain this...

 

The heads do flex. My old motor did and another I've built has. It's minute but if you want it precise tighten that head down.

My old head flexed enough after tq'ing it to the block that it wouldn't turn one of the camshafts and I measured those buckets 3 times. Then as a test I measured while installed and then with the head off (since I had to replace the head gaskets when I overheated that time my radiator exploded) and the values were off by enough. One of the buckets weren't exactly in the middle and was on the tight end of tolerance....I guess that little flex made it too tight.

 

If you're using ARP studs, the studs also have torque specs into the block. Since you've got everythign out, it might not be a bad idea to go ahead and replace the studs, too. I've heard stories of the stock studs stretching during the torque sequence and that if reused can cause incorrect specs

 

General rule is you can reuse the OEM studs once and only once. I know many have many times but once it's been tq'd down twice I wouldn't reuse them.

And I would NOT reuse ARP's unless you take the extra steps to do them right. Doug has a writeup on here but ARP's have been known to back out on the first good heat cycle which isn't easy to fix on a Subaru.

 

This is true for anyone that might be doubting him.

While its perfectly acceptable to set the clearances with the heads off they do need to be checked once the heads are bolted on. I've seem clearances change up to 3 thousandths.

Matt

 

Oh wow someone agrees with me....lol

 

HAR!. them buckets are expensive. each one must be correct.

this is one way of 'solving' the problem. buy one of each size. now you can use that set to determine which size you need on each of 16 holes. then you order those (or most since i guess some of the 'measuring buckets' could conceivable be used).

buckets are expensive.

about the torque before measuring. everyone says you should. and i would if i was rebuilding a motor. but maxwell power guy who is supposedly one of the top builders has supposedly said he does it with the heads off.

ymmv....

if i was rebuilding myself, i would probably buy a 'measuring set' but it like to buy stuff. best bet might be to try to hook up with someone who builds motors and see if he has some he could lend you.

also, i would replace the buckets if rebuilding. its not cheap, but then having a motor break down because you reused buckets, especially on another cam set, is stupid.

 

You guys are making this harder than it needs to be.

Get someone to let you borrow 4 buckets of various sizes, put them in measure them and order the right size buckets.

As far as Maxwell Power doing it off the car. I don't care how smart Dom is he is just flat out wrong about this. I've seen it more than once on Engines when I was at TopSpeed.

As far as the buckets wearing out, you can look at them and tell if they need to be replaced. I've never seen a bucket wear out under normal conditions.

Matt

 

Wait you not at Topspeed anymore?

 

Short answer is no

 

if you're going through the trouble to torque the heads down, why not get the parts up to operating temperatures as well?

 

Because those tolerances were designed to be checked cold.

 

even with aftermarket cams with different expansion coefficients?

 

The OP didn't specify that he is using aftermarket cams.

 

I realize this. just playing devil's advocate

 

nope

 

read above.

 

Even with aftermarket cams they should be checked cold.