Switching from 45 to 50 deg seats - done some testing

[midnightbluS10]

So you're intending on changing the cam? Changing anything other than lobe lift?

[KnightEngines]

Wow. That should turn out really well.

I hope there will be some dyno numbers for both valve jobs. The 50 should beat up the 45 everywhere.

It'll go on the same dyno & we can overlay the old power curve on the graph.

But I'm changing a bunch of little things, so it won't be just a valve job comparison.

[midnightbluS10]

Yeah, I had an aggressive 45 seat in there that behaves pretty close to a 50, 38/45/65/80 with a big throat. Gone to 45/50/65/85 with similar throat.

We're doing the 1.8 ratio jesel rockers, which will take it from .700" lift to .800".
We'll also be trying ETS Z85 fuel.

I ask because I don't think just a rocker swap will gain you the .100" you're looking for. To get .700" with 1.65's, you need something like .424xxx lobe lift and something like .444xx lobe lift with 1.8's to get .800" lift.

1.8s on a lobe with .424xxxx lift won't get you .800"(.763" actually) unless I've forgotten how to do math all the sudden. Lol. So I'm assuming you're changing the cam.

[KnightEngines]

Cam has .454" in & .438" ex lobes, it's staying, the gain in .050 & .200" duration with the 1.8 rockers should be enough.
Can always add more duration at next freshen.

[midnightbluS10]

Thanks. That's what I was wondering.

[KnightEngines]

Speaking of which, I wonder if someone on here can calc the change in .050 & .200 duration with the rocker change...

[cjperformance]

Speaking of which, I wonder if someone on here can calc the change in .050 & .200 duration with the rocker change...

I recon Stan Weiss on here is the gun with this sort of thing mate.

[randy331]

Speaking of which, I wonder if someone on here can calc the change in .050 & .200 duration with the rocker change...

I measured it at the valve before.

On a 258* lobe it had 262 at the valve with a 1.7 Jesel shaft and 264 at the valve with a 1.8 Jesel .
I used tha same lash on both rockers. I have the .200" numbers somewhere here, but not sure where.

Randy

[GARY C]

Speaking of which, I wonder if someone on here can calc the change in .050 & .200 duration with the rocker change...

Rule of thumb says going from a 1.5 to a 1.7 adds 4 @.050 but the best I could measure on mock was around 3 but i am guessing it would vary some based on the rocker used.

[KnightEngines]

Cool, so I'll likely end up with a cam that behaves like a 272/278, perfect.
I'll check with both rockers when I put it together to confirm.

[KnightEngines]

Finished the heads for this & have checked & set up the new Jesel 1.8 ratio rockers - they did their homework on these, mint sweep even with .800" lift:

20191129_103806 by tony knight, on Flickr

20191129_103537 by tony knight, on Flickr

20191129_103400 by tony knight, on Flickr

20191129_103410 by tony knight, on Flickr

Also finished the intake manifold:

20191127_163821 by tony knight, on Flickr

20191127_163615 by tony knight, on Flickr

20191127_163610 by tony knight, on Flickr

20191127_163657 by tony knight, on Flickr

20191127_163517 by tony knight, on Flickr

20191127_163408 by tony knight, on Flickr

20191127_163358 by tony knight, on Flickr

20191128_093457 by tony knight, on Flickr

20191128_093403 by tony knight, on Flickr

[steve cowan]

She looks pretty Tony, real nice.
With the jesel how much spacers under the bar, on my 215 darts you had there, I had to add 2x 0.100" jesel shims to get good sweep. That is with 0.100" longer valves.
I like the position for vac pump pick up,
Is that where they all go when you set them up.
Anyway, looking forward to dyno results, going to be a beast

[cjperformance]

Looking great !

[KnightEngines]

Steve - .150" shims for these, but valves are .250" longer than stock.
Often I just pull vac from a cover, but this is gonna turn pretty hard so I'm not restricting oil flow up top (keep the springs cooler) so likely it'd pull oil from a cover, so valley vent it is.

[steve316]

I have seen a lot comp. engines running spring oilers; I guess they add to spring life as well as more consistent pressure.