1.8 L-Jet to 2.0 L-Jet. Any advice? Options

[mapguy]

Howdy,

I have just torn down a bone stock '74 1.8 L-Jet from another 914 with plans to build it back to stock. Plan is to drive my 914 with this engine while I build the original 2.0 the way I want it. I get experience building my first type 4, and get my teener back where it belongs. On the road.

I have the parts available to swap out the crank, rods, and P/C from a '76 2.0 to make it a 2.0 L-Jet. I'm very tempted to do this, as I rarely turn down cheap horsepower! No replacement for displacement, right?

Any land mines I should look out for? Main concern for me is the stock L-Jet system. I understand I might have to tune the MAF for the extra displacement, but I can't find anything discouraging me otherwise. I found an article that details a 3-step process for MAF tuning, but am too lazy to look up the link. Do tell if you know something I don't.

More details:

As implied, stock '74 L-Jet system
Stock '74 1.8 heads (41x34, I believe)
web cam 142/lifters
necessary machine work
Cylinders honed and new rings (I have a set of 94s in excellent condition)
Full re-seal on engine and all peripherals
New fuel lines, vacuum lines, etc etc...

One other thing, I haven't built many engines, but all the ones I've been involved in pop through the intake when first firing them off, and one in particular did it several times before finally lighting off (my old bus engine was a PITA to get running first time). Won't this be dangerous for the MAF on first start? All my experience is with carbed engines. Does this just not happen on FI engines?

Any advice is greatly appreciated.

[mapguy]

One thing to add:

My cocktail napkin compression calculation comes out around 8.1:1. I'm thinking that sounds about right, but again, I'm open to advice/criticism.

I'll also be at the G&R Sunday if anyone wants to poke fun at me. (IMG:style_emoticons/default/poke.gif)

[ClayPerrine]

I have already done this. It works fine. I have even run 1.8L L-Jet on a real 2.0 motor.

Don't mess with the air flow meter. It will compensate for the extra displacement.

Are you using 1.8 or 2.0 heads? If you use the 1.8L heads, you are limiting yourself on the valve size. You could always have them redone with 2.0 valves. That will help a bunch.

If you use the 2.0 Heads, you will need to be careful about the intake hoses. The runners on the 2.0 have slightly longer tubes. You can compensate by using radiator hoses in place of the intake hoses.

The 1.8L throttle body is the limiting factor. It is way too small for a 2.0L motor. There is a bus throttle body that is a bolt on replacement for it that is much bigger. I saw it in a thread here, but I don't have the link handy.

Everything else in the induction system will be a bolt on, plug and play setup.

Good luck!

[ClayPerrine]

Make sure you static time the ignition to prevent the pop through the intake.

Set the engine on the timing mark for 7.5 degrees. Using points, connect a test light to the point lead, and the other end to the positive battery terminal. Turn the distributor until the light just goes out. That will set the distributor in the correct spot. Make sure you have the wires on right, and you shouldn't have to worry about the timing.

[Dave_Darling]

Is the 142 a hydro cam? I'd stick with solid lifters, myself...

--DD

[914Sixer]

Clay is right about the 2.0 bus set up. Go to theSamba and see if something is available in the the way of the throttle body and intake. If you go that way you can use the 2.0 bus heads. New ones of those are available for $400 each, about the cost of rebuilding your old 1.8's.

[mapguy]

Thanks all!!

Is the 142 a hydro cam? I'd stick with solid lifters, myself...

According to the Web Cam site, this is a stock solid lifter grind - http://www.webcamshafts.com/pages/automobi...693_002437.html

I like web cam quality, and decided to pay a bit more for a quality cam and lifters in this one.

I have already done this. It works fine.

Thanks Clay!! This is exactly what I was trolling for. Thanks for the advice on the AFM and the bus intake. I'll start scrounging for one, and not tuning the AFM will save some time.

Set the engine on the timing mark for 7.5 degrees. Using points, connect a test light to the point lead, and the other end to the positive battery terminal. Turn the distributor until the light just goes out. That will set the distributor in the correct spot. Make sure you have the wires on right, and you shouldn't have to worry about the timing.

Interesting... I have always set the static timing with a timing light and set it to when the light just comes on for #1. I will give this procedure a shot this go-round and will give plenty of rum to Jobu.

[mapguy]

you can use the 2.0 bus heads. New ones of those are available for $400 each, about the cost of rebuilding your old 1.8's.

Don't the 2.0 bus heads have much smaller valves? I was planning to stick with the 1.8s I have due to the larger valves and the fact that they appear to be in great shape. I would consider bus heads if they are better for this application, but that might come down to a wallet-driven decision. If the 1.8s are cheaper to refresh, I'll go that route.

This engine was in pretty good overall condition when I tore it down, just really dirty. It had never been apart, and other than the cam and lifters (toast) looks pretty good on initial inspection with mics and fingernails and what not. The cylinders still had the hone marks in them, no sunken valves, etc. I'm hoping the machine bill will be pretty small to get it ready to reassemble. Machine shop will be the judge of that, though.

[type47]

Set the engine on the timing mark for 7.5 degrees. ...

What's the theory behind which/where to time the engine? L-Jet is set at 7.5, D-Jet is set at 27 (ish?). If you put L-Jet on a 2L, you wouldn't use the 27 for a 2L? If you put D-Jet on a 1.8, would you use 27 degrees? So the timing degree is induction dependent? If I put a CIS system on a 2L, would I time it at 27 degrees?

https://www.youtube.com/watch?v=K_A7rPcvYCM

[pilothyer]

Set the engine on the timing mark for 7.5 degrees. ...

What's the theory behind which/where to time the engine? L-Jet is set at 7.5, D-Jet is set at 27 (ish?). If you put L-Jet on a 2L, you wouldn't use the 27 for a 2L? If you put D-Jet on a 1.8, would you use 27 degrees? So the timing degree is induction dependent? If I put a CIS system on a 2L, would I time it at 27 degrees?

https://www.youtube.com/watch?v=K_A7rPcvYCM

The Timing for the L Jet 1.8 is set at only 850 RPM thus the 7.5 BTDC Set it at that and then check it at 3500 RPM You will be close to or right on 27 degrees BTDC. It is really a matter of what rpms full advance comes in.

[type47]

OK. So theoretically you could time a D-Jet motor to 8.5 degrees at idle and check for 27 at 3500? I'm not suggesting this but there is a linearity in advance between 850 and 3500?

No, wait a minute. I remember I was told there are two advance springs in the dizzy so it's not linear

[revhi109]

I am also running 2.0 Cylinders with 1.8 heads. Now I'm curious about the restrictive throttle body. Does anyone know a part number or inner diameter dimensions for the bus 2.0 TB?

[type47]

There is a bus throttle body that is a bolt on replacement for it that is much bigger.

Here is one/are some FS on the Samba. (no affiliation)

http://www.thesamba.com/vw/classifieds/sea...s=throttle+body

If I recall, the 2L engine started in the bus in '79 (maybe 78?) and continued through until '83.5. I looked in a VW online parts catalog for a part number for an '81 Vanagon but it gave no pn and listed it as NLA.

[Root_Werks]

I converted a 2.0 with carbs to L-Jet, the thread is here:

http://www.914world.com/bbs2/index.php?sho...104990&st=0

[MrKona]

I am also running 2.0 Cylinders with 1.8 heads. Now I'm curious about the restrictive throttle body. Does anyone know a part number or inner diameter dimensions for the bus 2.0 TB?

The stock L-jet throttle body has a 45mm bore. Vanagon with the 2.1 engine throttle body is 50mm.

I'm running stock L-jet on a 2.0 engine, but the project has been on hold for the past couple of years. It runs, but I haven't sorted it. But I have a Vanagon throttle body in my parts bin and this thread inspired me to switch out the stock L-jet body.

But I'm already finding that the flat spot on the lower shaft of the vanagon TB that engages the TPS is in a different position than the 1.8 L-jet shaft.

What is means is that when the Vanagon TB plate is in the closed position, the 1.8 L-jet throttle position switch is at about half throttle position.

I can't use the stock L-jet shaft because the recessed area in which the plate fits is sized for a 45mm plate and not the 50mm.

Since the TPS is a potentiometer, this will affect the voltage signal going to the stock 1.8 L-jet "brain." How would one (or can one) compensate for this with the stock brain? Does the input from the TPS have that much of an effect?

[MartyYeoman]

I thought the TPS is a binary switch, only activated at WOT.

[MrKona]

I thought the TPS is a binary switch, only activated at WOT.

Marty - I just put a multimeter on the leads and it looks like you are correct. I saw resistance changes (just moving it without installing on the TB) only at the closed and near full throttle position. I guess that's why it's called a throttle position switch. (IMG:style_emoticons/default/biggrin.gif)

Unfortunately, the L-jet TPS stops the full range of motion of the plate when using the shaft from the vanagon TB.

I tried turning the TPS around 180 degrees. In that case, the TPS allows the TB plate to move from closed to full throttle position, but there are no resistance changes.. The mix/match of components appears not to engage the TPS to the full throttle position, even when the vanagon TB plate is at full throttle position in the TB.

I hope I'm explaining this clearly everyone. Let me know if pictures are needed.

[MrKona]

Of course, I could solve the entire issue by making the recess on the 1.8L TB shaft 2.5mm longer on each side to accommodate the 50mm TB flap.

I have an extra 1.8 TB for parts. I think I could probably do a half-decent job removing the metal with a bench grinder.

[ClayPerrine]

The L-Jet throttle body has a throttle position switch. It has two sets of contacts, one that is closed at idle, and one that is closed at WOT.

If I were you, I would file the end of the vanagon throttle body shaft to make a new flat for the throttle switch from the L-Jet throttle body.

[MrKona]

I ended up lengthening the recess to fit the Vanagon plate on the stock 1.8 L-jet throttle body shaft.

I created a separate progress thread here.