To stroke or not to stroke??

[Talyn]

Matching the ports eliminates turbulence and increases flow and there is no reason NOT to do it.

There is a reason not to do it. You will have no reversion dam left. That wouldn't be a problem on a perfectly tuned exhaust for the engine that provides good scavenging, but show me proof of a single exhaust system for this engine that show that. Most exhaust systems aren't even built for a stroker, but with the 4.0L i mind. Also, opening up the port that much without a flow bench and your just asking for problems.

 

[87manche]

you will need to do something about fuel, so larger injectors at least.

thta depends on the motor and how it was built. A cheapo stockish stroker does not need larger injectors. See my post above about 24# injectors fouling plugs and running like crap.

it was a good place to stop and swap plugs though. Yes, we MADE him come take that photo, at least he was a good sport about it.

 

[Talyn]

What was your AFR?

 

[87manche]

What was your AFR?

who knows, he didn't have time to really tune it before the crawl, but with 24# injectors it wouldn't run for crap, belched black smoke and fouled out a complete set of plugs. THe renix should have fuel trimmed it up, it seemed to with the 19# injectors, it ran great the rest of the weekend.

 

[Talyn]

THe renix should have fuel trimmed it up,

That is what I would think. Used injectors?

 

[87manche]

That is what I would think. Used injectors?

I'm not sure, but it didn't idle, and was way way rich. He slapped the 19lb injectors in friday night and it was a completely different motor saturday. With the 24lb injectors the IAC was disconnected just to get it to start, afterwards he hooked up the IAC and with the 19lb injectors it started, idled and accelerated great.

 

[Talyn]

I had tried a set of used injectors and it idled like crap. Turns out they were clogged. I knew they were going to be a problem when I opened the package and smelled stale fuel. Had them cleaned and flow tested. Still came out less than a new set.

 

[cruiser54]

There is a reason not to do it. You will have no reversion dam left. That wouldn't be a problem on a perfectly tuned exhaust for the engine that provides good scavenging, but show me proof of a single exhaust system for this engine that show that. Most exhaust systems aren't even built for a stroker, but with the 4.0L i mind. Also, opening up the port that much without a flow bench and your just asking for problems.

I just matched the ports to the gasket and tapered it in an inch or so at the most. The manifolds were quite close to the gasket size and required very little porting. I didn't hog the whole thing out all the way into the valves. It runs great.

 

[FlexdXJ]

Used injectors?

Not sure of the 24# were used or not. he had his GF bring a set of injectors when she came down the next day. That thing ran great after the injector swap.

 

[woodkrawler]

I'm running the Ford Blue 24lb injectors on my 4.7L. I've got about 350 miles on it so far and it idles very smooth around 800 RPMs. I did have the rotating assembly balanced so I'm sure that helps.

 

[xj bmx]

So i was reading on Jeepstrokers.com on injectors and its still a "never use stock on a stroker" and "im using stock" conflict.

You guys are saying the Renix ecu and fuel system should figure it out and make up the difference, Same with the H.O.?

Im going to be useing my 92 setup and such the block is also from the same era (53008405 Block, 7120 Head).

Another thing my brother is dumbfounded that our computer can figure out that there's a different injector in there, how does it?

It seems that as 87manchie mentioned a beefy build will work with a 24# and a more mild build will do with 19#s. Is this the seeming trend?

 

[Talyn]

Another thing my brother is dumbfounded that our computer can figure out that there's a different injector in there, how does it?

It doesn't sense there is a larger injector in there. It measures the exhaust for the air fuel ratio using the O2 sensor. It then takes the reading form the O2 sensor and adjusts the injector pulse width to get to the AFR it wants under most situations. But not at initial start, warm up, and WOT, which it uses a pre programmed map with some adjustment.

 

[xj bmx]

Ok, I got my motor Sunday, it is bored .030over allredy and does seem to have verry low miles. I'm going to have it checked for cracks an see how worn the walls are, Im hoping I May get away with not needing to bore and get new pistons, but thats prolly verry unlikely.

I also gave my friend/builder the low buck rockcrawler
build list and have him start finding the parts and such.

 

[dieselenthusiast]

You could always buy the Mopar Stroker, know it's done right, and feel safe with the warranty.

 

[Talyn]

If he is spending that much his best bet would be Hesco, not Mopar.

 

[dieselenthusiast]

If he is spending that much his best bet would be Hesco, not Mopar.

What kind of warranty does Hesco have?

 

[Talyn]

Don't know, but I haven't seen any proof of Mopar's warranty on their stoker. Besides Hesco's work is proven. You can actually talk to the people that build their engines on the phone.

 

[dieselenthusiast]

Don't know, but I haven't seen any proof of Mopar's warranty on their stoker. Besides Hesco's work is proven. You can actually talk to the people that build their engines on the phone.

I had the dealership look it up on the computer. They have the part # and the warranty listed. I'm sure Hesco does a good job, that's why they should offer a good warranty. I'm just saying if you're going to drop the coin, why not make sure it's done right and have a warranty to back it.

 

[Talyn]

How do you know that the mopar stroker is actually quality? Do you know anyone that owns one? Do you even know what is inside it? Any one can put a warranty on an engine, it does not make it good quality.

 

[kastein]

So i was reading on Jeepstrokers.com on injectors and its still a "never use stock on a stroker" and "im using stock" conflict.

You guys are saying the Renix ecu and fuel system should figure it out and make up the difference, Same with the H.O.?

Im going to be useing my 92 setup and such the block is also from the same era (53008405 Block, 7120 Head).

Another thing my brother is dumbfounded that our computer can figure out that there's a different injector in there, how does it?

It seems that as 87manchie mentioned a beefy build will work with a 24# and a more mild build will do with 19#s. Is this the seeming trend?

Talyn already covered the injector vs computer bit extremely well, so I won't.

My take on why it wouldn't idle well with 24# injectors is maybe at idle, so little fuel is required that the computer didn't have fine enough grained control of the injector pulse width to avoid running extremely rich. The slower the injectors pass fuel, the grainier your injector pulse control can be without losing precision on the amount of fuel you're actually injecting.

On the other hand if you end up running lean when you're really beating on it, you need faster flow injectors because the ECU can't make the injector pulse long enough to inject enough fuel.