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jmortensen 11-13-2010 01:52 PM

5.3 buildup for lightweight autox car
Will be running my 70 Datsun 240Z in SCCA X Prepared class. Car will weigh 2250 lbs and have NASCAR style flexplate 7.25" dual disk clutch, T56, 4.11 rear gears with a 24" tall tire on a 15x14 rim.

So far I have the engine, a 5.3 L33 out of a 2006 1500 pickup with 33K miles on it. It looks brand new inside. I picked the 5.3 because this class has weight based on displacement and I figure a 5.3 with some bolt-ons will have enough power that I will have some trouble putting it down, and I get to have a car weight that is about 100 lbs less than would be required with an LS1. I have installed ARP rod bolts. I have the dual clutch and flex plate with ARP crank bolts, and a set of Sanderson shorty headers (not coated). Stupidly, I bought the Edelbrock 7118 setup. Need to figure out the rest from here.

I already know that I made a mistake buying the 7118 setup because apparently it is rev limited to 5500 rpm, but I think I do need the lower profile dual plane manifold for hood clearance, low rpm torque won't hurt out of slower corners too. So at least I may be able to salvage the manifold out of it.

I had planned on a BG Race Demon 650 with annular boosters, based on a recommendation of a friend who has driven a similar car built with an LS2. The car will pull a lot of lateral g's, so I was planning on the road race version. Speaking of g's, also planning on LS1 oil pan and improved racing baffle, or ATS baffled pan with 3 qt accusump.

Need a cam recommendation, and also would like help to figure out the pulleys. I will run an alt and PS. My longblock didn't come with either the pump or the alt, and I figured I'd replace the water pump. So then the question is should I change out the crank pulley and start over from scratch on the pulley system? I have a water pump for an LS1 that I bought cheap, so I'm leaning that way. It would be nice not to have to fabricate everything for the pulleys. I can do that kind of work, but I'm SLOW at it, usually end up doing things 2 or 3 times to get it just right, and I'd like to get this car running for next season if possible. There is still a lot more work to do on the car too.

Any advice?

bigmandengo 11-13-2010 03:16 PM

I own both intakes and have had them side by side. The dual plane is the same height as the victor jr. The front might be about 1/4" lower, but thats it. I run a 218/226 .595/.598 on my 5.3 and it runs strong.

ramdaspadhye 11-13-2010 04:04 PM

I would get a set of 243 heads and have them milled to 58-59cc chambers and get yourself a 218/222 with around .600 lift on a 110+4, should have torque out the ASS especially in a light car


Wait, i read that wrong. For some reason I thought you meant you were limited to 5500 rpm's... Whats your rpm band in auto x? 3-6k?

jmortensen 11-13-2010 05:26 PM

Yeah, I figure probably 3-6K is where the power is most important. Also heard some people warning against revving higher than about 6500. See lots of posts from drag racers going to 7K, not sure if the warning had more to do with it being an autoxer or what. Thoughts there also appreciated.

The L33 already has 9.9:1 compression, so I'd like to do the cam swap and change out valve springs and pushrods without pulling the heads.

Pop N Wood 11-13-2010 06:12 PM

Good to see you on the dark side, Jon.

Kwik performance sells a street rod set up that will let you run a PS pump with an alternator above the driver side head. They will fit any WP spacing you want to run, from vette to truck. Price isn't bad.

I am running a GMPP with Holley 750 with a 3 inch tall drop base air cleaner and have adequate hood clearance on my 240. I even run a slight carb spacer, about 1/4 inch. I copied Mark Ickard's engine mounts though. I got the engine so far back and so low I had to move the heater hoses and hood latch.

My LS2 has the LS2 vette oil pan. Another advantage of making your own mounts. It is suppose to provide better baffling than the F body pans.

ramdaspadhye 11-13-2010 06:38 PM

What are the class regulations with regard to mods?

jmortensen 11-13-2010 07:02 PM

Pretty much open on the engines, just the displacement/weight limitations. I don't want or need 1000 hp, I figure anything over about 400 whp will probably make the car slower, especially since that will be 150whp increase from it's last iteration and probably 200 or more lb/ft of torque. I think it's going to be a handful. I'm comfortable with carbs, so I'm going that way for now. Goal to start is 350-400 whp and then work up from there.

Glad to see you too Pop. I've looked at your posts on HybridZ re: the belts but it was a while ago, and I thought you had just done alternator and water pump. I'll go have another look.

Pop N Wood 11-14-2010 08:37 AM

Yeah, I'm only running an alternator.

Here are the Kwik options. Just noticed their alternator and PS pump street rod set up is $319. A little more than I thought. But they have options for any belt spacing. Should put the alt up high so no strut tower interference.

there are some other set ups that put that alt above the passenger side head and keep the PS pump where it is.

jmortensen 11-14-2010 11:20 AM

Do you have a thread on Hybrid Z with your motor mounts? I can't use the John's Cars mount because I cut the TC rod mounts off of the frame and redid them. Was going to try and get the engine further back and to the right.

Pop N Wood 11-14-2010 07:19 PM

No, never got a build thread. This is a link that Mark originally sent to me. Amazingly it is still good, although the pic links are dead

I have a pics of the cross member in my album here. Note the passenger side mount is about an inch forward of the driver side. I had to remake the aluminum vette motor mount on the passenger side out of mild 3/16 steel to get it to clear the JTR headers.

I used the vette mounts and S&P biscuit mounts. Really solid, not much give.

This style of mount gives almost unlimited flexibility positioning the motor. I offset the engine a full inch to the passenger side and got the motor so low and far back the crank pulley is almost right on the steering rack. No way to use an F body alt since it sits right on the steering knuckle. Having the engine so low gave plenty of hood clearance for the carb.

There is room for the Kwik perf alt above the head. You will need to use the street rod set up since the vetter mount will put the alt into a strut tower. I like the denso alt I used since it is a few pounds lighter than the delco units. 85 amps is plenty enough for a carb'd application. To fit a full sized, 14x3 drop base air cleaner I had to move the hood latch like Pete Paraska did. I routed the heater hoses to an AN bulkhead penetration just above the passenger frame rail. Probably not an issue with a track only car.

I sort of forced myself into building my own mounts since the TKO trans I used is a couple inches shorter than a T56. Even with that I had to dog leg the TKO shift lever. But when all said and done the shifter fits in the stock hole better than it did with the L6 and retained the stock center console. I even tapped the shift lever to reuse the Datsun shift ball. Car looks dead stock on the inside.

When installing the cross member I wrapped the frame rails with another layer of sheet metal, then welded some I think 3/8 pipe inside the rails to keep the bolts from crushing the rails.

If I had to do it again, besides going with a T56, I would look into using different rubber in the mounts. Instead of the biscuits I would make something along the lines of what BRP hot rods sells. Not their mount kit, but rather the rubber piece they use with their mount plates. Seems like that could be fabbed into the same cross member and take up less room than the vette motor mounts.

River City Speed 11-14-2010 08:13 PM

I have seen a couple of Z's with a Victor Jr. and an air cleaner under a stock hood.

jmortensen 11-16-2010 12:15 PM

Hmm. What I like about your mount is that you can slide it back and forth until you hit the position you want. I was going to go for a solid mount though, and I have some K member type braces from the crossmember to the TC buckets which would definitely interfere. I had looked into motor plates and nobody seems to use them, so I was just going to make my own mounts from 3/16 steel that bolt to the block where motor mounts normally attach. Looks like I'll be on my own for fabbing mounts.

I'll have to look into the Kwik stuff a bit more. $300 doesn't put me off if it saves me some fabrication.

Pop N Wood 11-16-2010 05:42 PM

See if you can run a piece of pipe or tubing straight up from your K member to plates on the motor. It is pretty easy to drill some holes in 3/16 plate and bolt them to the block. In that last pic I posted you can see where the vette mounts sort of flair out complicating the headers and steering shaft clearance. You can run them straight up and down. The blocks have 6 bolt holes for plates so you should have a lot of front to back room to position things.

I would still use some type of cross bolt to ease getting the motor in and out though. Weld some ears on the plate and use a bushing style mount like these trans dapt units:

jmortensen 12-15-2010 07:51 PM

Talked to TSP again, ended up getting a 220/224 with .581 lift and 112+2 LSA. A little more conservative than I was inclined to go, but I kept thinking "power under the curve" and TSP did suggest a smaller cam than I was originally thinking due to the smaller displacement. Got the pushrods and springs to go with the cam, and also a gasket kit and a dual roller chain which they suggested due to all the accel and decel forces. In doing some reading I'm thinking that this should come out to about 400 bhp, which I figure will be about 150 hp more than I had with the old 6, and torque will probably be up 200 or so lb/ft. That should be enough to keep me busy for a while.

I've gotten a little sidetracked on dash fabrication and electrical work in the meantime, so hopefully I'll get the electrical done and then get the suspension buttoned up and I'll be ready to take it off of the rotisserie and start working on motor mounts and maybe accessory routing.

Pop, I have the old Maxima/300ZX alternator from the last motor, and it only has maybe 40K miles on it. Is that basically what you are running? Can I get a serpentine pulley and just use that?

Pop N Wood 12-15-2010 09:05 PM

Most likely, yes. What I noticed is Denso alternators have two different shaft diameters and multiple wiring configurations. The pulleys do interchange for shafts of the same diameter. I ended up pulling an alternator off one car (91 Celica with a 4 rib pulley) and a 5 rib pulley off another car (a mid 80ís Supra). For clearance reasons I needed a smaller diameter alternator with the power lug coming straight out the back. The 5 rib pulley matches the LS motor.

Here are a couple of good links on denso alternators. The first link has better pictures and dimensional drawing, while the second link shows all the different connectors and pulley configurations. The second link cross references them by part number as well as make and year of car that came with that part number.

One tip if you go pick and pull hunting for a pulley, an impact wrench gets the pulley nut off with no drama, but in the salvage yard you can use a hammer to smash the case into the rotor. This locks the rotor in place. Great fun.

jmortensen 01-18-2015 01:27 PM

Takes me a while, but I get there eventually.

First start up of the 5.3. Not really ready to start tuning yet, but first impression is that I can't just open the throttle quickly, as it will die. Have to ease into it. I do have 1:1 secondary linkage on it, guessing I might have to go back to the progressive linkage. Thinking that the flexplate/button clutch might have something to do with this, curious to know if anyone has generalized carb tuning rules for motors without the inertia of flywheels. Along the same line, it doesn't want to idle at less than about 1800 rpm. Hopefully I can get that down to a more reasonable level. In the second video, there is a fairly loud "tink" noise that really caught my attention at 22 seconds in. No clue what that was.

Horsepwraddict 01-19-2015 12:02 PM

1:1 linkage totally changes how things are tuned and can be quite finicky.

jmortensen 01-19-2015 01:52 PM

Yeah, I think taking that off and putting the progressive linkage back on is going to be the first step in trying to tune it.

Because it was using the 1:1, I squared up the jetting and was running 70s all around. would it be a good idea to go back to the 70/74 that was in there? It's been a while too since I messed around with it. I seem to remember the 74's were in the secondary side. That sound right?

Horsepwraddict 01-20-2015 03:41 AM

Originally Posted by jmortensen (Post 18625050)
Yeah, I think taking that off and putting the progressive linkage back on is going to be the first step in trying to tune it.

Because it was using the 1:1, I squared up the jetting and was running 70s all around. would it be a good idea to go back to the 70/74 that was in there? It's been a while too since I messed around with it. I seem to remember the 74's were in the secondary side. That sound right?

Yes, 70/74 isn't a big spread but that might be what it likes. Start there, you can always change accordingly later on.

jmortensen 01-20-2015 05:03 PM

Adjusted the linkage to progressive again. MUCH better. Now need to swap the jets, then I think it's probably time to finish the car to the point where I can drive it and use the wideband or just take to a dyno and let them tune it.

Any suggestions on the timing pill to use? I'm not using the 6010, I've got the Edelbrock carb swap setup with the 5 pills. Got #3 in there now, as that seemed to be what most drag racers were using.

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