TheSamba.com :: View topic

Mon May 12, 2008 9:41 am

Greetings -

Let's get something straight - I am not going to bore this motor. This will be a pure 85.5 stroker. Period. I really don't want to hear:

For the money...
Might as well bore it...
You can get into the high-13s if you..

Nope. Not interested. I merely need someone to do some math with me. Here's what I have to use on this motor. Let me also say that this motor will look stock when installed - single carb, etc.. again, I just want a stroke increase.

1) Stock DP heads 35*32. I will get these P&P.
2) I can get 85.5 "B" pistons from AC/N.

With those two factors, here are my questions:

1) How large a displacement will the P&P DP heads support?
2) Will a 34-PICT support that displacement?

In particular, I am looking at a 78.8 or 82 crank, because if I do some math, with "B" pistons, I'm coming up with:

78.8 (1810cc) - 69 = 9.8 / 2 = 4.9mm longer stroke up the jug, but the "B"s will shorten that by 5.67 for a net of .77mm shorter stroke up the jug. If compression becomes too low, I can get the jugs machined down.

82 (1883cc) - 69 = 13 / 2 = 6.5 longer stroke up the jug, but the "B"s will shorten that by 5.67 for a net of .86mm longer stroke up the jug. I can use spacers/shims to keep the piston from hitting the head.

So, is my math correct?

Thanks -

Mike

Mon May 12, 2008 9:48 am

visket wrote:
With those two factors, here are my questions:

1) How large a displacement will the P&P DP heads support?
2) Will a 34-PICT support that displacement?
Thanks -

Mike

Your math is correct.

I have ported and polished DP heads on my 2180, but I have larger valves.
You can put a 34PICT-3 on any size engine, but it linits the amount of air and fuel that will get it.

Remember that an engine is an air pump, the more air and fuel you put in the more power it will produce.

Personally I would not run a 34PICT-3 on anything more than stock. Lets face it, you can wake up a bone stock 1600DP just buy adding dual carbs... even small ones.

Mon May 12, 2008 9:50 am

No one makes 85.5 B pistons.

Mon May 12, 2008 9:53 am

Jimmy111 wrote: No one makes 85.5 B pistons.
I guess that's a problem.

Here's another thing to think about.

Run 100 yards and see how long it takes. Now do it again but this time you have to breath through a drinking straw.

Mon May 12, 2008 9:56 am

I checked. John does have them.... :shock:

Mon May 12, 2008 10:19 am

Nice! I love math. So I'm looking at either a 78.8 or 82 crank.

I would tend to agree that the 34-PICT might a bit short on breath. I'm not too concerned if the motor runs out of air after 4,500rpm, though. This motor will rarely see above 4K (my wifee-poo will be driving it..).

My method of madness: I was going to start with the 34-PICT and if it is too restrictive, go with an aftermarket 40 or 44 something-or-another. If it gets to that point, what opinions do we have on an aftermarket SINGLE carb setup?. Again, looking for grunt, not E.T.s.

Mike

Mon May 12, 2008 10:24 am

What is your goal here and what do you want out of it? I mean, well seriously not being an ars here but if you're dead set on all this then you really don't need anyones opinions cause your mind is set and thats cool. I'm with Glenn about needing more fuel, not only cause of the displacement but you're talking about P&P heads. I guess I just can't comprehend going through all that trouble to stifle the motor.

Mon May 12, 2008 10:36 am

visket wrote: what opinions do we have on an aftermarket SINGLE carb setup?. Again, looking for grunt, not E.T.s.

Mike
There's nothing like dual carbs. Even small dual carbs are better than a larger single carb.

Mon May 12, 2008 10:39 am

Hi -

I am merely trying to build a motor that will provide lots of grunt, and is a stroker, that looks stock. Please don't get caught up in getting every last bit of HP out of my motor. Please don't get caught up in the normal 1776/1915, etc.. I'm going to build a mild stroker.

If I absolutely need to, I'll put a bit bigger carb on it. The question is which aftermarket carb is streetable and breathes better than a 34-PICT? I suppose the question would be which single carb would work well on a 1776/1915, seeing as the 1810/1883 displacement is smack-dab in the middle of those two? Any experiences with any of these on a 1776/1915?

EMPI HPMX 40/44?
Dell 40?
Kadron?
Weber 34/40?
Zenith?
Holly 750cfm double-pumper?

Thanks -

Mike

Mon May 12, 2008 10:49 am

You can use the PICT 34. Not a problem. I ran one before on a 2332 and it ran just fine but had no power at all above 4000 rpm. If you are driving on the street only it is not an issue. But if you will drive on the freeway, there is no power at all for passing another car. Just make sure you use either the stock distributor or a SVDA.
My second choice is the Holly 750 double pumper. :shock:

Mon May 12, 2008 11:04 am

Thanks Jimmy -

We'll give the 34-PICT first crack at it.

I was also going to run a stock cam.

I have a couple stock dizzys and an SVDA hanging around, and I'll test those out to see which one behaves nicer.

Most of all - thanks for verifying the math on the crank/pistin combos. I'm probably going with the 82mm throw, seeing as thin spacers will be less $$ than machining down the cylinders.

Sweet!

Mon May 12, 2008 12:05 pm

I have a Weber 40 IDF center mount on my 1915 and on an 1835 and 1776 prior. I would recomend that. It takes a little tunning to get it right but once you do, it works like a charm. :wink:

Mon May 12, 2008 1:30 pm

honestly, with horsepower aside; duals will be way more efficient, and probably net you better gas mileage to boot. the whole single mount, carb runner thing is an achilles heel. imo.

Mon May 12, 2008 2:35 pm

I'm running a 1745 (76mm x 85.5) in my bay. Lovely torque increase. I daresay you're aware of this but in case you aren't, if you use stock rods you'll have to do alot of clearancing of case. Get H-beam rods and it'll save you alot of work.

The best thing to do with any single solex carb is to throw it in the middle of a very deep lake. With a well set-up pair of Dellorto 36's you'll get better performance and BETTER MPG TOO. I'm assuming US gas prices are going up at the same rate ours in UK are, why opt for the thirstier carb?

Mon May 12, 2008 3:35 pm

The reason for the single carb is to look stock. If I were worried about mileage, I would convert the car to electric.

Good point WRT the clearancing. Obviously, the 78.8 (1810) isn't going to be as bad as the 82 (1883). Would a 78.8 still require clearancing with stock length rods?

I would rather clearance the case than buy longer rods for torque's sake. Nothing a Dremel can't handle, or are we talking an air-tool?

How did you go about building the 1745? "A" pistons and cylinder spacers?

Mike

Mon May 12, 2008 4:49 pm

Run dual 34 ICTs, or dual 35 PDSITs.

Get it over with, We run dual 40 Kads on a 2332 motor, it has power, and gets at least 20 MPG HWY.

but is great around town.

Think about it, Kads or duals at that, were period accessorys/Modifications.

It will not look stock. it is already bigger, it will overheat cause of it being lean, might as well put something on it to help it out.

you seem to be stubborn, well get over that, my dad built this 62 with my mother in mind, and gas mileage, she isn't going to gun, it.

fior the money, keep it stock. you seem to be to stubborn to upgrade carbs.

I wouldn't run a stock carb on my 2109, I would at least run my dual 32 PDSITs off my fasty on this motor before running a single 34. You need to look at both sides, gas is at least 4.00 a gallon, do you want 5 MPG, or 20MPG?

Run duals you and your wife will be happier.

Mon May 12, 2008 5:00 pm

Nice. I have dual Dell 40s on my 2110 (with the upgrade kit, and vacuum, so my SVDA can work it's magic), and dual Kads (bigger vents and vacuum) on my 1915. Both work fine. Thanks.

Let's move on to what is important right now - clearancing for the 78.8/82. Is that something I can do with my Dremel? I've cleaned up case chaff with the Dremel - no problem - but will it have enough oooomph to grind away the necessary metal?

Thanks -

Mike

Mon May 12, 2008 5:18 pm

Buy a case that is clearenced, it will make life easier.

Mon May 12, 2008 5:50 pm

visket wrote: Nice. I have dual Dell 40s on my 2110 (with the upgrade kit, and vacuum, so my SVDA can work it's magic), and dual Kads (bigger vents and vacuum) on my 1915. Both work fine. Thanks.

Let's move on to what is important right now - clearancing for the 78.8/82. Is that something I can do with my Dremel? I've cleaned up case chaff with the Dremel - no problem - but will it have enough oooomph to grind away the necessary metal?

Thanks -

Mike

A die grinder with a selection of carbide burrs is much better, a dremel is a mosquito by comparison.

To clarify your desires, you are doing this for more torque?

You want more bottom end and want to use a stock carb?

I am intrigued at the persistance to simply stroke. If you are going to all the hassle looking for 85.5 b pistons, clearancing etc why not bigger bore and dual carbs?

Even duals and an exhaust and some head work would give the stocker a heap more go, possibly more than your stroked with stock everything else.

Not trying to tweak your nose, just asking.

Mon May 12, 2008 6:31 pm

Hi -

I already have a 2110 (82*90.5) and a 1915 (69*94). Both are big-valve, dual carb motors, and boogy woogy. They are fun and all that, so let's just say I have a hair in my butt for pure stroker. Fair 'nuff?

We were going so nicely when we weren't second-guessing what/why I'm doing this. I do want to continue on this virtual engine build, if I may. Last we left off was clearancing.

I will need to take the case in for the stroker clearance anyway. Will they know enough to clear room for the rods? Fredster (above) mentioned clearancing, but is that "more clearancing" than what the machine shop will do anyway? I don't recall needing to do any more grinding on my 2110, but then, those are 90.5 barrels.

Mike