Type 4 questions

[buzzkillg230rc]

Hi,
Im new to the forum and thought this would be a good place to ask about some concerns i have in regard to me rebuilding an engine.

I currently have a 76 Porsche 912e, its stock with 94mm pistons and 71mm stroke. it also has the complete fuel injection on it working. the reason for the rebuild is due to an exhaust valve leak. (hence it wont pass smog) .. I'm in the process of dropping the engine and since its going to come out for the heads to be worked, I was considering bumping the engine up to a 2056 using a 96mm kit and retaining the stock crank.

My questions are:
1. in doing this can I still use my stock heads or do they need to modified?
2. if i bump up the displacement, would i have issues in passing smog assuming everything is functioning as it should?

any responses and help is appreciated.

Thanks

[Bsherrard]

welcome to the forum. you might want to take a look at the air-cooled technology forum (http://www.shoptalkforums.com/viewforum.php?f=47)
there is a lot of good information there. I am not an expert but I am rebuilding my 912E to a 2270 and have done a lot of research and read many forums related to both the 2056 and 2270 upgrades. My understanding is that to go to a 2056, you may want to do some minor modifications to the heads. You should be aware that the heads on these engines are notorious for getting cracks due to overheating / heat cycling so that may very well be the issue with your exhaust valve leak. They also suffer dropped seats. Finding someone to work on the heads may be difficult unless you live in California and it will not be inexpensive. You can go to type4store.com and look up their 2056 kit to get an idea of what a complete overhaul/rebuild would entail based upon the Jake Raby kits from back in the day. You can use this list as a starting point and then identify what parts you can reuse from your engine, what parts you can source from other (less expensive) places and what (if any) parts you need to get from them. If you need new heads, the options are the RS+ head from the type 4 store (expensive but the best) or get some made up using the new castings available from AApistons.com I am aware of at least one other person doing a 912E that was able to get heads made from these castings from Brothers Machine in California. From what I have read, going to a 2056 is the absolute most you can do and still maintain the original EFI and smog. I have seen posts of people saying they were able to pass the smog in California with that setup and the stock cam. I'm sure others will have more to offer but this may at least give yo something to think at.

If you interested, I have a build thread here: http://www.912bbs.org/vb/showthread.php ... d-for-2037

Good Luck, Brook
p.s. it helps to give your name when you post. People are more willing to reply to a personal request.

[wreck]

Just curious on the 912 heads , are they the same as the 2lt 914 , i.e. different spark plug angle and 3 intake manifold studs ? if they are just normal type 4 heads then you have a few options depending on your budget . new standard AMC heads are a good option . the bigger the budget then that opens up for porting and bigger valves etc . If in the States then Len Hoffman or EMW would be worth a call . AA pistons have a fair range of stock and modified heads as well , I'm just not sure on the quality of their valves etc.

There are a lot of pit falls in building a reliable type 4 . things like new oil pumps not fitting and deck heights(longer cylinders) need to carefull attention, there is normally people on here that can give good advice and know the engines inside out .

[Bsherrard]

here is a link to a whole bunch of threads that someone gave me a while ago. lots of really good information on type IV builds.
https://www.thesamba.com/vw/forum/searc ... h_forum=12
The 912E heads are the same as the 914/2.0. They are 3 stud and have the same spark plug angle.
Len does not do any work on old heads, only does new ones which are sold through the type4 store. I am getting a set of the RS+ for my rebuild and had him increase the valves to match the LE180's that Jake used to use on his 2270 kits.
Brook

[buzzkillg230rc]

My name is DeAngelo
Im not far from brothers and might go pay them a visit after i pull the motor. Thanks for the links and responses.

[Bsherrard]

DeAngelo -
any update on your 912E project?
Brook

[raygreenwood]

To be more precise....yes....the 2.0L 914 heads are notorious for cracking. Not the 1.7L or 1.8L.

Also....none of the type 4 heads......used normally and maintained properly in TYPE 4 ASED VEHICLES .....meaning 411, 412, 914, 912....are notorious for dropping valve seats. That is an issue with type 4 heads used in the VW bus.....which weights twice as much, has the aerodynamics of a brick, low gearing and chronically overheat the heads.

All of that being said....in the type 4 2.0 engine.....specific to 914 and 912.....at this late date in time virtually all of the castings ard 40 + years old....and will cost far more than they are worth to have welding done, new seats etc.

You can now buy brand new 2.0L 914 castings from several places. Do some seraching here. Ray

[buzzkillg230rc]

DeAngelo -
any update on your 912E project?
Brook

Hi All,
I had the heads rebuilt by Brothers Machine Shop in Ontario, I also went with the bigger cylinders and pistons, bumping it to 2056cc. I used my stock cam and really only swapped the piston,jugs and used the rebuilt heads.
On thanksgiving day I attempted to take the car out for a spin around the block for its first time after a 20 min break in, the porsche gods thought otherwise as my rocker arm stud cam out on the number 3 cylinder. I ended up dropping the engine again and had that repaired. since then iv'e been tuning the car and just recently took it for smog, I ended up failing smog by 1.92 on the CO side. everything else was great. we attempted to lean the car out a tad using the bypass screw on the AFM. unfortunately the car started backfiring after the change (it was not the bypass screw causing the backfire) turns out my EGR/oil breather tube cracked at the joint and was sucking in air, along with that I found my fuel pressure regulator vacuum line unplugged. As of Friday last week (Jan 5th 2017) I fixed the tube, but i feel the car is not running right once again. yesterday I went through the engine and performed a leak down test and found cylinder 1 is loosing 20% psi (per my harbor freight tester) when i listen to the engine i hear it leaking slightly via exhaust valve. I'm debating on dropping the engine to examine the heads and maybe return them to the machine shop if needed. I don't even have 100 miles on this rebuild and just find it odd that the head is leaking.

DeAngelo

[Bsherrard]

DeAngelo -
sorry to hear about your problems. Saw your posts over on the 912BBS. Really doesn't make sense about your heads leaking?

I haven't even started my rebuild yet. Should get my cam bearings this week and then hope to start putting it all together the following week.
keep us posted on your troubleshooting.

Brook

[raygreenwood]

DeAngelo -
any update on your 912E project?
Brook

Hi All,
I had the heads rebuilt by Brothers Machine Shop in Ontario, I also went with the bigger cylinders and pistons, bumping it to 2056cc. I used my stock cam and really only swapped the piston,jugs and used the rebuilt heads.
On thanksgiving day I attempted to take the car out for a spin around the block for its first time after a 20 min break in, the porsche gods thought otherwise as my rocker arm stud cam out on the number 3 cylinder. I ended up dropping the engine again and had that repaired. since then iv'e been tuning the car and just recently took it for smog, I ended up failing smog by 1.92 on the CO side. everything else was great. we attempted to lean the car out a tad using the bypass screw on the AFM. unfortunately the car started backfiring after the change (it was not the bypass screw causing the backfire) turns out my EGR/oil breather tube cracked at the joint and was sucking in air, along with that I found my fuel pressure regulator vacuum line unplugged. As of Friday last week (Jan 5th 2017) I fixed the tube, but i feel the car is not running right once again. yesterday I went through the engine and performed a leak down test and found cylinder 1 is loosing 20% psi (per my harbor freight tester) when i listen to the engine i hear it leaking slightly via exhaust valve. I'm debating on dropping the engine to examine the heads and maybe return them to the machine shop if needed. I don't even have 100 miles on this rebuild and just find it odd that the head is leaking.

DeAngelo

How do you know its the head leaking?

You performed a leak down test and found 20% leakage on one cylinder...at what...100 miles? The 20 minute break-in is for the camshaft and lifters only...and 100 miles of travel does very little toward total and complete break in of the cylinders, pistons and rings.

Typically on a well built type 4 engines I do not consider the cylinder break in complete until about 1000 miles....and usually I still see compression readings rising steadily but in small amounts through 5000 miles on numerous builds. Also....have you re-checked your valve adjustment?

Did you lap the cylinders to each seat? Or...did you use the head gaskets...which you should not. VW stopped using those for good reason and sent out a tech bulletin many years ago. Ray

[Bobby74]

If its only leaking out the exhaust valve, check the valve lash.
If the valve lash tightened up (zero), it will hold the valve off the seat.

If you have proper lash and it still leaks, the valves weren't lapped into the seats....
In that case, it MAY seal eventually, but you might have to take it back off if it doesn't start to seal or you could risk burning the seat/valve.

Also check your ignition timing, if the distributor was bumped, it may have shifted your timing way off. That may be causing the other backfiring you were describing, if its not a vacuum leak.