I want to make my engine strong, but I don't want to get parts that are not neccessary for street driving. I want to know what the weakest points are on the MPFI 2.8l.

 

exhaust, headers

 

This isn't engine, but.. Transmission! These things don't last long without a cooler on em.

Engine wise..I can't think of anything in particular that seems to be prone to failure...but some big draw-backs to power are the entire exhaust system, which includes the factory exhaust manifolds and Y pipe particularly. The stock heads SUCK. Period. And I believe the ports are also badly matched. I don't see anything too wrong with the upper intake manifold though..looks a decent design to me. Timing chain tends to stretch on higher mileage engines...a double roller set will fix that..

That's all I can think of for now.

 

If you want your engine to run strong and healthy, I recommend a complete fluids change, and that you go over all your vacuum lines and check all of your sensors. Clean your throttle body and IAC valve and IAC passages. Replace any ignition components that need to be..particularly spark plugs, wires, and cap and rotor.... Get your fuel injectors cleaned. A lot of the time the magic bottle just isn't enough..I hear these Multecs get pretty crappy without a good cleaning. Ask the people who sent them to Cruzin Performance..I believe they're all EXTREMELY satisfied with the injector cleaning!

Basically, do TomP's infamous list and your motor should run pretty healthy...and that'll help you make power much easier, not to mention make your engine 'strong'.

 

The early 2.8ls had a smaller rear main. Along with a 2 piece rear main and caused many problems.

I belive the commen problems on the newer mpfi units is the location of the coil. Right above the exhaust. This causiing them to get hot, and go out quickly.

Timing chain on ANY engine should be replaced at high miles.

I belive my dakota is in need of its 3rd.

 

3rd?? Good *** man! My Camaro had 107,000 on the original chain and when I checked timing, it only fluctuated by about 1 degree.

 

I would say the weakest part of the 2.8 is the EGR and vacuum setup.

The second weakest is the aftermarket avaibility of parts.

 

Well, I already did or do all of that stuff. I like driving my engine in the 3,000 to 6,000 rpm range. I keep it below 4,000 rpm most of the time because I don't want to break anything. I was mainly asking because I would like to drive in the upper rpm band without worrying about breaking any of the drivetrain.

 

High mileage engine and hot rodding dont mix. When I bought my SC in 99 it came with a racing slick. After driving the car for 3 months the motor had a problem with a lower radiator hose. Well once I took apart the motor I found that the crank was cracked in many places and it was almost cracked in half. "not too sure if driving the car after the head gasket blew caused the crank to crack and but I'm pretty sure that caused it to break in half" Drove the SC for another 6 days until she would start no more. Nearly everthing in the bottm end was worn out Not to scare ya or anything but I'm dang sure the lil 2.8 was rodded to death before I purchased her. But the block was still good and its running strong after the rebuild.

 

Christ...your crank was all cracked up? The bearings must've been trashed, along with just about everything else! That's scary!!

 

Yes it was scary almost everything was worn down to copper. Funny thing was the car ran fine even before the radiator hose came off and blew and cracked the heads. But at least the block was still in great condition.

 

Man, I am glad something like that didn't happen to me. I don't take my car into the upper 4000 range to often, maybe if there is long stretch on a road with nothing, but cornfields on either side.

 

The 2.8 part....

 

looks like somebody needs to read THIS



see if anybody makes good, quality head gaskets. Don't neccessarily go for the cheapest parts, but maybe higher priced quality parts that will last longer.

 

ROFLAMO that made my day

 

The dak 3.9l is known for bad/weak timing chains. It came with one. Dealer put one in few years ago. Its starting to have the same symptoms it did then. I just need to get the s10 up n running so I can have the one down a week while I do it

 

I thought this was common knowledge!!!!
Maybe not (but should be)

 

Don thank you for stepping in- Last time I gave advice on this everyone said I was nuts- fact is that the 2.8 and 3.1 blocks are not as strong in the bottom end as the 3.4 motors. The 3.4 blocks are cast thicker than the earlier 60*V6's as well as the 3.4 heads. Don has a very good reputation in California for his knowledge and work on third gen cars and has a shop full of useless 2.8 & 3.1 motors sitting around as proof. The cranks will easily develop about a 1/2" of endplay in a hurry if you abuse them.

 

All these things are scary thoughts considering I REGULARLY went WOT in my Camaro DAILY..basically, half of my accelerations were WOT because the thing just felt so damn slow even though it wasn't. And without a tach..I dunno what kind of rpms I was turning. Felt like near 5000 every time..maybe past.. I bet my engine was trashed and I didn't even know it!

 

I'd have to say the bearings.

4 people I know have had their bearings **** up in their 2.8 making the connecting rods knock. And sometimes dmg to the crank

 

Well, I dunno about that... maybe poor maintenance and hot rodding don't mix? Who knows what happened to that motor before you got the car.

If that were the case, my 2.8's time would've been up years ago! The clock's still running (+246,000 miles)... I tell ya though, I can't wait until I rebuild a junkyard 2.8 and drop it in- I'm going to take apart my original 2.8 for shts and giggles, just to check out the bearings and everythign else. I'm also going to check the cam lobes- I bet they're worn down to nothing by now.

I'd wager to say the weakest point is the transmission, if it's an automatic trans from 82 to '86... but that goes for ALL f-bodies, including the v8 guys. Neglect that fluid (like Nixon says, the 700r4's run hotter than other trannies, and heat = dead fluid), and your trans will have a fit. 82-83 200C 3-speeds were so bad that GM didn't keep using them. 84-86 700r4's had a lot of problems (lucky me!), and 1987 brought quite a few improvements to the trans. I'm on my 3rd trans, and I'm surprised it's still alive. Hopefully it stays that way until the summer.

 

I must be lucky since I have an 87, tranmission runs pretty smoothly, and I have had no problems with it.

 

Dev...from what I've seen of shot 700-R4's..they shift smooth for quite some time. At least the older ones. My friend had an 86 Camaro and his tranny shifted SILKY smooth..felt beautiful....but he'd tell me how it'd slip out of gear sometimes in first...and how it occasionally won't get into 3rd or Overdrive...

 

hey i got a 700 r4 and in the morning when its cold and its been sittin overnigh when i put it in reverse i have to wate a couple seconds before it goes in revers but it only does that when its cold, is that normal?

 

tranny fluid has to heat up some to get propper pressure to function. that's why you need to route aftermarket tranny coolers propperly so fluid doesn't get too cold.

 

What he said.. If you get on the gas pedal a little (I know, I know, this is stupid) when the engine is cold, you probably notice it hesitates in shifting gears too...same reason...cold fluid = thick fluid = pressure outta whack = shifting inconsistencies.

 

Timing Chain? What's a timing chain? I asked the tech at the Chevy dealer when they had my water pump off if I should have had the timing chain replaced. He was like is it making noise? I said no, then he said then it's fine. Every time I talk to the techs at the dealer they laugh when I ask about a timing chain. The one guy said to me these aren't imports with plastic chains or belts, they are American cars with steel chains made to last. I have almost 160k miles on my timing chain and it's never been changed. Did some of you just change your chain for the hell of it?

 

I would have to say that the weakest and hardest to correct part on the 2.8/3.1 is the bottom end. The crank is not up to a whole lot of high RPM power, and the webbing in the block and the mains are puny compared to V8 ones. That being said, I have sprayed mine with Nitrous for the past 7 years, it now has 168K miles on it, has never had the timing chain changed, and still starts and runs good. I have never had a minute's trouble with the tranny either, although when using the nitrous, it slips some when it upshifts.

The heads can be ported, given a valve job, and the gasket surfaces matched. There are Cams available, as well as aftermarket timing sets that are much stronger than stock. You can move the coil, and there are headers now available. The bottom end, however, cannot be significantly strenghtened without a lot of high $$$ parts and custom work being done. I believe that was the biggest weakness in the design.

 

Thats the entire main reason for upgrading to a 3.4, the block mains are a whole heck of alot stronger than the 2.8/3.1 block.