Maybe, but I doubt you would ever notice the difference. For an engine like this you want to stick with catalog parts as much as possible otherwise the cost goes thru the roof. When you stick with catalog parts you only have so many choices for parts.
470 stroker shopping list
- Thread starter wingrider
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Maybe, but I doubt you would ever notice the difference. For an engine like this you want to stick with catalog parts as much as possible otherwise the cost goes thru the roof. When you stick with catalog parts you only have so many choices for parts.
wingrider
Active Member
I have been working a little with compression ratio calculators, and wonder of if I am putting in a number wrong. FYI, I am using Diamond pistons CR calculator.
With a flat top piston, should the number be positive or negative? Seems like the logical thought would be to make it positive, because it would add to the combustion chamber, correct?
With a flat top piston, should the number be positive or negative? Seems like the logical thought would be to make it positive, because it would add to the combustion chamber, correct?
LowDeck451
Well-Known Member
Not to derail, and may be of help to the OP but, since the favorite RAS 1.6 rockers are gone (or have been re-released, but are over $1K ?..) which rockers would you choose today for a build like this? Thanks.
If you are talking about a flat top piston with flycuts for valve relief, then yes, that is what it says in the instructions at the top of the page. Add the flycut (or dish) cc's as a positive number.
Compression Ratio Calculator | Tools | Diamond Racing Pistons
wingrider
Active Member
Thanks for the reply! Just wanted to be sure that I understood that to be correct.
I am currently waiting for a reply from Mahle to see about custom pistons, and if they say no, then I think I will go to the diamond piston with the -12.5 dish in them, and go with a 6.7” rod.
Need to get some pistons on the way so the machinist can do his work.
I am currently waiting for a reply from Mahle to see about custom pistons, and if they say no, then I think I will go to the diamond piston with the -12.5 dish in them, and go with a 6.7” rod.
Need to get some pistons on the way so the machinist can do his work.
The Icon piston is a good choice, and uses a 6.635" rod. They list it as a 468, instead of a 470, because they use a stroke spec of 3.910 vs. a 3.915, which gives the additional ci. It's a nice combination that makes good power with off the shelf parts. I believe the Molnar crank is a 3.915" stroke, so you just don't need to cut the deck as much.
Yep, agree, except I think it is a 6.535" rod.
Yep, I fat-fingered that one. 6.535" it is. Thanks for the correction Jim!
wingrider
Active Member
I am looking real hard at the Diamond racing piston with the -12.5 dish in it. Seems that would give it 10.5-1 compression with my thoughts of what to put on it.
I was filling up the commuter car the other day (diesel), and happened to look over at the E-85 pump. That got me thinking, wonder if I should make the boat run on the E-85? I do understand it has less BTU rating than gas, and at wide open throttle you burn more than the gas counterpart, but it is significantly cheaper here.
If that is a good idea, should the compression be a bit higher than 10.5-1?
Thanks again for everyone’s help!
I was filling up the commuter car the other day (diesel), and happened to look over at the E-85 pump. That got me thinking, wonder if I should make the boat run on the E-85? I do understand it has less BTU rating than gas, and at wide open throttle you burn more than the gas counterpart, but it is significantly cheaper here.
If that is a good idea, should the compression be a bit higher than 10.5-1?
Thanks again for everyone’s help!
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It sounds like you are trying to make your life more difficult, and expensive. Save the hard decisions for the cam, based on cruising rpm, and the the correct prop diameter and pitch.
If I understood correctly, you already have the crank and rods. A piston that fits that combination is all that's needed. Use the dished Icon IC839 for pump gas, and the flat top IC825 for the E85, with the Trick Flow heads, and move on to working on the cam and prop.
wingrider
Active Member
Don’t know for sure, but this barge will get pulled out each day, and there is a good chance that we won’t be going very far.
At this very point in time, all I have is the block. Everything else is up for grabs. If E-85 is a good option, I think the Mahle piston is what I would go with.
At this very point in time, all I have is the block. Everything else is up for grabs. If E-85 is a good option, I think the Mahle piston is what I would go with.
I do not think that E85 is a good option. I built a normally aspirated, single 4bbl 500" stroker with 13.5:1 compression, and ran it on E85. It made 928 HP.
I can get a small block street stroker to go over 600 HP on pump premium. I will never again build an engine for myself that I cannot run on pump 91 octane. No more E85 for me.
I can get a small block street stroker to go over 600 HP on pump premium. I will never again build an engine for myself that I cannot run on pump 91 octane. No more E85 for me.
LMAO! Sounds good to me as well but you know how people are!
Why didn’t you go to 500?
If that is the thought, why not go to 512, wait! Isn’t there larger? Why not go to the top?
Wait! Don’t do that ether!
You’ll get ragged on for not going to a aftermarket block for a 632 engine and you would be stupid not to right?
Isn’t there a way to go to a 755 cubic inch big block?
Why not?!?!
It’s only money and you’d be dumb not to do it right? Bigger is better!!!!
It’s only money! Screw it! Spend it!!!
You can make more!
In fact, according to the population here, not only are you shorting yourself a lot but not spending a few measly bucks more and not going to the max in developing your own big block that goes to 1,500 cubic inches is also a dumb thing not to do. After all, you wanna go gas and make power right?!?!?
NEVERMIND WHAT YOU WANT TO DO OF COURSE!!!!
I ain’t go the money, time and Patients to do weird stuff out of the box stuff.
Pump gas can do just fine!
wingrider
Active Member
Wow! Lots of power with that E-85 set up!
After looking over the compression numbers on the Mahle pistons, I come up with 10.37-1 compression. I should think that is low enough to safely run pump gas.
After looking over the compression numbers on the Mahle pistons, I come up with 10.37-1 compression. I should think that is low enough to safely run pump gas.
I'm thinkin' you did understand my point.
famous bob
mopar misfit
Gotta get you to quote outside the quote tags! ;)
wingrider
Active Member
Alright, took the advice of you guys, and ordered the IC839’s.
Guess that leads to another question. What ring set should I run? These pistons have 1/16-1/16-3/16 inch ring pack.
I have run Hastings rings in a couple of bikes, but never had the chance to go fresh with a V8.
Guess that leads to another question. What ring set should I run? These pistons have 1/16-1/16-3/16 inch ring pack.
I have run Hastings rings in a couple of bikes, but never had the chance to go fresh with a V8.
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You can run a low tension pack with around a 14-16 lbs oil ring. It will free up power, and won't need a vacuum pump at that level. I like the Hastings oil ring, but I prefer the Mahle/Perfect Circle rings with a Napier second. Either one will work well though.
wingrider
Active Member
Well, the plans changed a bit. I had ordered a set of Icon pistons from Jegs. They stated that they would ship directly from the manufacturer so I would get them sooner. I have gotten three different shipping notifications, and they keep backing up my ship date. My most recent email received today said that they would be shipped 3/19. Last one said they would ship 2/9. Hate keeping the machine shop holding my block this long. Ended up cancelling that order, and put in an order for some Diamond pistons. They are going to hopefully be here at the end of the week.
I have been wondering a bit of which cam I should be looking at. I figure a roller cam might be a good idea in the boat, but don’t want to get to aggressive with the cam grind. Anyone have any suggestions for me?
I have been wondering a bit of which cam I should be looking at. I figure a roller cam might be a good idea in the boat, but don’t want to get to aggressive with the cam grind. Anyone have any suggestions for me?
famous bob
mopar misfit
Same here !!
wingrider
Active Member
Yes, after reading a bit about E85, I have also come to conclusion that it would create some troubles down the road that I don’t really want to deal with. Locally, I can get 91 non oxy fuel, so that is what I am going to shoot for building this engine.
As far as the cam, I was once told that wet exhaust doesn’t like more than mid 220’s at .050 duration. I know the exhaust manifolds I am planning on using flow better than the old Chrysler logs.
As far as the cam, I was once told that wet exhaust doesn’t like more than mid 220’s at .050 duration. I know the exhaust manifolds I am planning on using flow better than the old Chrysler logs.
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