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512 cid C series on Dakota chassis- build thread


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I tried to bump my starter to get the motor to #1 tdc compression stroke so I can set up my distributor and wires- I also decided to do it the ‘right’ way and clock the slot in the intermediate gear to 12:00/6:00 so the wires will lay right and it will be factory correct. 

 

“Tried” because I only got three or four bumps in a row with my hand over the plug hole to feel for the compression stroke before blowing the 150 amp fuse on my 1/0 gauge +12v cable by the battery. And I put it in an awkward spot too. I got it off and now I have to decide between ideas I have to fix it:

 

1- ‘safety first’ run a ford style starter solenoid near the battery that gets triggered by the starter trigger wire, then connect the two big lugs on the solinoid with a smaller fused circuit. That way it will run through the fuse except for during cranking.

 

2- ‘oem ma mopar knows best’ run that sucker straight from the battery to the fat lug on the starter. Every oem setup I worked on was like this but usually only a short run of wire. I’m strongly considering this because of its simplicity. I feel ok about it because my fat positive cable runs through a heater hose everywhere it touches the frame then inside a generous amount of rubber lined p-clamps under the cab. It’s not near fuel or able to move or rub. Plus I have that negative disconnect switch I can flip if there’s ever a problem. And it’s already the right length to reach perfectly to the battery

 

3- buy a much bigger fuse and hope the starter doesn’t pop that. This would be a good option if I was confident about it but I think there’s a reason I bought a battery with a ton of ‘cold cranking amps’.

 

Also I’m feeling foolish for not just buying 50/50 antifreeze or at least using an empty one to mix 50/50 myself before pouring. After letting it sit overnight the radiator is still brimming and only a tiny bit of that is water. I need to drain a gallon out and replace it with water- from what I’ve read it will not cool well pure a/f concentrate. Or I can just run the motor until it sucks in some coolant and add water them. 

 

I was trying to catch up to Farmer who’s already plowing his snow with the bumper of his big block truck but setbacks are the best when you’re already in your own driveway on jackstands not in a ditch somewhere with $11 and no phone. After I restore power the next operation is trying to run all the fans and lights at the same time and see how that goes. I did find a loose connection on the back of the alternator so I’m glad I was poking around there. The charge stud had a burr on it and felt tight but needed another turn to hold the ring terminal tightly. That coulda gotten pretty hot. 

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a starter can easily draw well over 150 amps, especially on a fresh engine build, a larger displacement or higher compression ratio.  the ford style solenoid isn't going to do anything more for you over a direct to the starter Mopar style hookup than add a couple more connections and complicate a simple starter circuit.  Personally, I'd get rid of that high amp fuse setup, hook it up Mopar style and keep the system simple

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Good choice on ditching the fuse. It looks like you have the battery cable well insulated. I am surprised at your choice of  battery terminals though. Those cheap clamp-on terminals are a problem waiting to happen - especially under the truck. The link below shows a great system that is foolproof and offers a much better electrical connection.

 

https://youtu.be/SXDkNMDDrBs

 

 

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Yeah they do suck. All battery terminals seem to need a little cleaning once in a while though. I like the pellet of solder deal in your video that’s smart. My whole battery and mount need revision. When this one gets swapped out I’m going to go with a sideways mounted redtop for access and convenience. 

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I got my dipstick tube secured to a header bolt, felt for compression and got #1 a few degrees before tdc, and ran all the  sparkplug wires.

 

I have to go open my shop in a little bit so no priming the fuel system and breaking in the cam (hopefully tomorrow) but I wanted to check and see if it would light off so I sprayed a shot of ether down the carb and turned the key. She spoke! Baby’s first words! No more cranking till I can get serious with the timing light and ready to crank up the curb idle for break in. 

 

 

 

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Not gloating about the unproven motor but as far as the wiring goes I’m psyched. Last motor I built I managed to set it up 180° out and didn’t get that immediate fireup that you want to keep lube on a new cam.

 

”love it when a plan comes together”

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Haha, i shouldn't admit it, but when i ran my plug wires, i put them on clockwise. I knew better, i had just primed the oil pump with my priming shaft (counterclockwise), but i guess i wasn't thinking, she fired right away, but only on 1 and 3 probably, it took me a minute before i realized what I'd done. Switched them and she fired right up. ?

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Radar, i wouldnt sweat having concentrate coolant in it, if your block was dry I'm sure you'll get a couple gallons of h2o in it after she runs for a bit, i hate burping them though, in my experience it seems when the thermostat opens, half what was in there burps back out and makes a mess, before it finally settles down. 

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My buddy stopped by this morning for extra hands & eyes on startup. Since my fuel filler is not vented I was able to prime the fuel system by blowing a few psi into the tank with my mouth on the vent hose. I ran it up into the rear passenger stake pocket and the top is folded over and stuffed back down to keep rain out. That operation works really great- I thought I’d need some gas in a squeezie ketchup bottle to fill the bowls but the see thru filter and carb filled right up- squirters deliver plenty!We solved a couple small fuel leaks and got started trying to light her off.

 

 

It was acting stubborn and lighting fires in the carb for a few tries. Tried 180° out in case I boned the sparkplug wires on the distributor and no dice, so we flipped them back and re-checked the firing order. The battery got a little weak so we charged it and tried again while I twiddled the distributor and we got her lit off and brought her up to 2700. I set the timing and locked down the distributor around 35° with no vacuum advance. I marked my original distributor position and it ended up actually pretty close to there.

 

Oil pressure was good. The pipes all got hot but nothing melted or spilled. I didn’t check the volts to see if it was charging. It was running super rich and gave a couple pops so we shut her down and with the throttle blades open real far it dieseled a little and gave a couple more backfires. It took another gallon and a half of water in the radiator so that’s looking good. 

 

I noticed the accelerator pump nozzles were weeping. Turns out the floats were both real high. Blowing into the gas tank vent acts nicely as a priming pump so the front bowl was easy to set without having to disconnect the coil and crank the mechanical pump but man that back float adjustment is tucked in. Pain in the butt! There is no getting a screwdriver on there so I made due with baby vicegrips. I think the rear bowl is good now? The front is dead on. 

 

My buddy left for work at noon and I had the battery charging while I set the floats but I want to give all that spilled gas from setting the floats a good amount of time to evaporate so I don’t burn this sucker down if it coughs out the carb. So I am inside smelling like gas but happy. 

 

It felt like five mins of high rpm break in time on the clock so far but it was probably more like 3- adrenaline rush!

 

The fancy digital battery charger says 100% I’m gonna watch a dumb show or something then go give her another turn after any gas is for sure dried up. 

 

Here’s a pic of how tucked in my float is:

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I went back out and fired it up. Toward the end of the couple minutes running it there was a rattle- well it was very evident now. It sounded like it was in the driver’s side valvecover and after it didn’t go away like a lifter that just needed to pump up I shut her down and opened up that valvecover.

 

What a pleasure to be able to work on the motor inside the generous firewall recess! The valvecover came off quickly and I discovered that #7 exhaust rocker wasn’t making contact with it’s pushrod. It didn’t just slip off the side- it was 1/2” shorter than all the others. Also the last two rocker shaft bolts had backed out. At first I was worried they stripped out of the aluminum head but no they were fine. 

 

This is my first mopar big block and I am a believer now- it only took 30 mins to get the carb, intake, and valley tray off to inspect the lifters. There is no coolant in the intake and I used the brown stuff that never really dries to seal up the steel valley tray/intake shim. 

 

Good news/bad news. The bad is that when the shaft loosened up I took out both lifters for #7 cylinder. The exhaust lifter had the pushrod cup sitting next to it in the valley. The intake lifter had its pushrod cup stuck and cocked inside it. 

 

The good news is that even though the exhaust lifter puked its guts all the pieces are accounted for and I don’t have to drop the oil pan. Also the bottoms of the lifters and the cam lobes look perfect and never got a chance to mate in so new ones should be fine. I’m going to see if I can order a couple lifters and get back together next week to try break-in again. 

 

It’s wierd I was more nervous and anxious this morning before I started working. Now I feel relaxed about it. A little disappointed but just a little more work than planned no big deal. 

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Well thats exciting, but too bad about the lifters. I'm curious as to why the rocker arm bolts backed out. 

You seem to be in a good mood about it, so thats good.

Its funny how it makes a guy smile when a new engine comes to life, its a cool feeling.

I wonder what your neighbors thought when they saw you blowing in the rear corner of the box! Lol

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Yup- plenty of excitement this morning! At least I got almost two more gallons of water in there for a healthy 50/50 antifreeze mix, got it roughly timed, I know that the ignition, charging system, afr meter, & tach work. 

 

I was a little bummed when I double checked my pushrods by rolling them on a glass table- had to order a replacement. The one that smashed into the lifter didn’t look bent but rolling it told another story. 

 

I should be out messing around with the motor again in another week. I hope it goes smoother next time but a little three steps forward two step back is fine as long as I keep moving forward!

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I dunno, simply why am asking .... what I am wondering.

With Aluminum heads, does the rocker shaft bolts need some stick em stuff applied to the threads?

Would they need torqued,  warmed up and then re-torqued?

 

I dunno, but seems expansion/contraction on the aluminum heads would be different then cast iron heads.

I know you are ten steps ahead of me on the answer, just bringing up the question.

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Nope just one step ahead- was just talking to a mechanic buddy about weather blue loctite would work in such an oily spot. 

 

I’m thinking proper torque and re-torque after a heat cycle. I just gotta get that break in period out of the way with the flat tappet and I can actually start tuning, see if the trans works, get an alignment, rub the surface rust off my rotors with a bunch of ugly stops, find out if I have enough vacuum at idle for my power brakes, plus the little bit more welding and sheetmetal work I was planning to do before startup.

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I also think a lot of people that run aluminum heads are also running big cams and high spring pressures. I’m trying to use my cubic inches for power and keep the rpms down, plus the hydraulic flat tappet wouldn’t like high spring pressure anyway. And I would need max wedge or bigger port heads- at least the big ‘trick flows’ to make a screaming 512. So no exotic valvetrain stuff for me. 

 

The race crowd uses studs in their aluminum heads. I also read a lot of forum posts about how fsm says 25 ft/lbs torque and that is scary tight and folks go 15 lbs? A lot just snug them up by hand- I certainly always did before...

 

So I dunno now I’m scared of pulling out threads. I think I’ll brakleen the holes and hand tighten with blue loctite. 

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If you get the threads clean and dry the Loctite will bond. And once set the oil won't effect it. You may also consider some Loctite primer just prior to application of the Loctite. That will help ensure the brake clean won't interfere with the bond. Also, when in doubt, use red Loctite...

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What a bummer. At least the damage was minimal. On the bright side - you now know you left enough clearance to get the thing apart if needed.

 

Waiting for the brown truck to arrive will be torture. ?????

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Truck came! All new comp 8.555” replacement pushrods and I got a couple lifters soaking overnight in fresh oil. Still gotta get some bolts & maybe studs- at least grade 5 maybe 8 whatever I can find locally tomorrow morning before work.

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