4.0 stroker part 2

[Joopin]

Well I got an estimate for the stroker from my mechanic today... 2800 bucks. A basic rebuild is 2000, a remanned is 2400, and hes estimating 2800 for the stroker. He said he would be giving me a brake (usually does) because I do so much work with him plus he would like to put this proceedure on his "list of stuff he does" He has done strokers but never a 4.0.

One of the reasons it will be that much is beause he has to get some parts machined. He is talking about decking the block (snitty mentioned), boring it out .060 over, and the engine has to be reballanced. I would have to pay a core for the crank not to mention other stupid little stuff that add up.

This is a big decision for me, I do have the money, but I will be without my jeep for almost 2 weeks. I was thinking of just waiting till the rebuild got absolutley necessary too... One thing is I never acutally got it checked out to see if the rings are actually bad... I will be performing a compression check on it this week, what psi should I be looking for? Is there any other things I can check for to know it needs a rebuild?

Anyways, what do you guys think, should I do it? I wish I could do it myself but I don't have the time or place to do it.

one more question, the rated 180 HP of the 4.0, is that at the flywheel or rear wheels?

 

[jeepin916]

Transmission fluid is lookin' ugly

flywheel most manufactures rate there HP at the crank or flywheel cuz thats the true power of the engine, and after the power is transfered thru the drive line about 30% is lost due to heat and friction, but with a stroker and the right parts you can make 250 to the wheels easy

 

[Snitty]

warn winch cover

yeah... the 4.0's rated power is at the flywheel...

there really is no reason to go .060 over... but... a bore is a bore, and you usually pay the same amount... i just always prefer to leave some wall in the cylinder for future builds... then again... you'll pay the same for the extra cubes, and it will be the second life of the engine... so it might not be a bad idea if you want that muscle...

if you do deck the block, i would suggest getting a thicker head gasket or low compression pistons to keep the compression down so you can stay on pump gas, and save the engine life.

i'm about ready for a rebuild myself... when i'm ready... i'm goin stroked

 

[Joopin]

Well I'm thinking I will just go for the stroker, its only a paycheck and a half more! Snitty, the research I did said to get a thinner gasket actually (.043) to keep the compression up. My mechanic looked over everything I found and he said it all makes sence, I just have to go find that gasket from jeep, injectors (24psi) from ford, and a fuel pressure regulator from ford.

I actually never even had my engine checked to see if it need a rebuild... I am going to do a compression check this week, and if it works out I will just delay this project till it's necessary... there are other things I need to do to the jeep besides this.

 

[redrooster]

So what does he say he is going to do for the $2800? The whole thing..in and out.
What all do you have to do? swap crank, new pistons, new rods, bore it, deck it, rebuild kit, what else?
Are you going to have the head reworked? Might as well port it if so. Porting is not that big a deal.

 

[Snitty]

i dont' know why you'd want to have the compression up... the stroker itself brings the compression to between 9.5 and 10:1.... you don't want it any higher than that, or you're gonna be paying a lot for expensive gas... then... if you deck the block down, you're raising the compression again... i'd say to go with a thicker gasket, but a GOOD thick one that won't blow out... but... if you are ok with running the compression high, it WILL give you more power... just work a few extra hours of overtime to keep the gas in the tank

 

[jeepin916]

Call All 258's..

hehehe overtime for gas hehehehe

 

[Joopin]

Redrooster, 2800 is for everything, the machining, parts, and labor. I don't know if he was going to port the head, I know he does a valve job in the estimate.

Snitty, one of the sites I found about the 4.0 stroker mentioned using a thinner gasket... but now that I think about it, perhaps it is thinner gasket OR deck the block... hmm. As for the cam, there is one recommended for the job, I got a part # for a Comp Cam.

 

[Junkpile]

Lower Control Arms

What do you mean there is a cam recommended for the job? What job? Who's recommendation? The cam makes or breaks the engine. Second to the cylinder heads, it is the most critical element to a properly matched combo. Considerations for picking a cam are the operating range that YOU intend to drive in, final gearing, vehicle weight, engine compression, and at least ten other major things. You can build an engine that makes awesome power, but if you stick it in a vehicle that isn't setup to take advantage of that engines power producing characteristics(which is for the most part determined by the cam grind).....you're just pissing in the wind. Call Comp's tech line, they are a very helpful company. Don't just order a part number, call and ask questions. Have info such as compression ratio, gearing, weight......handy when you call.

 

[Snitty]

i'm much with junkpile there.... you're gonna have to find where your operating rmp range is in your most used conditions. gotta know what part of the range you want your powerband... it would be best to find what the specs would be AFTER the rebuild, compression ratio, total displacement, valve diameter, flowrate of the head, flowrate of the injectors, type of exhaust, type of intake... it can all factor in... the cam controls the flow of everything that goes in/out of the cylinders, it is good to know what else will be factors in that flow

 

[Joopin]

I'm not just pulling ideas out of my arse here... I want to do things right the first time more than anyone. This is one of the sites I was talking about earlier http://www.jeep4.0performance.4mg.com/stroker.html look about half way down the page and it states:

Stroker engines need a longer duration than stock camshaft to maximise horsepower and torque. Click on the image to the right to go to the CompCams catalog.
The aim is to produce maximum torque over as wide an rpm range as possible. Stroker engines built with a compression ratio (CR) of about 9.5-9.6:1 will derive maximum benefit from these camshafts:

Crane #753905 204/216 degree cam
CompCams #68-231-4 206/214 degree cam

A stroker built to a CR of 8.8:1 that'll run with 87 octane fuel will benefit from a shorter duration dual-pattern cam for more low rev torque:
Crane #750501 192/204 degree cam
CompCams #68-115-4 192/200 degree cam.

Also www.accuatepower.com states

Cams are stocked in two durations: 250°/260° and 260°/272°. Both have .456/.484(5)" Intake/Exhaust lift.

There are a couple of options out there so there is a decision to be made when the time comes. The RECOMMENDED CAMS listed above have been used before I will just have to narrow things down. I think by calling these companies and the lifetime experiance of my mechanic with building engines, we can make the best decision for a cam.[/url]

 

[redrooster]

I'm afraid I don't know enough about Jeep fuel injection to be much help. The GM system I have on the 360 uses a MAP (manifold absolute pressure) sensor to determine the vacuum in the engine. As I was saying, a cam can change the vacuum and cause problems in the fuel injection. I was getting a check engine light set off by a code that represented low vacuum due to the cam I have. It was telling the computer to turn the ignition off at random times. This made it stall at low RPM's. It took many chip flashes to correct the problem.
Make sure you ask Comp Cams about the effects it will have on your fuel injection. If you don't ask, they may assume you are going to carburete the engine.
Somebody with more Jeep fuel injection experience needs to chime in on this.
I'm all for the Stroker. They are bad to the Bone.

 

[Joopin]

Well when and if it is done, it will be done correctly... the guy doing it is one of the best I have found in the area. Now I just have to figure out if I want to do it. 2800 is alot of money. I bought the jeep for 3200!

 

[Snitty]

A stroker built to a CR of 8.8:1...

that is pretty low compression for a stroker... you'll have to use low compression pistons, thicker gasket, possibly dish the head, or a combination of such to keep it that low.. that is right about where the stock 4.0 compression is

 

[ecor]

Stick with the research that you have done. The more that you talk to those who have done it the room for error there will be. As for the parts in comparison to the rebuild parts there are quite a few and the jump in cost seems about right. As for decking the block I wasnot sold on it. When I talked it over with Hesco they really did not seem keen on doing it unless you where trying to get out a couple of extra pony's. I don't know if I would go all the way to the 60 over either. Snitty is right, if something goes wrong later you will have some room if you go with the 30 over. Also you will not gain that much for the difference in Bore. As for the cam stick with the crane cam, that one is being used by many for this app and that cam ws produced as a hesco knock off. Hesco is the one that made the original kit for Jeep, I think he knows what he is talking about.

 

[redrooster]

HESCO definitely knows what they are talking about and they make big bucks for it. I'm surpised they didn't charge you $1.99 per minute to talk to them. They make the Mopar fuel injection kits and are pioneers in building Jeep motors as well as anything else you can throw at them. They also make the larger diameter throttle bodies for Jeep and superchargers for the 4.0 and 2.5L. I have been in their shop and talked with Mr. Hurley when I had fuel injection problems. He know his stuff. They are pricey though. If you can get him on the phone to divulge info then take advantage. They'll make the money up on one of those high dollar Ferraris I saw in the shop.

 

[ecor]

I guess thats the advantage of being a business ower, we were talking shop. Very helpful guy, and definetely knows his stuff..

 

[Joopin]

What are you saying, you called this guy at HESCO and picked his brain about the stroker? Give the number up! I need some professional advice and it looks like you found it. I actually just emailed JP magazine and asked them to do an article on building a 4.0 stroker.

 

[ecor]

(205) 251-1472

 

[Joopin]

Thanks dude