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Group 31 batteries

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Prospect62

Group 31 batteries

I did search but didn't find much...

MY 85 IDI is in need of new batteries. I've heard here and there that Group 31 truck and tractor batteries are a good, high CCA upgrade. I have heard some say they fit right in "plug and play" style and I have heard some say mods are needed to the battery tray to either lower the battery or make the tray wider.

I can get a 925 CCA Group 31 battery for $79 each at my local heavy truck dealer, which is about half the cost of new Group 27 batteries from WalMart. I'm thinking I have to make this work somehow - the cost savings alone are worth some tinkering, plus I'll be in there doing a 3G swap anyway.

Has anyone here ever put Group 31 batteries in an IDI-powered Bullnose that can speak from experience?

1985 F250 4x4 6.9 IDI T19 4-speed Dana 70U rear/Dana 44 HD front 3.54's - Proudly bone stock w/ 235 85 16 MT's

1986F150Six

Re: Group 31 batteries

Administrator

A search brought this up:

https://www.oilburners.net/threads/group-31-batteries-in-80-86.70928/

https://www.ford-trucks.com/forums/1348889-group-31-battery.html

https://www.ford-trucks.com/forums/1438638-what-battery-do-i-need.html

Prospect62

Re: Group 31 batteries

A search of this forum didn't find much...

I did see those results on other forums. I wanted to ask here because people here seem to have voluminous knowledge and experience.

1985 F250 4x4 6.9 IDI T19 4-speed Dana 70U rear/Dana 44 HD front 3.54's - Proudly bone stock w/ 235 85 16 MT's

Gary Lewis

Re: Group 31 batteries

Administrator

I'm running a Group 31 in the starting slot on Big Blue, but a 31 wouldn't fit in the aux spot as it was too tall and would hit the hood. So I went with a Group 34 there.

And while BB has a gas engine it does have the factory aux battery compartment in the factory spot, so that's the same as a diesel would have.

Also, I have a later Ford battery mount in the starting spot, so it may sit higher or lower than the Bullnose mount - I don't know. But I can say the Group 31 battery's negative post is very, VERY close to the hood.

Bottom Line: I do not think you can go with a pair Group 31's in a Bullnose.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

AuroraGirl

Re: Group 31 batteries

I dont know how they mount or look like in bullnose, but if its an AGM 31, all you need is to find a way to positively secure it sideways which would either require a lot of extra.. stuff.. modification, changing the bracket position, or maybe its as simple as laying it down and bam. lol. prob not that easy, but as long as its agm you could even do it UPside down if you have a bracket in which the posts would be clearign the bracket, but I doubt that too

Those usually come with a handle they are so heavy, so its definitely something youd have to want bad to contort that under the hood etc

AuroraGirl

Re: Group 31 batteries

https://www.winterfabonline.com/product/group-31-battery-tray
found a decent tray that is fabricated and affordable that would probably do the job. just finding a spot becomes the difficult part

Gary Lewis

Re: Group 31 batteries

Administrator

In reply to this post by AuroraGirl

I'm confused. You said you don't know how they mount in a Bullnose but you have an '85 IDI, so surely it has two batteries? And the one on the driver's side should mount just like my aux battery, which is shown below.

But you are right, some batteries can be mounted sideways or even upside down. Are the ones you are looking at AGM?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Group 31 batteries

Administrator

Prospect62 is looking at a sub $80 economy battery from the local heavy duty truck dealer.
I doubt very much that it is AGM.

It seems Gary is the only one who has one in a Bullnose (and that is in the bigger Bricknose battery tray)
I don't have an answer or comment beyond that.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Prospect62

Re: Group 31 batteries

They're not AGM. I was just curious if anyone put them in their bullnose. I took some time to inspect the truck over the last couple days and it looks like they'll fit. I'll keep everyone posted if I end up doing it. Thanks for the responses.

1985 F250 4x4 6.9 IDI T19 4-speed Dana 70U rear/Dana 44 HD front 3.54's - Proudly bone stock w/ 235 85 16 MT's

AuroraGirl

Re: Group 31 batteries

In reply to this post by Gary Lewis

No I have a 1996, I dont own a bullnose lol. You must thought I was the OP. I was sharing some thoguhts about AGM and a possible tray if there was a way to mount one sideways(it would allow the fitment of another 31 if desired if it was possible) haha sorry for that mix up

Gary Lewis

Re: Group 31 batteries

Administrator

Ok, my bad. I'll blame it on COVID, from which I'm trying to recover. (That's my excuse for everything right now.)

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: Group 31 batteries

Sorry to hear you caught it, Gary.

Hopping it wasn't during your last vacations. Seems to me that a hurricane would have be enough for this trip.

Take care.

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: Group 31 batteries

Administrator

Actually, there were two hurricanes and COVID. Fiona chased us north, as you know, and then we were to fly from Montreal to Charlotte and Ian decided he was going there first. So we changed course to DFW.

Then when we got home we were feeling ill so the next morning we took the test. You are supposed to wait 20 minutes to read it, but at 2 minutes mine was yelling "Dude, you have COVID!" That was 13 days ago and I'm still feeling like someone is sitting on my chest. And I'm tired. But each day is a little bit better.

Gary, AKA "Gary fellow": Profile