4BD1 injection timing

[JDNSW]

I am planning to check the injection timing on my engine, but I seem to remember someone telling me the figure in the manual is incorrect - anyone know for SURE what it should be?

[p38arover]

Ring Brad at KLR Automotive (02) 4721-3675. They know the 4BD1 - their favourite engine. All three of the mechanics have 4BD1-T powered Land/Range Rovers

Ron

[THE 109]

Had a go at checking the timing on my engine today but couldn't get the marks to line up on the crankshaft aswell as the injection pump,did quite a few revolutions in the hope that it would come up but no luck.
In the end I removed the timing cover, re-aligned all the gears and reset the valve lash. Then I counted how many revolutions of the crankshaft it would take until all the timing gear marks would line up again.
Anyone want to take a guess at it?

Eric

[Bearman]

10 degrees btdc I am pretty sure John.
Just checked my book and that figure is for the 4BD1T. It says 13 degrees for a NA 4BD1

[lambrover]

Had a go at checking the timing on my engine today but couldn't get the marks to line up on the crankshaft aswell as the injection pump,did quite a few revolutions in the hope that it would come up but no luck.
In the end I removed the timing cover, re-aligned all the gears and reset the valve lash. Then I counted how many revolutions of the crankshaft it would take until all the timing gear marks would line up again.
Anyone want to take a guess at it?

Eric

45, how many was it?

[wrinklearthur]

Had a go at checking the timing on my engine today but couldn't get the marks to line up on the crankshaft aswell as the injection pump,did quite a few revolutions in the hope that it would come up but no luck.
In the end I removed the timing cover, re-aligned all the gears and reset the valve lash. Then I counted how many revolutions of the crankshaft it would take until all the timing gear marks would line up again.
Anyone want to take a guess at it?

Eric
2 .

[THE 109]

Not even close, it took 107 turns of the crankshaft give or take a couple as there is a possibility that I miss counted once or twice.So a couple of tips are to remove the glow plugs and disconnect all the injection lines before you start. I had the radiator out aswell to get a socket on the crankshaft nut.
For anyone trying to do their timing and can't find the marks you now know that you could have quite a job ahead of you, checking for the marks every revolution.

Eric

[Dougal]

Do you just want to check the timing or do you have an issue that needs resolved?

I've run the whole range of timing adjustment on my 4BD1T and simply through experimentation found the factory marks (on the pump mount) by coincidence are the best place to run my engine.

More advanced gives you a louder engine with more vibration and a fraction more power. On a turbo engine it delays boost arrival.
More retarded gives you a smoother and quieter engine with less bite but on a turbo engine it brings boost in a little sooner too.

A few hours experimentation (one of the bolts is an absolute PITA to get to) will show you how your engine responds and you'll then know exactly where you want it to be.

Regarding the timing marks. I think my flywheel also has a mark that shows up at TDC through a hole in the engine bellhousing.

[THE 109]

Dougal,

I was checking the spill timing after rebuilding the engine which I made sure the gears were fitted properly.I thought the injection pump mark which is seen through the inspection hole in the timing cover would come up every 2 revolutions or so,but after about 10 turns I thought there was something wrong.While the timing cover was off it was a good learning experience to find out find for sure how many turns to get all the gears to line up again.
The flywheel mark you mention will show TDC but won't help much for the injection pump mark.
The bolts for injection pump aren't a problem at all,the outer 2 I used a normal spanner.The inner 2 I used a couple of 3/8" drive wobble extensions coupled with the ratchet and socket.
I have set the timing at 10 deg but haven't tried it yet,been busy doing other things.

[Dougal]

I came to the same conclusion regarding the front timing case gears. I figured they might never line up again, but it's good to see you had the staying power required.

Last time I had the pump off I found TDC, hoped I had it on compression instead of exhaust and just fitted the pump with the window and mark lined up. The backlash in the gears means it doesn't line up quite as well as I was expecting it to.

Big relief when it started.:D

[THE 109]

After speaking with my ex boss about it he said it's normal,some detroits are 96 turns and others can be in the hundereds somewhere.He mentioned if you're not paying close attention you could miss the mark as it goes past,he's seen fitters turn engines for hours and still not get it.

[HotWired]

Quick question.

1. When installing the pump, It is done at TDC and the advance line/pointer in the inspection window lined up. Then timing is set by turning the injector pump left or right?

2. Or do you install the pump at 10-13 degrees and the advance line/pointer in the inspection window lined up.

Reason I ask is when I first rebuilt the engine, and reinstalled it I did #1 (according to the manual) but found Id loose power on any slight incline. I then rotated the pump (pulled top away from block) and this fixed the problem.

Just want to make sure that it is set up correctly.

When I checked the timing according to the manual below. I found that when fuel appear at the top of delivery valve holder #1, the timing mark was some distance to the right of the 'TDC' mark. I assume this is after TDC and incorrect?

Thanks for the help.

http://img6.imageshack.us/img6/7504/zz4t.jpg

[HotWired]

Having another look at it. I think ive installed it correctly. As both inspection plate pointers line up on TDC. I also remember lining all the letters up during assembly.

So only real question is now. Is the timing right with the IP pulled away from the block and fuel showing past the TDC timing mark?

[Bush65]

R & R the IP when #1 is at TDC, on compression stroke (both valves closed).

Note because of the helical cut gear teeth, the camshaft of the IP turns slightly as you remove it. You need to have the timing gear at the same location before replacing the IP to allow for the reverse rotation. The marks should be lined up when the IP is back in place.

Also note that the Vee belt pulley that drives the coolant pump and alternator is fitted to the hub with a rubber insert, to make the assembly into a harmonic balancer, it is not unknown for the pulley, with the marks, to have moved out of the correct position.

Regarding the old posts about the alignment of the timing marks on the idler gear, the reason that it tales 102 revs for the marks to re-align is because the gears on the camshaft and IP have 50 teeth and the idle gear has 51 teeth (the pinion on the crank has 25 teeth. So for one rev of the crank, the idler, camshaft and IP rotate by 25 teeth. This is exactly 1/2 turn (25/50) of the camshaft and IP but 25/51 of a turn of the idler gear. BTW this is waht is called a "hunting tooth" and is purposely done to spread tooth wear uniformly.

[Offender90]

10 degrees btdc I am pretty sure John.
Just checked my book and that figure is for the 4BD1T. It says 13 degrees for a NA 4BD1

Brian,

What year is your manual from? - my October 1988 manual says 13 degrees BTDC for a turbo engine (non boost compensated pump).

[Bush65]

Brian,

What year is your manual from? - my October 1988 manual says 13 degrees BTDC for a turbo engine (non boost compensated pump).
Up to 1988, timing for a 4BD1T was 10* BTDC, post 1988 it was 13* BTDC