OST-019: Collaboration

[oldeskewltoy]

The bowls have had a basic shaping to them, they now match the valve seats. Note each port has a 2mm - 4mm bevel around the entire port. If you are sharp eyed, you'll note the far right port shows a bit of port work already



Here is a closer view of that port work....



Not an uncommon scene in one of my smallport heads - half done showing before and after in the same shot. I've removed the pocket @ the junction of port roof/wall and bowl roof/wall, but there is a lot more there then just a bit of smooth transition.


Maybe this view will help....



The right hand side of the port roof has moved significantly - the right hand side manifold edge is no closer to the gasket then the left hand side. What has changed is the bevel has been removed, and the port roof now has a gradual taper forward to the base of the splitter/guide bosses. This gradual taper allows for more high pressure air, while @ the same time beginning to get the air charge bending towards the valve.

[oldeskewltoy]

hmmmm, maybe this view is better






a simple comparison... right port is just about finished, left port is still untouched.


More to come....

[oldeskewltoy]

From the intake side to the exhaust side.... Getting the bowls and seats correct on the exhaust side took almost 2 days.... now all 16 bowls and seats have been ported




with the intake ports, and bowls and seats now prepared, the process moves to the exhaust side of the equation... another interesting 2 panel, below is #1 exhaust port... 2 views into it



The left side is still untouched, while the right side has been opened up by having the ports taper changed. The wall has been pushed out about 3mm, it now blends into the bowl smoothly - there is no "corner" for the exhaust gasses to have to flow around. The port roof has been worked so that exhaust flow moves down the port smoothly, allowing a more gradual transition for the exhaust gasses to flow together.


more to come........

[Niek]

Learning alot here

Are the wall thick enough that you can just take out 3mm from it?

[oldeskewltoy]

Niek Wrote:Learning alot here

Are the wall thick enough that you can just take out 3mm from it?

depending WHERE........ there is a lot more than 3mm available.... but in a few places.... it isn't even that thick

The ports themselves.... have SUBSTANTIAL room for enlargement.... for example, the TRD exhaust gasket is 38mm in diameter, where as the stock gasket is 33mm, and the stock port is about 30mm

here is a head with ports opened up to nearly 38mm




for those with 4AG experience... there are a few things in the above photo that is VERY unique to Formula Atlantic... can you find them???

:wink:

[Project D]

For the obvious:
Blank plug for the distributor hole and the water outlet on the back of the head + the front cover (instead of the oil pump) and the dry sump of course.

What intrigue me more are the little holes in the cam lobes -> are they for keeping the lifter lubricated ?

Also both side of the engine seems to have been machined down.

[oldeskewltoy]

Project D Wrote:For the obvious:
Blank plug for the distributor hole and the water outlet on the back of the head + the front cover (instead of the oil pump) and the dry sump of course.

What intrigue me more are the little holes in the cam lobes -> are they for keeping the lifter lubricated ?

Also both side of the engine seems to have been machined down.

those are holes in the cam lobes, if you look carefully you can see them in the intake cam as well. They are there for additional oiling. Concerning the machined down block, the transaxle unit uses the oil pan as the additional mounting points.

other changes... all Allen cam bolts, with no cam cover studs... the oil filter mount has been disabled... both holes are plugged, the oil filter now is fitted to the dry sump pump... rear external drain allows excess oil to drain back to the dry sump pump



A new common site in my head porting posts.... a 3 panel of one port straight down the throat....


the typical caveat... the bottom photo is showing only about 1/2 the light of the other 2 because anymore and the photo would have washed out.

The top photo is just the matched bowls and seats, the middle is with the majority of the material removed, and finally the bottom, nearly finished.

[oldeskewltoy]

I'll take more photos in the morning, but I managed to get to my friends mill.



The holes in the adapter have been elongated. Tomorrow I'll drill and tap the 2 ends so that I can set the adapter to the correct height. There is a bit of a space issue, so I'll be using Allen head set-screws to properly locate the adapter.

More to come......

[oldeskewltoy]

Below.... the finished adapter. I ended up using 6mm allen set screws. You can see them on the ends... and how much the adapter needed to be raised....




I used Loctite green to keep the set screws in their place. the nice thing about green loctite is you use it after, it chases down the threads setting up in a few minutes. This also allows me to be confident that after shipping, and the installer, the plate should be in the same place.


Here is a slight more focused view of the problem.....



.... and after adjustment. The port has also gotten a bit more of a flair to it, since the adapter is exactly the size of the gasket, the ports edges also had to be the size of the gasket.

[oldeskewltoy]

oldeskewtoy Wrote:The clients head went off to Loynings this am.... the guides are being replaced,


With luck I'll see the head back end of the week, or the beginning of next.

Well.... The Supertech guides will not be used () the O/D of the guide is .4342"-.4344". The guide holes in some cases are as large as .4340". The size is mostly because this is an old used head, it has seen thousands of heat cycles.

Loynings feels that a 2 to 4 ten thousandths (.0002" -.0004") interference fit is not enough, they prefer at least a .001" interference fit. Sooo the Supertech guides are not large enough in diameter and so will not be used. Its a shame really....the aftermarket frequently only caters to standard parts... even when the factory offers std and O/S.

Replacing the Supertech guides will be a set of OEM guides that ARE O/S... they are .0019"(.05mm) larger O/D then the standard valve guide.

THIS is one reason I try NOT to replace valve guides... there is no way prior to removing the old guides to know if std or O/S is required.


So the head will likely be @ the shop for closer to 2 weeks so the parts can arrive from Toyota's Cincinnati depot