Forced induction Stroker help

[themonkeyman]

**I apologize in advance for the long post**

Hello all, I'm new to this forum, but not to jeeps. I have an 87 YJ with a 258 in it. I am planning to build a stroker with a supercharger on it. I know I may come across sounding like a power-hungry noob who does not know any better, but please take me seriously, I plan on doing this engine right, and have planned on an 18-24 month time frame and a figure somewhere around the $2 grand mark for engine only. I realize the SC will run me about another grand. I will likely install the engine and run it naturally aspirated to break it in gently while I assemble my SC kit.


Here's the plan: 4.8L supercharged~shooting for approx. 400hp @crank (yes I AM crazy)

I plan on running forged internals, (pistons and rods anyway), and want to run somewhere between 10 and 14psi of boost. I hope to find a 12CW crank in decent shape because I've heard that it is stronger, although marginally. Is that correct?

I plan on a CR of 8.5:1 to remain pump-gas friendly once boosted. I realize I will need to run a 0.00 deck clearance for best quench under boost. I will figure out if an intercooler is necessary once boost is closer at hand.

To get a 4.8L engine I know I will need to run a .060 overbore, correct? (if I come out at 4.7L I'm ok with that, not trying to go crazy overbore and endanger cylinder walls)

I will be using a block from a 93 Cherokee if it matters, and a 7120 head, with LS1 valves and roller rockers. I plan on a mild port job, I realize I do not need a super-high flow head since it will be a boosted motor. Are the Yella Terra's the only roller rockers made that fit the 4.0? The $500 price tag is a bit hard to swallow just for rockers...

My main issues are finding the aforementioned forged internals. I cannot afford to have everything custom made, so i need to know where I can find forged rods and pistons that will give me my 8.5:1 CR and a 0.00 deck clearance?

Thanks to anyone long-suffering enough to read through this entire post, and thanks even more to anyone brave enough to help me out! Seriously, thanks a bunch though, this forum is an amazing tool, i plan on learning all I can--Graham

[heartlandoffroad]

Hi first I'd like to welcome you to the board. It sounds like you got a good game plan and 400hp is not out of the question at all.

**I apologize in advance for the long post**

Hello all, I'm new to this forum, but not to jeeps. I have an 87 YJ with a 258 in it. I am planning to build a stroker with a supercharger on it. I know I may come across sounding like a power-hungry noob who does not know any better, but please take me seriously, I plan on doing this engine right, and have planned on an 18-24 month time frame and a figure somewhere around the $2 grand mark for engine only. I realize the SC will run me about another grand. I will likely install the engine and run it naturally aspirated to break it in gently while I assemble my SC kit.

I'd say the 2K mark might be a little shy. You will have $1000.00 in "PARTS" just for the head.

Here's the plan: 4.8L supercharged~shooting for approx. 400hp @crank (yes I AM crazy)

I plan on running forged internals, (pistons and rods anyway), and want to run somewhere between 10 and 14psi of boost. I hope to find a 12CW crank in decent shape because I've heard that it is stronger, although marginally. Is that correct?

I plan on a CR of 8.5:1 to remain pump-gas friendly once boosted. I realize I will need to run a 0.00 deck clearance for best quench under boost. I will figure out if an intercooler is necessary once boost is closer at hand.

To get a 4.8L engine I know I will need to run a .060 overbore, correct? (if I come out at 4.7L I'm ok with that, not trying to go crazy overbore and endanger cylinder walls)

I will be using a block from a 93 Cherokee if it matters, and a 7120 head, with LS1 valves and roller rockers. I plan on a mild port job, I realize I do not need a super-high flow head since it will be a boosted motor. Are the Yella Terra's the only roller rockers made that fit the 4.0? The $500 price tag is a bit hard to swallow just for rockers...

Yella Terra is going to be your cheapest rout Harland Sharp and Jessel make sets also.

My main issues are finding the aforementioned forged internals. I cannot afford to have everything custom made, so i need to know where I can find forged rods and pistons that will give me my 8.5:1 CR and a 0.00 deck clearance?

Use the Stroker CR Calculator to to get the numbers you are looking for.

Thanks to anyone long-suffering enough to read through this entire post, and thanks even more to anyone brave enough to help me out! Seriously, thanks a bunch though, this forum is an amazing tool, i plan on learning all I can--Graham

[themonkeyman]

Hey Heartland, thanks for the welcome and your reply.
I've been lurking on some of your performance-build threads, quite impressive

Does anyone know the specific dish volume and pin height of the Hesco pistons:

http://www.hesco.us/shop.asp?action=det ... catId=7569
*EDIT*

Just found these:
http://www.hesco.us/shop.asp?action=det ... catId=7569

I guess they are the correct ones for my application, but again, wondering dish volume and pin height. Plus, they're 10 bucks cheaper!



Also, the hesco "performance: rods, are they forged? For $479 i should hope so, but again, no real info. They are a 6.150 length, so pin height would need to be known before I can do any real CR/deck clearance calculations. If anyones got info, thanks.

Thanks for the tip on the roller rockers, I think they will most likely be worth the price. I realized after posting that the $2k mark was a bit low, considering just the short block will have a grand in forged internals bolted into it... Hehe we sure have an expensive hobby, eh?

Thanks again!

[heartlandoffroad]

Thanks for the compliment on my builds.

Here try this spreadsheet you should be able to build what you are looking for in this and it will give you some of the answers you are looking for.
http://www.editgrid.com/user/brewmenn/stroker

[themonkeyman]

That link just goes to a spreadsheet for a .040 over build with some really short rods. Is there a calculator hidden in there? I could not figure out how to edit anything or plug my build numbers in...

[hot_rod_hooligans]

That link just goes to a spreadsheet for a .040 over build with some really short rods. Is there a calculator hidden in there? I could not figure out how to edit anything or plug my build numbers in...

Same here, I want to go with a longer rod length, I'd like to have some way to start figuring out pistond dish and cam selection.

[RAPTORFAN85]

Hesco's pistons are 1.375 pin height. The HESDP40060 pistons are 24cc the other's I can't say.

Hesco's performance rods are regular 4.0 rods (6.123 length)
They machine the top balance pads down so the forged pistons will fit on them,
they also resize them and install ARP rod bolts.
They are kinda steep for what is at heart a stock 4.0 rod

[dwg86]

$479.00 For stock Jeep rods????? No way! I would buy these instead.
http://cgi.ebay.com/ebaymotors/ws/eBayI ... &viewitem=

Then have custom pistons made for your application.

[themonkeyman]

Hesco's pistons are 1.375 pin height. The HESDP40060 pistons are 24cc the other's I can't say.

Hesco's performance rods are regular 4.0 rods (6.123 length)
They machine the top balance pads down so the forged pistons will fit on them,
they also resize them and install ARP rod bolts.
They are kinda steep for what is at heart a stock 4.0 rod

Wow, I am apalled that they charge that much for basically a reconditioned stocker! Thanks for the info though, I thought maybe they were an 18cc piston, but my CR numbers kept coming in way high. Thats good to know. Stock pistons have the same 1.375 pin height, correct? I seem to think so.

So any other ideas for forged rods gents? I don't think I can afford a grand just for rods (about what I figure custom-made rods would cost) I know I don't trust stock rods--reconditioned or not-- at 12psi of boost. I'm gonna do some digging about maybe some ford or chevy rods I can bastardize into the AMC block.

Thanks againf ro teh info guys, LOVE the forum!

--Graham

[dwg86]

http://cgi.ebay.com/ebaymotors/ws/eBayI ... &viewitem=

[themonkeyman]

OK, so I found some SBC rods that seem like excellent candidates:

http://store.summitracing.com/partdetai ... toview=sku

They have all the right numbers (the pin hole will have to be opened by 0.004 for jeep pins to fit) Except I think the bottom end width is too narrow. They are for a SBC so I believe the bottom end width is is .940, which is far too narrow for the jeep crank. I doubt there are any shortcuts around that?

[heartlandoffroad]

Try this link now I think it will work now.

http://www.editgrid.com/user/heartlando ... CALCULATOR