My first type4, probably 2056

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TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Wed Nov 22, 2017 2:07 am

Yes, Clatter's topic is a reference, I read it at least two times. Very good info in there!
What I still did not understand completely is what are the first areas to remove: near the cap screws (somehow lateral, near screws), or bottom of the con rod cap. "First, the sides get ground away, then, if that's not enough, the cap edges get rounded."

TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Sat Nov 25, 2017 10:47 am

One question on connecting rod balancing jig: what shall be the horizontal axis, red - con rod centerline, or blue - top bearing surface (support surface of the con rod)? Pic from Clatter's topic. I found an interesting recommendation, to suspend by two strings each end, so the support will be more stable.
1283682.jpg
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TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Sun Nov 26, 2017 7:54 am

On rod balancing I have found a video showing another method: balance small end first, then weigh the rods directly and bring them down to the lowest one. This would mean that also the big ends will be balanced. Unfortunately both scales I can get have 1g precision, not lower (not even one decimal...).
I installed the NPT plugs: tightened by hand then used a tee on the inbus to give 1.5 more turns. It was very hard to turn them 1.5 turns, so I am confident they are well tightened. I did not use a torque wrench (recommendation from https://www.pegasusautoracing.com/docum ... =TECH00097 ), but it defeinitely felt like a lot of torque...

Next (this week): balance pistons and rods, and file the notches on con rods as per VW technical bulletin.

TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Sun Dec 03, 2017 6:19 am

I had a small vacation this week, so I took some time to work on the connecting rods. Please excuse the "chaos" on my desk, I set up the balancing jig just for quick pictures, the real work was in the annex due to resulting dust.
I started with (in grams):
Rod 1 Overall 807
Big end 547
Small end 260
Rod 2 Overall 801
Big end 551
Small end 250
Rod 3 Overall 806
Big end 546
Small end 250
Rod 4 Overall 807
Big end 556
Small end 251
And ended up with 545g big end, 250g small end, 795g overall for all rods.

Pics of the jig:
20171203_122259.jpg
20171203_122614.jpg
20171203_122706.jpg
And here is how much I had to take from the heaviest big end:
20171203_122748.jpg
And I also made the notches for oil spray, as per VW Bulletin, using a 60 degree small file:
20171203_122723.jpg
Next week I have to order the Porsche valve adjusters and some parts for the 944T brakes, and on with the pushrod length measurement.
I would also like to work a bit on the heads and intake manifolds, and oil pump and case. I want to blend the transitions between the holes. I have seen in some topics that a blue "ink" was used to see how the holes line up and where to remove material. What is that substance, or how can I check the alignment of the holes and mark where to grind? Maybe for heads it is easier removing the valves and have access to the parting surface. Anyway I think I have to remove the valve springs and put some light ones instead of the double springs for the pushrod length check...
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TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Sun Dec 03, 2017 10:19 am

I forgot to mention, pistons and bolts are spot-on 500g each. No need for balancing.

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Piledriver
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Re: My first type4, probably 2056

Post by Piledriver » Sun Dec 03, 2017 10:18 pm

Its called "prussian blue" or machinists blueing.

You can usually fake it with sharpie marker...

Mod the cheaper part. (The pump or manifolds) vs. the heads or block.

Don't go too crazy matching the manifolds to the heads, the main thing is the port is the same or bigger than the manifold ---it cannot step down or impede flow due to blocking.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Mon Dec 04, 2017 2:49 am

Thanks Pile. I tried to find it locally, again no success. I'm sure there are equivalents used but I do not know the names. For Prussian Blue I only find acrylic paint. I will try to use Methylene Blue which seems to be also in the composition of Dykem steel blue, or a sharpie with slow drying.
I will modify only the manifolds to match the head ports (which were hand ported by Jakob @GBOT); manifold holes are smaller than the head ports. Same for the pump, I want a smooth transition for oil.

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Piledriver
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Re: My first type4, probably 2056

Post by Piledriver » Wed Dec 06, 2017 1:47 am

Dykem same thing just a brand name.

Note: Removing material is easy.
... so is removing way too much.

As long as the port you are flowing into is bigger, and no part obstructing into the flow, the negative effect on flow is very minimal to the point of not being really measurable in meatspace.

Ages ago Jake did some dyno tests with (IIRC) 40 IDFs using the generic off the shelf 48mm inlet manifolds, much smaller than the ports at the gasket, and filled CNC ported versions with a perfect port match/angles and flow path/hole size etc.

There was absolutely no difference on the dyno, didn't even change the jetting a smidge.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Wed Dec 06, 2017 5:10 am

OK on the intake to head port diameters, but still I want to check the difference between them. Thank you!

I need a bit of education on the oil system, more precisely on the oil cooler bypass. I know how it works, but I did not find the oil pressure at which the cooler is bypassed. For example, at cold idle the pressure could be 50PSI, which would mean the cooler is bypassed. But my thinking is that at hot high RPM the oil cooler would also be bypassed because the oil pressure is high... This doesn't sem right. IF I am to drive at constant 3500-4000RPM, how do I keep the oil temp down if the cooler is bypassed?
This is why some time ago I was asking about an oil thermostat which relies only on temperature: block the oil bypass up, and use a thermostat parallel to the oil cooler. So if the oil is cold, the thermostat will bypass the oil cooler and as it heats up, it will direct the oil to cooler, like in the picture below:
Oil_flow_cold_hot.jpg
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Piledriver
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Re: My first type4, probably 2056

Post by Piledriver » Wed Dec 06, 2017 8:25 pm

The magic crossover pressure is supposedly ~42 PSI...
...and what "doesn't seem right" is, in fact, precisely how it really works. :lol:

That's why too thick oil and/or big oil pumps cause "unexpected" temperature/pressure headaches when bolted into an otherwise stock system. Don't feel bad, it has confused ~everyone at some point.

It is a very effective, very simple and reliable system if left unmolested, and unless you are building some extreme-condition tolerant wonder it probably will work perfectly fine with a properly working oil system left dead stock.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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Clatter
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Re: My first type4, probably 2056

Post by Clatter » Thu Dec 07, 2017 8:16 pm

Ideally, in theory, you want an even taper from the butterfly to the valve seat..

Most 'ported manifolds' are only ported about an inch or two up from the gasket surface.
"Oh, You don't need to do all that... The valve seats are just going to fall out of it anyway!"
- Doug Ellsworth

Beginners' how-to Type 4 build thread ---> viewtopic.php?f=1&t=145853

TZepeSH
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Re: My first type4, probably 2056

Post by TZepeSH » Fri Dec 08, 2017 9:09 am

Thank you for the clarification! I will keep an eye on pressure and oil temperature during drive. I can always add an oil thermostat later on.
Clatter, that is what I wanted to do, to port 1-2 inches above the gasket, to match the ports in the heads. But if that does not help in any way, maybe I will skip the task. Anyway I want to check with some ink to see how the holes match.

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Clatter
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Re: My first type4, probably 2056

Post by Clatter » Mon Dec 11, 2017 2:46 pm

I think I might not have been clear..

It's best to port the manifolds all the way up.

Many only do a couple of inches up, and , depending upon the size of the ports,
Leave a restrictive 'choke point' just above the ported area in the manifolds.

Because it's just labor, and not money, I really like to port manifolds all of the way up.
Get some long shank burrs, and make some go/no go plugs to check your progress..
"Oh, You don't need to do all that... The valve seats are just going to fall out of it anyway!"
- Doug Ellsworth

Beginners' how-to Type 4 build thread ---> viewtopic.php?f=1&t=145853

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