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Stroker 170?
https://slantsix.org/forum/viewtopic.php?t=14115		 Page 1 of 2
Author:  marc426 [ Sun Aug 21, 2005 1:12 pm ]
Post subject:  Stroker 170?
Hello everyone! Has anybody tested the stroker 170? I don't remember what site it was on but it's one of the big ones about /6.
So it supposed to be a 170 with a 198Crankshaft. Should do 210CI at the end of the day.
Did anybody try this before? Sounds great but i'd like to know more about it.
Thanks for your answers.

Marc
Author:  Charrlie_S [ Sun Aug 21, 2005 2:44 pm ]
Post subject: 
It has been done. Pretty sure Doc Dodge has one. But for the life of, I don't see a lot of reason to do it. If you take a 198 motor and bore it the same as the 170, you get the same cubes. A 225 is bigger yet, with a comparable bore. There is a small weight saving with a 210 low blck as compared to a 210 tall block. The only other reason, I can see to use the 170 block, would be to tell everyone you are running a 170, when you really have much more (can you say cheat).
Author:  SlantSixDan [ Sun Aug 21, 2005 2:48 pm ]
Post subject: 
Quote:
It has been done. Pretty sure Doc Dodge has one. But for the life of, I don't see a lot of reason to do it. If you take a 198 motor and bore it the same as the 170, you get the same cubes.
Maybe I'm misreading you, but this doesn't make sense to me. All slant-6s came from the factory with a 3.40" bore.
Author:  argentina-slantsixer [ Sun Aug 21, 2005 4:19 pm ]
Post subject: 
I think Doc has a 260 CID stroker 225... not 170. You can't really add that much by stroking and overboring a 170.... that would be a 198 or a 225. What you can do is use 198 connecting rods on a 225 but that would make less displacement. I don't understand Charlie_S's post... I understand that /6 where fixed bore diffrent strokes and block height for diffrent displacement. (You can say: Dan's right... :lol: )
Author:  panic [ Sun Aug 21, 2005 4:54 pm ]
Post subject: 
Rod length has nothing to do with displacement.
198 crank in 170 using 170 rods will shorten the rod ratio from 1.925-1 to 1.568-1 - don't know why you would want to do that.
Author:  MJF [ Mon Aug 22, 2005 3:40 am ]
Post subject: 
Docs strokers:

http://www.slantsix.org/articles/stroking/stroking.htm
http://www.slantsix.org/forum/viewtopic.php?t=26
Author:  Charrlie_S [ Mon Aug 22, 2005 4:43 am ]
Post subject: 
Sorry, let me clarify what I meant.
If you take a 170 block and bore it to 3.5, and use the 198 crank, you get the same cubes as a 198/225 block bored to 3.5, with a 198 crank. Since the cubes are the same, why would you want to spend the time and money to do this. A 198/225 block bored to 3.5 and a 225 crank is more cubes.
Author:  argentina-slantsixer [ Mon Aug 22, 2005 8:48 pm ]
Post subject: 
Quote:
Sorry, let me clarify what I meant.
If you take a 170 block and bore it to 3.5, and use the 198 crank, you get the same cubes as a 198/225 block bored to 3.5, with a 198 crank. Since the cubes are the same, why would you want to spend the time and money to do this. A 198/225 block bored to 3.5 and a 225 crank is more cubes.
now I understand
didn't understand panic's post neither.... maybe I'm reading too fast or my brains' dead...
Author:  MJF [ Mon Aug 22, 2005 11:45 pm ]
Post subject: 
Quote:
didn't understand panic's post neither.... maybe I'm reading too fast or my brains' dead...
198 stroke 3.625" with 7" 198 rod, rod ratio 1.925
198 stroke 3.625" with 5,7" 170 rod, rod ratio 1.568.

Bigger the ratio is, is better = longer rod is better. Helps the engine rev more freely at upper rpm. And reduces engine wear.
Author:  relic-lover [ Tue Aug 23, 2005 8:52 am ]
Post subject:  ...
Quote:
argentina-slantsixer wrote:

didn't understand panic's post neither.... maybe I'm reading too fast or my brains' dead...


198 stroke 3.625" with 7" 198 rod, rod ratio 1.925
198 stroke 3.625" with 5,7" 170 rod, rod ratio 1.568.

Bigger the ratio is, is better = longer rod is better. Helps the engine rev more freely at upper rpm. And reduces engine wear.
The other thing Panic was pointing out was the displacement is
not dependent on the rod length - displacement is a function of the
crank throw and the cylinder bore.
Author:  marc426 [ Tue Aug 23, 2005 1:55 pm ]
Post subject: 
Thank you all for all these infos! Well, i understood that i'd better go with a 198 and rebore it or even a 225 rather than messin' with my 170. Am I wrong?
Author:  slantzilla [ Tue Aug 23, 2005 2:13 pm ]
Post subject: 
Doug had a 210 in the Barracuda race car that got wrecked. IIRC it ran low 14's on moder and 12:97 on da joos. :shock:
Author:  Charrlie_S [ Tue Aug 23, 2005 3:07 pm ]
Post subject: 
It will be less expensive to build a 225 to a given power level, then a 170. Also you will be able to use "off the shelf" headers, since no one makes headers for the 170, any longer.
Author:  SlantSixDan [ Tue Aug 23, 2005 6:44 pm ]
Post subject: 
If you're going to the trouble and expense of swapping the engine, don't mess with the rare and hard-to-find 198. The only reason to like the 198 is that it came with extra-long connecting rods that work well in high-performance 225 buildups. It may be strategic for you to keep your 170 (2,8 litre) engine with French taxes and gasoline prices. There's a lot you can do to make it run better...
Author:  Tim Keith [ Tue Aug 23, 2005 9:19 pm ]
Post subject: 
The 1.93 rod ratio with the 7" rods is like Formula 1 spec, supposedly 2.0 is ideal, I'm told, although some OEM Hondas are only around 1.48

What would be the rod ratio be with a 170 crankshaft in a 225 block, assuming you could find custom pistons/rods to allow for the OEM compression height ?

No reason to do destroke a 225, just wondering what the numbers might be.
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