Engine cams

[Scgreen620]

The title says it all ... I've looked online I can't really find what I'm looking for ... Ssoooooo I must ask you guys .. Here's the deal I have an 78 620 with l20 b I'm finally going to rebuild ..it has a cannon intake manifold with a 32/36 and a aftermarket header (don't know the name) I want to upgrade my cam I don't know what I should go with I just want more power but I want to daily it ... actually it is my daily .. Any help would be apriciated ..

 

 

I did see that mike posted that the newer Nissan motor cams might work and might be cheaper but I would like to know what the difference would be ...

 

 

Please guys keep it positive :) thanks

[flatcat19]

Find a peanut head. Spend lots of money over at Isky's Cams website.

[wayno]

I am not a cam expert.

I have talked to my machinist about this subject after installing an RV cam in my L20b, for the best all around driving you want a stock L20b cam.

I had less power with that RV cam, but I didn't have the head to take advantage of the cam either, but even if I had had the proper head setup on it which I have, it still would not worked for my truck, as I need torque.

It's a balancing act, you need the proper head which includes valves, valve springs, lash pads with the proper porting, and the cam, then you need the proper intake with the porting needed, and carb/carbs and jetting, you need the proper exhaust made for everything before it, and all this costs lots of money, if you don't do it all, then it's a waste of money as it will not work properly.

I found that there is no substitute for cubic inches, after that engine I built didn't work for me, I built an LZ23 with a stock cam and dual SUs, I used a header, but the stock L16 exhaust manifold would have worked with a bigger exhaust system(2 inch maybe) after the two outlets combine, that engine moves my 3700lb Datsun 521 truck real good, it's just about the fastest Datsun I own except for my Datsun Roadster which weighs 1500lbs less.

Build an LZ hybrid engine/block, find an A87 closed chamber head with big valves and have the intakes ported to match a dual SU manifold, and find a good set of Dual SUs, put it in your 620 and you will be happy.

The thing about what I have told you here is that you can keep your truck a daily driver till it is all ready, and it will take just one or maybe two days to remove and replace it, hardly any down time, otherwise find another engine that has way more power to start with and convert over to that engine(KA/SR/VG/??).

I would go with the LZ23 myself, it was a dramatic increase in power to me, and the freaking thing starts up every morning.

[datzenmike]

Only an L series cam will fit an L series engine. The L20B cam is the same for all years of L20B, there was no SSS cam for them. A 'larger' cam, as wayno says, may make more power buy it takes away from the bottom end as it adds to the top. Cams do not replace displacement. Most driving is done well below 3K and this is where you need grunt to pull a heavy truck.  

 

If re-building it you will probably find it has more power than now. If you go with a cam, get one with higher lift and a very modest increase on duration. It will not give you power where you want it which is the mid range 2,000 to 3,000

[banzai510(hainz)]

Go with a name brand cam manufacture.

 

I found out the Delta out of Tacoma Wa their cam were actually smaller than listed.  Maybe thats what Wayno got.

 

I find out that bolting a 38/38 got more power and its a bolt in since you have a 32/36 on there already.

 

I have a 460lift 260 cam in my L16 with l20 head(521 truck).  Its should have come stock from the factory with this in my opinion.

Maybe if I have sidedrafts it will get awake n. But just seems like a L16/18 to me. Im not really thast impressed. at least in the L16/18. with a cam and DGV carb

 

theres nothing cheap about cam cahnge as one should use new rocker arms and find the cost of them 1st

[datzenmike]

L20B head will drop an L16's compression into the 7s because larger combustion chamber. So will any P nut head.

[scooter]

You can get your stock rockers resurfaced if theyre in half decent shape. I went this route because nos ones are hella expensive and some of the reproduction ones are good at destroying cams

[banzai510(hainz)]

Mike I got flattops in there also with the 38/38 I had once off idle it came alive

[Scgreen620]

So basically you guys are saying to upgrade the carb not the cams

[scooter]

If your just looking for a couple more ponies id just put a 38/38 on it and hog out the intake and match the head to it.

 

If you want it to haul ass, be prepared dump a big wad to get a fully prepped head and build that lz23.

[G-Duax]

Adding an adjustable cam sprocket can do wonders also.

 

The 521 I had a few years back was hard pressed to pull 4th on the freeway, and stay up with San Antonio traffic.

Had to go into the head due to a valve guide sheading a piece, and it transfering through the first 2 cylinders.

Made a few dents in the pistons, but nothing serious, so the head went back on once the piece was removed.

While putting the chain back on, I figured 'why not, let's try it', and I drilled the cam postion locating pin hole out, made an ofdet bushing, retarded the cam 4 degrees, and put it back together.

 

Made a huge difference! I could run easily at 70-80 mph, and had a good 20mph above that.

Lost a little on bottom end, but I never used it to pull anything anyway.

 

Years ago, someone made a kit to do this, that included a selection of different offset bushings., Don't know if they are around any more. But Nismo made a gear that had a lot more holes in it, and a chart on how to set it (a real pain in the back side),

and Tomie, Kamari, and one other company in Japan made true adjustable sprockets.

 

This engine I have now got either a Tomie, or the Kamari (Don't remember, just grabbed it out of my stash), when the cam went in. It was just set at zero, since I know that the compression was weak anyway.

I will spend time at the local strip playing with it when my new short block goes in, to dial it in.

 

If anyone has the Nismo sprocket, and you don't have the chart, let me know, as I have a picture of the last one I brought in out of Japan.

[Stoffregen Motorsports]

Call an engine builder, on the actual phone, tell them what you are going to do with your car/truck, the details of the engine, how much money you want to spend, etc and they should be able to give you a solid recommendation. Often times purchasing a cam is just the tip of the iceberg. Springs need to be chosen, valve heights need to be measured, rocker geometry needs to be set.

 

This question comes up A LOT here on Ratsun, and the information is always the same. What you guys don't know (maybe you do) is that guys are still developing cams for the L series engine. Not just Isky (who hasn't updated their profiles in 20 plus years), there are quite a few cam grinders out there producing cams with more modern cam profiles than first appeared in the Frank Honsowetz book in 198?.

 

The modern cam profiles are quieter, produce more torque, are easier on valve springs and rockers, etc.

 

I think a better question would be, does anyone know of a good engine shop for Datsun L series engines. I can think of at least a couple guys to call.

[banzai510(hainz)]

Isky cams are old grinds but actually have them in stock . Well a few years ago at least. New cores also I belive.

Schneider and Webcams will do a cam if you sent it in. They stopped making new core grinds a couple years ago.So regrinds will use Thicker lash pads as the ground the back side of cam to get the lift. So thick retainers and springs are needed. New Rockers also.

 

When you call a cam guy selling they will sell you anything and say this and that. Then eventually get tired of talking to Datsun guys on phone cause they have no money.Believe me the companies would say this.Troy at the 510 outlet would tell me this and say I got to get back to work then spend time on phone.  Best to ask a racer on here first of whats a good grind.

 

Just like the guys at Delta in Tacoma Oh RV street ect.... When I mic the cam find out it was smaller lift than what they said it would be. actually same as stock with a little more duration

 

I like the Scheider cause it had a fast open and slower close

[flatcat19]

Who is building modern cams for the L?

 

 

Most of the sites I have looked over are all regrinds.

 

Like Hainz just said, Isky is the easy answer because they have new cams, in stock.

[G-Duax]

There are a few floating around on eBay & Yahoo-JP.

I would think that there are more than a few members who have some stashed away, but would part with one if asked.

I have a small pile of them, but not willing to part with any just yet.

My mildest (264 duration) is in the head on my 1600 (no lie, it's a 1600) now, but when the new project short block goes in, I plan on trying something a little hoter, say 270+. If that works for me, I probabably sell the 264.

[datzenmike]

The stock cam is 248 duration but this is measured as soon as the lobe begins rising. Most cam makers specify a 0.050" lift. Applied to the L series the duration is much less maybe a lot less.

[Stoffregen Motorsports]

Who is building modern cams for the L?

 

Rebello is still developing cams for that motor. 

[datzenmike]

Likely they are for very modified LZ or LKA hybrids. Not much use on a stocker.

[Stoffregen Motorsports]

Well that's my point. The common perception of swapping cams is that they are for high performance only. Some of the newer cams are very nice to drive on the street.

 

A couple of the profiles I am thinking of are best suited to a mild L16, L18, L20B with DGV Weber.