Eagle project

[Dhaos]

This project is a little odd to say the least but it's how it came together.
1986 Eagle wagon with a stroker being bored at the machine shop with myself doing the heads and all the other bits. It has good paint and is rust free.
I have a rear axle from my amx I plan to swap soon and I have a 727 lockup transmission with a hughes converter already that I haven't installed because a loose converter with the 258 would be painful to say the least.

The stroker motor itself(which is what this site's about) is a 2005 block being bored 60 over with a 12wt crank, 4.0 rods, and the higher compression forged pistons from KB(945s I think?). The cam is the solid crane 238/248 at .050 profile 112 split. The heads have just been rough cut so far and are having nickel added to the floors, exhaust, and chambers by a friend before I port further. Depending on the shape of the chambers, I plan to angle mill it 1 degree as well. I will make the intake and header once I have the long block assembled and I already have the dimensions plotted, but I want to have the head finished to match as the 1.5 OD pipe fit inside the exhaust port already and the intake is much too small. I will definitely post measurements for my header for those interested in building one for an eagle.

I have an intake I'm butchering at the moment to get a flange out of(already has the injector bosses too if I don't mess it up too much).

There may be no real gain for doing the excess work, but it's fun nonetheless and there's a unique sense of pride that goes with making the parts, even if they're no different in power than the factory pieces. I will post pictures of the bottom end once the machinist gets finished with the bore/balance.

Any advice would be great as well, I don't know everything.

[IH 392]

Plan on running it on E85?

[Carl]

Very cool project. Do you have a plan for motor mounts for the 2005 block?

[I6FAN]

I like how you really opened up the exhaust port bowl, but be careful here as the pinch-point between the valve and bowl (spark plug side) there is a really thin area. Someone had a cut up head that showed this really good, but I don't know where I saw it? What do you plan on doing for the intake and headers; sounds like something custom???....Cool!

[Dhaos]

If I get a double post, I apologize, it didn't submit my last one.

To IH392, I do not plan on running E85; I know these engines are detonation prone but I believe I'm addressing what I know from the outside looking in to cure this problem. The bore is wider than the chamber and the heads are going to be filled quite a bit with metal as well as the cylinders beveled to 4" at the top from the machinist to lose the sharp edge. I also know these engines overheat and I haven't addressed this issue yet but I know there are many radiators and water pumps that would assist me here. Lastly, I believe the intake manifold does not distribute air evenly in the current design and I hope to address this making a manifold that is hard to explain.

To Carl, I have read that the block needs to be ground a bit and plates made for the pumpkin, I planned on lifting the front and this would fix two problems at once.

To I6FAN, I'm not porting much to the center of the cylinder despite the port being biased towards the center of the chamber as air doesn't generally like to flow along the center side of a port. If the exhaust port was to the outside of the chamber like the intake, I believe it would flow much better but there is a nice head bolt in the way or a water jacket.

I plan to make the intake and header. I've made many sets of headers and it's not as complicated as it is just time consuming measuring over and over. The primaries will be 1.625 stepped to 1.75 with merge collectors I've already had made for this application. I also plan to use a termination box so I can run mufflers. The intake will be swept over the valve cover with the throttle in the front similar to a supra design(with longer runners of course). The overall header length will be 41 inches from the valve and the intake will be 24.5 inches from the valve to the trumpets in the plenum.

[Dhaos]

Attached is a picture of the collectors, I may bring them down slightly smaller than 2.5" as with 3 cylinders evacuating exhaust on a 720 cycle lends itself well to scavenging on it's own as every 240 degrees a cylinder is pushing exhaust and with my cam at 248 at .050(solid making it pretty much 240 anyway). Most engines that aren't American V8s have collects 2-3 steps above the primary size in race trim instead of the typical huge collector made for V8s. This is a large reason I chose this cam above others that were available along with the LSA. Splitting the intake in halve will really help the idle characteristics and lend itself to 2 types of resonance tuning, but the layout is a mess; I'm up in the air on this idea and any advice is welcome of course. I have the aluminum on the way and I'll show how I make the intake as well. A 2x4, rebar, and a mallet do wonders for making good runners.

[I6FAN]

What exactly do you mean by "megaphones and termination box"? Dual or single outlet? Don't see too many custom header apps on these 6 cyl engines. I noticed down in Australia there is quite a bit of 6cyl popularity like with the Ford 250 crossflow.... One thing I see that I wonder how it would do on a Jeep engine is what they call a Try-Y header arrangement; three sets of two (1&6, 2&5, 3&4 pairs 360 firing degrees apart) connected to one. Anyway enough of my rambling, will be watching your thread!

[Dhaos]

A megaphone is just that, a pipe that expands from 2.5-4.5 inches etc. It prevents the air from reverting up the pipes. There is much debate on their effectiveness, but I've seen them work when there are a lot of curves in the pipes where the air on the short side will go backwards. This will be a dual outlet without an x-pipe. A tri-Y header would be interesting to see. I might build one up if I can get a jeep body to get measurements from as I'm annoyed enough with measuring how close I have to get 2 pipes out above the front diff already.

A termination box is simply a large enclosure that acts like open atmosphere. If the headers have collectors tuned to a certain length, having them enter a large chamber(a gutted truck muffler for example) will act like "open atmosphere," and as long as the exit is large enough to allow the air out without a restriction there "shouldn't" be a loss of power, only the added weight and your ears thanking you in the end. V8s use 8-10 times a cylinder displacement per bank if running them. I attached a picture for a basic example I found.

[I6FAN]

Okay, that's what I was thinking. If you want more info on that try-y, theres a "extractor" company down-under called Pacemaker headers. Their the ones I see with that configuration. They also make the three front and three rear into one like most everyone here uses. I'm thinking it may be more of a street system where by better for top end(???)....anyway thanks for sharing.

[Dhaos]

I checked them out, that's a pretty nice design. It looks like it would work well for 99% of jeep applications and scavenge quite effectively. Mine is more of an RPM dependent design that targets a single RPM, so it's not for anyone here really. I got the pipes in today, but as you can see in the picture, they sent 16g on the 1.625 instead of 18. I know this may not sound like a big deal, but the inside diameter is 1.495 and I also attached a pic of a 1.5 OD pipe that I have inside of a port , so the proper pipe diameter will need less work with a punch(fyi, all headers on the market are 1.5od pipes for this motor, that I could find anyway). It wouldn't be so bad if I hadn't already waited 2 weeks for it. Even ups hates 29 Palms. Still waiting on aluminum and the machinist is waiting on bearings.

[Dhaos]

Wow, it's been busy at work. Just got the parts back from the machinist. The head ended up warping from the welding(even though it was in a furnace). Adapt and overcome, I'll need another head though. The block was bored .060 with a loose wall clearance and fine cross hatchings for the chrome upper ring I'll be using. The crank cleaned up at .010/.010 which surprised me. Pistons are the Keith Black forgings with higher compression pressed on 4.0 rods. The rods and pistons were balanced separately before the crank was balanced. I plan to assemble it after I bevel the cylinders to prevent hot spots(and help put the rings in ). Now, the waiting game again for locating another 91-95 head and getting the right pipes.