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  View original topic: Stock 1600 Engine Build for a '69 Bus
Jack_O_Trades Thu Oct 02, 2014 2:44 pm

I posted this in my bay window build.

http://www.thesamba.com/vw/forum/viewtopic.php?t=604090&highlight=

I thought I might get more specific engine help over here. I have been doing my research but questions to come up. I don't know what the etiquette is for multiple threads but I think I will keep my engine questions to this section of the forum.

I am in the process of preparing the components for the short block and sourcing ancillaries that I may need. I started with a running engine, albeit not very well running and hope to get back to that if not better.

This is basically a stock 1600 that will be used as a weekend warrior driver. I am more concerned with OG reliability than lots of power. I do geek out over the technical aspect of the engine build though

I have been spending some quality time with the engine case. It's cleaned up now but some odd things popped up. From what I can determine, this is basically a Frankenstein engine. I came across some paper work that shows the engine was rebuilt in 1977. After that I don't know. The vehicle was driven for another 13 years up until 1990.

This is my first VW engine so nothing really screamed out at me as being weird. But the more I read up on the the variants of the type 1,2,3, flags start popping up.

As I was cleaning the case I noticed that it had two oil pressure relief valves (front and rear). For a '69, it should only have one. I started researching the stampings and I guess the case is a '71. I'm OK with this because they are supposed to be more robust right?





What looks to be an AF I think is just a poorly stamped AE



Another odd thing about the case is the cylinder studs are 10mm (with case savers) vs 8mm. I haven't read anything indicating this to be typical. But it seems like it would be a good thing as far as sealing up the cylinders.

Also the case threw me off because only the crank shaft journals had been bored to +1mm. I miced the diameters of the crank and cam journals and they are within spec.

Adding to the confusion, the engine was equipped a 30-pict-1 carb matched to a 205T dizzy. I guess this is a good combo but not typical for the 1600 engines.

Here is what I am planning on doing with the engine. I already have the dual port heads which required me to pickup a new intake manifold.

For the carburetor and dizzy, I have a couple of options. The first one which I was going to try is a 34-pict-3 carb matched to the 205T which, based on my understanding is an SVSA dizzy. From my research it seams that the 34, with vacuum advance and retard is more suited to a DVDA dizzy. I have yet to find one of these.

If the 34 doesn't play well with the 205T I was thinking of trying it with a SVDA which has vacuum and mechanical advance. This is the one that I am looking at.

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-043-905-205

If that doesn't work...

As a final backup, because it seems that the 30-pict and 205T are made for each other, I was looking at an adapter plate to make-up the 30-pict to the dual port intake manifold

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-113-129-029-KIT

From what I have read, the 30-pict is supposed to provide better fuel economy. However my 30 carb may be due for a professional rebuild.

Can anyone offer real world experience or suggestions on which route to go with? I want to keep it simple and reliable.

Thanks

Jack_O_Trades Thu Oct 02, 2014 2:47 pm

This is from a previous post on static balancing some of the parts in engine

After reading, researching, and reading some more (mostly from the blog posts of Mr Hoover, Samba threads, etc..)on different aspects of balancing, I have been making my own attempts at balancing.

There seem to be two schools of thought (probably more than that, really) on static balancing. One is that you weigh everything (pistons, wrist pins, rods, etc...) and bring the heaver item to that of the lightest one in the group. The other school of thought is that you match assemblies so that the total assembly (piston, wrist pin, rod) is the same as the other three sets.

To me, it seems to make sense to try and bring the individual components to exact as possible. This could potentially lead to a stacked tolerance error greater than if you match assemblies. However, with discrete component balancing at least the parts are not matched and can be swapped or replaced without too much fuss.

So far, I have been happy with the parts I have purchased. Everything has been within VW spec on weights. However I am trying to get my parts exactly equal to each other within the my scales ability to resolve which is .1g.

My pistons came in at 361.9g. three of the four were exactly on. I had to remove around .6g from the forth piston to get it exact (within my ability to measure).

My wrist pins were a different story. I was expecting these to be exact but they ranged from 128.4g to 127.8g. It's not much of a variance but I can make it better. I still need to do this.

I spent some time on the connecting rods. I wanted to get this right. My understanding is that you want to the total weight of the rods to be exact and you want the center of gravity to be the same along the length of the rod. One way to do this is to suspend one end of the rod from the center of it's pivot and weigh the other end of the rod from the center of it's pivot. I read articles and watched videos on this and decided to make my own fixture for measuring this. It took me four or five iterations to come up with a fixture that would give reliable, repeatable results within the precision that I was trying to accomplish.

My first iteration consisted of supporting the rod on dowel pins and gage blocks but this had fundamental flaws. Here is a picture of my final setup which looks very much like stuff that you can purchase. Silly me for trying to reinvent the wheel.



I used the digital scale to measure the wrist pin end while suspending the crank shaft end.



I used my triple beam balance to measure the total weight. My balance only went up to 610g and my scale only went up to 600g so I had to get creative because my rods were heavier than this. On the balance you can add a bias to it. In this case a couple of washers at the end of the beam. My bias was 16.1 g according to my calibration weight. This was enough of a bias to measure total weight of the rods.



Initially the rods were weighed in at

_ _ Wrist Pin _ _ Total Weight (not including 16.1g bias)
#1: 189.6g _ _ _ 597.3g
#2: 190.8g _ _ _ 595.3g
#3: 190.4g _ _ _ 595.0g
#4: 189.6g _ _ _ 597.3g

These are within VW spec but again, I felt I could do better than this.

A straight forward method would have me remove weight from 2 and 3 at the wrist pin to get the wrist pin weight to the same as 1 and 4 but then I would have to remove total weight from 1 and 4 and risk affecting the center of gravity.

It's hard to explain but I was able to play around with where on the rod I removed weight so that I didn't have to do too much removal on all four rods.



Here are the final numbers after balancing

_ _ Wrist Pin _ _ Total Weight (not including 16.1g bias)
#1: 189.5g _ _ _ 594.5g
#2: 189.8g _ _ _ 594.5g
#3: 189.8g _ _ _ 594.5g
#4: 189.5g _ _ _ 594.5g


This is acceptable and basically pushes the repeatability of my setup.

Once I balance the wrist pins, it will be on to the crankshaft, flywheel, and pulley. I have no way of dynamically balancing these components so I was thinking of just doing a static balance of the individual components and then trying to get the assembly statically balanced. Any thoughts on this?

Also, I started prepping the cylinders by painting them with flat black Rustoleum and baking them after drying.



Next step with these is to check the ring gaps.

bugguy076 Tue Oct 07, 2014 4:09 am

I can see you want it as good as possible. When you check the ring gap, error to the high side of the specs. An extra .001 gap is fine. Too tight of a gap is a bad idea.

Boolean Tue Oct 07, 2014 5:38 am

Really good fixture for the rods. Thats the only method that works every time.
Not sure how it was done in the pictures, but ball bearings in the rotating bushings are better than plain bearings.
By the way, did you ever think about how much oil is stuck to the outside of each rod at speed? And that each rod lives in a different oil spray environment?
Just messing with you here...



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