I ported my head gasket...

[1bolt]

another person who thinks the people @ the car plant don't make mistakes. did amc design their engines to foul #6 due to low fuel pressure and poor heat control? Because I'm pretty sure that is a common problem with stock 4.0s.

No, its not a common problem.

apparently you aren't out servicing vehicles as a mobile mechanic for a living while periodically disassembling 4.0s for various reasons and noting mentally any significant info.... such as puckered #6 pistons more than any other piston. It's like I see a ton of subaru 2.5 cars are in a junkyard for burning down but not the 2.2 & 2.0s. Is the 2.5 prone to fires? The proof is in the pudding. The jeep just suffers from convection more than anything and the coolant is always @ a state of flash boil around the combustion chamber so instead of liquid carrying away heat you make vapor do it. Then you feed a fuel rail in series and think you keep the same injection amount across the board? C'mon you know you wanna drill holes in a "perfectly good" head gasket

Trying to ignore the fact that you're using anecdotal evidence (and even then ignoring that it sounds a little like you're just making up the anecdotal evidence) humans have whats called "selection bias" which often leads them to conclusions that they want to believe in. I know all about this, I've been on both sides of that coin. In relation to Strokers, there's the almost impossible task of educating Jeep enthusiasts about (for example) Horse power versus Torque, the "old blocks are better than newer blocks" nickle content thing (little to no difference), or a big one for me, disproving the notion that the 0630 and older heads "flow better" than 0331, because they designed the 0331 head with much smaller exhaust ports.

In your case you've done a mod, without any rigorous scientific testing or even rudimentary scientific testing, and when someone was skeptical you supported the idea behind your mod by attacking the competence of engineers who spent 50 some odd years evolving the engine, with no appearent evidence, and a "story" about your own supposed long time experience. Which sounds, If you'll pardon me for saying a little too convenient... Kinda like the kid in high school who did have a Girlfriend... she was just in Canada...

Jeep I6's don't tend to foul #6 plugs more than another there's never been a common thread observing this over the years here or on various other jeep community sites, and that is a good litmus test... But forgetting that for a moment: running hotter on one cylinder does not cause plugs to foul... just the opposite... Running hotter burns oil/fuel more completely.

That's not to say this mod might not be able to provide some utility under some circumstance or another unknown... that's just saying there's no good scientific basis to do it... until you test the individual combustion temps with 6 pyrometers before and after with normal head gasket, and modded head gasket and establish scientifically that the idea has some utility, then there's no point in doing it except possible as a rudimentary long term Guinea pig test, where you measure wear rates of each cylinder after the engine dies. Let us know how that turns out.

[1bolt]

the belt driven clutch fan will pull twice to four times as much air as ANY! electric POS fan, when the ambient temps rise you'll likely have over heating issues.

Jeeps tend to need the most cooling at times when a mechanical fan is pushing almost no air. A mechanical fan pushes the most air at high RPM's which is neither the Jeep power band, nor the usual expected operating range..

On the other hand when my high compression 4.6 that pings on low octane in hot weather is sitting in stop and go traffic, or idling over rocks: I am damn happy that my electric fan is blasting away at full speed even though the engine is at idle. In fact of all my Jeeps the electric fan equipped ones are by far the least problematic with heating/cooling. The ones with mechanical fans both tend to run hot in traffic especially if they were just running on the freeway before hitting the slow down.

Crawling along at low speeds is also common in 4 wheeling... Jeeps being by far the most popular wheeling rigs, you'll find a lot of Jeepers who are very convinced of the electric fan's usefulness. As far as the reliability factor goes... if you have a good quality solid state controller (I've burned out some cheapo's), I would wager that it and any electric motor of decent quality will outlast ANY "clutch" based fan. Electric motors are extremely durable... Especially compared to a viscous coupler in a fan clutch.

[IH 392]

My jeep does it fair share of stop and go traffic and has seen lots of rock crawling and TONS! of SAND time and the one and only time I recall it pinging was at 70mph on the freeway on a mild hill of all places?, must have been some CRAPPY! gas?, Jeep didn't seem to feel the need to put an electric fan on it and neither do I, and so far the OE clutch fan seems to still be pulling enough air at 14 years old and 153K miles, it hasn't ever offered to over heat once.

[Spliffotticle]

LMAO!!! You all did a lot of typing and I commend you. I said fouled #6 not plug #6. I apologize. I mean the WHOLE CYLINDER overheats and the aluminum puckers, creating microscopic hot-spots due to the new texture from the lack of heat dissipation, that aid detonation. But kudos to you all for the thorough replies. I was bored, sitting around wondering what I could post that would arouse intense emotional debates. I really do think I seen a picture of one that was custom ported where I drilled. It had blue silicone grommets and lining & stuff.

[Muad'Dib]

The bottom line is that the head gasket is designed to let coolant flow from the back of the head to the front. When you open up the head gasket to allow flow through the gasket, you disrupt this proper flow of coolant. This can not only create hot spots, but it can trick your coolant temp sensor into thinking that its much cooler than it actually is. Its not a good idea to run it this way and i dont think anyone would recommend it. If you feel confident running it that way, more power to you.. just dont be suprised when you run into HVAC, or cooling issues.

Also, in regards to running only the OEM fan, i would definetly consider getting it replaced or adding an electric fan.

To more throughly answer your original question, you will never find a gasket that has been set-up that way.

[Spliffotticle]

I will shoot everything with a temp gun to see what's going on but a clutch fan will not fit anywhere without redesigning my downpipe.... & that will be a cold day indeed because it was a PAIN to make. So, clutch fan=not an option. I agree that adding another electric fan might be a good idea but I haven't found a convenient place for it or even went over 210 to merit it.

[1bolt]

My jeep does it fair share of stop and go traffic and has seen lots of rock crawling and TONS! of SAND time and the one and only time I recall it pinging was at 70mph on the freeway on a mild hill of all places?, must have been some CRAPPY! gas?, Jeep didn't seem to feel the need to put an electric fan on it and neither do I, and so far the OE clutch fan seems to still be pulling enough air at 14 years old and 153K miles, it hasn't ever offered to over heat once.

You've been here a while surely you're familiar with the compression ratio/timing/heat related ping that some strokers experience, requiring higher octane, or fuel and timing mods. One of my strokers does this, due to being too cheap to spring for aftermarket fuel and spark management. It's high compression ratio + some summer temps sometimes require me to step up an octane grade. In any case, ping or not, I am much happier with an electric fan, the piece of mind alone is worth the mod... idling through an hour of stop and go on a 100* summer day with the needle never going over 190* the entire time with the AC on full blast is not going to happen with a mechanical fan.

[Spliffotticle]

Jeep didn't seem to feel the need to put an electric fan on it and neither do I

My stroker is in a 2000 Laredo. It came with an electric fan. Now I don't have room for a mech fan due to the downpipe from the turbo, as I stated, but in such tight quarters the mech fan simply doesn't move enough air for the required horsepower. I give it a big THUMBS DOWN.

[AlexTJ]

LMAO!!! You all did a lot of typing and I commend you. I said fouled #6 not plug #6. I apologize. I mean the WHOLE CYLINDER overheats and the aluminum puckers, creating microscopic hot-spots due to the new texture from the lack of heat dissipation, that aid detonation. But kudos to you all for the thorough replies. I was bored, sitting around wondering what I could post that would arouse intense emotional debates. I really do think I seen a picture of one that was custom ported where I drilled. It had blue silicone grommets and lining & stuff.

Both of my blown engines, OE 4.0 and Titan 4.7 destroyed the #5 piston. Does that mean it is a chronic problem? No.

I am curious just how many 4.0s you have seen with #6 issues?

In other news, anybody ever able to fit a Taurus e-fan on a TJ? I was literally less than a quarter inch away from having one, even after trimming the old fan bolts and the new shroud down to the minimum.

[Spliffotticle]

Both of my blown engines, OE 4.0 and Titan 4.7 destroyed the #5 piston. Does that mean it is a chronic problem? No. I am curious just how many 4.0s you have seen with #6 issues?

If you lose #5 again I would start looking for a 4 cyl. I have personally seen more than 4 #6 failures @ the junkyard alone ranging anywhere from subtle to obvious. The other pistons are typically not as bad. But I must be making up stories to piss of strangers

[Spliffotticle]

Belt-driven fan clutch will pull four times the air as any one of the two! POS machine electric fan, when the environment you may have a temporary increase in the problem of overheating.

Is that so? Then please share with us the cfm of a clutch fan opposed to an electric and the power required to use each one. I'm guessing....... that you're guessing

[gonridnu]

Not to enter the fray but mechanical fans do as a rule pull far more air than electrics. While I do not have data on jeep fans in particular the clutch fan on a Dodge turbo diesel pulls 12,500 CFM when engaged. If you have any doubts call the guys at Flexalite and quiz them. They sell both types of fans and their "opinion" is that there is no substitute for a mechanical fan on high horsepower street applications.

I think it comes down to the issue of if it works for your application than it works. Personally I like the way the XJ's are set up with both styles of fan as a redundant system. If either fails you can "survive" with the other.

One other note...water that flows over hot or cold parts at too fast a speed does not heat soak or give it's heat back. This is one of the the primary functions of the thermostat and it is not unusual to see engines in which someone installs a significantly lower temp thermostat actually suffer from increased cooling issues. Hot water that passes through a radiator at too high a speed will not cool and the inverse is true with regards to the block and head. Again, I'm not saying what you did is wrong as I have done similar stuff to race engines in the past. All I am saying is that increased coolant flow does not guarantee increased cooling.

now back to your regularly scheduled programming:)

[Spliffotticle]

In my case I think I will be better off. People have this attitude like "it was designed to be used like this blah blah" when the entire reason we have a forum to type on is because we applied parts from 2 engines that were not intended to make stroker babies. My porting was intended to allow just enough flow to keep the liquid dissipating heat instead of vapor. So far so good. The only thing I may need is an external oil reservoir & cooler so I can run a few more quarts. The turbo is so big it needs a bigger oil supply to not cook it.