OST-019: Collaboration

[oldeskewltoy]

OST-019 can be considered a collaboration from a few different view points...

1) My client is having a SoCal shop(name withheld unless they release me) rebuild his engine, so this is my first collaboration with another shop.

2) A looser definition for collaboration would be that this is not just a smallport head porting job, but it is also a port adapter to head porting job. I'm to port a largeport to smallport adapter as well.




The head and adapter arrive...



VERY dirty

No biggy, I'll get it cleaned too.

Anyone see the 1st sign of disturbed airflow???





WAAAAY too much FIPG/RTV... but there is far more wrong in there then just poor assembly



Here is some GREAT news... intake cam journal bearings #4 and #5... although the area is heavily sludged... the journals show no damage





More to come........

[oldeskewltoy]

Here are the chambers before dis-assembly...

#1 and #2


#3 and #4


I don't think I have to make note of the HEAVY oily carbon build up....




Here is the head, now disassembled, showing why there is so much crud... ALL the exhaust valve seals are showing heavy leakage



More to come.......


Psssst... can anyone detect the SERIOUS flaw I see?

hint - flaw is one of poor quality control

[cavey]

Not too sure, pictures are a bit unclear and not an engine builder/rebuilder: but it seems there are a lot of little ridges around the valve areas, potential hotspots for pre-detonation?


Looking forward to more pictures, especially of the head gunk cleaning process (or would that be just a nice washing machine?)

[oldeskewltoy]

cavey Wrote:Not too sure, pictures are a bit unclear and not an engine builder/rebuilder: but it seems there are a lot of little ridges around the valve areas, potential hotspots for pre-detonation?


Looking forward to more pictures, especially of the head gunk cleaning process (or would that be just a nice washing machine?)

hehehehe... no washing machine here, local shop does it for me.

the ridges around the valves can and will cause ping(pre-ignition, or detonation). I will be attending to those during the porting process, but those are common in all 4AGE heads.

from another forum Wrote:the machining for the valve seats doesn't looked to be lined up well at all with the ports, especially in cylinder 4

VERY good call...



the 2 views are of the same chamber... the views are slightly off angle to better show the bowls and seats





For comparison... this is chamber 2.






As bad as that is... when porting you must remember the direction of flow... the flaw above is bad enough, it pinches the airflow, but the real criminal in this port isn't the flaw you see....

its the flaw you DON'T see that is the problem!!!!



The above view is from below, the head is hung over the edge of the bench, the dental tool is hanging on the inside of the mismatched seat/bowl. This flaw is far more serious, as it not only pinches flow but it causes serious eddies which cause far more flow issues.


More to come....

[oldeskewltoy]

from another forum Wrote:So is replacing the seat a must in a situation like this? Or is grinding down the seat to the bowl an option? I'd guess it depends on the amount you have to grind down as long as you don't get to the face/valve contact surface?

The mismatch can't really be fixed because the seat is located at the center of the guide. The guides would need to be moved...

I will be consulting with a VERY exp person on this... as of now I see three options...
1) Cut the seat back upto the contact point of the valve... as you suggest. I've done this before.... but not nearly with as bad a seat*
2) put a shallow taper on the bowl to seat area. This isn't ideal, but it will smooth the flow past the seat.
3) this head becomes a core for use as an O/S valve head, while a more suitable head is found.


* I did a bit of creative negative lighting to show some of the specifics of the valves, and seats.

If you look carefully(bottom valves... far left side of seats), this set up shows thinned seats - note the 3rd angle changes its thickness as you scan from right to left

more to come...

[oldeskewltoy]

The clients head is so poorly cast, we jointly decided to replace his.
I checked my inventory on smallport head, all of them show some signs of poor placement... but a pair of mine have significantly less splitter mismatch. I chose one of those, and it is @ the shop getting cleaned.

oldeskewltoy Wrote:


WAAAAY too much FIPG/RTV... but there is far more wrong in there then just poor assembly

As bad as the bowl and seat are, or were.... the adapter my client is using (well known - name deleted) is poorly manufactured. There is a serious mismatch in the adapter as well.....





The gaskets I'm using are OEM Toyota... The ports are mis aligned by approximately 2.5mm. Now you can see the likely reason the gasket was not used in favor of the chemical sealant, the installer didn't want 2.5mm of gasket invading the airstream.

The problem isn't just the gaskets.... following are 2 views of the same port, one allowed to rest on the end studs, and one with the adapter pushed vertically on the end studs..

down


up


although it is better... the mismatch causes severely disturbed air, and not only is the bottom a problem, but with the roof of the adapter 2.5mm down, the highspeed, high pressure flow along the port roof and walls is significantly compromised.

I could port the top, and try to fill the bottom with a chemical compound...


and then I had a brainfart.... I'll slot all the bolts holes(about 4mm down), if need be I'll make the holes slots clean through. Once all the bolt holes are slotted, the 2 end holes I'll drill from the top(4mm bit), and cut 4mm threads through. then I';ll use 4mm bolts to raise the entire adapter to fit perfectly along the bottom, thus allowing me to have full clearance along the roof as well. I'll hand port any little discrepancies.


more to come......

[oldeskewltoy]

Now that both heads are back from getting cleaned....... a much clearer view of the overall problem can be shown.....

Below are 2 2-panel photos, the top views in each are the clients #4 port/bowls/seats, the lower view the replacement head showing #4 port/bowls/seats.

The first 2 panel shows the #4 port walls aligned....


and in this view... the guides are now what the photo is aligned on... NOT the port walls



As I stated to my client... the top head has nothing wrong with it... it ccould be still used, but for purposes of supplying a ported performance oriented head, the lower view(head) is a far better starting point

[oldeskewltoy]

Well... this has been a quiet thread.... because I went on a short vacation.


Now that I'm back... we can get back into the "new" OST-019 head. I've stripped the poorly cast head of its serial number... and I've added it to the new head.....



a bit squeezed... but legible....


Since I'm waiting on valves and guides, the beginning process for this head will be an overall deburring, as well as cam journal polishing.


The head prior to de-burring...




And after....



Can you spot all the areas I've de-burred???


more to come.......

[Bean]

nice work
the same areas I did on mine
around distributor gear area, both ends of the camshaft area and most important the areas of oil return (above headbolts and the big one middle of exhaust side) - oh and around the lifterpockets too.

I assume you also de-burred the cam journals - can't and shouldn't really be seen on those pics. The rest is quite obvious if one knows where to look

I'm off now to the garage to clean my head so I can start pre-assembly of my valves and cams to measure the valveclearance (lifter cam) so I can order the right sizes for final assembly.

[oldeskewltoy]

Bean Bandit Wrote:nice work
the same areas I did on mine
around distributor gear area, both ends of the camshaft area and most important the areas of oil return (above headbolts and the big one middle of exhaust side) - oh and around the lifterpockets too.

I assume you also de-burred the cam journals - can't and shouldn't really be seen on those pics. The rest is quite obvious if one knows where to look

I'm off now to the garage to clean my head so I can start pre-assembly of my valves and cams to measure the valveclearance (lifter cam) so I can order the right sizes for final assembly.

you know me well......

Everywhere there is an edge... I de-burred. Even areas not in this view... EVERY casting line, and machined edge... around the entire head got de-burred.

In the shot below... if you can tear your eyes away from all of the nice shiny new valves, springs, and guides... you can see quite a bit of the additional deburring this head received.




Here is a closer view... as you can see, I've gone over most, if not all the edges, and I've removed all the nasty bits...



even that big nasty ridge under the distributor mount is smooth.