Datsun B310 turbo coupe, A15 project

[Atomic]

Got some goodies:

 

I still have to confirm that all the dimensions are correct as ordered, so haven't had time to cross check yet

[Atomic]

Got these fast conversions and so far things are matching up:

Huge improvement on top land thickness

 

If anyone has an idea what might be the dome rise and dome volume units, would be nice to know. 

 

Datsun A15 turbo pistons		Convert	25.4	Original
Piston specs
Forging	F40097X	Inch	mm	mm
Comp Height		1.184	30.0736	30
Bore Size		3.0118	76.49972	76
Suggested Skirt Clearance		0.0035	0.0889	0.035
Pins
Diameter		0.748	18.9992	19
Length		2.5	63.5	63
Width or Wire Dia		0.49	12.446	NaN
Rings
Top Land thickness		0.28	7.112	5
Top Grvoove width		0.0401	1.01854
Top Groove Root Dia		2.746	69.7484
Second Ring Land thickness		0.18	4.572
Second Ring Groove width		0.048	1.2192
Second Ring Groove Root Dia		2.7098	68.82892
Third Ring Land Thick		0.08	2.032
Third Ring Groove Width		0.048	1.2192
Third Ring Groove Root Dia		2.7158	68.98132
Dome and Valve Pockets
Dome Rise		-0.325
Dome Volume		-20
Deck Thickness		0.525
Intake pocket Dia		1.6	40.64	37
Exhaust pocket Dia		1.325	33.655	30

[datzenmike]

Well it isn't cu. in and when measuring combustion chambers it's always in CCs. Everything else is in mm so CC.

 

Looks more like a dish piston top with a small dome in the middle.

 

Says the pin height is 1.184 (that would be inches) or 30.0736mm.... could you check from the middle of the piston pin hole to the top of the piston? If it comes up to the top outer edge, then hold it up and look across to the other side. If nothing above it then no dome.  Get a child's liquid medicine syringe and fill the dish to measure the volume. Add this to the combustion chamber volume for the total.

 

 

I told the pharmacist what I was trying to do and he gave me one.

[Atomic]

3 hours ago, datzenmike said:

Well it isn't cu. in and when measuring combustion chambers it's always in CCs. Everything else is in mm so CC.

 

Looks more like a dish piston top with a small dome in the middle.

 

Says the pin height is 1.184 (that would be inches) or 30.0736mm.... could you check from the middle of the piston pin hole to the top of the piston? If it comes up to the top outer edge, then hold it up and look across to the other side. If nothing above it then no dome.  Get a child's liquid medicine syringe and fill the dish to measure the volume. Add this to the combustion chamber volume for the total.

 

I told the pharmacist what I was trying to do and he gave me one.

 

 I have a plastic syringe in the garage actually. Everything was in inches, so that's why it was confusing what kind of unit it might be, but we will soon see I guess. 

 

The pin center hole goes to all the way to the top, so it's basically same as the stock piston as seen from the specs. They added valve pockets for some reason, even tho normal ones doesn't have them. Compression ratio will thus remain the same.

[datzenmike]

So the 'dome volume' is really the dish volume? 20cc? What compression are you shooting for?

[Atomic]

24 minutes ago, datzenmike said:

So the 'dome volume' is really the dish volume? 20cc? What compression are you shooting for?

Should be the same as before 8.9:1, or 8.5:1

Edited January 15, 2020 by Atomic

[datzenmike]

What's the purpose of the forged pistons? why not stock ones? Turbo?

[Atomic]

1 minute ago, datzenmike said:

What's the purpose of the forged pistons? why not stock ones? Turbo?

 

Turbo with 2 bar pressure

[Atomic]

As for niddy-griddy stuff from the new pistons,

* They have moved the first ring landing to 7 mm from previous 5 mm to move them away from the high temperatures.

* On top landing they have contact reduction grooves which reduce the friction by minimizing piston material in contact with the cylinder wall above the top ring. They also serve as a way to disrupt pressure spikes caused by detonation which helps to resist ring unseating
* The accumulator groove between the first- and the second ring to provide relief space for pressure that is escaping past the top ring before it attempts to pass the second ring. Therefore, it will support the top ring sealing by relieving pressure and it helps reducing ring flutter caused by pressure changes.

* ArmorFit skirt coating is a self adjusting liner that will reduce noise and improve piston stability when it's moving up and down. 

 

http://blog.wiseco.com/piston-coatings

http://blog.wiseco.com/ring-grooves

[Atomic]

Anyone knows a custom head gasket manufacturer? 

[datzenmike]

Have you given any thought to having them ceramic coated on top? It reduces heat transfer into the piston. What isn't absorbed can be put to work pushing the pistons. The combustion chamber and valves (specially the exhaust) can also be coated.

 

There is also the use of oil squirters to cool the bottoms of the pistons by drawing off heat, again reducing detonation. The KA engines have these and makes use of the high volume oil pumps. I assume you will be running an oil cooler.   

 

I would have the block O ringed if running a turbo. This completely seals the combustion chambers. Alternatively a solid copper head gasket, or both.

[Atomic]

I have a ceramic liner on the cylinder head and valves. I'm unsure about the piston coating now that they have been pre-heated and designed to take high heats. Aka my fear is that there is not enough heat to get a proper sealing anymore.

 

I was going to put some oil squirts to cool the pistons but we'll see how it turns out, I must talk with the machine shops about that, there is very little space from the oil galleys to the cylinder walls as the crankshaft balancers are quite big. 

 

Not sure If I'm able to O-ring that block, the gaps between cylinders are small, maybe if using siamese rings. I was under impression that copper gaskets will almost always require combustion sealing via O-rings in boosted applications? I'm trying to find MLS or copper gasket manufacturers for custom order or stock option for A15 motor.

 

All I can find is Tomei head gaskets for 79mm bore or smth

Edited January 15, 2020 by Atomic

[datzenmike]

If the gaps are small even more reason to ring them and use a copper gasket. The copper needs to be annealed to soften it and make it more flexible. The advantage to copper is they are reusable.

 

You only need the squirters to be out of the way of the crank throws. This begs the question of a windage tray and a crank scraper to manage the oil fog produced.

[Atomic]

1 minute ago, datzenmike said:

If the gaps are small even more reason to ring them and use a copper gasket. The copper needs to be annealed to soften it and make it more flexible. The advantage to copper is they are reusable.

 

You only need the squirters to be out of the way of the crank throws. This begs the question of a windage tray and a crank scraper to manage the oil fog produced.

 

Alright, I'll add that to the machine list next time. I should find some place where I can get the copper gaskets made to fit.

 

I might leave the oil squirts out as it is making things a lot more complicated. But I can talk with the machine shop about that. I might end up running just E85 and that will keep the temperatures lower compared to gasoline only.

 

[Atomic]

I wonder if the bore size on Tomei gaskets of 79 mm is just for the gasket hole size, looks like almost close to stock one between the cylinder liners:

[Atomic]

I took the cylinder head for quick check in our local shop. Meanwhile I went to the garage to weld in some temperature sensors:

 

Also got a new phone, loving the wide angle camera. It captured the discoloration of the stainless steel really well. I should be able to control cylinder spesific fuel target after installing these and then the cam position sensor. The temperature sensors will mainly act as a +-2% correction for the individual cylinder based fuel map.

[Atomic]

Got some quotations from couple of engine machining shops. I'll ask for couple more details before I make a decision. The cylinderhead should come from the machine shop this week. I'm most likely going to trance the cylinder bank and order a waterjet cut copper headgasket. I just need to know some material specs before i send it. This is turning out to be quite expensive to boost A15 motor with the results I'm seeking for. Probably would have been cheaper to buy another engine with same hp on stock. But most likely that would have been bigger displacement one. Oh well, let's see how far this A15 will let me push it.

 

And then I got some license plate lamps from the post:

[datzenmike]

I made one from a piece of copper flashing for roofing for a KA24E head. O.020" thick. Haven finished the build yet. 

[Mattndew76]

 

 

Edited January 22, 2020 by Mattndew76

[Atomic]

I have seen that video few years back. I'm not sure tho if the A15 block would require siamese rings between cylinders 1-2 and 3-4 due to relatively thin wall, maybe single ones could be doable. Somebody just suggested that I should just run only with copper spray between the block and the head, but I shrugged that as a funny joke.

[Crashtd420]

On 1/22/2020 at 10:29 AM, Atomic said:

This is turning out to be quite expensive to boost A15 motor with the results I'm seeking for. Probably would have been cheaper to buy another engine with same hp on stock. But most likely that would have been bigger displacement one. Oh well, let's see how far this A15 will let me push it.

I ran into that same situation with my L16.... I think the motor swapping is way over done lately that's the only reason I build my L ..... I applaud your effort....

[Atomic]

I have been thinking about the o-ringing and 0.041 inch AISI 304 ring looks good on paper. 

 

Bore Size		3.0118	76.4997
Suggested Skirt Clearance		0.0035	0.0889

 

Suggested bore size			76.67752	mm
Gasket bore size			76.93152	mm
O-ring groove dia center			79	mm

Edited January 23, 2020 by Atomic

[Atomic]

Welded the AN fittings for valve cover ventilation and crank case ventilation:

 

Also drilled a hole for the hall sensor. Next I need to put a trigger to the cam wheel

[datzenmike]

Isn't the oil fill cap a vent?

[Atomic]

13 minutes ago, datzenmike said:

Isn't the oil fill cap a vent?

It's sealed shut with a rubber gasket, so no. The original was a normal tubing outlet that i modified to clear out the intake manifold. Now I replaced that just with the AN fitting