+1

epoxy for bench testing only.

You need to weld in the areas that you want extra material.
Then the head needs to be heat treated back to original hardness.

 

It was stated in other posts, don't be dumb.

 

spyro i have sent you a Email. let me know if you receive it.

 

Ok, when you say ">0.5g at 9k" I have to ask you to clarify.

For one, are you saying it is greater than 0.5g out of balance and does need to be balanced beyond factory specs?


Besides that though, I had a factory crank measure out to 24 pounds of bearing load at 8500 RPM. This is equivalent to 3 grams of mass at the center of the rod journal.

0.5 gram-force bearing load @9000 RPM would mean less than 1 MICROGRAM of static weight at the rod journal. The imbalance caused by oil alone is several orders of magnitude greater than that. I assume you are not talking bearing loads and you simply mean that it is 0.5g out of balance and you would need to remove 0.5g at a known distance to have it balanced at any given speed. The 9k rpm then becomes irrelevant.


Do some places actually spin balance at high speeds though? I've done precision balancing on aerospace components and we always tested at the functional speed as it would help uncover vibration issues. We could track imbalance based on shaft speed and you would have modes of imbalance that were completely different due to different harmonics on the shafts. If you weren't on certain harmonics though, the imbalance would track along as predicted by simple centripetal acceleration equations.

FWIW, there is actually a pretty interesting video on the Ford Cosworth engine design of the 80s (turbo F1...) and they found a limit on their crankshaft design due to harmonics. I'll post up the link when I get home. If you listen carefully, you'll pick up some amazing info...stuff like 28 psi gauge pressure in the intake manifold and 9 psi in the exhaust header... Other then that, it is just a cool inside look at the Turbo F1 era.
http://youtu.be/xbB1qwhKaaE

 

I got my less than/greater than messed up. It was less than 0.5g out of balance and I presume that was just like a wheel/tire assembly (as highlighted), it was what needed corrected. I wasnt there when it was done so that is the only measurement I was told and remember. We have checked 3 or 4 cranks randomly, and have checked some aftermarket ones and come up with very similar data. I will call our machine shop and seek clarification or worst case scenario send another one in to have it checked again.

I guess for the time being disregard the measurements I listed, but our results of not bothering with it are still obviously valid. Jeff has told me before that on his 7 bolt 2.3 he had in his 2G it was balanced with EVERYTHING on it. Clutch/Flywheel, rods/pistons, Fluidampr, etc. and was out <1g at 8000. Again it doesnt exactly answer your question nor does it tell us what the crankshaft is, just the rotating assembly.

 

That crank I mentioned being out of balance was a 6-bolt crank. However, I should mention, I pointed out that it was like 3 grams out at the center of the rod. As far as how you would actually balance it, I believe it was less than 1g out. Not terribly far off from what you are saying.

Just wanted to make sure we were talking about the same thing and I think we are.

I just point it out because technically, you can't tell how out of balance something is by a weight alone. Without a distance from center, it means nothing.

 

What block mods are necessary on the engine as power rises?
I have done heads for Volvo 16 valve turbo engines and the blocks
need to be filled with concrete and steel plates added under the
main bearing saddles to hold the block together.
The car in the videos only has 1300hp so I wonder how a 1500 to 2000 hp
Mitsu will go.

Here are two videos from the same run:

http://www.youtube.com/watch?v=WTFJx...layer_embedded

http://www.youtube.com/watch?v=qhW7o...layer_embedded



Erland

 

Nice

 

LOL! Understatement of the year! 6.8 in a 4-banger in a bl**dy box like a Vulvo is nothing short of amazing!

Not sure about block strengthening: are the Volvo 2,3 engines also cast iron like the Mitsu?

 

Hi Erland,

What type of Volvo Engine are you using?
Aluminum of cast iron? 4 or 5 cylinders?

Do you have any topic that you are shearing your engine’s modifications?


ps: By the way, I am a Volvo owner (B4194T2) and I don’t think that “white blocks” are tough.

 

It is not my car, I just did the cylinder head for it.

Pictures of the head are here:http://www.topplocksverkstan.se/volv...Turbotopp.html

It is a special racing block from Motordesign in Sweden with steel main saddles
and a strengthening plate under all the saddles and the oil pan mounting surface.
It is a 4 cylinder red block Volvo engine type 230 bottom with a 234 16V head.
Keeping the block together is the biggest engine problem but it has run with a
concrete filled stock Volvo block before.
The blocks are in cast iron without any liners in them.
The engine is 2.5 liters today but he is going for a billet head and larger capacity this season.
The turbo manifold is nothing special, just as short as possible with cylinders 1-2 and 2-3 into a twin entry turbo.
They had to spread the cams on the dyno for best power but it seems to work even if the manifold should have been 1-4 and 2-3.
The manifold is 48 mm OD so it should be around 43mm ID.
I have not found any good info on the car on the web, only other people writing about it.
It runs a clutch less 5 speed transmission with a 3 plate 8" clutch made for Pro Stock racing here in Sweden.

Erland

 

Some links:

http://server.pure-pf.com/phpBB/view...hp?f=1&t=12319

http://forum.savarturbo.se/viewtopic.php?f=9&t=56625

Erland

 

Erland, is this the cylinder head that RSI supplied camshafts for? I am doing development work with one of my friends and am using RSI for the cams. I was told that a set of the ones we spec'd for Nathan's 2.5L (96x88 with 158mm rod) got sent to Sweden for usage in a car that was making 800+ but not much more.

thanks

Aaron

 

I believe Gunnar Lundström, the professor did these cams.
They are not very exotic or high lift I got into this project late and only did two heads for them.
The manifolds runners are to small but he did not want to swap the manifold at that stage so I made the head to fit the manifold.
4,5 bars absolute is what gives the power and careful selection of the right turbo.
I believe Turbo service in Sweden did the turbo selection and preparation.
Maximum power is somewhere around 8000 rpm but with a bigger runner area and higher lift cams it can rev a lot more.
There are 15.5mm cams available from AGAP in Sweden: http://www.agap.se/res/Default/agapk...rvolvob234.pdf
There are lots of guys running with these heads in Sweden and also with the newer white blocks 4 to 6 cylinders.
Several of the 4 cylinder 16 valve cars are above 1000hp but this one has the highest hp at 1303.
I am curious why Spyros believes that bigger exhaust valves are necessary because even going from 32 to 34mm loses us power?
He wants to use 38mm inlet and 40mm outlet I read here.
Here is another Volvo 16 valve dragracing engine: http://forum.savarturbo.se/viewtopic...it=16V#p447194

Erland

 

Its because he makes 1500bhp not 1300bhp. Do you rev to peak torque or peak power?