Author Topic: newb needs direction  (Read 3390 times)

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
Re: newb needs direction
« Reply #30 on: September 29, 2018, 09:40:57 PM »
Are you installing/adjusting it per the procedure in either the factory manual or Haynes manual? Do you still have the light that stays on?
Regards,
Henry
I installed the new one based on removing the old one (they're identical, except the old one was damaged when I pulled the gray plastic connector off)....initially I had the coil wound up too tight and it ran rich, so I rotated it clockwise and it seems about right now.
As of now the choke light is going off after start up. I recently replaced gauge cluster lights, maybe removing and reinstalling the oil pressure gauge straightened it out?
The LEDs are a nice change. T10 42smd
« Last Edit: September 29, 2018, 10:15:58 PM by DnSherrill »
1986 C10 5L LWB

Offline Henry

  • Frequent Member
  • **
  • Posts: 308
Re: newb needs direction
« Reply #31 on: September 30, 2018, 12:38:08 PM »
Hi Dn:
Well, if your choke light goes off after you start the engine and oil pressure comes up all should be well with the choke circuit. I wouldnt be too concerned about the oil pressure gauge reading 30 psi as I dont think they are calibrated to read accurately outside of 60psi. Your voltage gauge should be calibrated pretty close in the 8-14V range and it seems your voltage gauge is reading way too low...if everything is working fine electrically and the truck cranks fine maybe the gauge is bad or not connected correctly.
Regards,
Henry

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
ESC distributor to 4 pin HEI
« Reply #32 on: October 14, 2018, 09:25:01 PM »
I removed the ESC  5 pin distributor and put in a new 4 pin HEI vac assist distributor. Still no start and no spark. I measured voltage through the 12 ga solid pink wire that goes to the BAT terminal on the coil. 12.5 v with key in RUN but only 9.5 v with key at START. 0 volt with key out.
thoughts on why?
« Last Edit: October 15, 2018, 06:10:04 AM by DnSherrill »
1986 C10 5L LWB

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
Re: newb needs direction
« Reply #33 on: October 16, 2018, 08:11:13 PM »
after using a spark light tester, I'm getting good spark. I had been ignoring the fuel leaking around the air horn gasket and the TB gasket.  Also running very rich and very low MPG. This points to a bad float?
So I can try to replace the float or replace the carb with an eddy 650? which model would I get for my AT?
1986 C10 305 700R4
1986 C10 5L LWB

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
Re: newb needs direction
« Reply #34 on: November 15, 2018, 06:13:54 AM »
well, after lots of time spent (learning trial and error) it's clear that my 305 is done. very low compression, head gasket blown. Now to get a replacement. There's a machine shop builder near me that has a 400 0.60 over he'll sell for 1400 and I provide heads.  I found some 350 heads casting number 920 that I feel good about, recently rebuilt asking 300....I'm not feeling too good about the 400 0.60 over
1986 C10 5L LWB

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 423
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: newb needs direction
« Reply #35 on: November 15, 2018, 07:53:06 AM »
You are spending too much for a rebuilt engine and old smog heads (sounds like about $1700?).

You could buy a new GM 350 base 250 HP crate engine for about $1700-1800, including a full GM warranty, or move up to a Vortec 350 crate for about $1850 (much better engine overall).   The Vortec will also require a new intake, new flex plate and an electric fuel pump, but all other accessories will move right over.

You need to think about your overall plan before you spend money right away.  Buying an engine with old smog heads, like the 920 or the heads on the base crate engine, will put a hard "cap" on total power potential.  Regardless of what you do in the future, those heads limit what you can get out of a new intake, headers, cam, and other improvements.    Using a more modern head, like the Vortec or any of several low-budget aluminum heads, will give you a much better engine if your goal is something with 350-375 HP, or more.   

Good flowing heads and about 9.5-10.0 compression is where you want to start for a long term build.

Bruce

Bruce

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
Re: newb needs direction
« Reply #36 on: November 15, 2018, 08:40:20 AM »
thanks for the input Bruce, also to be considered, my dad lives about 3.5 hours away and has alot of old parts stored, including a 350 short block that may not need to be bored out. That might be the most cost effective. I only want/need an improvement from my 305....250-300 HP will be fine for the foreseen future
1986 C10 5L LWB

Offline DnSherrill

  • Newbie
  • Posts: 27
  • Newbie
Re: newb needs direction
« Reply #37 on: January 19, 2019, 08:21:14 PM »
update...
the 350 block was bored 0.030 with sealed power new pistons and GM powder rods, using the large valve heads from a 74 (3998920, 1.94/1.5) should end up with about 9.4:1...the cam is a hydraulic flat tappet  Elgin Black Ice ELGICE 200903, identical to GM pn 3863151, lift 0.447/0.447 with 1.5 rocker arms; duration 223/223 @ 0.50....
question:
should I stick with stamped steel 1.5, or should I consider going up to 1.6 roller tip or stamped steel?

1986 C10 5L LWB

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 423
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: newb needs direction
« Reply #38 on: February 07, 2019, 07:27:05 AM »
You have plenty of cam duration for your compression, so I don't see any reason to go to 1.6 rockers.  I would just compare rocker prices and decide how deep your pockets are.  Stamped steel will work fine, but rollers will reduce friction and probably reduce heat a little. 

When I installed a new cam and heads I paid a little more to get the Summit store-brand full roller rockers because I was using a new roller cam.  However, stamped steel would have worked fine.

Don't forget that if you go to roller rockers you will need to measure pushrod length (you need the tool), and you might need new pushrods.  Roller rockers will also not fit under stock valve covers, so you need tall covers.    I went through that whole process and it did add a fair amount to the price of my changes.

Bruce