l24 blocked engine build - Few Questions

[Jason240z]

Hi All.

So, i'm at the point where I'm putting serious consideration into my engine.  I've got all the parts below already.

JE forged pistons 35.0266 pin height, 0.6cc positive dome, valve cutouts

240+240 cranks

ATI Damper

Kameari oil pump/adjustable cam sprocket/chain tensioner-idler gear/ignition+Distributor

Schneider 290F camshaft+valvesprings+Retainers to suit

Fidenza alloy flywheel

e31 head(needs valve seats etc)

Worked head with big valves(need to work out what head as casing has been removed)

oer 45mm carbs on an OER manifold

New style Fujitsubo

Other nice little bits to suit.

 

Using the engine calculator and a l28 crank/l24 rods I get the below.

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As you can see, the pistons with the rods give a better rod ratio.  However pistons sit just below deck height.

I'm going to get some forged maxspeed racing type rods.

So, sticking with what i've got, I could stroke the l28 crank by 0.5mm? Can I get bearings to suit then? I've found 0.75 bearings in the UK so a 1mm offset will still be serviceable.

 

The block will be decked to ensure its flat, it seems drastic but i could take 0.5mm off there instead of doing the crank?

My goals are a nice fun feeling, cammy engine. 150bhp at the wheels would be nice.  I'd like peak power at about 7200rpm in my little perfect imagination.

My compression is a bit lower than I'd like to run with this combo, Squish is also too large.  This is what i'm looking to correct to 11:1

 

Final drive is yet to be fully decided, I've a plated subaru r180 4.44 LSD that i'm going to use(I've seem 4.11 CWP though which appeals), box will be an A, B or C type 5 speed. 14" wheels, 195/65/14 tyres.

 

 

 

Edited August 16, 2018 by Jason240z

[240260280]

Most HG are a bit more than 1mm. Here are measurements reported on the internet (1.1mm, 1.15mm, 1.20mm).

Run this newer engine builder version from your desktop. It comments on squish. Just open file with any browser. 

S30 Engine Modeller V3 Beta 3.zip

 

You can easily edit the html with a text editor to customize the lists.

Here is HG section with (Name, diameter, thickness) format.

 

 

Edited August 16, 2018 by 240260280

[Jason240z]

Thanks, it'll be a HKS 1.0 or a felpro at 1.0 ?

 

[Jason240z]

The more I look.  0.88 off the block height makes the most sense.

Gives me perfect squish at a 1.2mm gasket.  Also means I could in theory run the block with standard internals and a thicker gasket.

[Patcon]

How does decking the block affect the timing chain length? Do you have to shim the towers to account for the deck height? Even if the head doesn't get  shaved? How does that affect the valvetrain geometry?

[Jason240z]

Just now, Patcon said:

How does decking the block affect the timing chain length? Do you have to shim the towers to account for the deck height? Even if the head doesn't get  shaved? How does that affect the valvetrain geometry?

I've got a kameari chain tensioner.

Remember, people take 3.0mm off a p90 etc.

[Patcon]

3 minutes ago, Jason240z said:

I've got a kameari chain tensioner.

Remember, people take 3.0mm off a p90 etc.

I am unfamiliar with that particular tensioner.

I was just curious if the loss of deck height has to get dealt with the same way a shaved head would. If so, you could end up with a lot of shims under the towers and that seems like it would make valve train geometry difficult

[Jason240z]

https://www.rhdjapan.com/kameari-l-type-twin-idler-gear-earl-s-blue-l6.html

you can remove upto 4mm total....

[240260280]

Interesting on the 4mm data point.  I always wondered when the water passages at the bottom margin would loose their shape and also when there would be too much heat for the now thinner base of the head.

[Patcon]

2 hours ago, 240260280 said:

Interesting on the 4mm data point.  I always wondered when the water passages at the bottom margin would loose their shape and also when there would be too much heat for the now thinner base of the head.

I believe the 4mm total is the amount of distance that the tensioner has the ability to accommodate. I don't know that you could take all 4mm off the bottom of the head

[Zed Head]

I'm not an engine builder by any means.  But it seems like you're spending a lot of money on minor operations and odd parts just to create a fairly typical L6 engine.

Looks like a common L6 with ~10:1 CR, and a Schneider 290F cam.  And you're only getting 2.6 liters of displacement.  Adding 0.5 mm of stroke (expensive machining operation), then decking the block (expensive machining operation) to get piston height right seems drastic for not much, doesn't it?  How will these "domed" pistons  (expensive) fit the combustion chamber?  If they're not flat tops then you'll have to have the combustion chamber shaped exactly to the piston (expensive) to properly use "squish". 

An L28 might be a better starting point.  Just another internet opinion.

 

[Jason240z]

26 minutes ago, Zed Head said:

I'm not an engine builder by any means.  But it seems like you're spending a lot of money on minor operations and odd parts just to create a fairly typical L6 engine.

Looks like a common L6 with ~10:1 CR, and a Schneider 290F cam.  And you're only getting 2.6 liters of displacement.  Adding 0.5 mm of stroke (expensive machining operation), then decking the block (expensive machining operation) to get piston height right seems drastic for not much, doesn't it?  How will these "domed" pistons  (expensive) fit the combustion chamber?  If they're not flat tops then you'll have to have the combustion chamber shaped exactly to the piston (expensive) to properly use "squish". 

An L28 might be a better starting point.  Just another internet opinion.

 

Hi

Not quite fairly 'typical' all forged, fully balanced, 11:1CR. that should be quite reliable and pretty period, I think you skimmed the thread and didn't read the first post where I was looking at ways to alter the specs given the pin height.

Its a tiny dome on the pistons, -0.6cc, just enough to cover the valve cutouts.

if I decked the block, its circa £60 or $77.  Offset grinding is about $200, i wouldn't need to do both... if you read, it'd be one or the other.

And its 2660.5CC ?  (thats with +1mm on the crank), that'll be happy(as can be) revving to 7500-8000rpm

It matters as I want the original block.

 

 

Edited August 16, 2018 by Jason240z