| From | Message |
DaKarl
Dodge Dakota
JOIN HERE
6/16/2005
21:29:56
|
 Subject: Factory specs?
IP: Logged
Message:
I'm doing some stuff to my 1989 3.9L Dakota and I'm wondering about a few things about the truck...
1. Is the valvetrain ductile iron?
Are they "oilers"?
2. Is cam part# P4452808 (.410 lift) from Mopar (they seem to have only new parts, not for my gen 1 Dak)
3. Any good places to find the rare 1.7 ratio rocker arms?
4. As I will be doing a lot of adjusting, are the gaskets for the valve covers reusable from the factory?
5. Is a 5.2 L throttlebody recommended and, more importantly, is it just bolt-on?
6. Just for fun... I have no cat., should I run the hose into the air intake?
Any info would be appreciated as there's very little out here.
|
gen1dak
Dodge Dakota
JOIN HERE
6/16/2005
23:04:00
| RE: Factory specs?
IP: Logged
Message:
1. The rockers are stamped steel. The shafts are steel. My '89 has oiling lifters with hollow pushrods.
2. Yes, it's from Mopar Perf. Intake lift is .410, exhaust lift is .425. The recommended springs are P4286813.
3. Good luck. Let us know if you find them.
4. Typically not the OEM cork-style from pre-Magnum days. They are cheap, however.
5. The 5.2 is a direct bolt-on because it's the same as the 3.9. Save your money. The only upgrade is the 5.9 throttle body and computer. Mostly a bolt-on, but you need to enlarge the intake manifold opening to clear the larger throttle blades for best results. Nothing you can't do in a hour with a Dremel or other grinder.
6. No. You should cap the air injection system and at least remove the belt on the air pump, if you don't want to remove the pump.
|
gen1dak
Dodge Dakota
JOIN HERE
6/16/2005
23:08:18
| RE: Factory specs?
IP: Logged
Message:
Primary oiling is through the heads and through the rocker shafts. In the lst version of the pre-Magnum (LA) the oiling lifters and hollow pushrods served only to lube the pushrod cups in the rocker arms. In the Magnums, all rocker oiling is handled through the lifters and pushrods.
|
gen1dak
Dodge Dakota
JOIN HERE
6/17/2005
16:21:26
| RE: Factory specs?
IP: Logged
Message:
Primary oiling is through the heads and through the rocker shafts. In the lst version of the pre-Magnum (LA) the oiling lifters and hollow pushrods served only to lube the pushrod cups in the rocker arms. In the Magnums, all rocker oiling is handled through the lifters and pushrods.
.......that is.....In the LAST version of the pre-Magnum (LA)........
|
DaKarl
Dodge Dakota
JOIN HERE
6/17/2005
19:31:19
| RE: Factory specs?
IP: Logged
Message:
Ok, so the factory valve train is stamped steel oilers. I'm assuming that the 3.9L is the last pre-mag. The theory behind needing a 5.2 TBI is that headers and an air filter will lean out the mixture. However, I do not have the headers on yet, and it's extremely rich (I can smell the gas). I'll test it after the valvetrain and headers are installed to see if I need to bore out the intakes.
Thanks again, gen1dak!
|
gen1dak
Dodge Dakota
JOIN HERE
6/17/2005
19:45:19
| RE: Factory specs?
IP: Logged
Message:
The 3.9 started as a pre-Magnum, then became a Magnum in 1992. I get what you're saying about the TBI upgrade, but I'm saying the computer and TBI for the V6 and 318 are the same. You will see no improvement or greater ability to adapt to mods with the unit from a 318. You'd have to get the 5.9 TBI/computer. This is just like the 273 V8 and 318 V8 sharing the same carburetor way back when. If it's rich now, you have other issues that need addressing. Sounds like you need a new O2 sensor.
|
DaKarl
Dodge Dakota
JOIN HERE
6/17/2005
21:51:39
| RE: Factory specs?
IP: Logged
Message:
I have a feeling the truck was all stock when I got it, save for the tires. Since I got it in 2004, a few things may need to be done. It was kept in great shape otherwise. I think it may also be eating/leaking oil a bit, but not much. Once the air/fuel mixture is recalibrated, I suspect a gain in performance. It's "fine" right now, but every little bit helps. Oh well, as long as it starts in the Canadian deep freeze, it's OK.
I read somewhere else that the 5.2 TBI has larger injectors, so it would just have a larger fuel throughput. In theory, I would just replace the injectors and keep the rest of the TBI.
|
DaKarl
Dodge Dakota
JOIN HERE
6/18/2005
02:21:03
| RE: Factory specs?
IP: Logged
Message:
Hell, maybe screw the TBI and sensor crap. I was just reading the 1987 Dodge Dakota thread. They may have a point... the carbeurator setup seems to be the way to go. Only problem is the cold climate here. They are a pain because they have to warm up. I'm just rambling, but the Buick I had ran pretty decently, even for a POS with a carbeurator. I MAY get the carb setup for my truck, but there may be more to it than just replacing the TBI with a carb. It would be more simplistic to keep the engine tuned up with a carb.
Any comments?
PS... The Gen1's front ends are OK by me... they look kinda mean and off-road, but simplistic too. That's probably just me.
|
gen1dak
Dodge Dakota
JOIN HERE
6/18/2005
23:14:57
| RE: Factory specs?
IP: Logged
Message:
It's the same to do it...(a carb and intake).. for the '89. Well, if an automatic, you'll need a switch to flip and activate/deactivate the overdrive since the computer won't be handling it. As for the GenI front, people having an opinion is one thing. The rediculous part is how bent outta shape when they get a "right back at ya" tossed their way. The comment didn't even bother me. As I recall, the common refrain was that the angled front end wasn't an improvement.
On cold weather startup, a good solid ignition is the biggest factor. Adding the Edelbrock Performer will net quicker warmups (for the intake flow) since the aluminum transfers heat much more quickly.
|
DaKarl
Dodge Dakota
JOIN HERE
6/19/2005
00:39:10
| RE: Factory specs?
IP: Logged
Message:
Ya, I have that overdrive switch on the dash. I use it to downshift and when I want to accelerate really fast. I assume that the trans. will still kick down if I mash the pedal.
The sensor BS can drive some to insanity, but as they say, if it ain't broke, don't fix it. If it doesn't cost too much and does prove to be better performance, I'll go for the "old school" approach.
I probably will get a new ignition system, as I said before, it's probably stock. That could be the reason it's running rich. I'm assuming that that will be worthwhile, as the body and interior is in great shape. I'll probably hang on to it for another 10 years, assuming I don't total it. It has only 180 000 km on it.
Just for some advice, what carb would I replace the TBI with? Damn, I"m lazy!
See you in a bit.
|
gen1dak
Dodge Dakota
JOIN HERE
6/19/2005
19:49:02
| RE: Factory specs?
IP: Logged
Message:
While Holleys and Demons are great performance carbs, they tend to be quite a bit more difficult to sort out unless you're well-versed in such things. If I were buying right now, I'd snag an Edelbrock AFB or AVS, depending on how much I wanted to spend. The revived AVS (originally the Carter AVS of the late 60's) and the AFB (also a revived Carter model) are beautiful in form and function, and much easier for most to tune. The AVS is more costly...it's only been on the market from Edelbrock for a couple years. I currently run a Carter Competition Series 750 AFB, which incorporated all the improvements Edelbrock touts in their versions.
|
DaKarl
Dodge Dakota
JOIN HERE
6/19/2005
23:19:29
| RE: Factory specs?
IP: Logged
Message:
I'm almost to the point of thinking of just rebuilding the engine. However, being so old, I have to ask myself: is it worth it? I'll just see how much the carbs will run me up (assuming that is all I have to do). Chances are, if it's just a bolt-on type of operation, I'll probably get one for the time being. Depending on the truck's disposition, I may have it rebuilt and ported and polished. Then it would be with me for sure for quite a while... but that's down the road.
|
gen1dak
Dodge Dakota
JOIN HERE
6/20/2005
01:24:18
| RE: Factory specs?
IP: Logged
Message:
Ummm, this is on a V6? That may be a problem. Locate an intake manifold for carburetor use. I don't know if MP still carries them. If you can snag one, your biggest problem will be behind you.
|
DaKarl
Dodge Dakota
JOIN HERE
6/20/2005
18:50:58
| RE: Factory specs?
IP: Logged
Message:
OK, yeah it's a V6. I hope the cam is a V-6 model, too. The motor is a sturdy unit, but it could use a little more effeciency. As I said before, a carb is a lot more easy to tune and doesn't involve costly sensors. I'll call MP (Mopar Performance, I presume) and see if they still carry the cam (if it's the right one), the rocker arms, and carb&intake manifold. I'm guessing it doesn't matter what carb I use as long as it doesn't flood or starve the engine.
Then, according to the prices, I'll buy the stuff. I'm not in much of a hurry as I have headers on the way.
Thanks, again, gen1dak!
|
gen1dak
Dodge Dakota
JOIN HERE
6/20/2005
22:17:01
| RE: Factory specs?
IP: Logged
Message:
Correct cam. I just see so many similar posts, kinda forgot it was a V6.
|
DaKarl
Dodge Dakota
JOIN HERE
6/23/2005
23:10:12
| RE: Factory specs?
IP: Logged
Message:
I'll be using the info on this forum to see what's available in my area tomorrow. Let's hope and see if the Canadian market's OK...
|
DaKarl
Dodge Dakota
JOIN HERE
7/01/2005
06:35:42
| RE: Factory specs?
IP: Logged
Message:
Well, I have 1\2 headers on, going to finish up today and see the jump in HP and torque.
If needbe, I'll get the 1.7 ratio rockers from the more abundent 318 product line with appropriate pushrods.
As for the carb, I bought some new sparkplugs and will be putting them in after the headers. There is a week wait for the high temp wires, but the stock wires should be able to put up with headers for a week. They're angled so I can keep them away easily.
I'll see if the truck will be running rich after that. I believe that the O2 sensor is somewhere on the exhaust pipe, or on the manifold\header on the '87 models. Anyways, I will see how much those things cost and see if a carb is a better choice, becuase, to be honest, smog stuff sucks and it makes my engine compartment a jungle. As it stands right now the smog pump is just pumping air into the manifolds. What is the point of that?
Well, I'm keeping you posted. We'll see tomorrow.
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
