T4 Into T3 Build Questions - With Reference Links for Future Swaps

[nogoodwithusernames]

Spent the day off hunched over bits soda blasting case and heads, wire wheeling case hardware, and generally doing more stuff that nobody should care about but you are gonna get photos anyways. I can now walk past the case without immediately acquiring a layer of grime on my hands (Nothing in the background is clean it's just covered in soda so you can't see the grease in the photo )




Also both heads are matched 021.101.371 Q, and so far looking just fine to me. Though I'll send them to European Motor Works and have them check them over and at least put in new valves and seats. One interesting thing was some PO decided it was a good idea to double stack some exhaust gaskets to help seal better??

[nogoodwithusernames]

Spent the day doing yard work and cleaning tins, got most of them un-caked and cleaned up. I still can't believe how nasty this engine has been. Must have been leaking oil for most of it's running lifetime. Will be re-painting everything at some point before assembly.

[twodollardoug]

Half the battle is cleaning. But it sure helps when you are done. It's easier to keep it clean. And you will know right away when you have a leak. It's easier to find.

[Clatter]

Nice work!

Cleanliness is next to godliness..

I always assemble the tins one time to get them all bent into shape, and trimmed if needed, or cracks repaired or..?
Best to do this before paint than after it's too late. FWIW.

Here's some other type-4-into-type-3 conversion pics I saved from this site years ago FWIW..
https://www.thesamba.com/vw/forum/viewt ... tf#7106953

[nogoodwithusernames]

Thank you for the replies guys, I appreciate the feedback and encouragement. Reference photos for the boot adapters are appreciated too since most of the old photos on this site are dead. (Even though I've been through clatter's thread several times I had forgotten how much awesome info is in there.)

I have a few questions as I'm planning things in my head.

1: How do people block off the heater outlets on the fan shroud for using anything other than heater boxes? I've seen people use other exhausts but not sure I've seen details on blocking those off.

2: When getting the heads rebuilt I believe the general consensus for 1.7 builds is to go with 42x36 valves, are there any other things I should have them do when going over the heads?

3: Is the breastplate tin necessary on a conversion into the T3? (it's the one piece of tin I'm missing) I have no problem sourcing one, but what are the downfalls of not using it?


And sorry, no photos this post. Should be getting more done over the weekend though.

[twodollardoug]

You are going to run all the tin. Modified, homemade, or stock.

[Clatter]

1. jake showed years ago in testing that you want to leave those heater feed slots open.
Some kind of disturbance if they are closed causes a reduction in cooling.
Get a Vanagon shroud if you want to do it right.

2. 42x36 will force them to do new seats.
Any competent shop would address all of the other issues - cracks, plug holes, studs etc. even during a stock rebuild.
Get all of the jake valvetrain upgrades - bigger studs, solid spacers, swivel feet, etc.
Dressing the heads down with the better valvetrain hardware is a noble pursuit.

3. Try and find the top tins and breastplate from a 914.
it's like the t4 into t3 conversion was their intended use all along.
All the other tins will work with those 914 parts, at least Bus and 411/412.
Not Vanagon, though, the tins are a bit more differenter..

[Clatter]

A friend on TOS is going to be 3D printing a plastic bellows adaptor.
It will bolt to the T4 fan shroud like the 411/412 wagon,
But will have the flange on the other side to use the T3 bellows..

[nogoodwithusernames]

Just got off the phone with EMW, sounds like for this build heads are going to be stock 1.7 rebuilds, 42x36 is unfortunately out of budget for this build.

I'll source that upright tin, I've got everything else off the 1.7 core out of a 914 already so that works out nicely. I'd rather not have to try and make something like that piece at home, not sure that would turn out great.


So current plan now that I have headwork pricing:

• 1.7L longblock (66x90)

• Stock rebuilt heads

• Domed pistons (5-7cc dome, will measure when cleaned up more.)

• Estimating somewhere around 8.5:1 compression with an aim of .040" deck after removing cyl/head gasket and possibly cyl shims depending on deck.

• Either EMW "C" cam or CB "Street Power" cam. Both look to have close specs to the Web 86 (out of price range)

• MS EFI using stock d-jet plenum/TB and runners modified as required for modern injectors and MS sensors.

• Exhaust is up in the air, will run heater boxes if I can find some cheap enough. Otherwise I'll make up some 1.5" pipes with stubs (stainless cause I can ) and run the 2.0 Monza exhaust I pulled off my 914.

Sound like a good combo or should I change something around?

[nogoodwithusernames]

A friend on TOS is going to be 3D printing a plastic bellows adaptor.
It will bolt to the T4 fan shroud like the 411/412 wagon,
But will have the flange on the other side to use the T3 bellows..

That would be fantastic, I have several T3 fan housings that I could manage to make something work but a bolt in piece would be killer.

You know ETA and pricing of that?

[Clatter]

No idea on the adaptor, it's a pipe dram at this point,
-but-
I have seen the CAD file. That part is done (hard part).
Maybe you know someone who can 3D print in a high-temp plastic?


Why send off your heads to be re-built?
What's wrong with them?
1.7 heads in a 914 often don't need seats,
And most shops can do a valve grind or guides..

[nogoodwithusernames]

No idea on the adaptor, it's a pipe dram at this point,
-but-
I have seen the CAD file. That part is done (hard part).
Maybe you know someone who can 3D print in a high-temp plastic?


Why send off your heads to be re-built?
What's wrong with them?
1.7 heads in a 914 often don't need seats,
And most shops can do a valve grind or guides..

Honestly I just assumed they would need it. It never even crossed my mind that they would probably be okay with how often you hear of type 4 heads needing new seats.

Upon reading your comment though I decided to tear them down to bare heads and check them out a bit more. I managed to rig up my bench top drill press as a spring compressor and got all the valves out. They were all quite loose in the guides and the ends of the valves are all concave from the adjusters. New valves and guides are certainly in order. From what I could tell no sign of movement of the seats.


Got things cleaned up more today and started tearing down the crank assembly. I think al the journals are looking good, but I don't have mics to measure, just some calipers so I'll only really be able to tell if it's been ground undersize. Would I be able to plastigauge them to see if oil clearances are acceptable?

Some Photos:

[Clatter]

FWIW,
If you’re having to buy valves and guides and a valve job anyways..
If you end up putting in new seats,
42 x 36 costs the same as stock.

So,
If you do seats, go 42 x 36.

Plastigauge isn’t really good enough on it’s own.
I like to use it as a ‘sanity check’ to see if my bore gauge is on,
But it only works on the center main,
And it’s dubious on rod journals.
If this was a field repair, plastigauge would do it,
But a China bore gauge is like $60 new.

Better even if you can find an old-timer at a local machine shop.
An old-timer with a nice bore gauge and a lot of practice using it..
Pay the guy to do it once for you.
All motors from any continent use the same bore gauge for doing mains.
The guy is out there somewhere close,
Just have to find him.
Maybe a machine shop - like prototype machine shop vs. auto machine shop?

[nogoodwithusernames]

Sage advise on all counts, I'll slow down and weigh my options before making any decisions. I can think of a few places that might have a guy like that and worse case I buy a new tool (boo-hoo, such a shame)

I'm young and impatient but I do want to do this right the first time so I appreciate ALL the advice given, especially the advice I don't necessarily want to hear.

For now I'll keep getting things cleaned up and work on little things to help it go together smoothly.
I can bolt cylinders on and check if the deck is flat.
I can pull plugs and start cleaning the galleys.
I got a few sets of rebuilt 1.7/1.8 rods from when the local old timer VW guy closed up shop so I'll use a set of those and save these rods for a rainy day.
I'll start cleaning up hardware and rockers etc. as well.

Going back to the cooling boot, if he's willing to share the CAD file I can get it quoted from one of those online 3d printing places and see if it's worth doing.

[nogoodwithusernames]

Spent more time cleaning and soda blasting this weekend. Didn't bother with any photos of that but all the tins are cleaned and started painting some of the straighter pieces so I can get them set aside out of the way. One more day of blasting and I should have everything complete. All that's left is the fan shroud, fan, and a few nooks and crannies in the case that I missed the first time around.

I also got the galley plugs pulled, and upon first glance I though there were only 3 sizes, but after a closer look there's actually 5 so I'll have to find the tab I have open with the NPT plug sizes and get those ordered up soon. (I have quite a few tabs open for various reference material so it'll be nice to start closing some out )


I modified the TB I have to use the TPS I've been using in my old T1 megasquirted engine. Welded up a little bracket to position it on the end of the throttle shaft and I'm pretty happy with how that's looking. Just hoping it fits under the decklid as it seems really tall. Though it only added maybe 1/2", if that, to the total height so fingers crossed.



I also think that I'll be able to use my modern 14mm injectors in the stock manifolds with no machine work or modification required. That will require welding some fuel rail mounts to the stock injector mounts though, and I'll have to rig it up to see if it'll hold vacuum to be sure but it looks promising.