: Starter Differences from 472-500 ?



01devilledts
11-14-09, 10:06 PM
So after the 472-500 swap I did on my 68 SDV it has a little bit of trouble starting. I have a fuse/distribution block off the battery and from there it splits off and I have 4ga. wire to the starter, alternator and then a few pieces of 8ga to the misc. cabin power source's. In this fuse/distribution block, there is a 250a fuse.

My problem is when I try to start the new 500 it turns over pretty slow and sometimes blows that fuse. The starter was about 1 month old on the 472 and was a new starter when I installed it on that motor.

I think its having a hard time turning over the 500 for some reason and its pulling too much current and popping the fuse.

anyone have a suggestion?

csbuckn
11-14-09, 10:33 PM
maybe the starter needs shimming?

01devilledts
11-14-09, 10:46 PM
Would shimming it make a difference in the way it cranks over? I know to shim if it's grinding or missing. But it seems to make good contact when it extends. I just don't know if be ause ofthe stroke being bigger on the 500 if it would need a higher power starter

csbuckn
11-14-09, 11:08 PM
well i guess the only thing that really controls the power of the starter is the battery. Maybe a weak connection somewhere like at the starter? did you use stock battery cables or are they new aftermarket wire?

01devilledts
11-15-09, 12:02 AM
The cables are brand new and I made them myself (I do know what im doing in that dept) so i know its not the cables, also the battery is a 1800cca new battery with plenty of power.

I looked at the local parts stores website and im getting 2 different part numbers for 68 and 74 starters. maybe ill just go get a starter that is meant for that motor?

Angry Matt
11-15-09, 01:35 AM
The starters "should" be the same. I wouldn't put a fuse on the starter wire though. That should be directly hooked to the battery. How are your ground cables, clean? I have 2awg hot to the starter and 2awg ground to the block, then 4awg from the block to the frame, might be overkill, but it can't hurt. I also used a powermaster high torque mini starter and love it. $120 something from summit.

01devilledts
11-15-09, 08:45 PM
I added 2 good engine ground to chassis and then another battery to chassis ground cable, all 4awg and took the starter off the fuse block. It seems to be good now, I think my timing needs to be played with a little because when its hot and I try to start it it a little sluggish. I will play with that tomorrow since I wanted it to cool down so I could replace the coolant temp. sensor.

Thanks for the info guys

akimball442
11-15-09, 11:33 PM
The starter on any vehicle should be connected directly to the battery. This allows maximum current to the starter.

Generally, the starter is hooked directly to the battery, and then the fuse block is drawn off of the starter, usually through a fusible link. In other words, since the dawn of time, the big terminal on the starter is the main junction that all of the electrical circuits for the entire electrical system are drawn from.

If it's not hooked up this way, you should change it, because drawing the starter from anything but the battery itself is quite a fire hazard.

4 gauge wire is kind of puny, I'd almost go with 2, between the starter and the battery. When I rewired my 81 CDV, the battery cable I built goes directly from the battery + terminal, to the starter. The battery - cable goes to the engine block, with another piggybacked on it going to the frame. I used 2AWG welding cable, which is extremely flexible. The cable from the battery to the starter is wrapped with a silver kevlar heat reflective tape, to prevent damage from the exhaust.

At the starter stud, I piggybacked an 8 gauge wire that went to the alternator, with a 12 gauge fusible link, and I used another 8 gauge wire to the fuse box, also with a 12 gauge fusible link.

I replaced all the wires with new because of some corrosion.

If you're hooked up this way, check the grounds, make sure that your grounds are solid.

If everything is correct, and it still cranks slowly, try backing the timing off a few degrees. GM starters seem to hate timing that is too far advanced.

01devilledts
11-15-09, 11:41 PM
Great info, the starter is now wired directly to the battery, and everything else comes off the battery with a fuse-able link. as far as grounds, they are now how you stated. I plan to play with the timing tomorrow after im finished with work. Since the 68 doesn't fit in my garage, I leave it at my shop.