Another 4.6 Build

[4point6]

This project started when my 1997 Cherokee had a major overheating problem. The Jeep is your basic run of the mill '97 XJ - 4x4 with a 4.0L with automatic transmission. The motor had about 194,000 miles on it at that point, and was starting to get tired anyway. Basically the top radiator hose developed a leak - I kept driving to a convenient place to stop. In that extra mile or 2, some major destruction happened. I must have lost a whole lot of coolant, as the head gasket went, head warped, and 2 of the pistons were destroyed (#2 and #3):



Sorry about the picture size - still trying to figure out how to insert photos. Note pieces of ring (?) embedded in the piston top. There is a hole behind the top and middle rings about 1/2" diameter at both #2 and #3 pistons. As one might expect, this lead to a main seal leak. Moral of story - don't drive an overheating engine. Anyway...

After pricing out and almost buying a 4.0 long block ($1,600), I came across Dino's website, and started to look into building a stroker. My rough first estimate was $2,000, so I figured for an extra $400, it was worth a shot. This will be a DD, mostly highway time, but still a little off roading here and there. Right now it is bone stock, but it will see a lift kit one of these days...

So my build looks to be similar to Sean's build. I don't have all the details ironed out yet, but here are the basics:

258 crank w/258 rods
Silvolite 2229 dished to 26cc
deck block about 0.040 (depends on head cc)
Quench around 0.050
0.043 head gasket
older stock cam (the one thru '95 or '96)
CR = 9.1:1 +/-
99+ Intake swap
63mm TB
Exhaust = ?? - 2.5" min diameter
MAP adjuster

I'll post a parts list in the near future. I plan on using the stock injectors (23.2 #/hr) for now - we'll see how they work out.

I think I have all the parts now, except waiting for TB to arrive in the mail.

So far, engine is out of the car, disassembled, and block is at the machine shop. The head (0630) was way too warped to reuse (would have required like 0.026 planing to eliminate the warp - not good for CR). Luckily the machine shop had a spare head (7120) that he sold to me cheap. He is also the source for the 258 crank and rods (heavy style - 12 cwt). Some notes on the heads: 0630 head casting is much cleaner than the 7120 (at least the 2 I have to compare). 7120 has a lot of casting seams in the ports and bowl area. 0630 head ports and bowl are much neater, no really obvious casting lines. Regardless I will be doing a port/polish job on the head. Port job will be limited to matching the intake to the head (head has larger dims). No gasket matching. I am working on the head now - I want to finish that up, so I can cc it and figure the final decking req'd for the 9.1:1 CR.

Another note on the intakes. I had read that the 99+ intake manifold has smaller ports. My quick measurement comparison vs. the stock 97 intake shows the exact same measurements for the ports. I guess the 99+ intake gets its extra power (??) from the runner design.

[mecompco]

Another note on the intakes. I had read that the 99+ intake manifold has smaller ports. My quick measurement comparison vs. the stock 97 intake shows the exact same measurements for the ports. I guess the 99+ intake gets its extra power (??) from the runner design.

I am under the impression that the improvement comes from the runner design as well as the significat increase of internal volume (4300cc vs. 2600cc).

[seanyb505]

What you are looking to get out of your engine will play a huge part in whether or not you want to use the older style camshaft. Consider this: the 96 makes the same power as the 95, but lower in the rpm range. Some fun figures:
91-95 - 190hp @ 4750 and 225 lb/ft @ 3950
96-99 - 190hp @ 4600 and 225 lb/ft @ 3000

If you are going for a racing engine in which you will see high rpms frequently, you may want to look at the earlier style if you are going with stock. Since you said it was mostly DD and a little offroading you might be happier with the 96+. If you get a lift later and do more offroading you probly will be much happier with more usable torque down low. When I was told this I didnt really believe it and was sure that with more duration and lift the 95 stick had to be better. After a little more research and planning I went out and bought beefier version of the 96 cam.

[4point6]

Sean- regarding the new vs. old cam choice:

It was pretty much toss up between the two. I ran a bunch of scenarios using Engine Analyzer. I was using it more for trends in performance changes, vs. comparing exact torque and HP numbers. I got the stock 4.0 modeled pretty close to published numbers, then made changes from that model. Anyway, this first graph is a stock 4.0 with a 91-95 cam as "current" and the 96-01 cam as "last results":



Pretty much what you had said, older cam peaks out at higher RPM.

Then I ran it again as a stroker, with mods I plan to do. Again, 91-95 cam is "current", 96-01 is "last results":



Now there may be a fatal flaw in my runs, but I liked the older cam because HP kept going a little longer, and peak torque was a bit higher. The newer cam had a slight advantage in the lower RPMs for torque, but not a by a whole lot. HP difference at low revs was negligible. Agreed that I won't be spending a lot of time above 4k, but nice to know its there.

Like I said in the beginning, I could have gone either way with this choice. Not a whole lot of difference between them at lower RPMs for the stroker, also I didn't want to spend alot of $ on a new cam.

Which cam are you going with? I still have time to change my mind...

*edit* just saw you are using an Isky 13315/26

[seanyb505]

Yeah, I like to think of it as the best of both worlds. It has an asymetric pattern god for torque, have higher lifts for hp. Or so I like to think in my mind.

[4point6]

Got my bored 63 mm TB in the mail yesterday:



I ended up getting it from Jeff at Leigh Performance Machine. $90 plus core, turn around was super quick too. Quality was very good; the butterfly valve fit is really tight. Here is his link if you are interested:

http://www.strokedjeep.com/tbody.html

Not as cheap as the $60 ebay guy here (http://www.jeepstrokers.com/forum/viewt ... a&start=10, but at least he gives you a TB back for your money

Now I just have to finish up the port & polish on the head, and cc the chambers. Then I can calculate how much the machine shop needs to deck the block, and get them going on finishing the block and valve work. Hopefully next weekend will be assembly time...

[Shark]

id like to see those HP/TQ curves for some of the aftermarket cams out there. is there a linux version of that program?

"atleast they send your TB back to you". exactly.
you didnt spend the extra 10 bucks to powder coat it?

[fedrusion]

What is the sowtware you used to produce those curves? Very interested in seeing it.

[Muad'Dib]

What is the sowtware you used to produce those curves? Very interested in seeing it.

It shows it in his screenshot .. aka Engine Analyzer from Performance Trends:

http://www.performancetrends.com/EA30.htm

I have the Pro version in warez form if your interested in illegal sofware

[4point6]

you didnt spend the extra 10 bucks to powder coat it?

I ran the powder coated TB in Engine Analyzer, and it didn't give me any HP increase.

Not sure if there is a Linux version. Check Muad'Dib's post for the link.

I had run a few different cams, I'll try to post some more graphs when I have more time.

[fedrusion]

I had searched for it but didnt find it. Thanks for the link.

[4point6]

I got the header and intake manifold recently, here are some photos. I got the APN header to replace the cracked original one. You can't beat the price (about $150 including shipping):



Collector diameter is 2.25":



Primaries are 1.5":



Primary lengths range from 8" to 15" (+/-). For now I'm going to keep everything stock from the header back, until I get some more $$ for a cat back and high flow cat. I'll probably try to take the kink out of the stock down pipe now though. Not sure how though.

Also I am going to use the 99+ intake (picture was taken before removing the TB to be bored):



I'm using the KB 2229 pistons, to be dished soon at the machine shop:





Hopefully I'll finish up the port/polish this weekend, and then get everything back to the machine shop Monday, so next weekend I can start putting everything back together...

[Flash]

What is the sowtware you used to produce those curves? Very interested in seeing it.

It shows it in his screenshot .. aka Engine Analyzer from Performance Trends:

http://www.performancetrends.com/EA30.htm

I have the Pro version in warez form if your interested in illegal sofware

This is the on that i us.........kinda pricey, but i like it!

http://www.proracingsim.com/dynosimmainpage.htm

[seanyb505]

I just had the machine shop check my 2229s to make sure they were think enough to use from being cc'ed to 28cc, and they said they were actually 30cc, and still thick enough to use. So you have some room as far as how much you need them dished. Food for thought.

[4point6]

Well the machine shop didn't finish their work last week, so hopefully next weekend I can build. In the meantime, I installed some white face gauge overlays from here:

http://www.whitegauges.net/whitegauges_ ... sID=118203

Their 2000-2001 kit also fit my 97.

Should be good for some extra speed :