SB Stroker....One more time

-
I built a 408 with the Eagle steel crank and Probe pistons. The Pistons hit the throws so it would be good to test fit before balancing. With stock Eddy heads Hughes didn't recommend a cam any bigger than the HER2228 hydraulic roller unless I was going to port the heads. The duration is only around 228/[email protected]. It works with power brakes too and was very streetable (4 speed 3.55s) . A more aggressive idle would have been nice.
 
Mad Dart said:
I thought ALL stroker pistons were dished??

I know if you only had 5cc for valve reliefs only and a 4.0 crank with a 65cc head your compression will be 11.5:1 or so
Click to expand...

Oops! Mad Dart, you are correct. I had to double check, I am in fact using a STEP DISHED piston installed at Zero Deck...

enginepic2.jpg
 
mopardude318 said:
Oops! Mad Dart, you are correct. I had to double check, I am in fact using a STEP DISHED piston installed at Zero Deck...

enginepic2.jpg
Click to expand...


Maybe I should rethink my decision on using flat tops and thus 11.6 CR. If you can make 533+ HP with Dished pistons.... That may be the way to go that way I can for sure use pump gas....

moper said:
...........You could also go dished but I think if you do the idle will be a little rough as even the smallest dish puts it down to 10.2. As far as the cam....
Click to expand...

Moper, Can you help me out with this comment you made? So if I go down in compression and keep the bigger cam in the 251/257 @ .050 range it will idle differently than with the higher compression. Sorry if this is a stupid question.....

Thanks again for all the help guys.....
 
If you are building a pump gas engine definitely go with the dished piston. I have the KB745 forged step dish pistons in my sb stroker. With pistons at zero deck, .039" head gaskets, and eddy heads milled to 62cc I have 10.3:1 compression. Without milling the heads it would have been 9.8:1 compression; probably would have run on 89 octane.
 
340sFastback said:
If you are building a pump gas engine definitely go with the dished piston. I have the KB745 forged step dish pistons in my sb stroker. With pistons at zero deck, .039" head gaskets, and eddy heads milled to 62cc I have 10.3:1 compression. Without milling the heads it would have been 9.8:1 compression; probably would have run on 89 octane.
Click to expand...


340sFastback,
Thanks for the reply. Can you give me the specifics about your build? Also, any results like dyno numbers or 1/4 numbers? How is the idle quality? Also, do you have to do anything special to install a retrofit hydraulic roller cam. BTW, I love your car! A Green Fastback RULES!!!

Thanks
Jamie
 
fishy68 said:
Oh, ok. Yes that can be an issue with them also but I have never seen one wipe a cam because of it. If their way off I could see it happening. I have seen them too tight and too loose though.

The XE series Comp Cams is fairly aggressive but not nearly as much as a cam can be for .904 lifters.
Click to expand...

ditto, engle has WAY faster grinds.
 
340sFastback said:
If you are building a pump gas engine definitely go with the dished piston. I have the KB745 forged step dish pistons in my sb stroker. With pistons at zero deck, .039" head gaskets, and eddy heads milled to 62cc I have 10.3:1 compression. Without milling the heads it would have been 9.8:1 compression; probably would have run on 89 octane.
Click to expand...

Bill have you ever tried 89 octane to see if it will run on it without spark knock? I've read reports from a few other guys that claim they have no problem using 89 octane on iron headed engines with over 10.5 to 1 compression. They had the quench set up good. I assume your Eddy's are closed chambers and pistons at zero deck??

Haney I hole you don't mind me jumping in here and asking Bill a question. I figured it's good info for you also.
 
Here are the IC745 Forged Step Dish Pistons I am using in the 318/402 I am working on now. They have a 20.5cc Dish in them with 62cc heads and a .039 gasket compression comes in at 10.20 static and 8.73 dynamic at zero deck.

349 stroker etc 004.jpg

349 stroker etc 002.jpg

349 stroker etc 004.jpg


349 stroker etc 002.jpg
 
fishy68 said:
Bill have you ever tried 89 octane to see if it will run on it without spark knock? I've read reports from a few other guys that claim they have no problem using 89 octane on iron headed engines with over 10.5 to 1 compression. They had the quench set up good. I assume your Eddy's are closed chambers and pistons at zero deck??

Haney I hole you don't mind me jumping in here and asking Bill a question. I figured it's good info for you also.
Click to expand...


No problem.... We are all here to learn and DROOL!!!! Good question.
 
Edited in case someone already read it...

"the MM lobe is the 904 grinds"
Yes, but they require the high idle speeds and if posible the EDM lifters to oil the face. Not really something I would use in a street car, and not a hydraulic lobe.

I'm not sure I agree that Engle has "way faster"... It's been a couple years since I spec'd one from them so I'll have to dig up the lobe catalog. The MM line is very fast for solid flat tappets, and the Xtreme Mopar lobes are pretty fast. I'll do some digging and start a new thread on it.

Haney, what I meant was by reducing the static ratio, and keeping the same intake closing point, the affect is the idle will be less smooth and the off idle response will be slower. I don't think you'd ever notice the slower response, but you will notice a full point of compression less. IMO, you are fine for pump 91-93 at 11.5ish:1 so long as you keep the quench at no larger than .039 and run an aluminum head. I thik if you drop the static to 10.3ish:1 you will be able to run 87 if you want, but you're leaving a little power on the table.
 
Haney said:
Can you give me the specifics about your build? Also, any results like dyno numbers or 1/4 numbers? How is the idle quality? Also, do you have to do anything special to install a retrofit hydraulic roller cam.
Click to expand...

If you go to my photo gallery here on this site I have all the engine specs listed:

http://www.forabodiesonly.com/mopar/vbpicgallery.php?do=view&g=1058

I have not taken car to track or chassis dyno'ed it because I jumped right into another project after engine was installed ('88 Mustang 2.3 Turbo) .

Idle is rough due to 108 lobe separation angle. When picking cam pay attention to the lobe separation angle because it has a big impact on idle quality. I have a 2500 stall and with timing locked at 33 degrees it is very streetable. While the idle is rough the off idle response is instant. I don't drive the car daily so rough idle is ok with me.

I had to grind a small amount off the lifter valley ribs on the block to clear the link bars. Very minor grinding and the lifters dropped right in. With the small base circle cam nothing else needed to be done. I did need to run a bronze distributor gear which was not cheap.
 
fishy68 said:
Bill have you ever tried 89 octane to see if it will run on it without spark knock? I've read reports from a few other guys that claim they have no problem using 89 octane on iron headed engines with over 10.5 to 1 compression. They had the quench set up good. I assume your Eddy's are closed chambers and pistons at zero deck??
Click to expand...

I have not tried anything other then 93 pump gas but I bet my engine would run fine on 89 octane. I have my cooling system in excellent shape so that helps too. Pistons are zero deck with closed chamber eddy heads, .039" gasket, so it has a nice quench.
 
You must log in or register to reply here.
-

Back
Top