Got an 87 camaro, changed the engine for a 88 2.8 from a firebird.Did not change the computer. Car was running great. I got a knocking sound coming from the top part of the engine. On idle can't hear it,on throttle you can clearly hear it. Listened to it with a stethescope. Nothing at the block,heads,valve covers. The only place that I hear it is on the fuel rail and the intake on the passangers side. I can also feel it with my hand on the intake on throttle. Could it be the fuel pressure regulator or a bad injector that is running to lean. Getting no codes of error. Anyone got an idea. Got the old 2.8 for parts. The old 2.8 has bad main bearings.

 

Check each injector. Mine make very load tapping noises. Sounds a lot like valve tapping. But when you listen to each injector the sound is obviously coming from them. I also read a post on here somewhere that our injectors can be quite loud. I just had mine cleaned and tested so I know they are good.

 

Thanks for the info. i will take apart this week and let you know of the resaults. From were the sound is comimg from and your info it should be pretty close.

 

can you only hear it when under a load when driving it? it could be spark knock. if theres a lot of miles on it and it hasnt been kept up on, there could be a lot of carbon build up in the combustion chamber causing it. thats something to check into. cheapest thing to try, is run it close to empty. fill it w/ midgrade once and see if it gets better. if it does, get some combustion chamber cleaner of some type. thats what it sounds like from what you said.

 

If this would be spark knock. this means that I would have to check the sensor. I thing that it is pretty loud to be just a spark sensor. Then again what do I got to lose.I will give it a try. Thanks.

 

the tank is full for now. I well have to pump out the gas. The truck is also full. So this will take a few days. I never though that they had stuff to remove the carbon builtup. That wouldn't hurt. I'll chech this out to if I can find anything. Would you have any brands in mind? It would help.

 

now that i reread what you posted........ does it happen just when you raise idle or when its in gear and actually under a load. cause then it may not be spark knock, it only occurs under a load. that means in gear, under medium throttle or more. but its worth a shot anyway. GM top end cleaner seems to work really well to get rid of carbon build up. carbon build up makes the air/fuel mixture ignite on its own. the spark plug ignites a part of it too and the two collide, causing spark knock which can eventually destroy a piston or cylinder.

 

Ok here is were aim at. The sound seem to be really coming from the fuel block area. The sound ain't coming from the fuel pressure regulator. It's pretty low at that area any way. It's really loud on the fuel lines and the fuel block area. There is 2 injectors sitting right there. I removed the plenum, will try to get the injectors off and test them,also give them a could cleaning. The knock sensor seem to be in good condition. Well check the injectors in the other engine. If any thing looks fishy. Thanks again. I will give you guys updated.

 

knock sensor? i dont recall the 2.8s having one. where is it located on your engine?

 

On the right side of the engine at the bottom. You got to go by undernieth of the car to have access. You can't see it from the top.

 

mine doesnt have one. hmmmm. maybe its a canadian car thing.

 

Here is were aim at. Took the fuel rail off. Checked the injectors with an ohm meter. Every thing is fine.Now I will give them a good clean. That should help.But as I took all yhis apart. Here is what I found. There is a small hose that is connected to the fuel pressure regulator. ( about an 1/8 of an inch 2 inches long). That was cracked.It is a vacum hose. I think that this was giving a bad signal the the fuel pressure regulator. This is why I was getting the knocking sound on the fuel rail. Near the inlet and outlet. Hope that this works. At least i will know that the injectors are good and clean. Should of checked the fuel pressure.

 

Have you noticed any decrease in power?

Does the knocking get louder at lower RPMs the more you drive it?

If you have any of these symptoms, then it's probably a failed crank MAIN bearing.

In these motors, it's much more common for a MAIN bearing to go out than it is for a connecting rod bearing.

Unfortunately, most of these cranks have some slight imbalance to them from the factory.. all it takes is a failing harmonic balancer and a bad overheat just once.. to take one of the main bearings over the edge.


If that's what it turns out to be then my recommendation is to find yourself a 3.4 block... say from a 1993-1995 Camaro / Firebird. The one in those years are IDENTICAL to your engine.

You can drop it in without modification, just make sure you use everything north of the lower intake manifold from your old motor. You'll also want to keep the injectors from the larger motor, they are 17 pound injectors.

Other than that, the engine characteristics are the same... and the computer can handle it with no problems.

It's a great upgrade for those who still have a 2.8 or 3.1 but don't want to go through the hassle of a complicated engine swap. What's even better is that it looks totally stock.

Fiero owners do this all the time. Except... for our needs (Fiero owners), we have to drill starter holes on the other side of the block.

 

I now what you mean. This is what happened with the 2.8 in the back of my garage. The 3.4 sounds like a good idea. Got to look in to it. I read a post on the subjet a while back. Did not Know about the computer thow. I got a 350 in the works for know. But with the price of gaz and the way it's heading. Since I would like to use the camaro as much as possible during the summer mounths. I really don't know about that 350. If it becomes a week-end driverthen that is a different story. . The 350 is not preped yet. I would like to use the 2.8 for now. I will look into the 3.4 for cam, lifters ect. Thought of a 3.8,4.3. But I heard it was the same mods as a v8. The 4.3 uses as much fuel anyway.

I did clean my injectors by the way.2 fo them weren't that bad. But the othe 4. They were pretty clogged up. No spray only a stream of fuel. This should help. Hope to have the time to put it back together tomorrow.
2.8 to a 3.4, Heard that even the smog patrol can't even tell that its not a 2.8.

 

That's right... so long as EVERYTHING else is the same... you can use the 3.4 block (and the heads) and it will look identical. The only distinguishing characteristic is that:

A) It has a knock sensor (yours may not)
B) It has 3.4 cast into the side of the block instead of 2.8
C) The distributor hole is plugged (remove the plug and install your old distributor)

Everything else is the same.


Oh, the engine is internally balanced... your 2.8 is probably externally balanced... so whatever you do, keep the flexplate / flywheel with the motors. As in... take the flywhee from the 3.4 motor and use that with the swap. You don't want to use your flywheel from your 2.8 on your 3.4 or it will be out of balance.


Oh, and just remember... you MUST use 17lb injectors... whether you use the ones from the Camaro / Firebird, or you get a set of new Accel Injectors.

 

thanks for the info on the 3.8.
I got thing together. Started her up and it still knocks.
Took a valve cover off. To my surprise. Had a stamp on the head 89. This engine came out of a 88 firebird with a manuakl tranny. went to see a mecanic HE said that the 87 had a flex plate with weights. That the 88 didn't. Now I find out its an 89. What kind of flex plate would it need? looks like a 2.8. Will check the vin on the block. Cause it does have a knock sensor. Did pontiac have a 2.8 in 89? I wonder if it coild be a 3.1 block. with 2.8 externals?

 

found the problem I hope. Connecting rod bearing No 1 piston. rip the thing apart today and found it. I started to rebuild today.Should start her up tomorrow.

 

sweet ***** man you work fast!

hey man nice fieros! i love the notchback gt bodies.

i used to have a no option (not even a trunklight) 86 2m4. i learned to drive stick on it. tried to drive home on a flat tire and learned what fried clutches do too. loved it tho.

 

Sarted her up yesterday. Runnig great for a while. Then I get a little knocking. Openned her up again. 1 of the bearings was the wrong size. Waiting for the trade in. Then it should be ok.



Openned it up so often,that I think I can do this with my eyea closed

 

**** man!

 

Got a new set of mains for the connecting rods. Put them in. Started it up, she started to knock again. Ripped the( beep!) thing out of the engine bay. Openeded it up. The main bearing in no.1 cylinder was shot again. The piston pin does not seem to have any loose. The mains on the crank are looking good.
The journal for piston no1 is not perfectly smouth.

Took the other 2.8 apart, the one with the mains that are shoot at the crank. Removed the mains to check it out. The journals for the mains are not perfectly smouth either. Any one has an idea? Turnnig the crank is out of buget for now.


Had a look around for a 3.4. The junkyards are asking 1200$ to 1500$. This is no good when out of a job. Turnning the crank is about 500$ at the least.

 

If you're out of a job, my advice is just to hold off on any repairs unless you need it. I see you have an 88 GMC... so just hold off.. That's the thing that sucks about being out of work, you have plenty of time for projects, but no money with which to do the repairs!

 

I guess that your right. Since I about 70% of the parts for a 350 on hand. It is all apart in boxes. I will start to put it together.This should keep me busy and out of trouble
Thanks for the encouragement

 

i think mine is doing this did your ever find the problem??please let me know., i need my ride right now and cant afford costly repairs???????????

 

I'm sorry to say but a knocking at higher RPMs (one that you don't typically hear at idle) is usually a spun or worn MAIN bearing.

That's the bearing on the crank where it attaches to the block main caps (and not a connecting rod).

The 1st gen V6/60s are notorious for these bearings going out, I'm not sure why... some people think it's caused by poor tolerances in machining, or that it's typically a result of overheating at some point.

It really means that it's time to rebuild the motor, and since it IS a crank main bearing, it's not something you can replace with the block in the car either.

If you use thicker motor oil (I'd only recommend this for a motor that's on it's way out anyway), and you don't floor it at all and drive your car extremely conservatively... you can probably get away with it lasting a few more weeks... AROUND TOWN.

Definitely do not take it on the highway or you're going to end up on the side of the road, and the car in the junkyard (more than likely).

That said... if you have every intention of rebuilding this motor as apposed to replacing it, then don't even think about driving it anymore.