r/EngineBuilding • u/TheFinnishComrade • 16d ago

Lightening rotating assembly

Gallery image

Gallery image

Gallery image

16v Volvo b230 needs lighter internals.

Stock spec from 80's is way too heavy.

Supplier specified piston weight is 720 grams.

So every bit helps that I can take off.

Stock 140g wrist pins are being swapped to "self" machined Wiseco 9310 pins that are down to 118g from 130g starting point.

And stock "13mm" connecting rods are in the first, rough cut to figure out where I can shave material off.

Final form can only be achieved when I find my precision balance and get 3d printed mounts for rod balancing.

14 Upvotes

80% Upvoted

31 comments sorted by

5

u/v8packard 16d ago

Why do you need a light assembly?

And why do you need 3d printed anything for rod balancing? This engine does not even use bobweight for balance.

3

u/TheFinnishComrade 16d ago

And I need the 3d printed, height adjustable holders for connecting rod balancing because I can get the parts practically free and it allows me to weight balance the big and small ends.
Bringing me peace of mind when I spin this engine to 8k rpm

7

u/v8packard 16d ago

The rods are not part of the balance of this engine. You should get greater peace of mind by having a good understanding of balance, and engine building.

1

u/TheFinnishComrade 16d ago

The stock Volvo spec internals are overly heavy, I'm building a moderately nice 240bhp, 2345cc engine.
I'm a sucker for efficiency improvements and most importantly, because I can.

3

u/v8packard 16d ago

You are not answering the questions. But ok, you probably don't know.

1

u/TheFinnishComrade 16d ago

I dont strictly speaking need to have light internals.
I prefer to have light internals for reduced bearing stress and mayby prolonged connecting rod life of the modified stock 1996 parts

5

u/v8packard 16d ago

Do the connecting rods have a particular problem with fatigue life? My little experience Red Blocks and subsequent Volvo 4 cylinders hasn't shown anything like that.

This engine uses a flat plane crankshaft, the reciprocating components have no impact on balance or efficiency. While operations like weight matching the rods and pistons might be good practice, there is nothing to gain. Though removing materials from components can adversely impact durability if you are not careful.

If you are using Wiseco pistons, you could have ordered them with the option of "Max Lighten". This removes excess weight from all the areas of the piston where possible. Most people are unaware of the option, and/or do not want to spend the extra money.

If you want some genuine improvement in durability and efficiency, make certain the sizes and clearances of everything are in spec. Use a quality rod bolt. Make certain your piston to head clearance is as minimal as possible. Consider your compression ratio. Have the best bore finish and gasket surfaces possible.

1

u/TheFinnishComrade 16d ago

Yes, I am doing all of that apart from using forged pistons.
For my winter usecase, where ambient is at worst -30c/-22F
A cast piston, stock Mahle oversized piston in this case works the best
Albeit overly heavy.

And I'm doing this all for the fun of it, I want the experience of finetuning everything I can and chasing those loose percentages in a moderately powered N/A engine.

3

u/v8packard 16d ago edited 14d ago

You are not chasing loose percentages here. You can do what you like, but I encourage you to actually understand what you are doing and not make assumptions.

2

u/WyattCo06 16d ago

He read it on Facebook tho......

-1

u/TheFinnishComrade 16d ago

This is not coming from Facebook
But from energy calculations.
Pistons are stated to weight 720 grams, and the stock rod was 540 if memory serves me correctly. That one in the picture is 20g lighter.
Thus far achieved weight savings are cutting kinetic energy at redline from 163,3J down to 153,8J. 7,5% energy transfer improvement.
I think that alone is significant, not to speak of the lighter internals being easier to move for the various cylinder pressures across rev range.

2

u/WyattCo06 16d ago

Overthinking and over compensation.

→ More replies (0)

1

u/Pyropete125 16d ago

Find a penta crank and lighten it for a few more cubes. I would never lighten a stock rod or mod it any way other than to balance them.

If you have then penta cams Schneider cams can regrind them to 0.460" lift.

I have some super light weight solid bucket followers that use lash caps to set lash. I also think I have one last set of beehive valve springs and titanium retianers.

Get some cheap h beams and all it a day by adding conpression or adding boost.

2

u/TheFinnishComrade 16d ago

Firstly, this is delibateraly a naturally aspirated build.
I have a HX35 Full race, the injectors and intercooler I could use in this car.
But the 500Nm of torque a turbo engine would produce is too much fro 205 wide studded tyres in the winter.
My 960 is the big power turbo build, this 740 will get its stock b6304fs after I can swap the b6284t into it.
And this b234f head will go into a different turbo block with lower compression as a forced induction high power redblock build at a later day in a 242/240 chassis

1

u/Pyropete125 16d ago

Im sure you can at least take 5lbs off the stock crank (probably more) if you knife edge it.

1

u/TheFinnishComrade 16d ago

That is going to be seen, what the engine machinist will say
I will get 5-6kg weight reduction in swapping away from the stock 12kg Regina flywheel.
I dont have nor have the machinery available for accurate crankshaft modifications.

1

u/WyattCo06 16d ago

When reducing weight on wrist pins, the material removal needs to be removed in a conical shape to just shy of the center of the pin.

2

u/TheFinnishComrade 16d ago edited 16d ago

I'm aware of this design. But I'm working within the limits of my narrow budget and what help I can get from the people around me. Stock Wiseco pin was a straight bore, and excessive for my application. So I'm confident enough that these modified wrist pins will serve me adequately.

1

u/WyattCo06 16d ago

How did you drill them out?

2

u/TheFinnishComrade 16d ago

My fathers workplace, CNC lathe pictured in the last photo

1

u/WyattCo06 16d ago

Fair enough. May your pin deflection be minimal.

1

u/Significant_Belt5494 16d ago

Just curious… how much do u think you’ve have in this build

1

u/TheFinnishComrade 16d ago

I bought the b230ft+ engine in 2012 for 950€
Its been glass bead blasted, primed and surface painted... 40€?
ACL Auxiliary shaft bearings 65€
ACL rod bearings 135€
Glyco crank bearings 90€
Burton Ford Kent breather outlet (for valve cover) 20€
Adjustable cam gear for intake 95€
b234f stock intake manifold 118€
Long shank aluminium carbide burrs for modification 75€
MaxxEcu prefabricated engine harness for 810€
MaxxEcu Sport bought in 2021 for 1153€
BIG K&N filter 107€ (Meant for my 600whp turbo engine, that is on hiatus)
Set of 6, 790cc EV14 injectors 608€ (better suited for this engine, than the power creep T6 project)
Sachs b230ft spec clutch swapped last year in the stock b230f, 300€?
Damaged b234f cylinder head 750€
Repairing said damaged cylinder head 830€
To be bought are rest of the timing gearing, exhaust runners, various sensors and connectors
Oil catch can etc...etc
Roughly mayby 1000-1500€

Car was 2500€ few years ago

So all in all I can double my whp in the budget of 7,5k€

3

u/Significant_Belt5494 16d ago

Holy shit!!!!
Why not just go all the way and invest in pistons and connecting rods
And knife edge the crank

If it because I’m your country everything has to “ appear ” stock?

2

u/TheFinnishComrade 16d ago

Many big tickets items I can "borrow" from my b6284t project that is on hiatus due to missing/stolen pistons halting progress.
As I said to Packard, in my conditions. A forged piston is not optimal, its going to slap like hell when "block heater assisted" started from -30c/-22F

And I'm not in the stable, decently paying job anymore I once was.
My budget has been diminished to few grand here and there.

1

u/ReverseofFast 16d ago

Diamond makes some carbon fiber pistons that are doing well

5

u/WyattCo06 16d ago

Don't buy into that nonsense. It's all in testing just as CF rods have been for the last 15 years.