392 Stroker Hemi Build

[Dynamic]

Well, I finally got Project Hemi on the road. It's got about 300 miles on it now, and I'm zeroing in on the final tuning of the engine. It definitely runs good, that's for sure.

 

I spent some time yesterday getting the rear ride height where I wanted it. I ended up lowering it exactly one inch. I may go another 1/2" or so, but it definitely looks better now than it did. The wheels and tires I put on it are a little larger in diameter, and whole lot wider than the stock size, so they fill out the wheel openings better.

 

Here are some pics...

 

 

 

 

Edited September 25, 2016 by Dynamic
Bad pictures

[Frankstein]

Nice work!!         will you try it on dragstrip?

[notlimah]

That looks good Jon! I'd love to see the looks on peoples faces when you lay into it during a race!

[Dynamic]

Not sure about the drag strip just yet, but it does run pretty good! Now I just need to concentrate on getting this transmission to shift well. I haven't done anything to it yet, but it's time! The gear ratios are great and work well with the Hemi, but the shifts...not so much! Time to come up with some valve body calibrations that work.

[Oceansky]

On Friday, July 08, 2016 at 10:23 PM, Dynamic said:

Nice ride...

 

It sounds like you have some decisions to make. If you want a 5.7 based 392, I would not hesitate to recommend the parts that I used. The one big decision you'll have to make, though, is whether or not you're going to run a supercharger because that will drastically affect the compression ratio you spec out for your build. With the pistons that I used, and the chamber size in the heads, my compression ratio is about 10.8:1. This would be quite high for a supercharged application. I would shoot for closer to 8.5:1 - 9.0:1 if I were going to supercharge mine. The lower the compression, the more boost you can run.

 

I don't believe the '07 Hemis used VVT, so camshaft specs should be easy. If you want that idle chop, you're going to want something in the high 220's or low 230's on both sides (duration at .050") on tighter lobe centers. This will maximize valve overlap, which gives that idle lope. But, it also drastically complicates tuning. Early 5.7 Hemi heads are happy in the .550"-.580" lift range, plus then you can get valve springs that work well and are affordable. I am using PSI LS1511 springs (which are a GM LS valve spring) on mine. My lift is .575"/.585". The other thing about camshafts is that a grind that is spec'd out for a supercharger is going to look quite a bit different than one spec'd for a naturally aspirated engine. I'm a big believer in custom ground camshafts. Get exactly what you want, not an off-the-shelf compromise...

 

As far as headers go, I haven't tried any yet, but there are a couple of Ram 1500 P/U long tube header sets that look like they may fit. It's a tight squeeze on a Durango/Aspen, especially on the driver's side, but I think the Dynatech headers may work. I'm basically a header snob, and only recommend stainless steel long tube headers. In my opinion, shorty headers are not worth the hassle. You still have to reconfigure the front part of your exhaust system to get them to connect to the rest of the exhaust system, and most offer little gain over the stock manifolds. Stainless looks good, last longer, and won't rust like mild steel headers will.

Hey guys,

 

I just came across this forum and I have to say that you dynamic provided me with some much more information then other forums I have read over the last few weeks. I just torn down my motor out of 06 dodge ram with 210,000 miles and ready to send off to the machine shop. Any advice on what to look for in the shop, questions I should ask?  I am looking to go with the 392 so I would like to copy your build. This will be my very first build so I will be taking it slow. (Mechanically inclined though) Any other advice for me that you could throw my way, I would appreciate it greatly. Also where are you located? 

[Mopar1973Man]

Dynamic is located in Newman Lake, WA. I would give him a call for information. His contact information is listed in the vendors area.

[Oceansky]

I appreciate your response..thank you 

 

 

[Dynamic]

What would you like to know about it? It cost a small fortune to build, but it was a fun project and it runs great. I'm still tweaking the tuning around a bit, but it's pretty close now.

 

I don't know what your skill level and equipment is like, but I thoroughly blueprinted this engine, including a VERY tight quench. So, you'll need access to equipment to very accurately measure deck height and piston protrusion (out of the hole) if you want to exactly copy my build. I ended up at a little over 11:1 static compression ratio.

 

You'll also need to be able to accurately degree whatever camshaft you use, and measure piston-to-valve clearance. Not doing this on a Hemi is really rolling the dice, especially if you use 6.1L valves like I did.

 

Anyway, this engine has about 6K miles on it now. I broke it in on standard oil for the first 1000 miles, and then switched to Mobil 1 synthetic like I do on all of the engines that I build. I literally uses ZERO oil, so that's always nice...

 

Jon

Edited March 5, 2017 by Dynamic

[Oceansky]

I would like to copy your build completely since it is different and would be easier for me being that you know exactly what you did if I am having trouble with anything. 

I don't have everything that is needed to measure the deck height or pistion protrusion, so I can buy all that or borrow from a friend who has a shop but would rather just buy my own. 

I started making the list of all the parts needed so I can get everything delivered. 

Where did you order from? I'm seeing that one place has the crank, rods but not the pistons. The rods/pistons take a. 927 floating pin correct? Not seeing pressed. What brand bearings do you recommend?  

Should I use the comp cam double roller timing chain? Did you buy a new cover or just clean up your old one? 

 Should I wait for all my parts then send block to the machine shop ? 

  Can I switch to a 6.1 intake or do I need to stick with 5.7. I'm not seeing a wire harness adapter to bring the throttle body towards the front. 

  As far as headers what did you go with? I have a set of stock srt but thinking about putting kooks long tube. Already spending 7-8 g so why not spend another 1300. I don't know if I am getting to far ahead with everything but I like to have my whole plan of action before starting so everything matches properly. 11:1 sounds perfect! This truck will just be to cruise around since I have my daily driver.   I appreciate your help with everything 

 

John 

 

 

[Reedsautoservice]

On 4/29/2016 at 10:20 AM, Dynamic said:

Several guys have expressed interest in a thread about the 392 stroker Hemi that I'm building. I figured I'd go ahead and chronicle everything the best I can.

 

I'm still waiting for some parts to show up, but here's the basics of what I'm doing.

 

The stock Dodge 5.7 Hemi has a bore of 3.917", and a stroke of 3.58", for a total displacement of 345 cubic inches...or 5.7 liters. I am having a little fun with this one, so I'm boring it .010" just to clean up the bore. I'll be using Mahle forged pistons specifically designed for the crankshaft and rods that I'm using. Speaking of crankshafts, that's where all of the fun will come from on this particular engine. Several manufacturers make a crankshaft for both the 5.7 Hemi as well as the 6.1 liter Hemi (they share the same stroke) with a stroke of 4.05". Why 4.05"...? That's kind of an arbitrary number, isn't it? Well, with a 5.7L block, bored .010" over, and a 4.05" stroke, the engine displaces exactly 392 cubic inches, and the same crank in a 6.1L block (also bored .010" over), yields a displacement of exactly 426 cubic inches... Both of these numbers are throwbacks to the Hemis of old...the old elephant engines.

 

Up top, I'm keeping the 5.7 heads, but I'm installing the larger stainless valves from the 6.1L's. Replacing the intake seats is something you'll want to do on ANY Hemi engine that you build because they are notorious for dropping them even when mildly overheated. There is not much of a press-fit from the factory, and they drop right out when they get hot enough. So, since I was having the seat replaced anyway, I had larger seats installed in both the intake and exhausts to accommodate the larger 6.1L valves. The OEM 5.7L valves measure 2.0" inches on the intake side, and 1.55" on the exhaust. The OEM 6.1L valves are 2.08" on the intake, and 1.6" on the exhaust. Plus, the 6.1L valves are much lighter due to the hollow stem on the intake valve, and the exhaust stems are sodium filled for better heat transfer away from the combustion chamber. I am using PSI LS1511 valve springs with Comp Cams spring locators to keep them in place at the bottom. These were both made for the GM LS engines, but work great in the Hemi after machining the top of the valve guide down to .510". Valve spring installed height is set at 1.8". These springs have exactly 135 lbs of pressure on the seat at 1.8" installed height. Perfect...

 

As far as the camshaft goes, the stock 5.7L cam is VERY small...! In the last Hemi I built (in my wife's Durango), I used a 6.1L SRT8 camshaft, which is quite a bit "larger", and runs very nice. On this build, I'm taking things a step further and had a camshaft ground with 221 degrees of duration (at .050") on the intake, and 227 degrees on the exhaust side. Lift is .575" on the intake, and .585" on the exhaust, and the lobe centers (LSA) are pretty wide at 115 degrees. This will help it play nice with the computer at idle.

 

So, that's what I'm building...a 392 cubic inch "stroker" Gen III Hemi engine with ported big-valve heads and a custom ground camshaft for an '04 Durango that I bought.

 

Pictures to come...