OST-017: Ed Sullivan it ain't!

[oldeskewltoy]

from another forum Wrote:What's the throat diameter?

The valve seat throat diameter currently is.....




I'll know more about the after once I get the head back with the O/S seats installed

[oldeskewltoy]

oldeskewltoy Wrote:The valve seat throat diameter



I'll know more about the after once I get the head back with the O/S seats installed

The intake throat went from around 26.07mm, out to 27.7mm a gain of 1.6mm, or a gain of about 6.3%

The exhaust just GREW.... from 20.97mm out to 23.84mm, a gain of 2.87mm or a WHOPPING increase of OVER 13%


Here are a pair of unique views... I doubt ever seen anywhere.... top is the exhausts, bottom the intakes.

Left side have the seats roughed out, right side is raw uncut seat






and last for this post... the progression of chamber #3... top view as it arrived, the next view shows it with the un-machined seats



And as I like to toss in quick little quizzes... what work, besides the O/S seats, can also be seen in the lower panel??



More to come

[oldeskewltoy]

All the intake ports are now finished. I've done what I could with the short radius, and the overall size is now set.


Now that the intakes are set, we move on to the exhaust side. Now that the O/S seats are in, the exhaust sees a cutting bit :eek: :eek: to get the "new" shape correct.



The first thing you notice is the overall increase in size... if you are careful you can see this expansion proceeds beyond the valve guide. Note the increase between the bowl wall and guide, and the splitter and the guide



This increase in volume is evident from the port view as well. Top view was the "finished till O/S seats installed"....



and in the bottom view... the lopsided look with the left bowl now shaped to accommodate the volume needed for the O/S valve.... the right hand bowl awaiting its massaging

[oldeskewltoy]

Been a while... sorry. As I've said a few times, this is my first O/S valve head, and since I was using a cutting bit inside the bowls for the first time, I've been focusing on getting it right.....

A fond photo... now part of a 3 panel



see how things have changed even more


So, here are the four O/S exhaust ports... in order(#1 on left, 4 on right)



The obvious signs this is an O/S valve head... the thinned splitter, and the ample volume to flow past the guide, what you can't see from this perspective is the ample room on the other side of the guide as well.


So, since those don't show it all, here is a view @ a single bowl...



:eek:

Another view... this time a 3 panel of the progression of exhaust port #3


focus on the splitter and watch as it changes based on need



Now for a unique 2 panel... the top half of the photo below is above... the bottom half is the updated photo showing the bowl work complete. The lower view was mirror imaged to show port to port comparison




Finally... for those who have been following my work... I often show how the head can "bend light"... No added light to the following photo... no camera tricks... the ports take the available light and direct it out of the head




Cams are being built as I write this... The Kelfords were not available, so we went with a Web grind not known in these parts (these parts = 98% of 4AG users....)

Web
Intake - #797 Valve lift .410 (10.410 mm), Duration Adv 297°, Duration @.040 (1 mm) 259°
Exhaust - #1043 Valve lift .400 (10.160 mm), Duration Adv 300°, Duration @.040 (1 mm) 250°

Once the cams arrive, the bucket cradles will be machined for clearance. And then the head goes back to Loynings to have the seats machined, and check the valves for valve to valve interference.........

much more to come.......

[oldeskewltoy]

oldeskewltoy Wrote:Cams are being built as I write this... The Kelfords were not available, so we went with a Web grind not known in these parts (these parts = 98% of 4AG users....)

Web
Intake - #797 Valve lift .410 (10.410 mm), Duration Adv 297°, Duration @.040 (1 mm) 259°
Exhaust - #1043 Valve lift .400 (10.160 mm), Duration Adv 300°, Duration @.040 (1 mm) 250°

Once the cams arrive, the bucket cradles will be machined for clearance. And then the head goes back to Loynings to have the seats machined, and check the valves for valve to valve interference.........

much more to come.......

Along with big valves... you get BIG CAMS



Here is a photo comparing the new 797 Web camshaft to the stock cam :eek:



How much larger....?????

stock



THIS much LARGER!!!



As you can plainly see, the bucket cradles will need to be machined a bit so these camshafts can turn in their bores :eek:



Got a quick quiz question for the viewers....

Why does the Web 797 camshaft (total duration 297)



Look more like the HKS 264 below, and looks like less duration then the 272 in the photo below????

[Niek]

damn that are some big lobes
guess u'll be running some strong non-oem springs for that aswell

[Project D]

oldeskewltoy Wrote:Got a quick quiz question for the viewers....

Why does the Web 797 camshaft (total duration 297)
Look more like the HKS 264 below, and looks like less duration then the 272 in the photo below????

I would say it's all about lift & ramp

[oldeskewltoy]

Niek Wrote:damn that are some big lobes
guess u'll be running some strong non-oem springs for that aswell

TRD springs... good to 10.7mm of lift

Project D Wrote:

oldeskewltoy Wrote:Got a quick quiz question for the viewers....

Why does the Web 797 camshaft (total duration 297)
Look more like the HKS 264 below, and looks like less duration then the 272 in the photo below????

I would say it's all about lift & ramp

The ramp rate on these cams are actually a bit softer, then most 4AG cams. these cams have almost 40 degrees of ramps, while many 256-272 cams have 36 to 38.

The key here is these cams have over 2mm more lift them the HKS cams, remove 2mm from the nose of the Web cam, and you'll end up with a very fat lobe indeed!

[oldeskewltoy]

Another OST 2 panel...



.....................................before./\...................................................................after./\..............

[oldeskewltoy]

from another forum Wrote:What made you pick those cams Dan? Vs even more lift? That duration? just curious.

Also the "soft" ramp is going to have a lot of overlap! As you may know, aggressive ramps allow you to get the duration you want with out as much overlap at low lift = nicer idle and driveability under 3500 rpm or so. Keep up the good work

Client is actually planning on racing this head... so little need for nice low rpm manners...

The original cam choice if you go back to the beginning was the Kelford 193HV-B

oldeskewltoy Wrote:Yes... I'm told Kelford 193HV-B. 300 max duration, 10.5mm maximum lift

We waited on the Kelfords, but no one seemed to have a set, or knew when a set would be available, so I gave the Kelford specs to Web, and they sent me back their options...

The PRIMARY reason for the Kelford, and then the Web, was these cams were the largest lift that we could find that would work with a single spring*, and didn't have an astronomical price * TRD 90501-AE851 - The TRD spring is capable of lifts in excess of .415"