Lobo Posted June 22, 2014 Report Share Posted June 22, 2014 so i have a L20b from a 78 620 that im putting in my 521 i want to do a mild build on it cause this is my daily driver here is what im thinking L18 pistons (thinking about boring but not sure how much) mild cam (not sure on size) porting intake on head to match gasket w53 head l20 intake l16 exhaust manifold weber 32/36 already have electronic ignition setup i think im running 1 3/4 to magnaflow that is the basic setup im looking at after doing a bunch of reading and suggestions ,thoughts ? and yes i do want to run the l20 keeping it old school Quote Link to comment
metalmonkey47 Posted June 22, 2014 Report Share Posted June 22, 2014 L20 block. 86mm bore A87 head 1 5/8th intake ports w/ larger valves Z22 crank Z20S long rods (6'' long) .475/.260 cam 2.25'' exhaust weber 38/38 OR Z car SU's Beastly motor. Get to work! 1 Quote Link to comment
datzenmike Posted June 22, 2014 Report Share Posted June 22, 2014 L18 pistons (thinking about boring but not sure how much) Well they are the same bore but smaller dish so the compression will go up to 9.12. If rebuilding it have the block bored to the next oversize and get oversize pistons to match. If they still make L18 pistons.. mild cam (not sure on size) Yes, keep it mild. porting intake on head to match gasket port the head to match the gasket as well and smooth in about an inch. w53 head this is usually a closed chamber head and will raise the compression even higher to 9.91 which is a little too high for a daily driver. In addition the intake ports are smaller than the W58 head. I would find a U67 head. Much larger intake ports and the compression does not change from 9.12. (see exhaust below) L20B intake Your stock '78 intake will work just fine. L16 exhaust manifold This will perfectly fit the U67 head weber 32/36 good choice already have electronic ignition setup Also good i think im running 1 3/4 to magnaflow I think the stock pipe is 1 3/4", so if it's in good shape this is fine. If thinking of having one bent up go to 2" but not more Quote Link to comment
wayno Posted June 22, 2014 Report Share Posted June 22, 2014 As MM said, find another head than the W53, they all have small valves and small intake ports unless someone has opened them up, it costs money to open one up, I should know as I have done it a few times. The A87 head comes in a couple different versions, closed and open chamber, small and big valves, it is easy to find a closed one with larger valves, and smaller intake runners, but all that needs done is to hog out the intakes to match the intake manifold which is cheap compared to all the work needed to a W53 head to make it comparable. The U67 head has the big valves, and large intakes, but is an open chamber head, but you are buying pistons anyway, so you can buy them to have the CR you want, so that would be the route I would take, it is likely the cheapest route. so i have a L20b from a 78 620 that im putting in my 521 i want to do a mild build on it cause this is my daily driver here is what im thinking L18 pistons (thinking about boring but not sure how much) mild cam (not sure on size) porting intake on head to match gasket w53 head l20 intake l16 exhaust manifold weber 32/36 already have electronic ignition setup i think im running 1 3/4 to magnaflow that is the basic setup im looking at after doing a bunch of reading and suggestions ,thoughts ? and yes i do want to run the l20 keeping it old school Quote Link to comment
Lobo Posted June 22, 2014 Author Report Share Posted June 22, 2014 well I have a u67 sitting in the garage that needs to be rebuilt so maybe I will go that route as of pistons if I can't find a set of l18 what do you guys suggest Quote Link to comment
Lobo Posted June 22, 2014 Author Report Share Posted June 22, 2014 and cam suggestions on that ? Quote Link to comment
ggzilla Posted June 22, 2014 Report Share Posted June 22, 2014 If you want a mild cam, use the stock L20B camshaft. 1 Quote Link to comment
wayno Posted June 22, 2014 Report Share Posted June 22, 2014 and cam suggestions on that ? Pistons are not my thing, I just asked folks what I needed for my LZ23 and they told me what piston gave me what CR with my CC head, I needed to be around 9 to 1, I think it came in at 8.9 to 1, as for the cam, all I know is that the bigger the cam, the less torque one has, i don't rev my engines high enough to rate a cam other than a stock one, 4500rpms is about the highest I go normally. Quote Link to comment
ggzilla Posted June 22, 2014 Report Share Posted June 22, 2014 Going from 8 25 to 9.1 is a gain of about 2 HP. Going from 2.0 liter to 2.3 liter is more like 15 HP. 1 Quote Link to comment
TENDRIL Posted June 22, 2014 Report Share Posted June 22, 2014 driving around town i wish i had a smaller cam, but when im on long drives/freeway ....im glad i have a bigger one but i also have dual sidedrafts Quote Link to comment
wayno Posted June 22, 2014 Report Share Posted June 22, 2014 driving around town i wish i had a smaller cam, but when im on long drives/freeway ....im glad i have a bigger one but i also have dual sidedrafts I have dual SUs, makes the work truck go fairly good, but when I loose the trailer and unload everything out of the truck, it screams. Makes me wonder how it would run if I had the SUs rebuilt, I actually drifted it a couple weeks ago around a corner from a stop, and it's a dually. :lol: 1 Quote Link to comment
ggzilla Posted June 22, 2014 Report Share Posted June 22, 2014 Tendril, why that? Are you turning 6000 rpm on the freeway? Quote Link to comment
TENDRIL Posted June 22, 2014 Report Share Posted June 22, 2014 any chance i can get, but i did not choose the cam it came in the motor, i would prefer a bit less to be all around happy Quote Link to comment
laotsu Posted June 22, 2014 Report Share Posted June 22, 2014 buy my 6" rods, get some Z22e pistons, bore the block to fit the pistons, put the U67 head on the bored block with the L20b crank in it. Maybe add some Mikuni 44s? Quote Link to comment
flatcat19 Posted June 22, 2014 Report Share Posted June 22, 2014 Flattop Z pistons(81-83). Bore block to match. U67. Nice carb(s). Enjoi. Quote Link to comment
datzenmike Posted June 22, 2014 Report Share Posted June 22, 2014 L28 flattops with U67 would give you a 1997 cc engine and 10 to one compression with a U67 head. A bit much for me. 6" Z20E rods and pistons is 1951cc and 9.94 6" Z20E rods and Z22E pistons is 1997cc and 10.0 Lets not get carried away here. Compression increases efficiency but it's a race car thing where the expensive and cost of high octane fuel isn't a problem. For a street car keep it simple and easy to live with. Quote Link to comment
laotsu Posted June 22, 2014 Report Share Posted June 22, 2014 I got 9.15:1 and 2045cc on my combo. What hg height are you using D-mike? Quote Link to comment
datzenmike Posted June 22, 2014 Report Share Posted June 22, 2014 L16/18..................... 207.45mm L20B, Z20/Z22........ 227.45mm Z24/KA24E/DE...... 247.45mm It was late and I took shortcuts. If it's still wrong this morning... I haven't had enough coffee. The Z22S and early Z22E pistons are too tall for the 6" rod and would hit the bottom of the head. Only the later Z22E pistons (which I have been told and believe to be flattops) will work. If they are in fact dished, let me know and I can recalculate for a lower compression. L20B block and crank, 6" Z20E rods and late Z22E pistons open chamber head...... 2040cc motor and 10.766 Quote Link to comment
Lobo Posted June 22, 2014 Author Report Share Posted June 22, 2014 so with the z20e rods and z22e pistons you don't have to do anything to the crank cause im likeing the sound of that setup Quote Link to comment
laotsu Posted June 22, 2014 Report Share Posted June 22, 2014 I'm using the OZDAT engine builder which says a dish of 9.32. Seems accurate since I bought a set and they are dished. Quote Link to comment
Lobo Posted June 22, 2014 Author Report Share Posted June 22, 2014 and when you say "late" what years are you talking about Quote Link to comment
uberkevin Posted June 22, 2014 Report Share Posted June 22, 2014 Just a few weeks ago I swapped heads, the head that was on my l20b had a sinking valve so I needed to That head has a mild cam and gave me great top end power and now that I swapped the head its like driving a hole new truck. That's just me.. L20b flattop pistons with u67 head ported, dual SUs and mild cam boss!! Loved it! Now without the cam, again a different truck but still fucking sick! But again I've got a sinking valve on that head. Quote Link to comment
laotsu Posted June 22, 2014 Report Share Posted June 22, 2014 and when you say "late" what years are you talking about Z22S, early Z22E-- 35.5mm* / 9.32cc dish / 87mm bore Z22E, late------------32.1mm **/ ? / 87mm bore as seen here here is a fun way to waste some time and money Quote Link to comment
datzenmike Posted June 22, 2014 Report Share Posted June 22, 2014 I'm using the OZDAT engine builder which says a dish of 9.32. Seems accurate since I bought a set and they are dished. IF the Z22E pistons used in my calculations were in fact 9.32 and NOT a flattop then this will reduce the compression to 9.289 and when you say "late" what years are you talking about Z22S, early Z22E-- 35.5mm* / 9.32cc dish / 87mm bore [/size] Z22E, late------------32.1mm **/ ? / 87mm bore [/size] as seen here here is a fun way to waste some time and money The L20B block has only 227.45mm from the center of the crank to the top where the head is. The crank throw, rod length and piston pin height cannot exceed this or the piston will hit the under side of the head. 1/2 stroke.................. 43.0mm 6" Z20E rods........... 152.5mm early Z22 pistons....... 35.5mm ________________________ Total ......................... 231mm (the piston is now 3.55mm into the head. This tells us that only the later Z22E pistons with a pin height of 32.1mm will work. 1/2 stroke.................. 43.0mm 6" Z20E rods........... 152.5mm late Z22 pistons......... 32.1mm ________________________ Total ......................... 227.6mm... Within the allowable limit of .3mm above the block deck to allow for high RPM rod stretching. What small amount travels above the block is still well inside the crushed gasket thickness of 1.2mm I tried using the compression calculator but it asks too many questions and was confusing.... and often wrong. Quote Link to comment
Lobo Posted June 22, 2014 Author Report Share Posted June 22, 2014 So back to asking when did they start making the later z22e pistons I have tried looking buti can't get a definite answer on it Quote Link to comment
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