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L28 Timing

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Does anyone know of any tricks to set timing on a l28 instead of ripping apart the whole front of the engine and wasiting the new oil and antifreeze in it. I had to replace a headgasket and I am 99% sure I had the timing where it needed to be. But its sounds like it is off. Thanks for any help.

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Does anyone know of any tricks to set timing on a l28 instead of ripping apart the whole front of the engine and wasiting the new oil and antifreeze in it. I had to replace a headgasket and I am 99% sure I had the timing where it needed to be. But its sounds like it is off. Thanks for any help.

 

You mean the camshaft timing, correct? For ignition timing you know you can turn the distributor? Also, are you sure that the oil pump shaft is timed correctly?

 

You can check the cam timing by getting cylinder 1 at TDC with both valves on Cylinder #1 closed. Look through the hole in the timing sprocket at the notch. It should line up pretty closely to the mark on the cam tower plate.

 

Here is a good pic I found on the internet:

 

tm2b.jpg

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Double check all the stupid stuff. I've wired my spark plugs wrong way round the dizzy before. Damn thing started too! You never know what you might miss though.

 

Regarding the dizzy, just set it to TDC, pull the dizzy off and check to make sure the shaft is close to vertical. Should be pointing at about 11:45 with the face of the half circle pointing towards the back of the car. If that's good, then putting the dizzy in the middle of the range should be fine.

 

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How to determine if your camshaft and chain is installed correctly is described in the Engine Mechanical section of the FSM, with illustrations. All you have to do is turn the engine in its normal rotation direction and stop it at TDC, then eyeball the marks. It takes minutes.

 

While you have the engine at TDC you can also check the rotor in the distributor to see if things are correct there. It should be pointing at a spot between straight ahead and the left headlight. Put you #1 spark plug wire where it is pointing, then install the rest in order.

 

These two things are critical to getting the engine to run, but are very easy to confirm.

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Before you freak out about your compression numbers: do a valve adjustment. Tight valves can cause very low compression readings - the exhaust valve is held open longer. Then make sure you have a full battery, all spark plugs removed and throttle wide open when you do the test.

 

Sam

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I did a compression test and these are the results.

 

1. 120

2. 60

3. 90

4. 60

5. 140

6. 40

 

put some oil in the cylinder before you do your test, this will give you a idea about where the issue is.

 

if the compression comes up, it's rings (stuck / worn / broken or bad cylinder - scratches )

 

if it does not come up, valves or head gasket

 

I hope this helps

 

Nigel

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I am running the same problem as you.Your compression reading for Cyl#2,4 and 6 are too low. Brig your corrosponding piston on TDC and blow air through spark plug holes and if the valve is bent you can listen the hissing sound.

 

If you fix this problem let me know as I have pulled the timing out and now facing the same problem as you.

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I think you are getting off track:

Your car ran before? if yes lets forget about compression testing for now. Deal with it later if you cannot start using a normal troubleshoot and you suspect you have damaged the valves.

 

Describe exactly what you did to get from a running car to a not-running car, did you remove the head, change the cam, adjust the valvetrain etc etc.??? more information is better.

 

Then work through it.

1. Determine the cam position is correct BEFORE TURNING THE ENGINE ONE INCH!!!

2. Determine you have correct spark and at the correct time using a timing light on cyl#1 at ~10BTDC, if not either your distributor position is wrong or your dizzy shaft. if you remove the dizzy shaft dont forget to reprime your oil pump before reinstallation.

3. check your Firing order is correct

4. now start looking for fuel, disconnect the distributor and crank the engine a few cycles... are the plugs wet? if not you have an EFI issue. Double check your injector firing by using a screwdriver to listen to injector pulses (place one end on the injector, one on your ear and crank listening for "click click"

5. If EFI is to blame search for loose connections, poorly installed connectors etc.

6. FAILING ALL THIS you may need to do a proper compression test and determine if you have some busted or bent valves...

 

Cheers,

-pete

Edited by kolonelklink87

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