OST-029: California here I come......

[oldeskewltoy]

Looks real good especially the short turns and the chambers.

exhaust #1




all the chambers



More to come........

[oldeskewltoy]

More to come........

After the cut, with the valves fitted... waiting for checking chamber volumes....



This head was cut .018" (.457mm) My caliper can't figure out if it is .45, or .46





"Volumes" to come........

[oldeskewltoy]

Since this head is coming here to Cali. Is the customer going to do any kind of camshaft or just use the stockers? I'd be curious I know that my web cams in my N/A engine wouldn't pass smog.

Really? which Webs? My AE86 used the Web 294 grind and they passed, albeit with a new OEM type cat, but they passed. And I'm pretty sure OST-019 passed using a mild cam, but it needed a bit of ignition timing tweaks to pass.

Most likely my client will be running a set of the "big", or early stock cams if he can get himself a good pair. There is a Cat cam that MIGHT work, its their shortest, lowest lift cam, it measures 214 @ .040" lift, with a gross lift of 8 mm. The Web 294 cam is 214 also, but @ .050" lift.

"Volumes" to come........

Checking chamber volumes on the cut head.... it is down to 35.1cc (tolerance = + or - .1cc)




So we can move on... besides waiting a week for the machine work, that same time was used to get new springs....



16 new OEM springs...


Now its just left too assembly.....



More to come.....

[BOBLOOK]

California ? would those mod affect the ca emission drama on there ?

[oldeskewltoy]

California ? would those mod affect the ca emission drama on there ?

They shouldn't....... Nothing I've done is actually drastic. For the most part I'm just improving the original casting by port matching the seats-bowls-ports to more closely match the original design. The surface machining of .018" is not beyond the normal range. A multi angle valve job is not beyond typical. The slightly raised compression will not hurt either.

The client has selected to run a pair of MILD upgrade cams. He purchased 2 exhaust cams from Cat Cams 7105136 on my recommendation. They have the same timing as the OEM cams, they have a bit more lift, and a bit more duration... without it going to an extreme (emissions unfriendly)

What are swirl generators? I can see everything else you pointed out thanks.

First apologies... the more common, and in this case correct term is actually "tumble generators"





This kind of tumble generator promotes lower air speed performance by causing the incoming air to rotate as it approaches the valve. The theory is it helps to fill the valve area better. It also may act as a passive emissions device... to further aid in air-fuel mixing so more complete combustion can occur.



More to come....

[oldeskewltoy]

Installing valve #8... apologies to AC/DC... my timing was off by about a second....

http://youtu.be/fu2GHerEnME

[oldeskewltoy]

The valvetrain is now assembled....






Cam caps buffed....




Just waiting on those new cams.....



More to come......

[oldeskewltoy]

As I alluded too, the cams have arrived. They are a pair of Catcams 7105136 exhaust cams. As the box labels, and the cams indicate.



Since I'm setting the valve clearances, and the cams are more or less identical, I've labelled them "I", "E" so there can't be any mixing of one to the other. This will also help my client get them back in the right places once the head is bolted on.






These are a MILD bump in duration and lift over Bluetop cams.




Just a reminder... early TVIS cams are 240 total duration, 204 duration@ 1mm lift, with 7.5mm cam lift.



Ok, why go with such a "mild cam" a few reasons: 1) California emissions, that on its own can make or break this build. 2) My client is keeping the stock 9.4 to 1 pistons - he will be adding a thinner head gasket, and the chambers are smaller, but this engine won't be breaking past 10 to 1, so keeping as much trapped compression (DCR) is important. The ramp on this cam is pretty aggressive ("foot" is only 13 degrees) so even though the cam is "mild", it isn't as mild as the numbers appear...



The intake timing @ 1mm lift for this exhaust cam used on the intake side would be 4ATDC to 36ABDC. Now add in the head cut to the cam timing (albeit not a huge amount) will move cam timing closer to 2ATDC and 34ABDC... all with 8mm lift and all the "extra" duration from 1/2 lift on.

Only time will tell, but this should bring a nice LEGAL smile to my client


More to come......


EDIT - not thinner headgasket, so only compression bump is from 1cc smaller chamber (about 9.6 to 1)

[oldeskewltoy]

So last "quiz" on this head....

What's up?




more to come.....

[oldeskewltoy]

So last "quiz" on this head....

What's up?




more to come.....

really? no one even has a guess??? Even a quick view @ the pic title gives MOST of it away.... "disassembled_exhaust_valves_for_tipping.jpg"

How much easier can I make it???


alright.... what is seen above.... the intake cam is in, the exhaust cam is not only not in, but all the exhaust valves are out in box-stock type cardboard, each marked with two series of numbers (1-8), and a second series that appears to be measurements (apologies for not marking the type of units used).

So the story.... The new cams were unpacked, and I began on the exhaust side. I used all 2.9mm shim to begin, and once the cam was tightened into place, and I checked... I managed to get 3 readings... all .0015" (spec on exhaust is .25mm, or .0100"), the other 5 were just too tight to even get a measurement. So, I removed the 5 shims, and fitted 5 of the thinnest shims I had, remeasured and found to get proper clearances I'd need to order 7 shims ranging from 2.5mm to 2.70mm.

To make a LOOONG story much shorter... the second series of numbers that appear to be measurements are measurements of how much each of the exhaust valves need to be tipped. Tipping the valves will get their clearances back to a range were special ordered shims are not required(2.8-3.1). It will also allow for a 2nd valve job to be done on this head and still be able to shim it, something that would not be possible if I didn't tip the valves today.

Now the good news... the intake side was set just fine, no weird things there. 5 valves are set @ .008" and the other 3 are @ .009"




more to come....