L20b 2.4 build

[datzenmike]

.... and open up the areas around the valves closest to the combustion chamber walls. Nice smooth radius. Think of the trumpet shape of an air horn or velocity stack.

[Lorenzo p]

So put in some L28 44mm intake valves and leave exhaust valves alone? Also which length? I’m assuming 115.2 mm as it’s the same as the length as the L20’s? 

[Stoffregen Motorsports]

Same length valves, yes. Have the machinist keep the valve tips as close to stock height as possible, so the rocker geometry remains untouched. With some skill, the tips can be set to exactly the stock height so you can even use the stock lash pads.

[Lorenzo p]

I finshed installing all pistons. Everything clears and rotates freeley. I sent the cam and rockers off to delta cam, so now its time to port and polish, gasket match the head. heres some pics

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[Lorenzo p]

And no links for Big Mike. 👊

[Lorenzo p]

What up guys! So I got my head back from the shop put it all back together (new cam 460 lift and new exhaust valves stock height)and my intake valve springs are more compressed than the exhaust springs. When I was setting the valve lash the geometry on the exhaust looked way better than the intake, to the point where the intake cam lobe was almost falling off the hardened steel part of the rocker. Should the intake and exhaust rocker adjusters all be roughly the same height? Because the way it is now the intake rocker adjuster has to be about half an inch higher than the exhaust to set the lash correctly. I know I could use different lash pads to correct this but then I have one thickness on intake and stock lash pads on exhaust. I hope this makes some sense. 

[datzenmike]

Sounds like the intakes were ground and maybe the exhaust were missed? Borrow a vernier caliper ($12 on Amazon) and measure the base circle, that's the narrowest part of the cam profile, then across the widest part of the lobe. Subtract and this gives the lobe lift. Multiply by 1.5 to get the actual valve lift. Stock L20B is 0.413" valve lift on intake and exhaust. Something seems off here. 

[Lorenzo p]

So what would cause my springs to be at different heights? Valves are all stock lengths. I sent the came to delta cam btw. Sunken exhaust seats?

[Crashtd420]

On 12/1/2022 at 6:27 PM, Lorenzo p said:

So put in some L28 44mm intake valves and leave exhaust valves alone? Also which length? I’m assuming 115.2 mm as it’s the same as the length as the L20’s? 

 

1 hour ago, Lorenzo p said:

What up guys! So I got my head back from the shop put it all back together (new cam 460 lift and new exhaust valves stock height)and my intake valve springs are more compressed than the exhaust springs. When I was setting the valve lash the geometry on the exhaust looked way better than the intake, to the point where the intake cam lobe was almost falling off the hardened steel part of the rocker. Should the intake and exhaust rocker adjusters all be roughly the same height? Because the way it is now the intake rocker adjuster has to be about half an inch higher than the exhaust to set the lash correctly. I know I could use different lash pads to correct this but then I have one thickness on intake and stock lash pads on exhaust. I hope this makes some sense. 

 

So you used L28 intake valves, and you have an issue with setting the lash properly....

Did you verify the old vs new valve length? 

How do the look in the combustion chamber?

Are they both seated properly?

[Crashtd420]

So just poking around looking at parts I see both 43mm and the 44mm valves.... the do say they fit the L4, I also saw an early intake valve that was shorter but only 43mm.... 

 

I'll go back to the question how do they look in the combustion chamber? My guess is they are not seated as deep as the exhaust.... 

 

[datzenmike]

43mm is 1.7" Try again.

 

L20B intakes are just under 1mm shorter than the exhausts.

 

If valve seats were replaced and the seats set too deep or ground down too much the valve tops would be higher than the intakes. How about a picture of a combustion chamber?

 

If intake valves seats were not set into the head far enough or not ground down enough they would look shorter than the exhaust springs.

 

Perhaps a bit of both. Exhausts slightly too deep and Intakes not deep enough.

[Crashtd420]

14 hours ago, datzenmike said:

43mm is 1.7" Try again.

 

.

 

I was referring to diameter.... 

I thought the 44mm diameter L28 valve might be a different length than a 43mm diameter valve for the L20b..... 

I remembered seeing a shorter valve sold for the L28, I dont remember if it was for certain castings or early or later year heads..... but that short valve was only 43 mm diameter.. 

[datzenmike]

Right! The L6 did use different length but it was minor.

[Lorenzo p]

Update. I had the machine shop cut the intake valve seats to match the exhaust. Now the rocker arm adjusters aren’t all the way up. Engine is all assembled, everything clears and rotated freely. https://imgur.com/a/RH8iFLD

[banzai510(hainz)]

great job!!!!!!!!!

 

[datzenmike]

 

Only problem is the filter.

[Lorenzo p]

Why? Is it shit?

[datzenmike]

It's only good enough to use to mask the oil filter location when you paint the block.

[Lorenzo p]

Ok,so got motor installed in the engine bay and went to put the cab mounts on and my floor pans are rusted to shit right in those areas. So I’ll be cutting out the bad areas and welding in some new 16g steel. https://imgur.com/a/wKbW54i

[Lorenzo p]

Got my engine running!https://imgur.com/a/Wj118wW

[1001001SOS]

Wow that sounds great, congrats on the progress!

[datzenmike]

What did you use to fill the 20mm gap above the L20B timing chain cover and the underside of the L head?

[Lorenzo p]

Nothing. I didn’t have a gap. I’m confused?  L20b u67 head. Stock l20b timing cover no gap right? Or the gap where the z24 head gasket runs a little short on the front of the timing cover?

[Stoffregen Motorsports]

Mike is thinking you used a Z24 block. Which is taller. So there would be a gap.

[datzenmike]

Ah... so an L20B or Z22 bock bored to 89mm? The Z24 crank won't fit without clearance grinding the block. Is this what you did???