Just thought I'd start a thread on my upcoming winter project.  I got my 240z in May of last year. The car was nicely restored in 2010. I've done a few things to it in the time that I've had it including, wheels/tires, headlight covers, lowered it, ST sway bar kit, pertonix ignition and the most significant is that I converted the car from an auto to a 5 speed about a year ago. 

 

 The L24 in the car has had an head gasket leak of oil to the outside since I've gotten it.  I was going to put on a new head gasket, but this quickly snowballed into me just wanting to put in a rebuilt L28.  After searching for a while I stumbled across just what I wanted on craigslist. A rebuilt L28 F54 block, E31 head. The seller didn't know a whole lot about the engine so I had to do some research. I found out it was built by Ritalon Engineering in Wisconsin. I couldn't find any contact info for them other than an mailing address. So I sent some photos and information to them. 3 weeks later I got a phone call from Larry there. He told me a lot of good information about the engine. He didn't know which exact engine it was but told me all the usual stuff he did with them. So, sounds like its' bored, .040, some head porting, arp studs, shot peened rods, American Custom 071 cam (pretty big cam, I don't have the spec in front of me right now.) Should be about a 10.5:1 comp ratio. 

 

My plans: I'm going to start sometime in the next few weeks on the swap. I've just placed a bit order from MSA for all new gaskets, hoses, hardware, electric fuel pump and one of their coated 6-1 headers. I also ordered new motor/trans mounts, and a mangnaflow muffler as I'm not in love with my current dynomax sound. I'm also going to be ordering Z Therapy's SU rebuild kits with SM needles.  I'm also going to have the trans rebuilt while its apart since the 2nd gear synchro is done. I plan on keeping my stock roundtop SU's at least to start (with the aforementioned SM needles). Maybe in another year or so I'll go to some triples though. 

 

I decided to just get a baseline so I can compare the old to new engine when I'm done. So I went to the local dyno this last weekend. I gave the car a good tuneup before hand. I had adjusted the valve lash this spring. I set full timing at 38 degrees, dialed in the carbs with a colortune and synced them. 

I was going to be happy with anything 100+ at the wheels and really happy if it hit 120+. Amazingly it put down 128rwhp and 130 lb ft! They ran it once in 3rd and once in 4th and the graphs were identical.  So, a very healthy L24....save for some tired valve seals since it smoked pretty good on deccel. 

I did notice on the chard (and on the street)...the power really drops off after 5.5K...is this normal for a stock L24? 

 

Anyways, that's it for now...below are some pics and the dyno video. I will keep this thread updated with pics and info showing my process! I welcome everyone's input. 

 

IMG_1134 by blodi, on Flickr

image2 by blodi, on Flickr

IMG_3897 by blodi, on Flickr

set by blodi, on Flickr

 

Dyno Video.....

Looks good to me! The cam has had material removed.

Glad to see a drilled cam and spray bar, that's what I'm doing too.

Hopefully you got to use your CZC member number for a 10 percent discount with MSA.

  On 10/12/2015 at 7:45 PM, siteunseen said:

Hopefully you got to use your CZC member number for a 10 percent discount with MSA.

 

Really? Man, wish I had known that. Live and learn. 

  On 10/12/2015 at 8:22 PM, blodi said:

Really? Man, wish I had known that. Live and learn. 

 

I give my number with my order and still get charged full price anyway.

There is a trick to doing it online, can't remember though, I always call. If you sign up for their Zmail you get alerts for free shipping promos.

Cliff

Here is the graph from my dyno the other day. Again stock engine other than a pertronix ignition and MSA 2.5 inch exhaust. 

ZDyno101015 by blodi, on Flickr

 

I forgot to mention I also picked up an N36 intake manifold as I've read it should pick up some hp over the 240 intake. 

The specs on my 071 American Custom Cam.... Lift:500 Duration:300. Should be pretty stout.

I've read the N36s use a thinner spacer.  If you can't find the 260 spacers you can change to longer studs.

 

FWIW

Cliff

  On 10/13/2015 at 4:28 PM, siteunseen said:

I've read the N36s use a thinner spacer.  If you can't find the 260 spacers you can change to longer studs.

 

FWIW

Cliff

Wow, I wouldn't have known that. Thanks! I'll have to pick up some longer studs. I quick search reveals that using the thicker spacers seems to be the way to go. 

  On 10/13/2015 at 2:08 PM, blodi said:

Here is the graph from my dyno the other day. Again stock engine other than a pertronix ignition and MSA 2.5 inch exhaust. 

 

More support that a free-flowing exhaust system can have a big affect.

 

You asked about the drop off after 5500.  That seems to be typical of the L6 engine, unmodified factory issue.  If I understand what I've read in the past, head work and cam profile are needed to extend the range.  My stock L28 isn't worth taking over 5000 RPM before shifting to the next gear.  You can see your torque dropping dramatically there in the dyno plot.

 

It would be interesting to know what kind of head porting Ritalon did, and if they installed bigger valves.  

 

And read up on zinc for the cam break-in.  It would be a shame to have break-in problems.

Forgot to say, I notice that the tape on the top of the engine says "Do not turn over".  Does that mean don't turn the engine crankshaft or don't turn the crate?  

 

Also see that the camshaft lobs have some wear so it's not a newly ground shaft.  Zinc may not be as critical.

  On 10/13/2015 at 5:59 PM, Zed Head said:

More support that a free-flowing exhaust system can have a big affect.

 

You asked about the drop off after 5500.  That seems to be typical of the L6 engine, unmodified factory issue.  If I understand what I've read in the past, head work and cam profile are needed to extend the range.  My stock L28 isn't worth taking over 5000 RPM before shifting to the next gear.  You can see your torque dropping dramatically there in the dyno plot.

 

It would be interesting to know what kind of head porting Ritalon did, and if they installed bigger valves.  

 

And read up on zinc for the cam break-in.  It would be a shame to have break-in problems.

Good to know on the powerband. Yeah, mine really isn't worth taking past 6K. 

Sounds like porting was somewhat limited as Larry told me this was more than likely a vintage car engine so there were limits I guess on how much porting could be done. I don't know enough about it to be sure. And as far as the valve...only way of knowing would be to take off the head most likely. I don't want to screw the engine up at all by doing that. 

 

 

  On 10/13/2015 at 6:03 PM, Zed Head said:

Forgot to say, I notice that the tape on the top of the engine says "Do not turn over".  Does that mean don't turn the engine crankshaft or don't turn the crate?  

 

Also see that the camshaft lobs have some wear so it's not a newly ground shaft.  Zinc may not be as critical.

 

Yes, it does say "Do not turn over" and the rest of it is smeared and illegible. So I have no idea why it says that. Larry had no idea either and says that tape wasn't from him. Unless someone it just means the crate or "hey dummy, there is no oil in this engine".  Everything looks good and in place up top. Maybe once I get it on an engine stand I can pop off the oil pan and make sure everything looks good below. 

 

I figure this engine had seen race duty before with this same build and was then refreshed to it's current state. The pistons have a bit of carbon on them so they have certainly seen use but the cylinder walls still have cross honing marks on them...as seen with my borescope. 

I guess it can't hurt to put in a zinc additive? 

Edited October 13, 20159 yr by blodi

Surely to god they ported the cylinder with that cam.  That'd be like sucking Jello Pudding through a coffee straw.