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-   -   8G glow plug TOTAL DISASTER (https://www.dieselplace.com/forum/63-gm-diesel-engines/379-all-other-gm-diesels/975080-8g-glow-plug-total-disaster.html)

upsmoker 04-08-2019 06:11 PM

8G glow plug TOTAL DISASTER
 
Here`s my situation in a nutshell, (i`ll post the whole "nut" later)
I`ve got two broken tips in the pre chambers on a 82 Oldsmobile 5.7 .Micro injector heads

There is no way with swollen tips, to any degree, that the tips would pass through the openings on the cups. The cups must be removed. Here lies my question. has anyone ever REMOVED a cup without damaging it.

Thank you in advance

dieselolds 04-09-2019 08:42 AM

In all the years using 8G plugs in those engines I only had one fail.Not much you can do but use a brass punch and hope for the best in getting the chambers out.

upsmoker 04-10-2019 06:47 PM

2 Attachment(s)
Had time today so decided to experiment on the removal of the pre-cups. All went really well after I got the first one removed so I could see exactly what was in that dark hole. Took my time with the first one, tap tap tap, measure measure measure, tap tap tap, measure measure measure. You get the idea. After using different materials as a drift on the first one, after the first cup was out, and I saw it`s construction, and the relationship of the injector hole and the glow plug hole(both holes are 6mm) I took a 3/16th. punch, ground the face slightly concave. The 3/16th drift gave me just enough space in a 6mm bore to give the drift a slight tip which is needed. 5 minutes the other cups were out

57diesel 04-11-2019 10:16 AM

Looks like some quality parts there. I have never seen one fail like that even when I was trying.



FWIW I didn't notice any performance difference going to Bosch plugs in my 5.7's.

upsmoker 04-15-2019 06:31 PM

Quote:

Originally Posted by dieselolds (Post 9812402)
In all the years using 8G plugs in those engines I only had one fail.Not much you can do but use a brass punch and hope for the best in getting the chambers out.

You and me both. I`ve had them die, never bulge that much, or rupture !!

upsmoker 04-15-2019 06:59 PM

Quote:

Originally Posted by 57diesel (Post 9812976)
Looks like some quality parts there. I have never seen one fail like that even when I was trying.



FWIW I didn't notice any performance difference going to Bosch plugs in my 5.7's.


Hard to believe it`s the plugs. I personally don`t know what to think. I`m too close to the situation to think anything but the worse.

This all started last december, I needed my truck, plugged it in for 5 or so hours, it was around 0 degrees, I never use the truck in the winter. Waited for the glow light to go off, started right up, after glow working fine, went in the house to let it warm up. Heard the cold idle circuit kick off, went out and the wait light was on!!! Truck was running fine, went got a load of firewood, unloaded and split the wood, turned the key to run, the wait light came on, then off in just a few seconds as it should, engine turned over too many times before starting. It always starts instantly. pulled 3 plugs that are easily accessible, all 3 dead but no bulging. Ordered new plugs and they all ruptured or bulged badly on first 4 to 5 second cycle. I installed a ford solenoid and momentary button before cycling. The only other thing I did was put stanadyne winter treatment in the tank because I had summer blend. I`ve drained the tank just in case
I`ve got a cigar box heaping full of old plugs from over the years, can`t get an 8G to do anything but die after about 15 seconds

I think since I have manual solenoid now I`m going to go 60G
scared to death of 8g`s now.like what was the last thing you ate before you got the flu? never eat it again

Did I over treat my fuel, bad batch of 8g`s (all8?)
wasn`t thinking of tearing down a 37 k engine for grins & giggles

dieselolds 04-16-2019 10:31 AM

Just a suggestion here but were the injection pump mounting nuts good and tight?Seen some 6.5 engines and heard of one 5.7 diesel with a loose injection pump and the pump timing was all over the place because of being loose.Were those 8G plugs USA made?They could be made almost anywhere nowadays.

JCDiesel 09-03-2019 09:04 AM

That's unfortunate hope you get it sorted out soon. I have alot of diesels and never any glow plug removal issues. Running 60G or Bosch 80034 plugs in all the vehicles except the new chevette which only accepts 33G and those are 5 second fast heat plugs. I have Bosch plugs and a button type switch in my 6.5 which is not momentary you push it in and it clicks and stays closed then push again and it clicks to open circuit. I installed it to not have to hold a button and its really nice. Long story longer last winter I was having trouble getting it started so I cranked the engine while the plugs were heating. The truck started it was probably around 0 degrees F and I went inside for 10 minutes to let it warm up forgetting the plugs were on. I was worried when I got in it but it started a little hard after that. I ended up replacing them shortly after. Old ones looked fine when I took them out nothing like those 8G plugs those are sickly looking.


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