83 d150 383 find

[Mooky]

Just traded a quad I had for a rock solid for michigan 1983 d150 2wd short box truck...and the kicker is it has a 383 in it...was a 225 slant six 4 speed....now the bad news is it has low oil pressure at idle and a light thunk thunk thunk when at load 2500rpm or so...plus the voltage reg on the fire wall literally melted the gel down the fire wall at some point......any thoughts suggestions...Ive smoked a volt reg before but I have not ever or seen one melt like this one has..runs great other than light knock but obviously doesn't charge...post pic's in a while..thanks

 

[Budnicks]

Never heard of a voltage regulator melting, wow.. serious over charge.. see what the voltage is at the alternator... the "thunking" maybe could be, a loose flywheel or something in the drive train, if it only happens under loads.. Good luck with the 83 w/383 4spd truck,sounds like a fun project... I hope you can get it smog-ed & registered, I don't know how bad it is to smog a 83 vintage vehicle, with an earlier engine in it, in Michigan...

 

[Mooky]

voltage was at 17 ..!!!...and also melted another reg...tried diff reg/alt...same spike.....added ground and the voltage was reduced to 15.3....so now I'm thinking add another ground? it has a ginormous ambulance type alt on it so I will be down sizing ...and the emissions laws in MI are partly why I'm still here.....as far as the knock, I let it idle minus the alternator and the warmer it got the lower the oil pressure got as well, all the way down to 4-5 psi....and its a d383 blue engine with an orange oil pump soooo I'm thinking somebody before me was thinking bad pump.....but I'm thinking bad main bearing.....but it is worth a look see as far as the loose bolts go and I will,,thanks keep ya posted:eusa_think:

 

[1badgtx]

You should check the numbers on the block to see what you really have..
Petty blue 67 gTx

 

[Cranky]

What is your idle rpm? And the size of the alternator shouldn't matter as the regulator is what controls it.

 

[Mooky]

numbers on the block ...front pad right side front of head are D 383, second row 4 C L .... I cannot really tell you what size the alt is except for the fact that it is abnormally large size...my pop's say's they were installed on some industrial use engine (ambulance, army, utility) 100 amp +.....the coil seems to get pretty hot as well..more so than usual....gonna mess with it tomorrow after work ...will take pic's as it was raining today

 

[Meep-Meep]

D383 = from a 68 model year. The block will most likely be cast in 67.

Just because the ALT has the capability of putting out 100A that does not mean that's what you get. The high charging voltage could mean a bad alternator.

 

[Mooky]

got home...put my 440's alt on it...now charges at a minimum..12.4....?....maybe wrong voltage reg?...it is an old slant 6 truck with an older 383 in it so maybe I have the wrong reg in there...it currently has the red 2 pin on the wall....and in the alt's wire harness there is a 2 wire plug and 1 wire is cut and I connot see where it may have lead too....but its running better and it idles at 850

 

[Budnicks]

An 83 should have a dual field (charging brushes) style alternator, 1 dark green wire going to 1 of the fields & 1 dark blue wire going to the other field, if you have a single field style alternator 1 of the 2 fields (brushes) will be grounded to the case of the alternator, that is "if I remember correctly"