The Stovebolt Site Forums The Shop Area The HiPo Shop Odd six thought - 194, 250 crank, +E85?

I've been doing some thinking about my L6 parts pile. I have 3 complete 250's, one of which is probably good, and a 194. I got looking at the specs and had a bad thought or two.
If I put a 250 crank in a 194 then the total length of 1/2 stroke +rod +piston height would be .15in taller than stock. Anyone know what the stock deck height clearance is?
With that same combo, if I swapped my 250 head to drop the CR just a bit, it would look like I could run E85 (given it's antiknock properties). Any thoughts?

Here's another - 230 pistons in a 250. Increases the height by about .15 also. And then addd my 194 head. Any thoughts?

Guess I may need to get out the measuring tools and tear one down to see...

Never mind - you don't read it anyway.

E85 works best with boosted engines and EFI.

running the 194 head will increase the CR a bit. If your going to go thru the problem of swapping slugs, use 327 slugs and get a proper piston and CR

Not sure there is anything to gain by dropping a 250 crank in a 194. The difference between the 194/230/250 is the crank.

To efficiently run E85, that is to get power and mpg back, you need to increase the compression and the amount of fuel. Can you still run gas probably not.

IF you want to increase the compression in a 250, use 307 pistons. If you would like to find the compression height of a piston there is a Keith Blacks web site.

Larry

The objective is to raise the CR's until E85 can be run efficiently. It has 20% less fuel energy and is 10% lower in price so to be as cost effective I would need to get 10% more power. Given the packaging of the engine the best bet looks to increase the stroke (more time under the expansion curve) and the compression (more pressure in the cylinder).

I have a set of 307's for one of my 250 gas projects, but that won't let me up the stroke.

I'm up on the piston compression heights. What I don't know and haven't been able to find is the nominal quench height (ie how far the piston is down the bore).

Dropping the 250 crank into the 194 would get me more cubes, but what I was really after is a significant boost in compression. The concern is the added stroke will raise the piston .15" up the bore, and I'm not sure if there is enough space for that. If not I might be able to turn down the top assuming there is enough ring land. Ditto with using 230 pistons, the added compression height is exactly equal to the increase of stroke 230 to 250. So if I used the 230 pisons and turn down the outer edges (make them clsoer to flattops) I should be able to pick up the CR.

I have built several 250's, and what you're proposing is simply to make a 250 out of your 194. The 250 piston comes to within a few thousandths of the top of the block already, so there's simply no room to increase the stroke any further. 307 V-8 pistons are flat-topped, not dished like the 250 piston, and they are a drop-in swap. I have milled a 250 head .050", plus installed the 307 flat tops, and we were still able to run 87 octane gas. That gives a compression ratio of about 9.5:1, which is simpler, and much easier than trying to cobble together some oddball mix of parts that cannot work in the first place.
Jerry

Thanks, hotrod Lincoln, there's what I was looking for. So if the pistons are already high up the block then I would have to cut the pistons so much that I'd not have enough upper ring land. At that point I would have to buy custom pistons or rods which would negate the whole point of the low-buck crank swaap.

Would have gone and done some figuring but the motors are outside and at 15 degrees and 30+mph wind my enthusiasm for motor teardown and measuring was nil.

Guess I'll build my E85 motor with the 307 pistons and spend my time in the head area. Thinking I will use my small chamber 194 head to start the CR off a bit higher , then play with it from there.

Thanks again!

Do your homework on compression ratio first- - - -once the head is milled there's no going back.
Jerry

I hear you about milling the head. Part of the reason I was looking at the crank swap was the presence of 2 integrated head 250's in my collection, would have been nice to put the cranks to use without the added expense of a new head and intake system.

One of the reasons I was looking at E85 was its antiknock behavior. Once I pull out the pencils (OK, computer) I should be able to see what I want to do. From what I can find E85 should be OK to run up to the 10:1 area with no additives, particularly since I don't race it or tow with it (that's what the 5.3 truck is for - abuse!). Just looking for silly amounts of fuel economy in my old trucks.

I have run straight alcohol engines at 13:1, but we were looking for power, not fuel economy. A foot of blue-white flame out of the exhaust stacks generally means not all the fuel is getting burned in the cylinders, but they sure sound, and smell good with that much alky going through the engine! A flathead Ford V-8 in a 34 3-window coupe Dad ran on the 1/4 mile dirt tracks around Middle Tennessee got 8 laps per gallon! It ran Methanol with a healthy dose of Hydrogen Peroxide mixed in!
Jerry