The adjustable pulley is to dial in the cam. Most engine rebuilders will recommend doing this on any non factory cam.

 k series valves have 8mm stems, 100mm length. Intakes 36mm head and exhaust 29mm

Datsun are 8mm stems but the length is longer. With a ground cam and adjustable rockers, some guys get away with installing them and having enough adjustment. Others shim up the rocker shaft posts, like joshua matthews did on here.

In australia Datsuns are common and cheap, hence a cheap upgrade. In Europe your machine shop might have say vw or bmw valves for example that work out cheaper for you. Valve stem thickness variations can be overcome by using different guides and retainers.

Alternatively your machine shop might get some aftermarket valve like a manley or ferra, which is what mine is doing right now!

Not sure if they are still active but it seems there is a class of racing in finland that have been using the k series engine. Might be worth investigating seeing as you are close to them for parts.

Kentcams sell single valvesprings to suit the T125  : VS35  and adjustable pulley :  S63

3F lifters and "Twin squish 4k pushrods" are the parts Toyota originally used in their solid lifter vertion of 5K so wouldnt call it mix and match.

Keeping Hydro lifters would need a different cam grind and New or resurfacing of lifters

20 hours ago, 7000rpm said:

The adjustable pulley is to dial in the cam. Most engine rebuilders will recommend doing this on any non factory cam.

 k series valves have 8mm stems, 100mm length. Intakes 36mm head and exhaust 29mm

Datsun are 8mm stems but the length is longer. With a ground cam and adjustable rockers, some guys get away with installing them and having enough adjustment. Others shim up the rocker shaft posts, like joshua matthews did on here.

In australia Datsuns are common and cheap, hence a cheap upgrade. In Europe your machine shop might have say vw or bmw valves for example that work out cheaper for you. Valve stem thickness variations can be overcome by using different guides and retainers.

Alternatively your machine shop might get some aftermarket valve like a manley or ferra, which is what mine is doing right now!

Not sure if they are still active but it seems there is a class of racing in finland that have been using the k series engine. Might be worth investigating seeing as you are close to them for parts.

There is in fact a Finnish website with performance parts but they only have available 7mm stem valves, that's why I thought 4K valves were 7mm stem.

Already contacted Kent Cams UK to provide me more in depth info on the T125 camshaft, and asked for the duration data at middle lift.

On 29/06/2017 at 0:46 AM, Clapped out said:

ps, personally I wouldn't polish your head ports, leave them rough so you get better mixture of your air/fuel, been there, done that, better results from being rough,

 

cheers!

What about the combustion chamber? Polish or not?

Quote

 resurfacing of lifters

Theory is that you get this done anyway, so the new cam has new surfaces to run on. Cam grinding company should do it, $70 over here.

I think there is a 'grade' of polish that they prefer these days, fine but not dead smooth.  Chat to Oldskewltoy about that too...

5 hours ago, Viterbo said:

There is in fact a Finnish website with performance parts but they only have available 7mm stem valves, that's why I thought 4K valves were 7mm stem.

Already contacted Kent Cams UK to provide me more in depth info on the T125 camshaft, and asked for the duration data at middle lift.

You mean Esa? Seems that page has been up for a while. I wonder if he still has all those bits available?

On 01/07/2017 at 0:59 AM, 7000rpm said:

You mean Esa? Seems that page has been up for a while. I wonder if he still has all those bits available?

Yes Esapeltonen. A portuguese guy is tuning a 3K to reach around 130hp (he tunes Datsun A12 engines for the National Classic Championship) and bought a lot of stuff from Esapeltonen recently.

Here is the head off my 5k 

Ported runners

Cleanned up chambers 

Recut the valve seat to suit 

A15 valves

A12 pushrods 

4k adjustable rocker gear

Blue holden 202 6cly springs 

Joshua do you have the diameters of the ports?

 

Catcams sent me this datasheet related to a camshaft. What do you guys think? Duration at 1mm I guess it's the same as your .050 

Edited July 4, 20179 yr by Viterbo

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Cleanned up chambers

 

Are you going to do the valves as well??  Just put the stem in a drill press or a drill in a vice and use kero or WD40 and wet'n dry sandpaper.

Start off with 180 and end up with 400grit, so they are polished clean. The air has to flow over that surface, critical at low valve openings. 

Same with the valve seats, they should blend seamlessly into the throats, and an hour with a flapper wheel will sort it out.

Maybe one day Dan will do a 4K head in oldeskewltoy and we can see what really can be done!

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Yeah, 50thou would be the 1mm reading. You can see how much duration is not really used, about 50deg.

The last 44deg on the inlet is the important part, just when it closes as the piston is heading up on compression. If you rotate the cam to move that it gives the greatest effect-  early gives more power low down, late moves the power up the rev range as it allows reversion at slower speeds. With a cam that big an adjustable wheel would be handy, I'm only using a 275deg and never worried about it.

On 7/5/2017 at 6:07 AM, Viterbo said:

Joshua do you have the diameters of the ports?

 

Catcams sent me this datasheet related to a camshaft. What do you guys think? Duration at 1mm I guess it's the same as your .050 

34mm

 

5 hours ago, joshua.mathews said:

34mm

 

Great. Anything on the exhaust ports? Tho they're square...

 

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Kent Cams sent me info about duration @1mm for both T124 and T125

T124 - 220º

T125 - 232º

 

Seems a bit low for such agressive cams. I think I'm going the Catcams route as they have lots of regrinds. Something not above 275º and with good duration at 1mm, like the Camtech 609 that altezzaclub showed me.

What needs to be done to the A15 valves besides recutting the valve seat? As far as I know they're 3mm longer? I don't have access to Holden or Chevy stuff as people usually use.

16 hours ago, Viterbo said:

What needs to be done to the A15 valves besides recutting the valve seat? As far as I know they're 3mm longer? I don't have access to Holden or Chevy stuff as people usually use.

U will have to space up the rocker gear

U have to find valve spring to suit i used holden blue 202

And datsan a12 pushrods

That is what i have done

The last piece of info I'm still missing is how much to enlarge the intake and exhaust ports. I tried a gasket on a stock head and the gasket holes are the same diameter as the stock ports, so I can't really gastket match them.

Edited January 28, 20188 yr by Viterbo