505cui stroker - dished or flat ?

Posted By: smoke

505cui stroker - dished or flat ? - 08/04/12 06:47 PM

505cui - Stroker question:

I was reading that many people are happy with their 440source-stroker kits.
I�ve two of these sets in the focus:

One with dished pistons and the flat version.
Since I�m looking for the lighter one, the flat would be my first choice.
Does anyone know how much more grams the dished version has? They do not have this data on their page.
Secondly the alu heads I have are around 75cc. This will pump the cr to 12.3:1 with the flats.
Which is a �lil too much for a street-friendly ride I think. I�d be more happy with cr around 11:1 to 11.5:1

Should I get the dished version with 10.9:1 or taking the flats including thicker (0.60 or 0.80) gaskets ? Or do I run with the thicker gaskets in other problems?

thanks

Posted By: 383man

Re: 505cui stroker - dished or flat ? - 08/04/12 10:03 PM

I use these 440Source dished pistons on my 493. I also used Indy EZ heads that were 75cc and at zero deck with the flattop I was at about 11.8. With these dished pistons I came in around 10.0 I think as we cut the heads a tad to get 10.6 as I built it with quench and for pump gas. I believe the dish area is 24cc. 10.6 has worked good for me using pump gas. I prefer having a tad more comp with quench then less comp with no quench. Ron

Posted By: ahy

Re: 505cui stroker - dished or flat ? - 08/05/12 01:34 AM

It depends on which heads you are running. If you are using closed chamber aluminum heads, best is to set it up for .040" quench... meaning the top of the piston comes up within .040" from the head at TDC. The easiest way to do this is to set up the engine at zero deck: the flat of the piston comes right up to the top of the block deck. Then use a .040 head gasket to dial in the quench.

With this setup, you will need a D shaped dish to get compression ratio in the 10.0 - 10.5 range for pump gas.

A stroker almost always needs the dish to achieve a pump gas compression ratio.

Posted By: Cab_Burge

Re: 505cui stroker - dished or flat ? - 08/05/12 02:21 AM

Quote:

505cui - Stroker question:

I was reading that many people are happy with their 440source-stroker kits.
I�ve two of these sets in the focus:

One with dished pistons and the flat version.
Since I�m looking for the lighter one, the flat would be my first choice.
Does anyone know how much more grams the dished version has? They do not have this data on their page.
Secondly the alu heads I have are around 75cc. This will pump the cr to 12.3:1 with the flats.
Which is a �lil too much for a street-friendly ride I think. I�d be more happy with cr around 11:1 to 11.5:1

Should I get the dished version with 10.9:1 or taking the flats including thicker (0.60 or 0.80) gaskets ? Or do I run with the thicker gaskets in other problems?

thanks

My 518 C.I. 400 stroker has a set of Ross custom 22 CC dish(complete dish, not reverse domes) that where originally set up at -.025 deck height with 84 CC open chamber iron heads and a Fel Pro .042 thick head gasket, that ended up making 9.25 to 1 comp. ratio. I switched heads two years later to a set of Eddy RPM(closed chambers) with 84.cc,I also switched the crankshaft from 4.25 stroke to 4.300 to make the motor a zero deck with Eddy RPM heads, I later switched those heads to a set of Indy SR with 75 CC chambers, ended up with 10.78 to 1 comp. with a .054 thick Cometic head gasket. It is barely pump gas friendly using Oregon non ethanol premium

If I had to do it over I would start out with a reverse dome piston so I could get a decent quinch area in the top of the cylinders, not a complete dish piston

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 09:39 AM

Thanks for all of your input.

Yes the heads are indy 440 EZ opened to mw-size. They should have
75cc. But i'll check to be sure.

It seems that all of you are valueing the quench (this means going with heavier dished pistons) much higher than the weight advance of the flats (and using thicker gaskets).
Is there no way to combine flat pistons and quench in this stroker build? Machining the pistons? What costs to expect roughly?

________________________________
regards

Posted By: ahy

Re: 505cui stroker - dished or flat ? - 08/05/12 12:40 PM

I believe the dish will always be a little heavier than a flat top of the same basic construction.

Either one of these made in forged aluminum is much lighter than a factory original cast piston. The slight additional weight of the dish shouldn't be a limiting factor on your build in terms of RPM or power. The heads will be done by 7000 EPM max. The lighter piston will rev a little faster.

If you really want a lighter piston or want to dial in the dish size exactly or both you can go the custom piston route.

Ross, JE, Diamond and others will maked a piston to your specs. They also offer additional lightening operations to machine out all un-needed weight. I used Ross custom on my 496 a few years ago to get the exact compression height, dish size and compression ratio I wanted. At that time, a custom dish was +/- $700. I don't know the going rate today. Extra lightening operations could add $100-$200. I worked with Muscle Motors to spec out and supply the rotating assembly. MM prefered Ross at that time so that's what I used.

Posted By: Dodgem

Re: 505cui stroker - dished or flat ? - 08/05/12 03:04 PM

The flat tops have the same quench 0 deck them and use a .039 head gasket. so what cam converter and gears??

also what is the intended use?

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 03:40 PM

Quote:

so what cam converter and gears?? also what is the intended use?

@dodgem,

compcams suggested a hydraulic cam for maintanance reasons.
They offered: Thumpr�, 283THR7
Car will be 4 speed with 3,54 gears
street use, maybe once/twice seeing the strip.
slightly rough idle accepted

question: Is there an hp-advantage zero-decking vs. -0.015 "in the hole" ?

Best,
smoke

Posted By: MR_P_BODY

Re: 505cui stroker - dished or flat ? - 08/05/12 03:57 PM

Quote:

Quote:

so what cam converter and gears?? also what is the intended use?

@dodgem,

compcams suggested a hydraulic cam for maintanance reasons.
They offered: Thumpr�, 283THR7
Car will be 4 speed with 3,54 gears
street use, maybe once/twice seeing the strip.
slightly rough idle accepted

question: Is there an hp-advantage zero-decking vs. -0.015 "in the hole" ?

Best,
smoke

Being a street car I would run the dish piston at
0 deck, .039 gasket... that'll give you the quench
and your comp that you want... it would end up saving
you money(if you go with Felpro gaskets)... then if
you want(and probably should) you can advance the
cam for better low end power... which closes the
intake valve sooner on the piston stroke.... remember
that the static compression is just a math number and
the dynamic is when comp really starts so the CAM is
the big part

Posted By: JohnRR

Re: 505cui stroker - dished or flat ? - 08/05/12 07:48 PM

Quote:

Thanks for all of your input.

Yes the heads are indy 440 EZ opened to mw-size. They should have
75cc. But i'll check to be sure.

It seems that all of you are valueing the quench (this means going with heavier dished pistons) much higher than the weight advance of the flats (and using thicker gaskets).
Is there no way to combine flat pistons and quench in this stroker build? Machining the pistons? What costs to expect roughly?

________________________________
regards

Doesn't the source use KB Icon forged pistons ? With a little searching on the internet I find the KB Icon flat top at 577g and the dish at 592g , hardly anything to worry about .

You want to build the engine which your quench distance as close to .040 as possible. Bringing the pistons to zero deck and using a .039-.041 gasket is the best way to do it.

The HP difference won't be a lot difference, but the street friendly nature with available pump fuel is what your bigger concern seems to be so that is what you should do.

Posted By: 383man

Re: 505cui stroker - dished or flat ? - 08/05/12 08:45 PM

Is there no way to combine flat pistons and quench in this stroker build? Machining the pistons? What costs to expect roughly

You can build the same quench with flattops and dished pistons. Thats why the dished pistons are still flat on half of the top as thats the part where it will make quench which is the same height as the flattops. Problem is on some with certain cc heads you may have to much comp for pump with the flattops. I know I was close to 12.0 with my Indy heads and flattops so I had to use the dished pistons to keep the quench at .045 and drop the comp some as I am at 10.6. Now if I would have used 84cc Eddy heads instead of 75cc Indy heads I may have gotten away with flattops as my comp would have been lower. With the Indy heads I believe you will need to use the dished piston and you can have quench with a lower pump gas friendly comp. I believe the flattop piston will have your comp to high for pump. Ron

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 09:31 PM

Thanks for advising guys.
Will deck to zero and use the dished version.
15grams additional weight per piston ...fine with me.
Using a 0.039 gasket will set CR at 11.19.

Posted By: RobX4406

Re: 505cui stroker - dished or flat ? - 08/05/12 09:45 PM

That's a small cam for a 500 inch engine.

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 10:08 PM

@Rob

hmmm,... do you have a suggestion what might fit better?
Please keep in mind that i've to avoid a rough idle...

regards

Posted By: Dodgem

Re: 505cui stroker - dished or flat ? - 08/05/12 10:24 PM

Quote:

Quote:

so what cam converter and gears?? also what is the intended use?

@dodgem,

compcams suggested a hydraulic cam for maintanance reasons.
They offered: Thumpr�, 283THR7
Car will be 4 speed with 3,54 gears
street use, maybe once/twice seeing the strip.
slightly rough idle accepted

question: Is there an hp-advantage zero-decking vs. -0.015 "in the hole" ?

Best,
smoke

well o deck with a .039 gasket gives .039 quench -.015 gives a quench of .054 not quite as good.

that is a mild cam definately go dish!

Posted By: RobX4406

Re: 505cui stroker - dished or flat ? - 08/05/12 10:26 PM

You want to avoid a rough idle? Did you tell the guys that when they suggested a tighter lobe separation angle cam.

Smoother idle, get something cut on a 110-112 lobe separation angle. Straight out of the catalog, I'd run a XR280HR-10 or the 286 before a thumper.

Since you look to want a roller, I'd call an engine builder that can order you a cam. Brian at IMM, member ou812, can order anything from the comp master catalog and get something that will work to your liking. Probably for the same or less money than a shelf cam.

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 10:38 PM

@Rob

since i wanted a maintenance-friendly cam, they advice me
to go with a hydraulic flat tappet...
I told them : slightly rough idle accepted .....
so in the end they came up with the 287thumpr.

Ok, of course i'll not buy directly over the phone
without consulting the wise guys here

thanks

Posted By: RobX4406

Re: 505cui stroker - dished or flat ? - 08/05/12 10:49 PM

The 283thr7 you posted above is the roller version. I still wouldn't run a thmpr.

IMO, you've got a serious mismatch of parts for intended use. MW port heads and a mild hyd flat cam, under .500 lift, no thanks.

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 11:00 PM

@Rob

you are absolutely right: missmatch.
I'll give them a call on monday to get a better suggestion.
regards

Posted By: RobX4406

Re: 505cui stroker - dished or flat ? - 08/05/12 11:03 PM

IMO, you need a different head for what you desire. Std port window would serve you much better.

Posted By: Cab_Burge

Re: 505cui stroker - dished or flat ? - 08/05/12 11:15 PM

Do not go to a full dish piston, it will have no quench

Been there, done that, my 512 Ross pistons have a 22 CC full dish, they weigh 456 grams without the wrist pins and rings

I have bulit a few BB Mopar stroker motors over the years,a lot more stock stroke pump gas motors, more than I can remember accuretaly now

I have learned a few things along the way from past errors

Do the math on what CC reverse dome it will take to make your intended compression ratio with all your other specs., IE deck hieght, combustion CC and so on and go from there

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/05/12 11:35 PM

Rob,

i know what you mean, but it can be done and
maybe our taste regarding rough idle differs

That's what i call a slightly rough idle, and
this ride even has a 12:1 cr.
http://www.youtube.com/watch?v=lN9uEzqzdA0

Posted By: JohnRR

Re: 505cui stroker - dished or flat ? - 08/05/12 11:57 PM

Quote:

Do not go to a full dish piston, if it will have no quench Been there, done that, my 512 Ross pistons have a 22 CC ful ldish, they weigh 456 grams without the wrist pins and rings I have bulit a few BB Mopar stroker motors over the years,a lot more stock stroke pump gas motors, more than I can remember accureatly now I have learned a few things along the way from past errors Do the math on what CC reverse dome it will take to make your intended compression ratio with all your other specs., IE deck hieght, combustion CC and so on and go from there

Cab the source piston should be a D dish

Posted By: 440Jim

Re: 505cui stroker - dished or flat ? - 08/06/12 12:17 AM

Double check the exact part number you are ordering,
but this is a picture from the 440Source web site of their dish pistons. Good "D" shape with some quench area.

You can even machine some off the top (0.00-0.030?) to reduce the dish to customize your compression ratio (decking the block to match). But I think the 11 CR you mentioned is enough.

Posted By: Dodgem

Re: 505cui stroker - dished or flat ? - 08/06/12 12:32 AM

Don't forget this is a 505 cubic inch engine that has a habit of making everything act smaller including the heads! Cam will almost be like an RV stock 440 HP at best!

Posted By: smoke

Re: 505cui stroker - dished or flat ? - 08/06/12 01:04 AM

yepp, of course they gave me the wrong cam...
I checked several stroker-kit seller but found only
two that offer the lighter 7.100 rod version.
440source and musclemotors......
Will have to find out which one is the better choice.

regards

Posted By: Streetwize

Re: 505cui stroker - dished or flat ? - 08/06/12 01:53 AM

A well designed 'D' dish can actually Enhance power on a (relatively poor valve angle) wedge....provided you have full quench as well. One reason is it allows the initial combustion flame front to expand from the center of the cylinder. It also can allow the intake port/valve to get a little more room ( for the same static cr) on the opening ramp to work with with the slug coming up to and then passing TDC. My 517 is right at 12:1 with a JE 'D' dish.

No worries there and I like the 7.1 rod....but get that broomstick of a cam out of there!!

Posted By: RobX4406

Re: 505cui stroker - dished or flat ? - 08/06/12 04:29 AM

Quote:

Rob,

i know what you mean, but it can be done and
maybe our taste regarding rough idle differs
That's what i call a slightly rough idle, and
this ride even has a 12:1 cr.
http://www.youtube.com/watch?v=lN9uEzqzdA0

My idea of a mild idle is like most peoples idea of rough. That cam they gave you as a recommendation is a puppy dog in a 505.

If that video is acceptable, I bet that Hyd Roller in that video is in at least the 250 at .050 range which is more along what I would run in a street car. Many people would think that's a rough idle or not street friendly so when you say "mild" you get what comp recommended. Ask Streetwize who posted in here, I believe it's his engine build.

Posted By: 383man

Re: 505cui stroker - dished or flat ? - 08/06/12 04:49 AM

Dont know if you can get a good idea of my 493's idle in this vid. Its a solid flat tappet speced by Dwayne Porter and I love it. It has 264 & 270 @ .050 with a lift about .592. With my 1.6 rockers its about .630 lift and its a 110 LSA. I have it in the eng on a 106 centerline. Dwayne is very good as you could call him and talk to him. Let me know if you would want his phone #. I usually pick my own cams but I went with Dwayne because I wanted a cam speced for this eng and I know he could spec a better cam then me. Ron

http://www.youtube.com/watch?v=bYIM2HLaOI4&feature=related

Posted By: Twostick

Re: 505cui stroker - dished or flat ? - 08/06/12 08:53 AM

Quote:

Don't forget this is a 505 cubic inch engine that has a habit of making everything act smaller including the heads! Cam will almost be like an RV stock 440 HP at best!

It may act smaller but it won't sound any smaller. My 493 has an MP509 with the 108 LSA and it idles just like a 440 with the same cam, 1100 rpm and rough lol. 76 deg of overlap is 76 deg of overlap.

The difference 500 cubes makes is that it will still pull from idle and it is swinging over 500 ft/lbs by 2000 rpm on.

If idle quality is a concern I would go with at least a 112 LSA. 505 cubes with the compression ratio you are looking at is going to have eyeball flattening, 600 SEL crushing torque no matter what and that is what you want on the street more so than the max HP number that can theoretically be wrung out of your combo IMHO.

As for the original question, I vote for the reverse dome and zero deck with .039 quench. Mine are Ross -34cc IIRC and the CR came in at 8.97 but mine is a 4.15 stroke. Bobweight was around 2200 if memory serves. Runs just dandy on 87 regular hurling 4800 lbs of C-body around.

Kevin

Posted By: BSB67

Re: 505cui stroker - dished or flat ? - 08/06/12 12:23 PM

Quote:

@Rob

you are absolutely right: missmatch.
I'll give them a call on monday to get a better suggestion.
regards

Honestly, I would recommend not calling Comp Cam. You will only get a different answer. What confidence will you have in the second answer? The fact that they recommended what they did the first time should be evidence enough to not go back. Call a Comp Cam distributor that has committed himself to the sport. I have used and recommend Dwayne Porter, but there are several good choices, just ask on this board. The additional advice/information that you will get from a guy like Dwayne is priceless.

Posted By: bentwheel43

Re: 505cui stroker - dished or flat ? - 08/06/12 02:06 PM

I have a 512" kit with 7.1 rod and flat top its like 12.46 compression.My cam is the 306* street roller it has 185# pumping compression.With eddy75cc heads and 93pumpgas and 34*timing.It didn't run better at 36*and 110 racegas in fact the pumpgas ran better.

Posted By: Streetwize

Re: 505cui stroker - dished or flat ? - 08/06/12 02:30 PM

This is an agressive bullet Hydraulic roller 264/268@.050 on 108's in my 517....very similar specs to Ron's flat tappet.

http://www.youtube.com/watch?v=jd8GeXYYkKU&feature=youtube_gdata_player

I agree that The stroker can sound as nasty as the same cam in a 440, the difference is the off idle drivabilty and roll on power will be much better, kind of the best if both worlds.

Posted By: Twostick

Re: 505cui stroker - dished or flat ? - 08/06/12 03:50 PM

Quote:

This is an agressive bullet Hydraulic roller 264/268@.050 on 108's in my 517....very similar specs to Ron's flat tappet.

http://www.youtube.com/watch?v=jd8GeXYYkKU&feature=youtube_gdata_player

I agree that The stroker can sound as nasty as the same cam in a 440, the difference is the off idle drivabilty and roll on power will be much better, kind of the best if both worlds.

The only reason I installed a 2800 stall converter on mine was to cushion the drivetrain from the 1100 rpm idle. It drove away just fine with the stock converter and 2.76 gears.

Ain't displacement grand?

Kevin

Posted By: smoke

Re: 505cui stroker - dished or flat? Meanwhile cam-talk - 08/06/12 05:32 PM

@Bobby,Ron + all

thanks for all your input. Helps to narrow to find the goal!
I listened to some additional files on youtube and soundwise
it might go towards a 110LSA, here's an example i like:
http://www.youtube.com/watch?v=yKaf3QiUI6k
by the numbers:
http://rides.moparmusclemagazine.com/ride/1192716/supergoatsack/1977/honda/civic/index.html

it's a solid ... and i'm going for a hydraulic. Not sure if they are different in idle-sound.

How much will the torque-curve change comparing a 108 to 110 LSA ?

I also would be interested in knowing what differences to expect in torque and hp-curve compared a 112LSA with 4 advanced vs.a 108LSA