Builds Another Prado in Montana (2 Viewers)

[AirheadNut]

This evening I removed what remained of the bronze pilot bushing. I tried the bread trick, but the bushing had lost about half its original thickness from being wallowed out by the input shaft, so there wasn't much for the bread to push on. I had to resort to cutting a groove in the bushing with a triangular file and then knocking it out with a small chisel. Will be replacing it with a pair of 6801-2RS sealed ball bearings.

A couple of weeks ago I pulled the headlights and headlight buckets to swap them for H4 housings. The headlight adjustment screws and the headlight bezel screws were heavily corroded, so I added a new set of adjustment screws and bezels to my last parts order.

 

[AirheadNut]

I drilled out what remained of the bezel screw threads in the headlight buckets and installed stainless M4 rivnuts. The buckets got a couple of coats of paint prior to reassembly.

New bezel screws were not available, so I picked up some M4 pan head screws at the hardware store instead.

I still need to install the wiring harness to convert the system to H4 style bulbs, but will need to add new ring terminals for the headlight grounds first.

 

[AirheadNut]

In designing a new adapter plate I have been giving some thought to corrosion protection. My old adapter was yellow zinc plated, but I don't think it would be economical to ship the adapter out to have it plated. I had also considered paint, but that doesn't seem to hold up very well in salty wintertime conditions. I would welcome any input.

 

[coldtaco]

In designing a new adapter plate I have been giving some thought to corrosion protection. My old adapter was yellow zinc plated, but I don't think it would be economical to ship the adapter out to have it plated. I had also considered paint, but that doesn't seem to hold up very well in salty wintertime conditions. I would welcome any input.

ever try that cold galvanized paint in a spay paint?

 

[AirheadNut]

ever try that cold galvanized paint in a spay paint?

Actually I have, but had forgotten about it. I sprayed the outside of my G-Wagen fuel tank with it after treating the rust. That actually might be just the ticket, especially with a topcoat on the exterior exposed parts.

 

[AirheadNut]

Getting close on my adapter plate design:

I have access to a lot of 1/4" polycarbonate sheet offcuts at work, so I think I am going to waterjet cut a test plate out of that to make sure all my hole locations line up and there is proper clearance everywhere.

 

[AirheadNut]

Replaced the rear main seal this evening. The original one wasn't leaking, but with around 220k miles on it I figured I might as well put a new one in while I have the transmission and flywheel out.

I also took the flywheel in to a local auto parts store to see about getting it resurfaced. Blank stares met me from the other side of the counter when I plunked it down. They had to go get one of the old guys from the back room to figure out what I needed...not terribly reassuring.

 

[87BJ74]

In designing a new adapter plate I have been giving some thought to corrosion protection. My old adapter was yellow zinc plated, but I don't think it would be economical to ship the adapter out to have it plated. I had also considered paint, but that doesn't seem to hold up very well in salty wintertime conditions. I would welcome any input.

What type of (assuming) steel are you making it out of?

 

[AirheadNut]

What type of (assuming) steel are you making it out of?

Not sure yet, I need to talk with the laser cutting people and see what they normally source. I think that a mild steel would be fine, preferably cold rolled so there’s no mill scale.

 

[87BJ74]

Not sure yet, I need to talk with the laser cutting people and see what they normally source. I think that a mild steel would be fine, preferably cold rolled so there’s no mill scale.

For mild steel id imagine they would be using 1008 or ASTM A36. Cold rolled will mean its hardness will be a bit higher which in your case would be a benefit. In your case wanting it cold rolled, there are more options (dependent on thickness) using 1008 because ASTM A36 is usually hot rolled.

Laser cut overall profile then counterbore critical holes/surface face?

I also took the flywheel in to a local auto parts store to see about getting it resurfaced. Blank stares met me from the other side of the counter when I plunked it down. They had to go get one of the old guys from the back room to figure out what I needed...not terribly reassuring.

In the past I've had my flywheels machined by Wes at Internal combustion and machine there in Belgrade. I also think Rob at Diesel Engine Machine Technologies (On the other side of Belgrade) machines them.

 

[AirheadNut]

For mild steel id imagine they would be using 1008 or ASTM A36. Cold rolled will mean its hardness will be a bit higher which in your case would be a benefit. In your case wanting it cold rolled, there are more options (dependent on thickness) using 1008 because ASTM A36 is usually hot rolled.

Thanks for the info! A lot of the stuff I weld at work is laser cut and formed at J.E.Soares in Belgrade, that’s probably where I’ll go to get the plate cut. Will have to give them a call and see what they have for materials. Going to go with a 1/2” plate thickness so I can reuse my flywheel and motor and transmission mounts.

Laser cut overall profile then counterbore critical holes/surface face?

That is the plan. The overall shape and all the clearance holes will be laser cut, and the remaining holes will be drilled/tapped/reamed/counterbored as needed.

 

[Bad Mojo]

I've been thinking about everything you have been posting about and getting the alignment correct for the input shaft, pilot bushing, clutch, etc. Are you thinking the transmission input shaft was never on the same centerline as the flywheel because there was just enough play in the entire system for it to bolt up and "function" but not last long term. Or are you leaning towards something else? Do you know if the input shaft was fitting snuggly into the pilot bushing when this first went together?

Additionally I am curious on how are you aligning everything now with the scan data. I get how you are locating the input shaft and Toyota bell housing holes, but did you also scan a VW bell housing as well to figure out the engine side bolt pattern?

Also hats off to you for just going ahead and making your own adapter plate instead of waiting.

 

[AirheadNut]

I've been thinking about everything you have been posting about and getting the alignment correct for the input shaft, pilot bushing, clutch, etc. Are you thinking the transmission input shaft was never on the same centerline as the flywheel because there was just enough play in the entire system for it to bolt up and "function" but not last long term. Or are you leaning towards something else? Do you know if the input shaft was fitting snuggly into the pilot bushing when this first went together?

Additionally I am curious on how are you aligning everything now with the scan data. I get how you are locating the input shaft and Toyota bell housing holes, but did you also scan a VW bell housing as well to figure out the engine side bolt pattern?

Also hats off to you for just going ahead and making your own adapter plate instead of waiting.

That is exactly it: the crank and input shaft centerlines were not aligned. From what I have read about this problem and looking at the overall design of the original adapter plate, this is due to the manufacturer being careless with how they align the engine (and possibly transmission) to the adapter plate. The transmission side had a pair of dowel sleeves around a couple of the transmission bolts, but those bolt holes on the bell housing are merely clearance holes and not necessarily precisely located like the factory dowel pin holes. On the engine side there were no alignment dowels at all, they simply used 90º countersunk bolts in a couple of locations to locate the adapter plate to the engine, and those countersinks are located on laser cut holes, not even drilled holes much less bored or reamed. Long story short, everything bolted up snugly with no play at all, but was off enough to wear out components long term.

Looking back at photos of the parts the pilot bushing was definitely much thicker, and would have been a nice fit on the snout of the input shaft originally. I remember the first couple of times mating the engine to the transmission it was difficult to get everything lined up right to slip in the last 1/2" or so. Pretty sure now that was the input shaft not wanting to slip into the pilot bushing because it wasn't centered up properly.

For the engine side of my new adapter plate I actually have an old CAD drawing of a similar model industrial VW TDI that shows all the bolt locations and many other dimensions on the engine. VW kept the same engine to transmission bolt pattern on all their 8-valve water cooled 4 cylinder engines from the mid 70's through to the mid 2000's at least, so that data is good for pretty much any older VW 4-banger. The only part of the equation I was missing was the Toyota bolt pattern and input shaft centerline.

 

[Bad Mojo]

That is exactly it: the crank and input shaft centerlines were not aligned. From what I have read about this problem and looking at the overall design of the original adapter plate, this is due to the manufacturer being careless with how they align the engine (and possibly transmission) to the adapter plate. The transmission side had a pair of dowel sleeves around a couple of the transmission bolts, but those bolt holes on the bell housing are merely clearance holes and not necessarily precisely located like the factory dowel pin holes. On the engine side there were no alignment dowels at all, they simply used 90º countersunk bolts in a couple of locations to locate the adapter plate to the engine, and those countersinks are located on laser cut holes, not even drilled holes much less bored or reamed. Long story short, everything bolted up snugly with no play at all, but was off enough to wear out components long term.

Looking back at photos of the parts the pilot bushing was definitely much thicker, and would have been a nice fit on the snout of the input shaft originally. I remember the first couple of times mating the engine to the transmission it was difficult to get everything lined up right to slip in the last 1/2" or so. Pretty sure now that was the input shaft not wanting to slip into the pilot bushing because it wasn't centered up properly.

For the engine side of my new adapter plate I actually have an old CAD drawing of a similar model industrial VW TDI that shows all the bolt locations and many other dimensions on the engine. VW kept the same engine to transmission bolt pattern on all their 8-valve water cooled 4 cylinder engines from the mid 70's through to the mid 2000's at least, so that data is good for pretty much any older VW 4-banger. The only part of the equation I was missing was the Toyota bolt pattern and input shaft centerline.
View attachment 3588775

Oh cool on getting the VW drawing. Are you gonna to add dowel pins into your design as well to help navigate that alignment issue in the future?

 

[AirheadNut]

Oh cool on getting the VW drawing. Are you gonna to add dowel pins into your design as well to help navigate that alignment issue in the future?

Yes, I'll be using the factory Toyota and VW alignment pins in the appropriate locations to make sure everything is aligned as it would be from the factory.

 

[AirheadNut]

Flywheel came back looking very nice:

Getting quotes for laser cutting from a couple of places, hope to have the plate cut and ready for machining sometime next week.

 

[AirheadNut]

Finally picked this up from the laser cutter yesterday! Very excited, the cuts came out beautifully with almost no slag.

A quick test fit on the spare transmission case and everything lines up great so far. Only the clearance holes are laser cut; threaded holes, locating dowel holes and counterbores will be done by the machinist.

Even the starter plate fits perfectly despite my unconventional solution for drawing its contour in CAD.

The parts are now at the machinist, not sure on timeline but it shouldn't be long now. I can hardly wait!

 

[svsisu]

Looks amazing!!!