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A question for 1.8L engine owners/builders
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raygreenwood
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Joined: November 24, 2008
Posts: 21476
Location: Oklahoma City
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PostPosted: Sun Oct 29, 2017 6:18 pm    Post subject: A question for 1.8L engine owners/builders Reply with quote

So.....I am building a stock 1.8L for a Samba and STF member for his 1974 variant.

Its going to be about 90% stock. The only signifcant changes are a Web #73, deleting the head gasket and if I can manage it...a bump to 8.0:1 compression from the sad and hot running 7.3:1 compression it had.

I have had no issues in the pastwith running and tuning the 1.8L with Web 73 and slightly better compression. Its an improvement.

The heads were built about 15 years ago by a reputable type 4 head builder and have been waiting shrink wrapped......no mention of who built them. ...until I get things sorted out since its been so long. If everything is perfect...they will be mentioned. If not.....well 15 years is a little too long to get bitchy about something after the fact right? They will be CC'd in the next day or two but it looks like there was just enough of a clean up cut to take a little out of the combustion chamber....which along with deleting the head gasket and base shim....may get me close in compression.

The heads have new guides with correct stem to guide clearance....new seats with good inside blend. The valves are hardened tip/chrome stem.....the brand....mmmmm....not 100% sure.....it "could" be Ivam.....has a diamond logo and SE next to it on the stem. They are not SI....I dont think. Just cannot remember that logo. If anyone knows that would be nice but they appear to be good valves.

The head part # 021 101 371 S

The owner took his old heads off of his original engine and sent them to be rebuilt.

The problem and the questions:

1. These heads....have 39mm x 33mm valves. The 1.8L 412....and every 412 and 914 I have worked on....have 41mm x 34mm valves.

Now...in the past....I have built a couple of all stock 1.8L ...with bus valves. And while I feel it made tuning a little more sluggish....they ran ok. Not perfect.....but OK.

However....I have never ran what are essentially bus heads on a 1.8L...with higher compression and a web #73...which is NOT bone stock cam. I feel a 5% decrease on intake and 3% exhaust....will be a loss with the new cam and compression.

What do those of you with experience think?

2. The valves....were ground with a single angle.....which I am not going to leave alone. I cannot believe they did that.

The owner.....sent his old heads...and if they were original (and I beleive they were)....either they rebuilt his heads thinking they were just going on a bus....or they simply swapped a set of finished bus heads off the shelf.

The rest of the build:
New lifters and gear of course.
NOS Kolbenschmidt shallow dish pistons with KS jugs as well....nice
NOS Kolbenschmidt main and rod bearings from 25 years ago....nice!
Double thrust cam bearings
Stock windage tray...with oiling mods
The stock type 4 pump I will rebuild....lap for endplay, pin the shaft and anodize the body
NOS new pushrod tubes....how nice!
Crank is nice....nice machine work. Have not meaured yet but its tag says .010 under.
Case is an EA and looks to be in good shape. I will get the bore gauge on it next week or so.
Porsche swivel feet adjusters
Solid rocker spacer kit from type 4 store.

Also....this appears to be a classic 1.8L engine from a 412....it has the 12mm flywheel seal bore.

Interestingly....the cam web where the threaded bore is that normally causes the type 4 "case syndrome"...already has a very cleanly done helicoil in it. Though I hate helicoils.....it is so nicely done that I will probably weld the safety feature feet onto the oil pickup bell and leave it alone. That will prevent accidental breakage.

Thanks in advance! Ray
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anglodeutsch4
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Joined: September 02, 2003
Posts: 169
Location: Clear Lake, TX
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PostPosted: Fri Nov 03, 2017 7:17 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

You running D-Jet on it? I had a Web 73 on the Nomad before it dropped its valveseat, I found I had to do some MPS recalibrations, and add some CHT sensor bias resistance to get the idle and low end response smoothed out with stock D-Jet and a 1.8L with that same valve setup.
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anglodeutsch4 (Samba)
73 VW 412 (the Nomad, dropped valve seat land now, argh!)
67 MGB (Built-In Rust from Abingdon)
2002 NB TDI (40 MPG)
2009 JSW 2.5 (love it, love it, love it!)
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raygreenwood
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Joined: November 24, 2008
Posts: 21476
Location: Oklahoma City
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PostPosted: Fri Nov 03, 2017 11:00 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

anglodeutsch4 wrote:
You running D-Jet on it? I had a Web 73 on the Nomad before it dropped its valveseat, I found I had to do some MPS recalibrations, and add some CHT sensor bias resistance to get the idle and low end response smoothed out with stock D-Jet and a 1.8L with that same valve setup.


No actually.....I run 1.7L with D-jet...have run web #73....and as you note....some tweaks to MPS and some sensor ballast fixes everything. I would never say that D-jet is easy....but I have it worked out. My next 1.7l build has a Raby 9550 cam going in with 42 x36 valves, 8.5:1 compression and a lot of little tweaks.

As I noted....this is a 1.8L with L-jet i am currently building. I have no issues with the web 73 with L-jet either.
Its the small valves ....and the combination of web 73 ...and L-Jet ... I was questioning.

The 1.7L's I run...drive and tune much better with 41x35 or 42 x36 valves.

The 1.8L I am building originally had 41x34.....but the shop that built the heads.....made the "assumption" that they were for a bus....and made them 39 x 33.

I have aready reached the decision to have them reworked to the correct 41 x 34.....but thank you for your reply. Ray
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Vanapplebomb
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Location: Holland, MI
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PostPosted: Sun Nov 12, 2017 2:53 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

Ray,

My experience with valve size on 1.8 heads is that carbed heads had 41/34 valves, and Ljet heads had the smaller valves. I haven’t seen any Ljet engines with the 41/34 valves.

Not saying that is always true, but that so far has been my experience. Wink [/quote]
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raygreenwood
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Location: Oklahoma City
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PostPosted: Sun Nov 12, 2017 3:22 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

Vanapplebomb wrote:
Ray,

My experience with valve size on 1.8 heads is that carbed heads had 41/34 valves, and Ljet heads had the smaller valves. I haven’t seen any Ljet engines with the 41/34 valves.

Not saying that is always true, but that so far has been my experience. Wink
[/quote]

There were no carbed 1.8s in the US. All were L-jet....at least on 412 and 914....and all Ichave ever seen came with 41 x 34. Ray
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Vanapplebomb
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PostPosted: Sun Nov 12, 2017 6:48 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

What I meant was I have only seen the busses with them. But if Ljet T4 engines have had them too, that’s possible. Just haven’t seen it. I wonder if there was any ryme or reason as to why some Ljet had small, and some larger valves?
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raygreenwood
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Joined: November 24, 2008
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Location: Oklahoma City
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PostPosted: Sun Nov 12, 2017 10:14 pm    Post subject: Re: A question for 1.8L engine owners/builders Reply with quote

Vanapplebomb wrote:
What I meant was I have only seen the busses with them. But if Ljet T4 engines have had them too, that’s possible. Just haven’t seen it. I wonder if there was any ryme or reason as to why some Ljet had small, and some larger valves?


Yes the 914 and 412 had not only larger valves but larger runners. Its all in the books.

The bus type 4 engine...whether 1.7, 1.8 or 2.0....is a horribly de-tuned, hot running, parts gobbling, low mileage mess...compared to the 1.7 anx 1.8 in 411/412 and 914......and even the 1.8L in 412 and 914....was detuned to some extent.

The bus had huge weight, very low gearing and smaller tires. It needed higher port velocity more than it needed higher volume efficiency.

The 412 and 914 had totally differnt ECU and AFM and put out totally differnt HP and torque. Thats why L-Jet in 412 and 914 are TOTALLY different engines than the bus.
Different valves, different,compression and different cam... and about 10hp more at about the same torque...but at a 400-500 rom higher peak.

Thats the problem. The heads were rebuilt years ago...and very well...but to BUS specs....not 412/914 specs.

And dont let me just insult the bus here Laughing .....the 412 and 914....1.8L were very robust...and miserable engines. Not nearly as miserable as any bus type 4 engine engine.....but due to emissions.....they upped the CC's from the 1.7L.....and went to larger valves and a decent fombustion chamber shape... which should have been reason to cheer....and put a simpler....though somewhat less adjustable....EfI system on it....ok....but then they dropped the compression....not just with a larger deck....or going to a flat top....but with a DISHED piston AND large deck.....and dialed back advance...and put a crappier cam in it.

So the 1.8L in the 412.. while it has half the piston dish volume of the bus....and more compression....and larger valves....its still a lean burning, hot runn8mg, sloppy....but reliable....combo.
I plan to keep the good parts of that combo....the Cc's, the chamber and larger valves and runners, and go to a better cam. It should drop 30-40° at the heads and pick up 10hp minimum.

Its kind of a moot question I asked now.....the owner and I booth agree we should have these frshly rebuilt heads....rebuilt again to proper specs. Ray
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