single-port performance

[Steve67]

found this cool thread again.
I didn`t have the time to update my single port engine so far but this winter it is going to happen!
I definitely want to use my Riechert dual 34 PCI setup. The heads are 1500 ccm single port heads with modified valve seats and modified stock valves (I think 35,5/32). Ports are opened to maximum possbile size when using the original copper sealing ring.

I am thinking about:
82x90,5
Engle W100 with 1,25 rockers
CR 9:1
Ahnendorp Customsport exhaust with 38 mm heaters
Shall I use bigger valves? Does that make sense at all with the 34 mm carbs? I think the venturies are currently 28mm.

[Zach Gomulka]

Interesting combo for sure. I would suspect the best thing to do as far as a cam goes is to have the heads flow tested. Then you could also easily see if the higher lift from ratio rockers would help. I can't imagine larger valves being beneficial with the small 34mm carburetors but who knows, you'll have a lot of pull with that displacement.

[Joel Mohr]

Food for thought...Totally stock 1600, 167 TQ, 117 HP...9 PSI

[leec]

Amazing power 

[Torben Alstrup]

Food for thought...Totally stock 1600, 167 TQ, 117 HP...9 PSI

Joel I think you need to check your calibration. Sometings not right.
Torben.

[Torben Alstrup]

found this cool thread again.
I didn`t have the time to update my single port engine so far but this winter it is going to happen!
I definitely want to use my Riechert dual 34 PCI setup. The heads are 1500 ccm single port heads with modified valve seats and modified stock valves (I think 35,5/32). Ports are opened to maximum possbile size when using the original copper sealing ring.

I am thinking about:
82x90,5
Engle W100 with 1,25 rockers
CR 9:1
Ahnendorp Customsport exhaust with 38 mm heaters
Shall I use bigger valves? Does that make sense at all with the 34 mm carbs? I think the venturies are currently 28mm.

If you stay with the 28 mm venturies I do not see any significant gain by enlarging the intake. The only thing you are likely to measure will be slightly better power below approx 2500 rpm. maybe 2800 since the engine has the ability to get into max flow sooner.
Retard the cam to 107 intake LC. At least that´s what i would do.

T

[andrewlandon67]

Man, I almost forgot about this thread! I never did end up building a big SP motor, but I bought a 1915 longblock that we'd had sitting around our shop for a while, fitting/powdercoating some tin for it, and running EMPI 44 HPMX carbs on it... still though, makes me want to get my old 1641 SP torn back apart and gone through, partially because it was a beast of a little motor, and partially to figure out what the hell cam is in it. With the jetting done in the Kadrons, the damn thing pulled its nuts off, right until 5k rpm, and got 30 mpg doing 75 on the highway without overheating. The best time I ever got out of it at the track was an 18.4 something at around 67 mph, in my full body/full interior '67 bug at 6000 feet altitude. Once I go through it, it'll have the ratio rockers still on it but with a stock carb, for simplicity's sake. Then it'll just have to wait until I find a good car to turn into my hotrod, so it can go back in the red car.

[MC Dyno Don]

 Lookin' Sweet  J.M.  nice numbers too..!! 

[Stevo_L]

i'm also building a new single port engine.
90.5*74 -> 1904ccm
35.5/32 manley valves, ported heads, shortened intake valveguides
9.5:1 comp.
CB 2239 cam  CB lifters
Riechert 34 PCI carbs
single pack exhaust 38mm

hope it will be ready this year 

[Joel Mohr]

Ya Torben, My Dyno IS a little tight(LOL)....funny thing, the single port with my kit makes almost 20 more LB/FT torque than the dual port...Hi Don! Thanks!

[modnrod]

Where's that damn "like" button again?
 

[Steve67]

thanks for your reply Torben. I will buy an adjustable camhaft gear and set the cam to 108° lobe center.

Stevo_L: keep us updated regarding your engine!

@ everybody: what crankshaft and con rods would you choose for this kind of engine? I guess I don't have to buy the real expensive stuff for approximately 100hp...

[Stevo_L]

thanks for your reply Torben. I will buy an adjustable camhaft gear and set the cam to 108° lobe center.

Stevo_L: keep us updated regarding your engine!

@ everybody: what crankshaft and con rods would you choose for this kind of engine? I guess I don't have to buy the real expensive stuff for approximately 100hp...

I will do my best

AA crankshaft and stock rods with new bushings and same weight.
Or AA crank with chevy journals and H-rods, fits a stock case with less modifications

[Stevo_L]

my heads befor and after

[Stevo_L]

my heads before and after
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[Steve67]

any news on your engine Stevo_L?

If been thinking about parts a bit.
I think I'll go for a CB performace 82 mm super race crank and super race rods with chevy journals.
I prefer 5,325 long rods so that the engine does not become to wide. I know longer rods would be nice as the ratio is only 1,65 but for the expected power output that should be alright.
Or what do you think?
Are Mahle 90,5 barrels and pistons worth the extra price compared to AA performance parts?
Can I use a new stock clutch or shall I go for something different?

best regards
Stefan

[Stevo_L]

Hey
only small updates.
tapered guides are in, chamber bored 2,5mm down to get stock width (74mm crank stock rods) and CR bout 9.5:1
next step is to cut the seats but my cutters are down, need to get new ones. Neway would be fine but i have to find a dealer to order.
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I had AA pistons and barrels in my old 2276, AA are also going in my new single port engine. cant say if the extra price is worth it 

82mm and 5.4 rods result in stock width, had it in my old 2276
with chevy journals you dont have to modify your case that much like with stock ones

dont know if the stock clutch is enough, i'm still thinking about what i should use 
a kennedy stage 1 will be more than enough i think

[Stevo_L]

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[Steve67]

thanks for your answer.
heads are looking good!

[axam48ida]

Here's my commuter and daily driver set up. 1600 single port, ports cleaned up, stock cam, with A1 1-1/2" header ran 18.48 in my 63 bug.i

[Stevo_L]

finally i received my neway valve seat cutters.
seats are on the outside of the valve, 1.5mm intake, 2mm exhaust.
heads are nearly done.
I only have to port the intake to match the manifolds and maybe cut the valves 30° on the lathe behind the seat.
and maybe open the cc around the intake valve, but then CR will be lower..   

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[Stevo_L]

machined CC around the intake valve close tot the cylinderwall
will be smoothed out with the small grinder
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[wph]

machined CC around the intake valve close tot the cylinderwall
will be smoothed out with the small grinder
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Your chamber cut looks very nice, is it possible to see a picture of the tool which was used ?
Depending of your valve lift I would add 30 or 35 degree wide top cut to your seat work.

Pekka   

[Stevo_L]

i used a 10mm milling cutter with a 5mm radius at the bottom
here you can see it. first test at an old head.
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unfortunately i have no 30° or 35° cutter
but there is also not much seat left at the top. I cut the seats to seal at the very outer side of the seat

for now i have the problem that my CCs are too small. only 43ccm
that will result as an CR to 10.4:1 (90.5x74, 1.2mm deck clearance)
i will open the CC around the exhaust valves too but not too close to the cylinderwall, because it will be too close to the spark plug
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[Torben Alstrup]

Dish the pistons.
T

[Martin S.]

Yes, while you've got the mill out, like mine in a bathtub shape to keep the squish bands intact. 

[Stevo_L]

I will mill around the exhaust and then we will see where the CR will be.
if it is still too high i will dish the pistons.

[Martin S.]

It was the same situation on my turbo. Here's a pic showing how far Steve went before dishing the pistons. Note he didn't go quite as far enshrouding the exhaust valve vs. the intake valve.

[Steve67]

I have similar issues with my 2110 single port engine. CC is now 49,5 ccm after machining around the valves.
Originally I was aiming for 9:1 with 1,2 mm deck clearance. That results in a 58 ccm cumbustion chamber.
I see no chances to create such a large chamber in a stock head, or what do you think?
Which maximum deck clearance and compression rate would be aceeptable for a street engine with 95 octane fuel?
I am not sure if the AA performace stroker pistons have enough material to be dished. What minimum wall thickness should I keep?
Thanks a lot for your input.

[brian e]

Last set of AA "B's" I measured were right at .250" thick at the piston face. I have cut a 7cc dish I quite a few with no problems.  I built a fixture to hold them in the lathe. They center on the machined lip under the skirt, and I hold them on with a dummy wrist pin drilled and tapped and a single bolt through the base of the fixture. I make my dish no larger diameter then the chamber bowl to keep all the squish bands intact. You will have to do the math, but a .070" deep dish, the diameter just smaller then a stock chamber will usually be about 5-7cc.  Since you have a mill you can also do an oval shape.  This was a 7cc dish. I believe it was .050" deep.  Just make sure the dish doesn't extend pass the squish flats in the chamber.  I did this one with a radiused single point flycutter.