L series race engine questions

[DISLEXICDIME]

I have had issues where the engine would brake up above 5000 rpm with the cam dowel on 3. but this was with a stock cam.

[Sealik]

I have had issues where the engine would brake up above 5000 rpm with the cam dowel on 3. but this was with a stock cam.

 

No 1 position for higher RPMs.

Mine is set at No 3 (advanced) because it's a heavy truck...better out of the 'hole' and doesn't slow down as much when I hit a slight incline.... with the lower RPMs

[GreaseMonky]

So i blew my L20b at the track last week, and so I have been picking up parts so I can just get back on the track, Right now I have a L18 with a A87 head, and a L18 with a w53 head. and will be getting next week a L16 with a A87 head, I would like to run my flywheel from my L20 and my cam from my L20, and I guess If I need to I could replace the 2 bent valves and run the U67 head from my L20. the l20 was all stock, except for MAYBE some balancing, I also may have one other option, and that is to run a L20B bottom end with any of these head combo's, and teh other L20 is all stock.

 

So i guess what would you guys recomend

[datsun 521 ute]

Have a look at this site, it's an engine builder for datsun/nissan engines. It is pretty cool and I have sat there many a nights putting together engine combos.

http://www.ozdat.com/ozdatonline/enginedesign/

Not only educational but good fun, enjoy.

[mrbigtanker]

put a Ls2 in it.lol you will have all the power you need.i still want to do it.

[DISLEXICDIME]

if you put the u67 on the l16 it will drop your comp to 7 to 1

[datzenmike]

So i blew my L20b at the track last week, and so I have been picking up parts so I can just get back on the track, Right now I have a L18 with a A87 head, and a L18 with a w53 head. and will be getting next week a L16 with a A87 head, I would like to run my flywheel from my L20 and my cam from my L20, and I guess If I need to I could replace the 2 bent valves and run the U67 head from my L20. the l20 was all stock, except for MAYBE some balancing, I also may have one other option, and that is to run a L20B bottom end with any of these head combo's, and teh other L20 is all stock.

 

So i guess what would you guys recomend

 

L20B flywheels will not bolt to the L16/18s

 

U67 will bolt to the L16 but as stated the comp. will lower to 7.72

 

 

 

Are you saying you blew up an L20B but you also have another L20B????

 

If so, swap the blowed up L20B head (U67) over to the other L20B and keep going.

[GreaseMonky]

What would the advantage of the u67 head over the others

[datzenmike]

Advantages? Well if used on an L20B it would have larger valves and ports than an A-87 and also square exhaust ports so the cast iron header from an L16/18 could be used.

[GreaseMonky]

ok I thought the a87 had square Ports, along with the w53.

[datzenmike]

They do. I'm saying you could use the L16/18 exhaust manifold on the U-67 instead of the 4 into 1 L20B manifold.

[GreaseMonky]

Ok, gotcha, All i have are the L16/18 exhaust mani anyway, but the porst are smaller on the w53 and A87 then the U67?

[GreaseMonky]

Or i may have another possibility of a Z20 bottom end

[datzenmike]

Yes indeed!!!! The Z20E is basically an L20B block that has flattop pistons and long 6" rods in it. Put the U-67 head and L manifolds on it and use the L20B motor mounts to basically convert it from a Z to an L motor. Compression would be 9.9.... nice.

[GreaseMonky]

Sorry to keep asking all theses questions, but why would i not run the A87, or the w53? especially if they are closed chamber heads, I run race race fuel, and its never driven on the street. and I would run my cam that was in my L20B before, which is, .480 lift/292 duration, on a 108 lobe center, and then I wanted to run my L20B flywheel, cause its been lightned,

[hobbes_the_cat]

This page explains all the differences in valve and port size for L series heads and decodes the casting numbers like A87, W53, ect. this will answer all your questions about which is better. http://www.olddatsuns.com/html/tech/head_ID_2.htm

[Stoffregen Motorsports]

I think they may not like the LZ24 idea, thats why I was staying away from it, the block is suppose to be stock for make and model, but not year, and porting is not allowed so i am stuck trying to find a large port head

 

So I'm confused, it is a 510 we're talking about right? The only "stock" engine for a 510 was a L-16. Do you have a rule book which explains it more clearly? What sanctioning body are you running with? If you are running SCCA or similar you will never get past the scrutineers with anything but a L-16, or MAYBE a L-18. You can stuff a L-20B crank into a L-18 for a 2150, but it is not easy.

 

If you need the L-16 block, the only thing you can really build is a 1700, which is a large bore, long rod, L-18 crank motor, using custom pistons. If you can use the L-18 block, then 87mm pistons and L-16 rods will give you a 1900.

 

If you can run the "tall block" motors (L-20B, Z-20, etc) then my favorite motor is a long rod 2200. Use a Z20 block (not Z22 as everyone thinks, because of the steam ports and siamesed cylinders), bore it to 89mm (using KA24 16V pistons or custom pistons), N85 rods from a Z20E and a L-20B crank. This motor gives all around the best usable RPM range of any combination. I built one once that dynoed at 220 HP and 200 LBS torque with duall 44 mikunis and ran on pump gas.

[GreaseMonky]

So I'm confused, it is a 510 we're talking about right? The only "stock" engine for a 510 was a L-16. Do you have a rule book which explains it more clearly? What sanctioning body are you running with? If you are running SCCA or similar you will never get past the scrutineers with anything but a L-16, or MAYBE a L-18. You can stuff a L-20B crank into a L-18 for a 2150, but it is not easy.

 

If you need the L-16 block, the only thing you can really build is a 1700, which is a large bore, long rod, L-18 crank motor, using custom pistons. If you can use the L-18 block, then 87mm pistons and L-16 rods will give you a 1900.

 

If you can run the "tall block" motors (L-20B, Z-20, etc) then my favorite motor is a long rod 2200. Use a Z20 block (not Z22 as everyone thinks, because of the steam ports and siamesed cylinders), bore it to 89mm (using KA24 16V pistons or custom pistons), N85 rods from a Z20E and a L-20B crank. This motor gives all around the best usable RPM range of any combination. I built one once that dynoed at 220 HP and 200 LBS torque with duall 44 mikunis and ran on pump gas.

 

Im not racing scca its circle track racing on the dirt

 

The rules state, "Engine must be stock for make and model" and "trans must be stock for make and model and year" my argument on the 510 is the later 510's i think there hL510 or something like that, but we are limted to a stock style intake, and a single carb, any two barrel

 

And from what i have read so far, those came with a L20B and a Z20

[Stoffregen Motorsports]

They did come with the L-20B and Z-20.

 

So ask yourself, do you want torque or RPM. Can you hook up coming out of the turns or do you want to keep your motor buzzed up andmake your pass at the end of the straight. If it's torque you want then I would build a 2300, if it's RPM then a 2200.

 

You might want to talk to Dave Rebello. I worked for him for almost 10 years and we built a few circle track motors while I was there.

[GreaseMonky]

Whats the best performing stock intake to use on a l20?

[Stoffregen Motorsports]

Whats the best performing stock intake to use on a l20?

 

That would have to be the A46 intake. If you have to run a stock intake, even the best motor will only make @ 140hp

[GreaseMonky]

We are limited to a stock style intake, and a single carb, but I have a bunch of intakes now, and trying to put a engine together for tomorrow to go race,

[Guest LoneWolf]

Thanks Hobbes_the_Cat for the web link page for "type of heads"... I have a L20 in my 510 and I have a U67 head...I have 280Z 5 speed tranny, I have a straight header aswell with 2.25 in exhaust, with electronic distibutor, original carb with K&N air filter...I don't know how much horsepower I have, I'm thinking probably 130... so from my self experience I think the U67 head works awesome on a L20...but I notice the the letter and numbers are slightly not visible ...so it leads me to believe that my U67 head has be modified(plained)...so my motor probably has been rebuilt at least twice...but I don't know if it an open chamber head or not.

[Sealik]

Thanks Hobbes_the_Cat for the web link page for "type of heads"... I have a L20 in my 510 and I have a U67 head...I have 280Z 5 speed tranny, I have a straight header aswell with 2.25 in exhaust, with electronic distibutor, original carb with K&N air filter...I don't know how much horsepower I have, I'm thinking probably 130... so from my self experience I think the U67 head works awesome on a L20...but I notice the the letter and numbers are slightly not visible ...so it leads me to believe that my U67 head has be modified(plained)...so my motor probably has been rebuilt at least twice...but I don't know if it an open chamber head or not.

 

The U67 is an open chamber head, shaved will raise compression

Should be shims underneath the cam towers to compensate for the amount "modified(plained)"....

[datzenmike]

Thanks Hobbes_the_Cat for the web link page for "type of heads"... I have a L20 in my 510 and I have a U67 head...I have 280Z 5 speed tranny, I have a straight header aswell with 2.25 in exhaust, with electronic distibutor, original carb with K&N air filter...I don't know how much horsepower I have, I'm thinking probably 130... so from my self experience I think the U67 head works awesome on a L20...but I notice the the letter and numbers are slightly not visible ...so it leads me to believe that my U67 head has be modified(plained)...so my motor probably has been rebuilt at least twice...but I don't know if it an open chamber head or not.

 

Measure the head thickness from the valve cover to the head. 4.248" is stock thickness. If the U67 is used on an L20B and has been shaved by ...

0.020" or .5mm the compression would be................ 8.732

0.040" or 1.0mm the compression would be............... 9.09

0.o60" or 1.5mm the compression would be............... 9.50