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Matt
Matt, Engineer
Category: Audi
Satisfied Customers: 20607
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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I have an Audi A4 1.8T 2001. I recently rebuild the engine

Customer Question

Good morning, I have an Audi A4 1.8T 2001. I recently rebuild the engine with my brother and we installed it. When we tried turning over it did not turn on, it sounded like it had no gas or out of timing. we reset the timing (DTC) and then tried to set the camshaft timing as well. But the camshafts were locked or stuck after the first jump. I purchased a new camshaft tensioner and chain and installed ut, same thing happened. We put the DTC about an inch passed the mark and the camshafts started moving, we went t turn it over and again it did not run. We noticed that ever time it turned as soon as the engine hit DTC the camshafts locked again slipping it out of timing. We do not know what is the problem, thats the only thing not letting us finish my car.
Submitted: 1 year ago.
Category: Audi
Expert:  Matt replied 1 year ago.

hello

sounds like the valves may be hitting the pistons

try following this procedure for timing the cams to each other with the cam chain on the back

Customer: replied 1 year ago.
Sir. We had the same issue even before we switch out the camshaft tensioner. That's why I have no idea why it would be doing this and it's the same reason we changed the camshaft tensioner.
Customer: replied 1 year ago.
Cylinder 1 is up and cylinder 2 is down, cylinder 3 is down and cylinder 4 is up. Is that normal?
Expert:  Matt replied 1 year ago.

hello

the firing order on this engine should be 1,3,4,2 so check that the compression occurs in this order as the next step

Customer: replied 1 year ago.
Ok, let say that the order. Would the pistons be okay in the order I have you? 1 up, 3 down, 4 down and 2 up? How do I do a compression test?
Expert:  Matt replied 1 year ago.

hello

that order can work out as assuming 1 is on its compression stroke and about to fire then 3 will be the next to rise and so compress and fire next and so on

to perform a compression test you need a compression gauge like this

http://www.amazon.co.uk/Sealey-CT955-Petrol-Engine-Compression/dp/B000R9ZK5O/ref=sr_1_1?ie=UTF8&qid=1448228150&sr=8-1&keywords=compression+testers

Customer: replied 1 year ago.
What is the compression number I al looking for? And there is no problem with the valves as in they won't get bent by turning so much? Is there a possibility I put the crack shaft on wrong? I just put it in and didn't set it to DTC when I tightent it up.
Expert:  Matt replied 1 year ago.

hello

on this engine it should be at least 7 bBar (103psi)

if the engien won't turn over at all then you won't be able to do the test

when you 1st fit teh crnak it can be in any position

the important timing is when you set the cams to each other and then set the cam pulley in relation to the crank pulley see attached

Customer: replied 1 year ago.
Is this for a 2001 Audi A4 1.8T AWM?
Expert:  Matt replied 1 year ago.

the differences between the apx and awm or are in the porting and strength of the internals , there's no difference between them when it comes to the setting of the cams

Customer: replied 1 year ago.
Is there a timing for the flywheel?
Expert:  Matt replied 1 year ago.

hello

as long as the engine is set to top dead centre on cylinder no.1 it's in the right place

Customer: replied 1 year ago.
When it's set in dtc foes the notch have to be in a certain position ?
Expert:  Matt replied 1 year ago.

hello there's a notch on the crank pulley and another on the cam pulley, both have to match up to their markers

see this drawing

Customer: replied 1 year ago.
Ok, so this is my question. I set the DTC on the crankshaft and the camshaft. The flywheel has a notch on it l, when all these are set in place the notch is facing 11 o'clock when I am facing it from behind the engine. Is There a DTC for the mark on the flywheel because I have heard there is. Also, if there isn't why is the cams locked at DTC? All we did was change the crankshaft, we did not remove the head at all.
Customer: replied 1 year ago.
On the diagram you posted twice for me, #2 what is that mark from? Is that the flywheel it camshafts?
Expert:  Matt replied 1 year ago.

Hello

that timing mark is on the flywheel , but to be honest as the crank pulley is keyed to the crank there's no need to double check the flywheel mark with the crank pulley mark

if you wanted to be sure the engine is on Top dead centre then use a dial guage with a long probe through the plug hole to touch on the piston

the dial gauge then is pushed back by the piston so you can then measure the top dead position

Customer: replied 1 year ago.
I see the piston on DTC when the crankshaft is set to it. Then why would the camshaft be getting stuck? I removed the tranny and I am thinking of removing the entire engine again because I have no idea why the camshaft sprocket is stuck when #1 piston is at DYT but when I pass DYC by an inch the camshaft moves freely.
Expert:  Matt replied 1 year ago.

Hello

OK sounds like the cam sprocket to the camshaft isn't correct as I suspect the cam timing is out so valves are touching pistons

I'd go back and double check the cam to cam timign with the chain is correct and then use a probe into cyl no.1 to check the piston position with the crank pulley marks

Customer: replied 1 year ago.
Could you give me a diagram for the cam timing and the how to use the probe. One question, how could nor the cam timing be off is I did. It not move it at all. Please explain so I could understand.
Expert:  Matt replied 1 year ago.

Hello

If you did not remove the cam sprocket / belt pulley from the cam or the small chain sprokcets off the back of each cam then this is quite odd

I suggest starting from scratch with the cam timing

1st use a gauge or even a stiff piece of wire down the plug hole and with all plugs removed have your assistant turn the engine over until you see the piston is at the top of its stroke - check to see that this matchs the marker on the crank pulley

once you have the engine at TDC next check that the 2 cams are correct to each other

so fit the chain tension tool that lifts the chain up between the 2 cams and set the marks on the sprockets so they match the marks on the head and check that you have 16 chain links between each cam mark

then try setting the cam to the crank with the belt - please note that the tensioner must be fitted to pull out the slack and get the position correct

Customer: replied 1 year ago.
I removed the cam sproket after the initial problem. As I explained the DTC is set on cylinder #1 and so is the crankshaft. The main issues is that the camshaft is getting stuck after the first jump and in DTC but when the crankshaft is set past DTC the camshafts start working again. Also, I was charged on my bank account already and my problem has not been resolved. I am still in square one as I was when I requested help. The info you have provided is good but it's info I already had and did not solve the issue with the camshaft locking or getting stuck.
Expert:  Matt replied 1 year ago.

Hello

OK if cam timing is correct and the cam to cam relationship is also corrrect then I'd say its a case of checking if the piston to head clearance is correct, if the pistons have been fitted back to front then the valve cutouts will touch, if the head gasket is too thin then the pistons will touch the head

if you have a borescope I'd suggest using that to check piston orientation so you don't have to remove the cylinder head to check

Customer: replied 1 year ago.
Hi and thank you for the response. Just one question, this would happen even if the head or the pistons were not removed? I just ts removed the crankshaft and installed a new one with new thrust washers. I don't have a borescope.
Expert:  Matt replied 1 year ago.

hello

OK in that case unless the rods were rotated when you fitted the crank then the pistons shouold be in the right orientation

however something must be touching somewhere

you can buy USB borescopes very cheaply these days so it migh tbe worth the investment

http://www.ebay.co.uk/itm/Waterproof-5-5mm-6LED-USB-Endoscope-Borescope-Snake-Inspection-Camera-Scope-1M-/381476242571?hash=item58d1c1848b:g:-x0AAOSwQTVV7pMa

Customer: replied 1 year ago.
Can you tell me What color are the rod bearings supposed to be to my car because I bought them from the dealer and they told me they come color coded and gave me yellow ones. If the rod bearings were wrong will that cause the camshaft to lock the way it is? I will look for that camera it might help.
Expert:  Matt replied 1 year ago.

the rods are colour coded from engine to engine and each engine is different

so you need to match the colour coding to the original parts than came out

however unless the rods are tight on the crank pin then the engine should still turn over fine and this won't effect the cam locking up