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daveosx
08-06-2019, 11:09 PM
I am doing a high millie overhaul on my GMT400
As I was rebuilding the distributor new pickup shaft end play and hardened gear for the roller cam.
I noticed that the rotor magnet was cracked in half.

Does anyone sell replacement magnets?

1project2many
08-07-2019, 12:55 AM
That's not good. AFAIK the magnet is part of the distributor shaft.

daveosx
08-07-2019, 03:22 AM
Yea I know
I used to have a half a dozen of both types in my tool box.
They are replaceable and there used to be a GM part number for them.
On the large cap you simply remove the reluctor ring screws and replace the magnet.
On small external coil HEI you drill the rivets out replace the ring magnet and use locking screws to reassemble.

FYI there are bulletins on this from 87 - 95.
Drive ability stalls intermittent at idle

Hoping someone still had one r knows a source

1project2many
08-07-2019, 04:23 AM
They are replaceable and there used to be a GM part number for them.

Long gone afaik. Possibly still available from Mercruiser? Chinesium parts are so readily available that few people are spending $$ on the real thing anymore.

daveosx
08-07-2019, 09:01 AM
Yea
I am going spelunking at the machine shop tomorrow Dan Cox has shiftloads of older stuff all over his shop.
if I am unlucky I will be diamond grinding some hard drive magnets tomorrow night.
Get my block back tomorrow got to ridge ream dingle ball and end gap the rings.
I have a really super nice Mac Tools Cam bearing tool but lost the part that holds the bearing, I have had the tool for 45 Years and lost the part 3 years ago.
Maybe Thursday I'll get the heads on and assembled.
Spent 7 hours cleaning pistons today with a bucket of carb cleaner.

Wow this engine really shows the Millage it was replaced by a ripoff dealer at 90K now at 275K it looks like the dealer swapped in a used car engine instead of the VinK block two bolt mains and powdered rods. Bummer but new short block not in budget. So I am doing and OLD fashioned rebuild like it was 1970 or something. I figure I can get another 80K out of the rebuild and I will replace the block then with a 400 Blueprint short block.

1project2many
08-07-2019, 02:04 PM
two bolt mains and powdered rods
Roller cam? I don't believe PM plus non-roller would have been a factory combination. The one ton and larger truck engines used traditional rods past 96. Maybe a Delco or over the counter rebuilt engine?

daveosx
08-07-2019, 07:31 PM
Who knows ?
It is definitely not a Vin code K block.
It is a 4 inch bore and correct stroke.
My truck is a 1500 series GMT400 so not a one ton.
My brother law owned it before me he claimed that the dealer put a new engine in at 90K.
It had the stickers on the valve covers Goodwrench but I do not think that it was.
Looks like it was a pull from a 87 caprice.
The roller bosses were in all the blocks except a few Marine from 87 on.
I have only seen one from a TPI block that was non-roller.

Mains and cam bearings worn out but it never knocked crank Mics fine the bores are ridged about .010. Ridge reaming and dingle balling it tonight.
I'll mic the pistons may have to knurled them.
It will be fine.

I am disappointed because I was considering a turbo for later.