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D-series Janitor
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Discussion Starter #1 (Edited)
I have been thinking about the possibilities of a honda head for awhile now so with an aluminum MIG welder and a bunch of tools I decided to build a better mouse trap (I think anyways).

I always thought the runners of a d-series head are kind of poor. The short turn is terrible and I think the overall design could be improved by raising the runners. Looks kind of like a flathead briggs motor to me . . .

Bought a b2 head from craigslist for $20 that had a burnt valve in it . . . and was covered in 20 years of sludge and never changing the oil.

(promise I'll add some pictures monday)

Tore it down, sandblasted and washed it in solvent . . . and put in on the superflow 110 bench we have at school.

The numbers are poor but keep in mind there is still some carbon build-up around the guides, this flow bench reads 6-7% lower than most of the benches I have seen on the internet, AND I fouled up the spring setup causing one side to bind slightly. Will fix that on monday.

So far numbers at 28" on the intake:

.100 - 57.5
.150 - 89
.200 - 114
.250 - 122
.300 - 124.5
.350 - 125

ran out of time and also noticed the bind. Also I will have to notch the piece of aluminum I am using to press down on both valves with one dial indicator.
 

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Well?
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interesting. curious to see what numbers you get with it at higher lifts.
 

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D-series Janitor
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Discussion Starter #3
Well got the bind worked out (used a larger diameter washer), cut a relief in the bar I was using to press down both valves . . .

AND cleared out all the excess playdoh I was using as a gasket. It got into everywhere and around the valves pretty bad. The Superflow bench I am using has a 4" and larger bore which is obviously way too big for this head. Cut a 3" hole in some 1/8" flat sheet metal and using c-clamps to hold down the head to the deck.

new numbers for today: (The valves still don't feel very good above .350" or so. I may have to notch the metal sheet . . .)

numbers are at 28"

Intake
.100" - 69
.150 - 105.5
.200 - 136
.250 - 150
.300 - 157
.350 - 164
.400 - 165
.450 - 166

Still a far cry from CHT's numbers of 216cfm. I seriously doubt these tiny ports could flow 216 stock though . . . I have to wear ear plugs the whistle is so bad from the turbulence. For a reference my ported 289 (ford v8) intake only went 201cfm @ .520" with a single 1.78" valve.

Anyways . . . decided to take the plunge and welded a little near the valve spring seat and did the first of two steps: Raise the runner.

Based on the cut-away pictures from the y7 thread, I decided to go up .300" which is almost up to the top of the port where the injector sits.





And to get an idea from inside the port:



Right now I think I am going to sleeve the water jacket break-through and epoxy it in and clean up over it. The plan is to raise the floor .350" with the aluminum MIG welder I have. It has a smaller head and can actually fit in this port now that I raised the top. Will get to it tomorrow morning if everything goes according to plan.
 

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Classic Man
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jesus. you went to town on that bad boy.

did the idea of tapering the port down towards the guides not interest you? it may be easier for you to use something like devcon or jbweld, or even clay, to do your testing, then when you find a good combination you can make it with aluminum.

just a thought
 

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Discussion Starter #6
did the idea of tapering the port down towards the guides not interest you?
huh?

it may be easier for you to use something like devcon or jbweld, or even clay
well the ceiling will definitely get epoxied . . . I am going to see what we have in the shop to use as tubing or just turn something down on the lathe and drill it.
 

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Well?
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start out large and taper down the port size the further in you go to up the velocity of the incoming charge is what he is getting at i believe. also, look at bringing the divider further out towards the port entrance to reduce the CSA if you wouldn't mind. I'd be interested to see if that hurts or helps flow. DO you have any way of measure port velocity on the flowbench?
 

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Discussion Starter #8
start out large and taper down the port size the further in you go to up the velocity of the incoming charge is what he is getting at i believe.
Most of the heads I have seen are opposite of that or get larger around the guide. I would imagine to keep the area the same with the guide/valve taking up room.

I couldn't really find any great pictures through google of some serious intake port molds but suffice it to say that CFE/Brodix/A460/etc all expand out around the guide.

also, look at bringing the divider further out towards the port entrance to reduce the CSA if you wouldn't mind. I'd be interested to see if that hurts or helps flow.
wouldn't know . . . usually the ceiling has the slowest moving air in the intake port but it could also affect cross-flow between each valve . . .

DO you have any way of measure port velocity on the flowbench?
no, we don't have a wand
 

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Well?
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the y7 head tapers down in the bowl area and thats believed to be the reason its such a torquey motor. i think the v8 heads vary to hondas based off a lot of things such as valve angle and position and the amount also. Hondas have tiny ass valves opposed to a big ole BBC/BBF setup. I saw a set of ford racing CNC 3v heads at carlisle and the further in the port the smaller it looked, at least to me anyway. maybe you could try different combos on each cylinder since this is just a test head
 

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()*#$(*$
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My take on the Y7 head is that the runners do generally taper down, but they have a rather substantial increase in CSA around the guides. Note that I said INCREASE in CSA. Not just keeping the CSA constant to compensate for the additonal volume of the guide and boss, buit an actual increase in the CSA. This is, I suspect, an attempt to increase flow through the valve by reducing turbulences and by using the vuloe increase to increase pressure. This seems to be done by many of the better porters out there, and is not just a Honda technique. Many of the "best" heads I've seen have the port open up before the transition to the seat opened up, then quickly tapered back down to the seat diameter. Also, I think this can be sued to shape and direct airflow into the cylinder, effecting the quality of the A/F mix in the chamber.
 

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Discussion Starter #11
the y7 head tapers down in the bowl area and thats believed to be the reason its such a torquey motor.
I wouldn't doubt it. I have played on the flowbench a couple of times and the obvious observation :D is that smaller ports create low lift velocity and in most v8 single valve heads the transition is above .300" lift or so. You would pick up flow under .300" but the real gains HP wise are from picking up CFM near peak lift and trying to minimize the low lift losses.

I saw a set of ford racing CNC 3v heads at carlisle and the further in the port the smaller it looked, at least to me anyway.
hmm . . . not sure on that one. I have seen a couple of ported modular heads and they don't hardly transition at all from port opening to valve seat (mostly NMRA real street heads).

At any rate I have seen some pro stock CFE and GM heads and they balloon out around the guides but again this is for a single (albeit GIANT) valve on a wedge head.

maybe you could try different combos on each cylinder since this is just a test head
well if everything goes to plan I will hang onto the head, built the carb intake for it and run a 13:1-14:1 n/a d16 in a crx. But will have to see on the flowbench if anything happened or not.

Also, I think this can be sued to shape and direct airflow into the cylinder, effecting the quality of the A/F mix in the chamber.
Right . . . superflow has a great picture of this in their flowbench operators manual. Will see if I can't get a picture.



Just for an update, I welded up the floor and the hardest part was like an inch or so behind the seat . . . couldn't get the welder far enough up there from the intake side and the floor caves away from the seat from the chamber side. Ended up welding as much as I could and epoxying the gap. Probably won't get to the sleeve water jacket idea until next week.
 

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Remember when measuring CSA around the valve boss to allow for the fact that the valve stem is also there when the engine is running.

The turbulence around the valve guide boss and valve stem considerably reduces effective CSA.
 

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Well?
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i wanna see some pics!!!
 

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WOW!!
 

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Discussion Starter #16
Well . . . after a long ordeal with Superflow we figured out that the 110 flow bench we have (since NOT their top of the line stuff) cannot be calibrated to the extent of the higher models.

We played around on the flowcom and got the most accurate readings for the bench.

SOOOO that meant re-doing a stock port to get an idea of what the ported/modified port will do.

STOCK intake (again a6/b2 pm3 head):
(lift - 28" H20)

.100 - 53.15
.150 - 74.80
.200 - 109.33
.250 - 134.50
.300 - 151.44
.350 - 160.15
.400 - 164.95
.450 - ~165
.500 - ~165

So in conclusion the bench STILL reads low, but I finally have all the little bugs worked out for flowing a honda 4v head on a bench and stand/micrometer setup for a standard pushrod v8 head.

and now for the major work:

PORTED/Raised - Stock:
(same values)

.100 - 73.42 - (53.15)
.150 - 103.5 - (74.80)
.200 - 128.21 - (109.33)
.250 - 143.87 - (134.50)
.300 - 153.44 - (151.44)
.350 - 160.85 - (160.15
.400 - 167.83 - (164.95)
.450 - 172.62 - (165)
.500 - 176.96 - (165)
.540(max) - 180.29 - n/a

So not as thrilled as I wanted to be above .300 but I attribute part of that to the desperate need for a valve job on the seats. I nicked one of the seats with the welder (able to get very close with cartridge roll) but I wouldn't doubt it would affect flow. Also I forgot (I know . . . I know) to calibrate the leakage for the modified port. This would also raise values 1-2% I am guessing.

Either way I think the validity of the crappy short-turn is in evidence by the much improved low lift numbers over stock but I have to admit the stock port is killer for the lift intended (.400") but you can tell it dies off right after.

Be interested to hear what you guys think . . . will get up pictures tomorrow afternoon/evening.
 

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Were you able to get any velocity readings from the ports?
 
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