OST-068: Smok'n

[oldeskewltoy]

OST-068 is a smok'n Blacktop, its burning oil.....





particularly from #4 exhaust valve (wet exhaust port)





Why is it smoking???

1 too many valve seals........... He is lucky that the extra seal didn't cause any damage other then burning some oil




My client was a little embarrassed, but it was decided he wanted more power anyway, AND besides those seats(2nd photo in post - above), and valves (below)....



....have seen better days, so I'm building another 20V engine.




more to come......

[allencr]

Wow, that's a new one!
If the guide's top isn't normally submerged, extra seal or no seal shouldn't oil it up that much, besides it's only 1 exhaust & isn't going to affect the com. chamber.
Burr on.

[allencr]

Wow, that's a new one!
If the guide's top isn't normally submerged, extra seal or no seal shouldn't oil it up that much, besides it's only 1 exhaust & isn't going to affect the other or the chamber.
Burr on.

[oldeskewltoy]

Wow, that's a new one!
If the guide's top isn't normally submerged, extra seal or no seal shouldn't oil it up that much, besides it's only 1 exhaust & isn't going to affect the other or the chamber.
Burr on.

bothered client.......

So what's the plan for this engine overall?

The plan...

the bottom end of the engine gets a complete rebuild, with new Toyota 81.5mm Blacktop pistons, rings, and new bearings. Additionally the bottom end will get fully balanced. The deck height will be set to provide a squish: minimum of .032" (max of .036").

The head has already (previously) been machined .004", I'll be taking about .004" to drop chamber volume about 1cc from before all machine work.

The chambers in this head are the best I've seen in any of the Blacktop heads I've worked - No chamber work will be needed :thumbs:

Now as nice as the chambers are... some of the ports are not so nice.

poor port alignment (core shift) here




and here....





Fixing said poor alignment




and showing a comparison of 2 intake ports - before and after work





More to come.....

[oldeskewltoy]

3 down........




more to come.....

[oldeskewltoy]

so... its been a while since I've updated... build is almost finished, just waiting on the new Cometic .036" 20V gasket.





old, and dirty, and look at the pock marks in the exhaust seats

port work complete - prior to valve job - exhaust seats still pock marked if you look closely




4 angle(exhaust), along with ground valves with back cut intakes



a bit closer view





Head is ready for re-assembled using Supertech springs




and as always... it requires small tools (tweezers required)






the bottom end got oversize(81.5mm) pistons, and a complete re-balance




along with a new MRP oil pan




more to come......

[allencr]

Thanks, looks nice & clean,
Looking at those 3 valves through the intake is always a neat thrill!
Were the other cyls clean & dry & smegma free?

Is there going to be any more finishing/grinding the comb chamber, all the area after the 45, on the 60 to 90 and the ridge around the seat?

[oldeskewltoy]

Were the other cyls clean & dry & smegma free?

Is there going to be any more finishing/grinding the comb chamber, all the area after the 45, on the 60 to 90 and the ridge around the seat?

dry for the most part, but far from free of build up.... no more work in the chambers... Blending the angles can improve flow(very small amount), but screwing up the seats by doing it wrong is just bad form. This head now will easily outflow what it flowed before.

[allencr]

OK.
I'd think that big aluminum ridge around the seat would do more then a bit, but I've got 0 flowbench experience and can only go by what looks aerodynamically pretty to my eye.
Thanks.

[oldeskewltoy]

OK.
I'd think that big aluminum ridge around the seat would do more then a bit, but I've got 0 flowbench experience and can only go by what looks aerodynamically pretty to my eye.
Thanks.

I've done both... when the ridge is bad enough..... I will do a little blending