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Alternator & Starter Motor Question


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#1 _LH8VD69_

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Posted 26 March 2019 - 01:45 AM

So I’ve been informed I need a hi-Torque starter motor as well as a 100+amp alternator for my new build, VN headed 304 block.

The first starter I enquires about was the CVR. The seller(Store) got back to me saying they only fit Toranas with stock exhaust manifolds. I thought it would fit as they rotate. Apparently not.

So the alternator, is anyone using one of the chrome or black 120amp Aeroflow ones?

Can anyone recommend a starter and alternator they know for sure would suit and any mods I may need using them.

Thanks in advance

Edited by LH8VD69, 26 March 2019 - 01:46 AM.


#2 76lxhatch

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Posted 26 March 2019 - 06:00 AM

Not sure you'd "need" a high torque starter unless you have some pretty serious compression. A new late model factory unit (VP-VT) is probably fine, they are not gear reduction but are higher output motors and smaller. If you get the version that has the solenoid pointing up rather than out the side clearance is probably better. Having said that I've had good luck with an "Excel" 35588 unit (only ever bought second hand so not sure where you'd get one). Its fairly compact and has a 1.3kW motor plus is gear reduction. Can be rotated into a couple of positions but doesn't help, can still be close to headers at the back edge of the solenoid. Can post a photo if needed to identify.

 

Alternators are tricky too, you need to figure out what RPM you are driving it at idle (pulley ratio) and get the details on the alternator output by RPM. Often the aftermarket 120A units don't even put out as much as a VN 85A one at idle which will be a problem if you really need that much output. I'm using a 140A alternator from an LS1 which puts out almost 100A at idle (2.1:1 pulley ratio and 925RPM idle) so no issues there, but does require pulley change for V belt, some minor fabrication to mount it, and the usual minor wiring changes. I'm also now having problems with the belt slipping at start since it loads up immediately, looking at options for a serpentine belt.



#3 Cook

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Posted 26 March 2019 - 08:30 AM

+1 on the starter motor but haven't actually fitted one up yet. Been advised by a few people that the old Commodore ones are ok, are smaller and with the solenoid straight allows for it to fit between the extractors. Cheers Ron



#4 Bigfella237

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Posted 26 March 2019 - 11:45 AM

Just be careful as some of those later Commodore alternators require a PWM signal from the ECU to tell them what charge rate is required.



#5 koalasprint

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Posted 26 March 2019 - 02:52 PM

As for the alternator I am running a standard Bosch 85A. It struggled a bit... until I replaced the alternator positive cable with a 140A cable. Now it has ample power. Make sure you do this or your wasting money on upgrading the alternator.

Now onto the starter. I am running early style heads with 4 into 1 extractors. 11:1 static compression. The old clunker starter worked fine, but it is big and heavy. The VR/VS and VT starters are called an eco starter. They do indeed have a gear reduction system. The VR/VS is 1.4KW, part BXH-136. The VT starter is 1.6KW and has a heat shield. it used to be part BXH-138A. But Bosch have now re-used that part number for the LS1 starter, so beware if buying new stock. Some people may have the old stock of the original.

My advice is to search facebook/gumtree/flee bay/wreckers for a used VR/VS or VT starter, they are getting harder to find. Steer clear of the Chinese copies.

BTW It is very hard(impossible) to take out the big heavy original clunker when you have a high capacity sump.

Cheers Steve.

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Edited by koalasprint, 26 March 2019 - 02:54 PM.


#6 koalasprint

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Posted 26 March 2019 - 02:57 PM

One other word of caution. Be very careful routing and installing the positive cable to the starter, It is easily shorted to earth or the other solenoid terminal, depending on the lugs used. I burnt out my first starter when the cable wore through onto the other terminal.



#7 mick_in_oz

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Posted 26 March 2019 - 08:34 PM

On mine, early style original starter, the big clunker, 363 cubes, 12.1:1 comp, big solid roller, starts fine hot cold or otherwise...

 

Also fits out between the custom merged collector long secondary Tri-Y pipes and ASR 7 Liter Pan.

 

Some friends love using the VT starter and have had good success with it, I'm too tight to buy one when my current starter is working fine.

 

Go LARGE on the charge cable from the Alternator, even better still, hook up and remote voltage sense if it has it available.



#8 Cook

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Posted 26 March 2019 - 08:57 PM

Don't want to jump in but thanks guys. Some great info there and I am just about at that point. Cheers Ron



#9 _LH8VD69_

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Posted 27 March 2019 - 12:52 AM

Cheers guys ill do some searching around

#10 Rockoz

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Posted 27 March 2019 - 08:28 AM

I had all sorts of starter troubles in a VK I had for a number of years.

Had a nice set of extractors.

Trouble is they were rather close to the starter.

I was replacing or rebuilding the starter regularly.

It was mainly the solenoid that was the trouble.

There wasnt enough space between the starter and the extractors for a heat shield.

The heat soak was doing funny things with the armature.

 

Eventually I found a bloke who had a modified starter motor.

It had been rebuilt with Ford armature, and main body with the field coils as well.

Pretty sure it even had the Ford solenoid.

But it is a long time ago.

After fitting it, I never had another issue with the starter motor.

Had the car for about 3 years after that.

 

Apparently the Ford stuff is better at withstanding the heat around the extractors.

The fella I bought it off was doing a fair bit of racing at the time, and he said it was a very common modification amongst those running 308s.

He had a VK sports sedan at the time and even ended up sharing a drive in the V8 utes a while back.

 

Asked him about the mods recently and he cant remember any of the details though.

 

Heat is a big killer of electrical stuff.

Ceramic coating the extractors is likely to make a huge difference, but would still consider heat shielding as a priority.

 

Heat shields too close to the starter wont work very well.

Need a decent air gap between the shield and the starter for them to be effective.



#11 VZ1_60

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Posted 27 March 2019 - 03:22 PM

re the alternator, it is worth having a chat with Bosch, I asked recently about some for sale on the web and eBay for a VK Commodore with electric fans, and these were the comments:

 

BXU12121 is better suited to static / constant RPM applications (this unit has a late cut in - ie higher AMP output at higher RPM compared to other alternators).

For street use, Bosch suggested BXU1296 or the standard BXH1238a which is 70amp and has an earlier cut in (lower RPM).

 

cheers John






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