OST-029: California here I 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]

oldeskewltoy Wrote:So last "quiz" on this head....

What's up?

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....

[oldeskewltoy]

This head is now done! intake and exhaust valve clearances have been set.




Now to get it boxed up and on its way to its new owner

[banpei]

And another epic serial by Oldeskewltoy comes to an end.

[Bean]

(03-11-2015 09:55 PM)banpei Wrote:  And another epic serial by Oldeskewltoy comes to an end.

don't worry I'm sure there will be more

[oldeskewltoy]

(03-11-2015 11:48 PM)Bean Bandit Wrote:  

(03-11-2015 09:55 PM)banpei Wrote:  And another epic serial by Oldeskewltoy comes to an end.

don't worry I'm sure there will be more

got an SR20DE I'm playing with..... if anyone is interested.....