All Small Six Is my head supposed to look like this?

[funkaholik]

I started stripping my engine down for paint, headers, water, pump, etc., etc., etc.

With everything out of the way, I noticed that the intake is far from level. At the front three cylinders, the log is perfectly flat, and the runners into the head are at the same angle. At the rear three cylinders however, the log definitely tilts up at the back and the runners into the head are at a more downward angle as it gets back towards number six. Is this normal? It seems like this configuration would make the cylinder distribution even worse than with a flat, even log intake. I haven’t found any photos online from this angle with all the stuff out-of-the-way, so I just wanted to confirm or deny that there is an issue here.

 

[drag-200stang]

Yes, that is how they are done and it is not by accident.

 

[funkaholik]

@drag-200stang Thanks for the confirmation. It looks so weird that I just wanted to be sure.

 

[funkaholik]

It would be very interesting to see the AFR data from 6 separate oxygen sensors, one in each header tube. Has anyone done that?

Even more interesting to see the comparison between the 1100, 2 barrel Weber, Offy triple carb setup, etc.

 

[TrickSix]

Water pump out is an excellent time to flush your block. With the pump gone the water jacket is opened up almost down to the bottom at the front of the engine. Put your garden hose on the heater nipple at the front of your head by the front header pipe in your pic. When you turn the water on there is a small hole at the front of the block that will spit a little water back at you, so be ready to put a finger over it! Lots more water will be spilling out of the water pump opening, carrying out a lot of rust and sediment. You can squirt more water with a second hose right into the water jacket there to keep things stirred up and in suspension to get out even more of the crud.

 

[Frank]

It would be very interesting to see the AFR data from 6 separate oxygen sensors, one in each header tube. Has anyone done that?

Even more interesting to see the comparison between the 1100, 2 barrel Weber, Offy triple carb setup, etc.

It's tilted to compensate for the engine tilt in the vehicle. It's a good design- the aftermarket intakes are on a level plane, which is a rearward downhill lean when mounted in the vehicle,, even the carb sits tilted. The back cylinders load up with raw gas daily, until the intake is hot. The factory design is smart. The a'market guys missed the mark by not emulating the the compensated plane.

 

[funkaholik]

@TrickSix Thanks for that tip. I planned to flush it out, and it's good to get those specific instructions for this block.

 

[powerband]

Engine sits @ 3-1/2 Degrees off level/flat, Offy Tri-Power Intake design keeps the carbs level/flat.
.
. ..
.
have fun
.

 

[ActionYobbo]

It would be very interesting to see the AFR data from 6 separate oxygen sensors, one in each header tube. Has anyone done that?

Even more interesting to see the comparison between the 1100, 2 barrel Weber, Offy triple carb setup, etc.

I was looking to find that information and your post was the only result. Seems like an area of research that needs to be investigated. I was interested to see if 2 1v carburetors mounted above ports 2 and 5 with the original carburetor location blocked off is better than a 2v mounted in the original location. If mounting 2 carbs is only equal then it’s just work for no gain but if it’s 20% better that’s huge

 

[funkaholik]

I was looking to find that information and your post was the only result. Seems like an area of research that needs to be investigated. I was interested to see if 2 1v carburetors mounted above ports 2 and 5 with the original carburetor location blocked off is better than a 2v mounted in the original location. If mounting 2 carbs is only equal then it’s just work for no gain but if it’s 20% better that’s huge

I would think that two 1V carbs mounted like you suggested would provide better distribution. Some sort of divider inserted under the original carb mounting location block-off plate might help, too. But of course without data we are only speculating. If I win the lottery I will build a dyno room and just play all day...

 

[chad]

some work on this is in the Tech Archive (blue line top of this page). Offenhauser (came over to automotive from marine racing)
has an ‘early’ anda late' triple carb adapter (lots on it right here in the “Search” function) for our log(s)...

Over the yrs (again. lots of reading w/search, dozens’n dozens of threads) just abt everything has been tried. I like AK Miller’s one
(I think he used Mikuni carbs, Keihins for today) per cyl. Imagine the 6 throttle linkage/cable ? 8^ 0

 

[funkaholik]

I like AK Miller’s one
(I think he used Mikuni carbs, Keihins for today) per cyl. Imagine the 6 throttle linkage/cable ? 8^ 0

I know a guy with 4 Mikuni HSR flatslide carbs on his Datsun and it's a screamer. The linkage (and synchronizing) for 6 carbs must be mind-boggling.

http://www.v-performance.com/products/air_fuel.html#mikuni_hsr_series_carbs

 

[TrickSix]

@TrickSix Thanks for that tip. I planned to flush it out, and it's good to get those specific instructions for this block.

I see you have your thermostat housing removed too. That opening needs to be plugged to do this flush. Either temporarily install the 'stat again or some kind of quick and dirty blanking plate.

 

[chad]

nice link in #12.
I found lots of info on this in UK when searchin. Just a bit for i6. Oz
seemed the place instead (linyx intakes, the carbs, demonstrations, etc). Yet UK
had as many X-flows as Japan (& theirs are current Honda, Toy, more).