Engine knocking, cluncking

[nomadclimbing]

Hello All,
I just bought this 1984 944. I took it to a general mechanic, not a Porsche mechanic, and he said it was the push rods. The car will start hot or cold and idles really rough at first and stalls. After it warms up a bit it will idle rough for 10 minutes or so. If I give it gas it dies most of the time or putters anyways. The sound is like a knocking, clunking and sometimes I hear a rubbing noise. Its hard to tell were it is coming from exactly but it doesn't seem to be coming from cam housing area. More from block or maybe the lower head. The exhaust has a whooshing sound like compression? Checked wires and cap and rotor all are new. Firing order is set right. Check exhaust manifold bolts all tight. I have not checked the timing could it have jumped a tooth maybe and if so would it bend any valves? I have posted a video of the sound at this site. Please look and any feed back would be appreciated. Thanks Mark

http://www.nomadclimbing.com/ebayporsche/index.html

[Slam]

Push rods. Huh. Mekanik?

Welcome to the board! There's more knowledge here than you can shake a torque wrench at.

I'm sure you're going to get many posts about changing your timing belts. If you don't know when new ones were put on, do them now. There's been lots written about this.

Have you changed all the fluids?

Check your coolant recovery tank for what we call milkshake. You'll know it when/if you see it. It's a mixture of oil and coolant. Also check your dipstick for the same thing. Have you drained the oil and had a look at it? It'll tell you some of the story. Look for a pearlescent sheen or metal flakes. If you find these symptoms together stop and first fix your oil cooler seals and change the rod bearings (Porsche service manual says to do this in the case of "mixing."). If the engine really is knocking you're too late, but lots of things can be mistaken for a knock so don't worry too much right now.

A compression test will tell you a lot as well.

Couldn't open the link but a whooshing sound may be something as simple as a cat delete. My car 'whooshes.'

I'm sure the guys here will have a lot more to say. Good luck!

[HondaDustR]

Pushrods??? No pushrods here. It's an overhead cam motor with hydraulic lifters that can get stuck or collapsed and will make a loud knocking sound at the cam housing.

Do the timing belt NOW if you don't know when or how it was last done. It is an interference engine and will destroy the valves if the timing slips. If there's a lot of filings in the oil, it could very well be a cooked bearing. The #2 rod bearing is prone to failure so I've heard. How's the oil pressure? If it's nice and high then there's a good chance the bearings are fine.

Poor running could be a number of problems (clogged injectors, bad electrical connections, bad fuel pump and or pressure regulator, dirty air flow meter, vacuum leaks, ect to name a few).

Here's perhaps the most valuable 944 owner's/DIY'ers resource, second only to infinite money.
http://www.clarks-garage.com/

and read through this as well. It's got most of the important stuff.
http://www.connact.com/~kgross/FAQ/944faq.html

These are actually relatively easy cars to fix if even if you're only slightly mechanically inclined. But you've come to the right place, as the guys here really know their stuff and will be able to help get her running proper.

[nomadclimbing]

Thanks for the quick replies. Checked the oil it look pretty good. Also the overflow tank looks fine. I actually started the car again after about 4 hours and it started out the same way but then it stopped the knocking for ten minutes then it came back. Also when it came back there seems to be knocking coming from cam housing also. Sorry about the video I have also uploaded to utube title is: 1984 porsche 944 engine knock and tag is: 944 knock

[Razorback1980]

+ 1 to those two. As already mentioned..check your oil pressure. If it's good, then that's a good sign...good meaning 4.5 to 5 bars when first started and down to three after warmed up. If it's lower than that...then it's going to be a long road. I didn't try the link yet, but if it doesn't work others have put their videos on utube. That will help us identify the problem. If it's a lifter it will have a clack noise at the end of it. I would put SeaFoam or marvel mystery oil in the crankcase for now just to see if that helps. If the lifters are clacking, then they are probably a little dirty and need some cleaning and that stuff will help with that.

One thing I've found on these cars is sometimes the cat will get plugged and the exhaust will make a weird sound so if it were mine, I would loosen the header from the cat and see if that doesn't help it run somewhat better and maybe even get rid of the knock.

Links, waterpumps, timing belts...all that stuff already mentioned except interval should approximately every 35,000 miles or two years I think is what most people here do.

Don't be afraid to use the search function here...it will bring you just about every answer to every problem you can possibly have. Rest assured if you are having a problem, then some of us have had the same one and the answer is already published within our archives here.

Also help us to help you by putting your car's information in your signature line. Each year is a bit different and there are many here that know each difference of each year...unfortunately I'm not one of them. Also information like whether it's an S, Turbo or just an NA car helps a lot too.

Welcome to the board and Porsche addiction.

UPDATE: OK, after reading your second post, definitely put some Sea Foam (AutoZone) in there and that should help with the knocking.

[Cking1975]

Sound to me like you are running on 3 cylinders..???

Whatever it is...its not good !

[Techno Duck]

What is your oil pressure? From the half a second in the video where it was visible, it looked like it was bouncing around. Either one of your lifters is shot or you have a spun rod bearing.

[nomadclimbing]

When I first start the engine the oil pressure is between 3 and 5 but drops to 1.5 when it warms up. I was running it for about 20 minutes earlier and the slapping or knocking goes away every now and then for about 30 seconds. It sounds to me like its a lifter slapping around. I would check it but I do not have a timing belt tool to put it back on. I also tried seafoam which help with the idling. It idles now at about a 1000 rpms pretty steadily. Doesn't seem to be missing anyways. If I very slowing press the accelerator I can get it up to 2000 rpm's before it wants to quite. I can drive it down the road at idle speed and it never quites running unless I give it gas. If it does stall it starts right back up. Checked manifold and exhaust and caddy. No problems there. I also have an 1986 and I switched the air intake and sensor which also seemed to help.

How trivial is the timming belt tool if I just remove the cam housing? Thanks

[Cking1975]

The timing belt is not the issue. The problem is internal...I would recommend finding a good Porsche mechanic in your area. You cannot make the problem simple, this engine needs a rebuild, probably on the top end. The head needs to be pulled and inspected, the more the motor runs the more damage you could be doing. This is just an opinion.

[968rz]

The sound in the vidoe is not the best but that sounds like a rod bearing to me.

[aj951]

That sounds like a stuck/collapsed lifter to me. If the collapsed lifter is not oil pressure related (meaning not enough pressure to pump the lifters up), then you will most likely need to replace the lifters. You will need a timing belt tensioning tool if you remove the cam tower and replace the lifters.


I am having similar problems myself. Mine was making this same noise and went away.

A.J.

[Razorback1980]

Considering your oil pressure, you have a spun bearing or a bad oil pressure relief valve....more than likely a spun bearing. Either of the two is causing you damage to the motor. Drain the oil but as it runs into the drain pan, make it go through an old white t shirt. Then look at the shirt under a bright light afterward and let us know what you find. I'm guessing you will find small metal shavings on the shirt.

The poor running is a vacuum leak. There are quite a few vacuum lines to check but I don't think that's your real problem....oil pressure is where you need to focus on first.

[Slam]

Rod bearings. Oil pressure gauges don't do that for fun. Do what Tom says and drain the oil through a white T-shirt (good one, Tom). Your motor is self-destructing, and you'll see a lot of metal in the oil.

The good news is that you can get good used engines in the States for really cheap.

[nomadclimbing]

Ok well thanks for the info guys. So far everything has been a big help. I just did a compression check and here are the numbers. #1 is 155 psi #2 130 psi #3 155 psi and #4 155 psi. So #2 is lower than the rest and lower than recomended, but when I pulled the cam housing the #2's lifters were in pretty bad shape. I was wondering if that would cause the drop in pressure. I'm planning on replacing the lifters with spares I have from my other car and replace the cam housing and recheck #2. Thanks

[Slam]

When your oil pressure gauge bounces like that, usually that means your rod bearings are shot or very close to it. Electrical faults with the gauge result in its either being full left or full right and unresponsive.

[HondaDustR]

Not to mention it looks like it's bouncing in time with the clunking.

[Razorback1980]

Bad lifters should make no difference in oil pressure.

I seem to remember that when these cars are autox'ed, they can throw all the oil in the pan to one side and make it lose pressure and then the rod bearings go out...especially prone to number 2 I think. They made a special plate you could put in the pan to keep the oil from moving to one side to protect your rod bearings and the later year cars came with it already in I believe. The part I can't remember is if it happened in all years or only to certain years/models.

[hpservertech]

Tom is right on the oil pan baffle. Sounds to me like you got a few issues, the biggest being a spun bearing.

[Techno Duck]

Weld in pan baffles are available from Lindsey Racing. Typically the problem is on constant high G left turns. Later cars had a slightly larger pan baffle and a deeper oil pick up tube. But the oiling issue is still present.

[HondaDustR]

...at least most exit ramps are right turns!