Engine makes noise after overhaul

[Gerke123]

Hello all,

We recently had the engine overhauled and rebuild it completely, Both the head and the engine block has been rebuild by professionals, yet when we first started the car, it was like starting an MK1 Golf diesel.
We have double checked everything, but i doubt this is how the car is supposed to run after a rebuild. We have checked the timing and ignition, and those were all on point. The valve clearing has also been done professionally by a company. The oil pump is working perfectly too.

The engine has now run for 30 seconds, and we dont have the courage to let it run any longer. Does anyone else have this happen to them before when starting a recently rebuild engine? And what can we do to possibly fix this without taking the engine out of the car again? 

-Gerke

[SanRemo78]

I'd be checking valve clearances first. They may need re-shimming to get clearances right.

[peteracs]

I think you need to be a bit more specific on what you mean by rebuilt……

First thing did you spin up the oil pump before starting or turning over the engine to confirm oil pressure?

When it was rebuilt did they use engine assembly lube to the crank, rods etc?

Did you check that the engine would turn over easily by hand without plugs installed?

Have you checked the cam belt timing before starting?

Just a few thoughts ….

Peter

[Gerke123]

Hello Peter,

Yes, we can check all that off. However, there was a point when turning the engine by hand was a bit more difficult. But after two full turns this went well. And on the starter motor without spark plugs it ran like crazy without any camming noise. Maybe the valve clearance could have something in it. But I had this done by a professional........

[stableblock]

Is the noise metallic?  Have you checked the exhaust manifold gaskets are correctly fitted?

[Gerke123]

Is the noise metallic?  Have you checked the exhaust manifold gaskets are correctly fitted?

What do you mean? I just looked at my engine reserve parts, but you can only put the gasket on one way and they are optically the same on both sides.  It is a metallic popping sound, just like a diesel engine.

can you explain that?

[rossocorsa]

Just a wild suggestion, I'm just wondering about cam timing, is there any chance that the cam pulleys are swapped over? This might  make the timing marks out. I'm not sure but I think they will fit either camshaft? I think that exhaust pulley has lip to the front and inlet to the back on early engine???
As I said just a wild guess, I'm no engineer and struggle with stuff.

[HFStuart]

Aux driveshaft hitting the crank? This can happen if it's not positioned correctly.

[Nigel]

Hi Gerke,

I assume you are seeing healthy oil pressure and you've double-checked the camshaft
timing including the aux shaft. I also assume you've re-checked the valve clearances.
With all this established it doesn't
sound like it would damage it to run it again.

I don't think you can post an audio on here, but if you or someone in your house has a
suitable media account, maybe facebook? post a clip of it running and share the link here.

Nigel

[capriblu]

Aux driveshaft hitting the crank? This can happen if it's not positioned correctly.

That would be the first thing I would be checking.

[Gerke123]

Just a wild suggestion, I'm just wondering about cam timing, is there any chance that the cam pulleys are swapped over? This might  make the timing marks out. I'm not sure but I think they will fit either camshaft? I think that exhaust pulley has lip to the front and inlet to the back on early engine???
As I said just a wild guess, I'm no engineer and struggle with stuff.

After this question something started to bother me. Checked this morning but luckily they are placed correctly.

[Gerke123]

Hi Gerke,

I assume you are seeing healthy oil pressure and you've double-checked the camshaft
timing including the aux shaft. I also assume you've re-checked the valve clearances.
With all this established it doesn't
sound like it would damage it to run it again.

I don't think you can post an audio on here, but if you or someone in your house has a
suitable media account, maybe facebook? post a clip of it running and share the link here.

Nigel

Hello Nigel,

The Aux shaft could be 1 notch off. I'll see if I can change this. If this is not the solution, I will see if I can load a video.  The aux axis is often mentioned here, so let's move on first.

I'll keep you informed.

[Gerke123]

Hello all,

I recorded a video of the sound coming out of the engine.

Here's the link to the video: https://streamable.com/f66hib

-Gerke

[Nigel]

Hi Gerke,
That helps alot.

To me that sounds like valve clearances too wide. However there could be an issue with
oil not reaching the top of the engine. Suggest you remove the 2 cam covers to see if
it's well lubed inside.
Did you check the valve clearances already?

Nigel

[HFStuart]

I think we can agree that sounds bloody awful. Unless it's something obvious like valve clearances or the aux shaft I think you have to take the head off.

To me it sounds really piston like  maybe even hitting the head but only way to be sure is to strip it.

[peteracs]

Hi

I would check the valve clearances regardless of what you have been told, sounds very much like may be too wide to me. As with Nigel also check you are getting plenty of top end lubrication as well. Checking them is a pretty easy thing to do.

Peter

[Gerke123]

Hello,

Thanks for the replies.
We have removed the cam covers and the oil is very much present at the top of the engine.
As for the valve clearences, we will have to talk to the guy that worked on that for 3 hours and have him work on that part again. he's on vacation this week so we sadly have to wait.
Once thats fixed, we will give you all an update on the engine.

-Gerke

[rossocorsa]

To me it sounds like something simply not set up right have you tried moving the distributor whilst it is running to see if it gets smoother?   

[WestonE]

I agree that valve clearances are likely not correctly set and frankly if your mechanic can not do that job I would worry about the rest of the work. Set stone cold spark plugs out by using the tappet depression tool one at a time after using a syringe to remove the excess oil. You obviously measure first with feeler gauges looking for 0.40mm inlet and 0.45mm exhaust clearances. The Haynes Beta Manual tells you how, but you need a decent stock of shims to replace those note the right size. Avoid shims smaller than 3.50mm to prevent cam damage. If you have saved shims from previous engines you probably have lots of 4.20mm! Note always measure the shim thickness with a decent digital vernier or micrometer. to check the actual size and never use shims with heat bluing or surface scuffing.

Good luck.

Eric 

[peteracs]

Hello,

Thanks for the replies.
We have removed the cam covers and the oil is very much present at the top of the engine.
As for the valve clearences, we will have to talk to the guy that worked on that for 3 hours and have him work on that part again. he's on vacation this week so we sadly have to wait.
Once thats fixed, we will give you all an update on the engine.

-Gerke

Hi Gerke

I suggest follow Eric’s comments, get yourself some feeler gauges and thereby have another pair of eyes check what is going on with the valves. It is very easy to check now you have the cam box covers off. If they are out then not a trivial job to sort, but at least you know and hence to ask the question why? Again as Eric suggests, I would then be questioning why he has not done the job correctly and hence what else is incorrect?

Peter