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

[nogoodwithusernames]

Adding to this mornings post, I'm still trying to figure out how to proceed with heads so if you'd pardon my back and forth and numerous questions...

So my thinking is if I buy new guides and stock size valves, have a shop press in the guides and install valves myself. Can I lap the valves to the seats and install them? Or do I need to have a shop do something to the valves before installing them?

I know that power comes from the heads and doing them up nice would be best *but* I'm not going for high end power, just a reliable small bump over stock that is pleasant to drive around town and on the hwy. So between that and being on a tight budget would it be a decent choice to go with that option? Feel free to call me out if this is complete wishful thinking.

[nogoodwithusernames]

Just took the case and crank to a machine shop right by work which thankfully measured out stuff for me.

Case 1-3 mains at 2.758", 2.7571", and 2.7575"

Crank 1-3 mains all 2.3605"

Crank rod bearing journals (nose to flywheel) 2.1645", 2.1648", 2.1645", and 2.1646"

I did some conversions and they look *just* on the edge of wear limits. Thoughts? Opinions?
I did put a std #1 in the case and it felt like a really good fit (had a set of std case std thrust .020 crank bearings laying around so I figured doesn't hurt to test fitment.)

[Clatter]

If bearings are broken in to each other and have worn-in to match,
It's not a bad thing to let sleeping dogs lie IMHO.
Just make sure they all go back exactly as they came out.
Traditionally, a type 4 doesn't get line-boring at rebuild time like a type 1.


A machine shop that does the guides for you would likely do a valve job as well.
You'll want a 'valve job' (seat grind) done when new valves are installed.
A 3-angle 'nice' valve job can go a long way towards making power and longevity.

You can do the spring/retainer/keeper/rocker assembly, geometry and all that..

[nogoodwithusernames]

If bearings are broken in to each other and have worn-in to match,
It's not a bad thing to let sleeping dogs lie IMHO.
Just make sure they all go back exactly as they came out.
Traditionally, a type 4 doesn't get line-boring at rebuild time like a type 1.


A machine shop that does the guides for you would likely do a valve job as well.
You'll want a 'valve job' (seat grind) done when new valves are installed.
A 3-angle 'nice' valve job can go a long way towards making power and longevity.

You can do the spring/retainer/keeper/rocker assembly, geometry and all that..

I may not have been super clear, the bearings that came out are used up for sure. I can see copper through the bearing material, so new bearings are a must. That was just the case and crank measurements I posted above.

[nogoodwithusernames]

Happy Monday all, nothing terribly exciting going on here. More cleaning and prep work. I did have a couple questions though.

Was cleaning hardware and discovered four of the M6 nuts have thread inserts. Why? I assume they are for the oil pump? I can't think of anything else that uses four of those little nuts.

My crank gear got a little dinged up pulling it off. (It was STUCK!) Can I put this on some sandpaper and clean up the high spots and call it good? The rest of it looks good, just the marks from the gear puller. (No it's not cleaned yet, one of the few things in the shrinking pile of dirty "junk" to go through so don't mind the oil and crud on it )

[Clatter]

A PO could have put those threaded nuts on - you never know what they'll do.

If you can file down the crank gear and get it to turn freely with no tight spots,
Then it's OK.
Those are tough..
Will have to assemble the whole thing and do a crank-and-cam only mock-up to see if it turns free.
So make sure to do all of your filing before..

I had a tin screw fall down the breather tower once and it mangled a crank gear worse than that. Still ran.

Used to be common practice to file down the teeth of straight-cut steel-on-steel aftermarket cam gear sets before install to help keep them quiet.

[nogoodwithusernames]

A few questions;

1: Do I need a flywheel O-ring and the metal gasket? Or is it an either or deal like a T1?

2: Do I need to move the input shaft bearing from the crank to the adapter flywheel? If so what bearing do I need?

[Bruce.m]

1) yes to both. O ring stops oil leak. Metal plate stops the flywheel falling off.
2) yes. Remove bearing from crank and fit (same part) to flywheel. In the correct location it will poke into the end of crank by a tiny amount. Measurement for a 914 flywheel below, yours may differ. Felt ring goes on the clutch side of bearing to keep out dust.

[nogoodwithusernames]

No exciting updates, wire wheeled some hardware and got some small pieces ordered.


Next couple of steps are:

When postage scale shows up balance pistons pins and rods.

Bolt on flywheel and figure out shims to order for end play.

Pull old T1 motor and put T4 case in to figure out hanger bar and fan inlet adapter dimensions.

Friday I'll be dropping off heads to get guides and a valve job.

[nogoodwithusernames]

Had some time after work now that it's not pitch black when I get home to check weights on reciprocating parts.

Pins are all dead on.
Pistons are within 2grams of each other. (Will wait until I have rings and check with a pin and rings before removing anything)

IMG_7180.jpeg

Rods however are going to need some work...

I pulled some out of my little box of rebuild rods I picked up from the local VW guy when he closed down. It looks like some 1.8s and some 1.7s based on the small end pad height. (don't know which is which just that they're different.)

IMG_7183.jpeg

So I grabbed four that are the same style but the weights are as follows; 760g, 764g, 785g, and 786g. You can see in the photo most of that weight is where the angle is ground into the cap, it takes part of the 021 number on the right set but on the left it's not even close to touching.

IMG_7181.jpeg

My question then is: Can I balance them in pairs and run them opposite each other? Eg. 2x @ 785g running opposed to each other and 2x @ 760g opposed to each other. This would in theory balance the reciprocating weight and so long as end to end balance isn't far off should be okay I think. Let me know if I'm crazy for even thinking of trying that.

[Clatter]

I’d be leaning on the grinder to get them all the same weight..

In Europe there were many sets of these rods lightened massively.
You would be amazed at how svelte a profile could result from that starting point.

[wreck]

I think with a 1700 it's best to stay with the stock valves anyway , 42/36 would be way to big for the engine combination you are building . For budget minded cam choice there is also the Scat C25 , which I think would work just as well
.http://vwparts.aircooled.net/SCAT-C25-T ... /20086.htm

[nogoodwithusernames]

Thanks for the tips fella's, didn't get anything done over the weekend. Wife had me helping her get the shed painted and a chicken coop put up. And so far no extra time off for COVID, everyone needs their food wine and beer and we keep those places running so still working.

Did manage to get the heads dropped off for new guides and a valve job so still making progress.

[nogoodwithusernames]

Picked up my heads yesterday. Going to be putting them back together and have a few questions. Stock springs okay to re-use? And should I grind the keepers or leave them touching like stock?

[wreck]

I wouldn't re use old springs unless you have a spring checker to verify they are still in spec . EMW should be able to supply springs . I've got HD single type 1 springs on one engine , they are a little it smaller and a snug fit on the guide boss but I have not had any issues .

The keepers must be checked and ground if they touch on both sides around the valve ,if that makes any sense . the grooves don't hold the valve only locate it, the pressure on the stem from the retainer wedged up the taper of the keeper is what holds every thing together .