[Tom Pugh]

I'm looking for an 800 CCA battery that will fit in the stock location of a '67 GTO. I'm fighting a hot start issue. The current 600 CCA battery is not getting it done. The best I've found so far is one with 720.. I'm using a new mini starter, heat wrapped., New 1/0-gauge battery cables are on order. What are you guys running?

[Sirrotica]

I've found that a shield is better than any type wrap. The shield allows air to circulate between the heat source and the starter as opposed to a wrap which slows the initial absorption of heat, but also retains heat after the engine is shut down.

YMMV but over the years the shield has worked fine for me with the Delco starters, I've never even had to resort to a gear reduction mini starter, even on my race cars with 12 to 1 compression.

I usually make my own shields from a piece on stainless, or galvanized sheet metal and bend a 90 degree on the bottom. I drill a 3/8 inch hole and install it between the outer starter bolt, and the aluminum nose casting. I make it as large as possible length and width to cover as much area as is practical and trim it to fit.

Rule of thumb is 1 CCA for every cubic inch for a conventional application so 720 should be well within having enough power. You might have to upsize cables over stock gauge to carry enough current without dropping amps due to resistance.

If you feel you need a top of the line battery that has 840 CCA, I've heard that this brand is one of the best, but very pricey as they list for just a whisker under $500. If you buy from their site use MORR to save 10%.

https://fullriverbattery.com/batteries/part-ft840-24m/

I hope this helps getting your problem solved.......

[Schurkey]

Originally Posted by Tom Pugh

I'm looking for an 800 CCA battery that will fit in the stock location of a '67 GTO. I'm fighting a hot start issue. The current 600 CCA battery is not getting it done. The best I've found so far is one with 720.. I'm using a new mini starter, heat wrapped., New 1/0-gauge battery cables are on order. What are you guys running?

What was the battery capacity when that car was sold in '67? About 400 CCA?

If 600 CCA isn't getting it done, there is something WRONG. You don't need a bigger CCA battery, you need to figure out the actual problem.

Which MIGHT be that your "600 CCA" battery has failed and only has 200 CCA when tested. Which is where I would start--a REAL load-test on your battery.

This is NOT the same as the quickie-test at a parts store, where they bring out a hand-held electronic device, hook two thin cables to your battery, and the machine plays Van Halen at the battery until it submits. Then it prints-out the results on thermal paper like a grocery-store receipt.

You're looking for a shop that has a bigass machine likely on a roll-around cart, with heavy "jumper cable" connections, that draws real power from the battery to assess it's condition using the built-in voltmeter and ammeter. A competent shop uses the same piece of equipment to verify starter amperage draw, and alternator voltage and amperage output. This same equipment can then do voltage-drop testing on your main battery cables, and the cable on the alternator output.

[steve25]

When did this hot hard crank issue start?


Is this a new build ?

Did you check to see if the advance weights are hanging up when the motors hot and you then have over 12 to 15 degrees of initial timing taking place?

[mgarblik]

Good suggestions have already been made here. But just to add. A larger battery will not solve the problem IF the 600 CCA battery is good. A REAL carbon pile tester like a VAT 40, VAT 60 or similar would load test the battery and could also measure the starter amperage draw. Finding a shop that has one and a human that knows how to use it may be difficult however. Everyone wants to use a tester that has an English readout and a moron can operate without any electrical knowledge. A couple simple tests you can do yourself. 1. When the engine is hot and acting up. Disable the ignition system, (coil), and crank the engine. If it cranks normally but does not with the ignition hooked up, you have a timing issue, probably too much advance when cranking hot. 2. Install a known good battery for testing purposes and see if the problem goes away. A 600 CCA battery is way more than any of these old cars came with and a gear reduction starter should take additional load off the system. I have seen some weak or defective mini-starters however. Especially the no-name cheap ones.

[The Champ]

Originally Posted by Schurkey

What was the battery capacity when that car was sold in '67? About 400 CCA?

You're close....

GOLD/PROFESSIONAL
Vehicle Battery
42 Month Warranty High Reserve
Part# 24GHR
Per Veh: 1
Years: 1967-1967
BCI 24, minimum vehicle Reqment: CCA 340/RC 70

340 CCA was what GM spec'd back in 1967 for the GTO 400 CI original battery.

The top current replacement for it is Part # 24GHR is the current ACDelco replacement for the OE battery.

This battery is rated at 700 CCA.

I have an 8 year old ACDelco version of the 24 GHR which is also a 700 CCA battery which works fine with my 462 CI motor.

I agree that the CCA rating of the battery is not the problem. 600 CCA should work fine. There is another problem. If the current battery is still producing at or near 600 CCA, then spend the money on the real problem, not a new battery.

[Gator67]

I agree that you should be good to go with a 600 cca battery and that you should start by verifying the battery’s health. I bought one recently that was bad out of the gate, and another that lasted about 6 months before it failed.

[GOAT8U2]

My 462ci
0 battery cable
4awg from starter to battery
Cranking timing at 10 degrees
Strong torque starter
With the Holley it needed a strong battery to bump cranking rpm and have high volts during cranking to help.

What is your current setup?

[Schurkey]

Originally Posted by GOAT8U2

0 battery cable
4awg from starter to battery

Huh? What is a "0 battery cable"?

Especially since most folks would consider the "starter to battery" cable as being "the" "battery cable".

[indymanjoe]

0 gauge wire is what i think he is saying

[Schurkey]

Originally Posted by indymanjoe

0 gauge wire is what i think he is saying

So the "battery cable" is zero-guage, but the starter-to-battery cable is four-gauge?

Aren't those two descriptions of the SAME CABLE?

[Tom Pugh]

thanks for the advice fellas .My combination is a 455, 9.5:1, roller engine. Nothing serious, just a good street engine, still has factory ac. I'm using a Summit mini starter, NEW 600cca Diehard battery and stock battery cables. She fires right up when cold, but after running for a while it will not start if left to sit (heat soak). The pinion on the solenoid will fire but the starter will not engage. If I hook up my jumper box to the battery the engine will fire right up. Thats why I am considering a higher CCA battery and thicker battery cables. I tested the battery with my tester and it indicates 6CCA/good battery. So, I assume the starter wants more juice to engage when hot/heat soaked . I am going to fabricate a heat shield for the starter to see if that helps. Any other thoughts?

[Lee]

Go with an XS Power or Braille AGM.

IGNORE the "CCA" ratings, they do not translate well to AGM batteries.

I've used the XS Power S925 and S975 batteries in cars similar and more radical than yours, and they both are more than adequate. Under normal engine starting situations, like your heat soak that you mention, they perform more like lead-acid batteries with over 1,000CCA. They are only about 25 pounds, too, amazing power to weight.

I've not used the lithium batteries yet, but they look to be even more amazing. 6lb. lithium = 25lb. AGM = 60+lb lead-acid.

[Schurkey]

Originally Posted by Tom Pugh

NEW 600cca Diehard battery and stock battery cables.

"NEW" does not mean "good".

Those cables are crying out for a voltage drop test. Corrosion under the insulation could be killing power transmission from battery to starter. Both the positive and negative cables need to be tested. See thumbnail, attached.

Originally Posted by Tom Pugh

I tested the battery with my tester and it indicates 6CCA/good battery.

Describe your tester, and test procedure. A link to the tester you're using would be a bonus.

Originally Posted by Tom Pugh

I assume the starter wants more juice to engage when hot/heat soaked . I am going to fabricate a heat shield for the starter to see if that helps. Any other thoughts?

I'd like to know the starter-draw amperage, and I'd want to know the open-circuit voltage of the battery.

A "12-volt" battery that has only 12 volts when tested under no-load conditions is mostly-discharged, or defective. A fully-charged battery will have 12.6--12.8 volts depending on battery construction.

[indymanjoe]

Originally Posted by Schurkey

So the "battery cable" is zero-guage, but the starter-to-battery cable is four-gauge?

Aren't those two descriptions of the SAME CABLE?

I tried to delete my comment LOL but yea after i read his i thought wth?

[Cardo]

Voltage drop test the cables. Do you have the star washer under the negative cable to the block? Those were there to help dig through the paint to make good contact.

[george kujanski]

"The pinion on the solenoid will fire but the starter will not engage."

Ok, so either the battery is poor, not being charged when the engine is running, poor connections from the battery to the starter, or poor internal connections in the starter solenoid.
When the solenoid drives the pinion out, it also makes an internal high current connection from the battery cable to the internal starter motor.

Attaching a jump box and having it start when hot (after running) seems to indicate the battery is not charging well when running.

George

[Tom Pugh]

Originally Posted by Cardo

Voltage drop test the cables. Do you have the star washer under the negative cable to the block? Those were there to help dig through the paint to make good contact.

will do. No star washer but dId sand off any paint before attaching it to the block

[Tom Pugh]

Originally Posted by george kujanski

"The pinion on the solenoid will fire but the starter will not engage."

Ok, so either the battery is poor, not being charged when the engine is running, poor connections from the battery to the starter, or poor internal connections in the starter solenoid.
When the solenoid drives the pinion out, it also makes an internal high current connection from the battery cable to the internal starter motor.

Attaching a jump box and having it start when hot (after running) seems to indicate the battery is not charging well when running.

George

sounds like I better hookup a voltage gauge.

[bdk1976]

I would wait until you install your new 1/0 cable before worrying about the battery. Report back after you get/install your new cables. I changed over to a mini-starter with 1/0 battery cables (power and ground) and my hot cranking problems went away.