95 Quad 4 loud tapping noise

so heres the scoop, i did a head gasket replacement on this car with a 2.3 liter quad 4 DOHC, had it timed perfectly, changed the oil out twice and ran brand new. after about one night of continusouly driving, about 50-70 miles the engine stalled out on the road after an oil press ligt was signaled. Got it running again and managed to drive it home doing like 4000 rpms (estimate) at 40mph. seems like engine has low compression, however it cranks over and starts quickly. now whenever i start it i have huge tapping noise that gets worse when rpms increase. i have no idea where to start with this but i am willing to do all the work myself, i went this far already it would be a shame to trash this car...
heres what ive done along with the head gasket:
new plugs
new timing chain with sprockets
resurfaced and cleaned head
new water pump
all new gaskets (where needed)

im pretty confident that the top half of the engine is running great.. unless its a valve problem or a lifter problem. its hard to single out where the noise is coming from being that its so loud it seems like its coming from the whole engine... any help/advice... how much would it cost if i did it... vehicle is just over 100,000 miles.. in great condition... any help would be great

sounds like a bent or snapped rod. probaly spun a bearing if so don't drive it u can snap the rod and it can shove it's self straight through the block. did it lose power after it stalled on u?

I bought a 95 grand am quad 4 2.3l DOHC car for $400 with no head, put the top end back together, changed the oil, new timing chain, new water pump, thermostat (the whole 9 yards), drove it 70 miles and it started ticking. Tore it all down, ended up being a bad rod bearing (bad enough the rod needed replaced, new crank, all new bearings) basically a complete rebuild. I didn't keep driving it (which saved the head), had the machine work done, put it together myself for like $800 + orig head & parts before rod bearing went out.

Your story sounds pretty familiar, if you want to do a check to see if it has the same problem as mine I can tell you how my mechanic friend determined it was the rod bearing.
1. at a low idle the oil pressure light would come on in the car
2. when he hooked up his oil pressure gauge it was boucing all over the place
(I tried my own rigged up one with some fittings & a dash gauge from autozone, but it wasn't accurate enough to pick up the problem, you need a mechanics oil pressure gauge)

good luck, hope its not your trouble, but #3 rod bearing goes out in these motors alot. I also had a mark on the #3 piston from where it was tapping the head.

yes it did loose power after it stalled and even kind of before it stalled. should i check this problem by tearing down the top half of the motor all over again or just drop the oil pan? can this job be done without removing the engine.. or do i pretty much have to tear everything down again.. thanks for the input..

If it were me i'd borrow a mechanics oil pressure gauge, take out your oil pressure sending unit (front cam, drivers side, pointing twards the brake booster) test the oil pressure. This will diagnosis if its a rod bearing or not & its a lot easier then any other way. If you can't borrow one or buy one then you can diagnosis it either way with the motor in the car (pull the head & look at the top of the pistons for a clean spot, or drop the oil pan - have to raise passanger side of the motor - pull the oil pump (not easy) - then pull the rod bearings) I suggest you look into finding an oil pressure gauge, but its up to you.

To do a rebuild the motor needs to come out of the car, block needs to be machined (for new pistons, check crank bearing sizes, and fix / replace crank & rods). If you do a rebuild I suggest you go all the way (fix rods & crank (or replace), new pistons, piston rings, rod bearings, crank bearings, oil pump balance shaft bearings, oil pump, water pump, thermostat, any timing chain parts you didn't already replace, gaskets, & have the machine shop check the head (cracks, valve guides, new valve seals, check valve seats, & lap valves) ) If you do all of this it will be like having a brand new motor. If your not confident in doing the build yourself you can pull the whole motor & have them put it back together, but doing it yourself should save a $300 - $400 (im guessing). Like I said I was at the same point as you are, built the motor myself with all the work & parts listed and I invested $800 into it. I had the timing chain off one tooth on the exhaust side after I put it back together, other then that it ran like a top (and still does). Now if I can just find that annoying vibration (like maybe the exhast I put on hitting the floor boards somewhere).

Good luck & I hope your oil pressure isn't bouncing all over the place!

One more trick if you buy a gauge, put a pair of vice grips on the soft rubber hose start the car, then slowly release the vice grips (so a pressure spike doesn't kill your new pressure gauge).

Just wanted to let you know, im not a professional mechanic, just a backyard one, but I design auto parts for a living, now I design axles, used to design pistons, & before that any part that came into the job shop I worked at. Im one step below an engineer, have been tinkering with cars my whole life, & have many buddies that are professional mechanics. While I don't know everything I have a pretty wide range of life experiences & know more about how auto parts (and other parts) are made then anyone would like to know. :banghead: Just wanted to let you know my advise didn't come from someone who doesn't know how to change spark plugs, but is by no means a professional mechanic.

what if i just go the easy way out and only replace the bearings?? would you reccomend this, or would it even work?

I do NOT recomend only changing the bearings, I can tell you by the time I got the piston hitting the head noise, both the crank and rod were so far worn down that both had to be replaced. Replacing just the bearings would be at best a temp fix, you'd probably end up spinning another bearing and being back in the same place you are now. Obviously you would like to have the car run right, or you wouldn't be on here asking whats wrong, now you have to determine if its worth putting enough time & effort into to do a rebuild, or if you should find a junkyard motor to get you by for a while.

If you decide to do a rebuild the machine shop may be able to get parts cheaper then you can (mine was cheaper then getting them thru an auto parts store). good luck

thanks for all of your help and the quick responses.. can you give me any advise on how to drop the oil pan. i took a look at it today and theres an antifreeze hose going right under the pan. do any motor mounts have to come off.. etc..? thanks for all of your help

Pull the passanger side cradle (frame under the oil pan on passanger side) it should have 3 bolts going into the car body, one bolt for the dog bone style lower motor mount (looks like an "8"), two bolts holding the lower A-arm to the cradle, and 2 bolts going to the sway bar mount (might be a "U" bolt). Its alot easier once this is out of the way (you will want to remove the tire before starting so you can pull the A-arm out of the way), be careful not to push the a-arm to far or you will pull the cv-joint (part of axle shaft that builds) apart in the axle shaft, easiest if you pull the cradle off of the a-arm, that way you don't push the a-arm assembly (a-arm, rotor, brakes, strut) instead your pulling the axle joint together.

Now take that steel tube you were talking about off (after you drain the coolant), you'll pull it off at the water pump & take the hose off of it, then remove the bolt that holds it to the oil pan.

Then you have to remove nut from a stud that goes thru the oil pan into the transmission flange. Then use a 7mm wrench to remove the stud & pull the spacer out thats between the oil pan and the transmission flange.

Unless I missed a step somewhere all you have to do now is pull the bolts for the oil pan and drop it down.

thanks alot Gmack.. and after that i should remove the oil pump and pick up tube and then the bearings are right there and i can just change them out like that?

thanks alot Gmack.. and after that i should remove the oil pump and pick up tube and then the bearings are right there and i can just change them out like that?

I think you are wasting your time and money by just putting in new bearings, but thats up to you. I suggest you either rebuild it, or get a junk yard motor and do a swap.

If you just replace the bearing im afraid you'll be lucky to get another month or so out of those new bearings. Look in the oil pan at the all of the metal, that will be everywhere in the motor, including the lifters (mine were completely full of metal shavings).

Before you remove the oil pump put your #1 cylinder at top dead center, the oil pump on this motor is driven off of the crank by a small chain. Then remove the oil pump (leave the oil pump sprocket in the chain) & balance shafts. Now you should be able to see the rods & find the bad bearings.

i would definatley agree with gmack and have to advise u on replacing all of it. cause when the bearing goes bad it u will spin it and it throws everything out of wack. and the problem isn't something that is minor if ur hearing it especially if u drove home with it like that. there is most likely alot of other damage.