Square ports

[chitwnvw]

So I have two square port heads, but they are not the same.

Part number:




Exhaust port:




Head to cylinder surface:




Last but not least, I cc'd the head and the 029 head had a volume of 53 ml, while the 071 one had a volume of 44 ml.

Anyone know what is up with this?

Is it ok to shim up the lower volume side of this engine to get CR in line from side to side?

[Randy in Maine]

Karl said it so well....we still miss him a lot....

http://www.thesamba.com/vw/forum/viewto ... nagon+head

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donemoto wrote:
Here's the problem; on my used parts rebuild (2000) engine, my 1800 heads have a streched valve on the intake of each head. I went back into my storage basement to get a different set. No valve adjustment on intake because rocker arm is up against valve stem.

What I have now are 79 and later squareport heads.

One is 021-101-321A With a step ledge where sealing rings goes.

Other head is 029-101-371B with no step ledge.

Can I get by with adding metal gaskets to 029-101-371B and leaving the gaskets off of 021-101-321A?

Or will I have to measure with feeler guages to make up difference?

Speedy reply would be appreciated. Thanx.


Are you sure about the part number of the 021 101 321A??
NO such number. Maybe it says 371?

021 heads are 1700/1800 heads. Which are oval port......

The 029 101 371B head is a 1979 ONE-YEAR-ONLY right side square port head.
It is NOT a later head for 80-83.5 Vanagons. Vanagon heads are part number 071-101-371A left and 071-101-371B right.

79-83 square port heads are NOT the same. 79 is ONE-YEAR-ONLY!!!!! The valve sizes are DIFFERENT.

79 head part numbers [cast on the heads]:
029-101-371A left and 029-101-371B right
Like the 76-78 oval port FI heads, it uses 022 109 612D 33mm exhaust valves and 021 109 601A 37.5mm intake valves.

80-83.5 part numbers [Vanagon]:
071-101-371A left and 071-101-371B right
These heads use the same 022 109 612D 33mm exhaust valves BUT they use the 021 109 601 intake valves which are 39.3mm.

A lot of people quote this site for reference, but I have issues with it:
http://www.tunacan.net/t4/reference/cylhead.htm

I have written him repeatedly about the part numbers of the 79 ONLY heads but I do not believe anyone there wants to correct the info.
A CRITICAL error is the size of the Vanagon valves. The intakes are NOT 37mm like the 2.0L bus FI heads. The intakes are part number 021 109 601 and are 39.3mm. Same as the 1.7L carb'd heads.

[chitwnvw]

Looks like a .05 " shim would do it, or I could try and get a few CCs closer with the dremel. I guess the part I don't really grok is what it does to the lifter and their geometry.

[Gypsie]

by pushing the pivot point of the rocker arm further away from the cam and lifter by using thicker shims on one side you will effectively create a situation where you are tilting the angle of the rocker arm such that as it moves back and forth it puts pressure on the valve at such an angle to potentially cause premature wear on your valve guides. The goal of the valve geometry dance is to have the pressure distributed evenly as it goes through it's complete stroke. (ie starts it's pushing on the valve stem on one side, straight on at the halfway point, and then pushes the other side of the valve stem during it's 2nd half of it's stroke.) This is a minute amount of angle we are talking about but after 1,000,000 or so strokes you can imagine the ever increasing wear pattern.

I suppose you could try to make it work by working push rods to make each side that much different so that the working angle is evenly distributed.
Are these from an engine that was running before you took it apart or are they heads purchased separately that you are wishing to use?

If from a dis-assembly then-

I wonder, if the heads were worked that much (as they appear to have been; that bottom image of the chamber looks like the fly cut zone is substantially under the plane of the quench zone), did the previous assembly include a compensation of sorts for that. Did you keep track of the chamber side sealing rings? I wonder if the side had thicker rings than the other. Same goes for the case side shims, thicker on one side than the other? Howzabout the push rods? Curiouser and Curiouser...


I say remove material from the under CC unit to bring it up to match the other, though 9 cc's seems like a crapload of material to remove.

[chitwnvw]

Did some homework today, I think this image does pretty good at illustrating what we are looking for as far as rocker to valve stem contact.



Unfortunately, I didn't know there were variations of the square port heads and I've already spent my $s on the machining. I am going to shim and check the geometry and give it a try.

[Gypsie]

Mmmmmm....Roller foot rockers.....deelish.

I think our high end in this area is the swivel foot.

[Gypsie]

(don't forget to include the piston dish cc numbers added to the head cc numbers).

And the man in the back row with the wild, twitchy eyes jumped up, shouted "AMEN" and ran cackling out of the room.....


Jim, you always serv up a plateful of morsels to think on...

Considering that I am hearing the machining $$$ are somewhat shy, or maybe done spent...

Could CHitwn do some serious figgerin' and dremeling/grinding (I hear it's pretty tedious...) to get a combination of shims (cylinders, rocker stands)...to come up with workable DH and CR?

It does seem like some serious rabbit chasing down this dark hole of imbalance....

You may just have to bite the bullet, Chi, and get some more machine work after crunching the numbers and seeing where the next $$$ are best spent...

Just ask yourself when you next want to have to pull your engine...(says the man that has pulled his engine 4 times in 24 months...)

[RSorak 71Westy]

Is the idea of getting another matching head just totally insane? This is what I would do.

[chitwnvw]

Is the idea of getting another matching head just totally insane? This is what I would do.

If I had the money. Don't judge, lets see how this experiment comes out, if after a month or two of driving... I may think about it in the spring.

[RSorak 71Westy]

You should be able to do a head swap with someone, for nearly no cost.

Or worst case sell 1 of the heads and use the funds to get a match.

[chitwnvw]

You should be able to do a head swap with someone, for nearly no cost.

Or worst case sell 1 of the heads and use the funds to get a match.

Hmmm, interesting. Worth a shot putting it on the Samba classifieds...Wonder which one I want to work with? Anyone know off the top of their head which part number is the bay, 029 or 071?

[Gypsie]

does Randy's post above help at all?

It seems to indicate that: The 029 101 371B head is a 1979 ONE-YEAR-ONLY right side square port head.

and

071-101-371B right for 80-83.5 [Vanagon]

That is if Donemoto is to be believed....

You didn't even have to use the search function

IMO: the 029 (with 53 CC's) will give you a better chance of matching up to another head.

[chitwnvw]

does Randy's post above help at all?

Seems to indicate: The 029 101 371B head is a 1979 ONE-YEAR-ONLY right side square port head.

and

071-101-371B right for 80-83.5 [Vanagon]

That is if Donemoto is to be believed....

You didn't even have to use the search function

Good lord, I somehow missed that. The valve sizes are different! I'll have to see what I have, my machinist pressed in new seats and installed new valves. Could be I've created a vanagon head with a smaller intake valve! What a mess!

[poptop tom]

Bad luck all around it sounds like. Crap. I iwsh that head I'd sent you was the correct one.......probably not an option now since you've got two square ports that have been rebuilt.
I've got nothing else here to help you out with unfortunately.

[chitwnvw]

Bad luck all around it sounds like. Crap. I iwsh that head I'd sent you was the correct one.......probably not an option now since you've got two square ports that have been rebuilt.
I've got nothing else here to help you out with unfortunately.

That was great of you to do. AircooledChris sent me two, both which proved to be unusable, which was really over and beyond. Then I found a cache of square ports that a repair shop had 'donated' to me years before. Wish I had know about the differences between the '79 and then later Vanagon heads. I guess that is the learning curve.