Group 31 batteries in 80-86?

[dunk]

Well it's getting chilly and in another month or two it'll be cold. My old small mismatched batteries (group 24 maybe) didn't cut it a few times last year. Truck gave me one brief shot in the morning when it was below zero so it was hit or miss for the coldest week of last winter if it'd start. I could just toss a pair of good quality 27s in it would be a big improvement, but I'd rather go big and not worry about it. Looks like local prices are $120+ for a good 27, $140-ish for a 31 so if they'll fit it's worth $40 to me.

LH tray looks to be about 13"x7" and 9.75" height to bottom lip of fender. RH tray is maybe 12" but no lip and room to hang over a bit and 7" wide with 9.5" height to lip of fender. So it looks like 31s should fit, so long as the hood closes. Not sure exactly how the hood sits but assume it's about to the lower lip on the inside where the bumpers go, or if the 9.27" height of a 31 is to the top of the studs or just the top of the battery casing. Anybody fit groups 31 batteries in an 80-86? Any issues with fitment particularly height with hood closed?

This would involve crimping new terminals on my cables for studs, maybe new cables if cutting back a bit isn't long enough. What size is good for pos and grounds? I seem to recall 3/0 between batteries and 2/0 for the grounds and starter? Now what I want to spend money on right now, but if I'm gonna spend it I'd prefer not to skimp on quality and be kicking myself later.

 

[snicklas]

If i remember correctly, the slantnose trucks are the easiest to put the 31's in. Just flatten out the "lip" on the edge of the battery and they drop right in. There is more room between the trays and the hood than the brick or OBS trucks. Do a quick search, there have been several conversions done on here is all body styles.

As for the cable ends, not sure. Have not played that game..... yet.... one of the new style formed ones is getting thin on my truck. I miss the old big lead lugs.....

 

[Can30Diesel]

It can be done! Here are 31's in my 85.

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[dunk]

Cool, that's reassuring. Did they just drop in and you cut strapping to fit for the hold downs? Looks like those screw on post to terminal adapters? If they fit then surely they should fit without those adding a little extra height if I do new terminals. I see Pep Boys is doing 25% off order online pickup in store, but only lets me add 1 battery to cart, but lets me apply discount code. Might be the hot ticket if these are a drop in deal.

 

[FarmerFrank]

I run 31's in everything.

Don't waste your time crimping ends on your battery wires. Yes it does work but soldier and heat shrink them for 0 worries ever.

I had enough slack on all the cables to cut and soldier on new ends. I did replace the cable to the starter but it was pretty raggedy

 

[Giddy-Up]

Everything dropped in for me no mods needed as long as you get the group 31s with post terminals

 

[Ruger_556]

Don't waste your time crimping ends on your battery wires. Yes it does work but soldier and heat shrink them for 0 worries ever.

That's not true... Battery cables should be crimped, especially if they are routed in any way that there is weight or pull against that terminal.

 

[Can30Diesel]

I had to lower one side's tray about half an inch, but otherwise they dropped right in. Here is old and new batteries for a comparison.

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[MIDNIGHT RIDER]

Group-31s fit in my 1985 like they were meant to be there.

Get the "stud" batteries instead of the post type.

If you can't or don't want to mess with altering the cables right now, tell the battery man that you need lead post adapters; they usually provide them free for the asking.

Thus, you can simply remove the adapters when you get ready to alter the cables.

I am a firm believer in "crimp and solder" on everything smaller than 4-AWG; anything bigger than 4-AWG gets CRIMPED only and no solder.

Saturate the copper strands with Vaseline, pack the ring-terminal socket full of Vaseline, and slather Vaseline over the terminals and studs once everything is attached, and you can forget the whole mess for the life of the truck; treated thus, the copper strands will look good as new years after the truck has rotted away in the scrap-yard.



Also, the original formed plastic hold-down "straps" work on the Group-31s, but it seems like I had to extend the length of the J-bolts.

As best I remember, I shortened the length of the J-bolts, maybe then threaded them farther down, then used coupling-nuts and all-thread to make the bolts longer; then again, that may have been on a different truck.

 

[theguruat12]

Best way is to crimp with a GOOD crimper, one of those hex jobs, or the hydraulic kind. Solder works, but it applies extra stress to the wire where the solder wicks down from the terminal end. If I had to make new cables tomorrow, I'd just use the screw-clamp on type until I could get a set of copper ring terminals properly crimped on with the right tool. JM2CW

2/0 for grounds and the crossover between the batteries, 3/0 from passenger's side battery to starter.

EDIT: Midnight, that's my mentality as well. Crimp and solder is double insurance, unless you're on the large gauge wire, then it becomes counter-productive with the added strain point a few inches down the wire from the terminal.

 

[Can30Diesel]

I made my own tie downs. I also pulled both trays, cleaned and painted them before they went back in.

 

[opusd2]

I put group 31s in everything from my 86 F250, to my 79 Bronco, to my 89 GMC K1500. Even had them in my 84 CUCV M1009 when I had it

 

[Diesile]

I'm running them in my '86!

 

[hce]

I have group 27, with a gear reduction starter. I have had to start it in -15 f ,no windchill, without being plugged in overnight, popped right off. Save the money and hassle on the batteries, invest in a gear reduction starter, good glow plugs and synthetic oil. I usually will only plug in if temps drops below 0. Also I saw no improvement from switching form 24 to 37 with the gear reduction starter.

 

[Kevin 007]

Im thinking of removing/relocating my washer reservoir, drivers side battery and coolant overflow tank and installing this puppy in its place.

19'' long and 9'' deep. 1125 CCA. I would remove the passenger side battery also and put the washer and coolant tanks in its place im thinking.