1.8 engine timing mark Options

[mcericmc]

There is only one timing mark on my 1.8 fan. It's visible through a notch on the rear side of the fan via the inspection port. Pelican parts info says the mark is TDC. Auto Atlanta says it's 7.5 degrees BTDC in the 914 tech tips 700 book. Can someone please tell me which is correct? I need to make sure the timing and valves are adjusted properly. (IMG:style_emoticons/default/WTF.gif)

[930cabman]

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wish I could be of assistance, but I have never seen only one timing mark

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[Jack Standz]

Photo

[wonkipop]

Photo

thats a D Jet fan - its different to the L jet 1.8
@mcericmc - the timing mark on the 1.8 fan is the 7.5 before TDC.
its the only mark if its an orig fan.

i think pelican parts may have confused their info with the D jet engines.
which do have a TDC mark on the fan (as well as several others).

[mcericmc]

Thanks. I think your right. What REALLY confused me is the photo Pelican Parts put on the internet of the template inside the hole showing the mark in the notch on the fan to be TDC.

From everything I've read, the mark on the fan should actually be at the arrow on the template at 7.5 degrees BTDC. Once I got that figured out, I was able to use the template to put a mark for TDC a little more than 1/2 inch to the right.

That picture really had me pulling my hair out. (IMG:style_emoticons/default/sad.gif)

[emerygt350]

I would always establish tdc regardless of what the pictures say. Never know if it is the original fan unless it was yours new.

[Jack Standz]

Ok, here's a follow-up to my previous attempt to post information on how to figure out where Top Dead Center (TDC) for cylinder #1 is on your motor. Please note that when timing the motor it is important to understand the difference between TDC when cylinder #1 is on its compression stroke versus the exhaust stroke.

You only need the TDC fan marking for valve adjustments and ignition timing. Any other marks on the fan or flywheel aren't needed. It doesn't matter if it's an ljet fan, djet fan, a bus fan, a 411/412 fan, etc.

Take a marker, white paint or even a crayon. If there isn't a mark there already, put a mark in the middle of fin #6 and fin #7 (TDC is actually a tiny bit closer to fin #6 than fin #7, if that matters to you). That's close enough to TDC for #1 cylinder to perform valve adjustments and set your timing. Even though a standard timing light can be used, strongly encourage using a dial back timing Iight.

Additional instructions start at the third post:

https://www.thesamba.com/vw/forum/viewtopic.php?t=699839

[Ninja]

Just adding verification...

I too, was perplexed by the no TDC and no 27 degree mark on my 75 914 1.8L

A swap to a 2.0l balancer is how I fixed mine...

Important to make a second TDC mark 180 degrees from the original. Make it a different color (mine's blue). This will allow accurate TDC settings for leak down testing on all cylinders.

IMO it seems silly that Porsche changed the harmonic balance markings just because of L-Jet.

Jack's method will work fine.

If you want to "fine tune" the TDC marks here's an accuracy test.

Remove plugs and do a leak down test with #1 at TDC compression. If you are within 1/2 a degree of perfect adding the leak tester will NOT cause the engine to rotate.

If you are outside this range the engine will rotate 180 degrees SO FAST it's hard to see it... (IMG:style_emoticons/default/ninja.gif)
Watch which direction it turns and cheat it a tiny bit in the opposite direction until the LD tester doesn't flip it over.

[mcericmc]

Thanks for the info.

[mjrrti]

There should be a notch in your flywheel that can be seen in the opening on the top of your trans bell housing that will be dead on TDC. I always put it there when I work on a new to me 914 and then go under the car on the bottom window and mark it there with 3 center punch dots for exact valve adjustment position also. It is helpful to be able to see the TDC mark and the center punch marks @ 180 from below to stay under the car when adjusting valves. (IMG:style_emoticons/default/biggrin.gif)

[ClayPerrine]

Just adding verification...

I too, was perplexed by the no TDC and no 27 degree mark on my 75 914 1.8L

A swap to a 2.0l balancer is how I fixed mine...

Important to make a second TDC mark 180 degrees from the original. Make it a different color (mine's blue). This will allow accurate TDC settings for leak down testing on all cylinders.

IMO it seems silly that Porsche changed the harmonic balance markings just because of L-Jet.

Jack's method will work fine.

If you want to "fine tune" the TDC marks here's an accuracy test.

Remove plugs and do a leak down test with #1 at TDC compression. If you are within 1/2 a degree of perfect adding the leak tester will NOT cause the engine to rotate.

If you are outside this range the engine will rotate 180 degrees SO FAST it's hard to see it... (IMG:style_emoticons/default/ninja.gif)
Watch which direction it turns and cheat it a tiny bit in the opposite direction until the LD tester doesn't flip it over.

The 1.8 engine is not timed at 27 degrees at ungodly RPMs. It is timed a 7.5 degrees at idle. The distributor curve for the L-Jet engine is not the same as the D-Jet engine, and timing it a 27 degrees can cause detonation and poor running in L-Jet engines.

[Jack Standz]

You are correct. That's how you time a stock ljet. (Although claiming that "only" 3500 or so rpm for djet is "ungodly" is a stretch. We regularly run our motor well past these "ungodly" RPMs. (IMG:style_emoticons/default/smile.gif) )

But, the Ninja never said that's how to time an ljet motor. He merely said that when he first ran across an ljet fan that had only one timing mark (at 7.5 degrees), it was puzzling. Makes sense when you are used to two marks. One at TDC and one at 27 degrees.

Things would be more helpful if VW had marked TDC on all it's fans (for example, bus motors, ljet don't have TDC marked).

[wonkipop]

There should be a notch in your flywheel that can be seen in the opening on the top of your trans bell housing that will be dead on TDC. I always put it there when I work on a new to me 914 and then go under the car on the bottom window and mark it there with 3 center punch dots for exact valve adjustment position also. It is helpful to be able to see the TDC mark and the center punch marks @ 180 from below to stay under the car when adjusting valves. (IMG:style_emoticons/default/biggrin.gif)

correct. there is. even for an L jet. as you suggest i have also marked the flywheel for valve adjustments when i am under the car rather than on top. no real need to refer fan markings while doing valves - which would be a pain in the arse. (IMG:style_emoticons/default/biggrin.gif) and no need to refer to TDC with an L jet doing tuning.

i have a feeling most 914s simply inherited the fan markings from the 411 and the buses.
esp easy to use the fan markings on a bus motor. fully visible. not sure if the L jet 412s got the same fan markings as the L jet 914s. maybe. never seen one. but no need for any other marking on an L jet when it comes to initial base idle tune setting.

[Jack Standz]

We had a 1.8 liter ljet motor in a 914 (now replaced with a 2 liter).

It needed a TDC marking for timing purposes.

Why? Because a previous owner had put carbs on it.

So, if an ljet fan ends up on your motor, do yourself a big favor and mark TDC.

[wonkipop]

We had a 1.8 liter ljet motor in a 914 (now replaced with a 2 liter).

It needed a TDC marking for timing purposes.

Why? Because a previous owner had put carbs on it.

So, if an ljet fan ends up on your motor, do yourself a big favor and mark TDC.

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oh yeah thats different.
i used to own a type 3 variant (twin carb aussie zero emissions spec) back half a life time ago.

i bet the 1.8 twin carb euro 914s have a TDC mark on their timing fans.
but never seen one. can't say for sure. but am guessing they did.

i think i have an engine shot of the 1.8 twin carb held in porsche museum which shows the tune up sticker. might try and dig it up. the timing sticker if legible might indicate what is on those cars.

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VW!!!!!!!
american emissions regs. !!!!!!!
its all about setting the car for emissions back then and in the good old USA. (IMG:style_emoticons/default/beerchug.gif)