Timing and Dieseling

[maxtwms]

Im not sure about the oil pressure because the gauge reads pegged at 60. I dont believe the gauge is bad either since it moves when i turn the key to acc. Ive been told I have a high volume or high pressure pump or something like that.. another issue to look at.

Regarding the timing terms. Im sure were talking about the same thing but confusing time and distance. Advancing the time means the spark fires earlier in the compression cycle (farther from TDC on HB and in cylinder), while retarding the time means it fires closer to the completion of the compression cycle.

Advance away from TDC (earlier spark)
Retard toward TDC (later spark)


That, or Ive gone crazy

 

[maxtwms]

BTW, when I had about 20" vacuum, it was before I set the time to "12deg" and it was probably running about "50deg" initial mech timing at that point. I quote 12deg because Im not sure if the outer ring is clocked correctly as was mentioned earlier. I quote 50deg for the same reason but also that it was so far advance (counterclockwise on HB) that it was blocked by other accessories and I just could see it.

 

[rt66paul]

Is your timing steady? or does it shift a couple of degrees? If it is not steady, you need to find out why. It could be the balancer, the chain and gears or even the distributer. Many original distributors have worn bushings and can cause problems.

 

[maxtwms]

The timing is consistent when I'm watching it with the light if that's what you mean. I bought a piston stop usually used for chainsaws so that I could find true TDC. I also replaced all spark plugs and wires. I bought a carb rebuild kit for my Holley 4175. Once I have applied all that, I can check the distributor to see if Its aligned with the crankshaft correctly to fire at TDC. Then if it's giving any fits, check the health of that distributor (Delco Remy, should be legit). hopefully that's all under the hood for now (till I get antsy) then it's on to fixing the 'chevy lean'. I think mine is from uneven rear shocks. Will report back.

 

[maxtwms]

Alright, so I finally got around to finding TDC and found that the original mark was off by 26.5°! I'm glad someone mentioned the rubber dampener allowing the outer cast ring to move. I found this using the piston stop. The orange dot is the original mark and the 2 small silver lines are where the piston hit the tool on either side of TDC. Then the long mark is splitting the two. I estimate 13° between each mark for a 7" harmonic balancer.

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[maxtwms]

I removed the carburetor to rebuild and set my engine at TDC on the compression stroke so I can check my distributor next. Then I'll throw on the clean carb and never know which thing made the largest difference. Oh also I'll need a new fuel line..

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[maxtwms]

While I'm thinking about it... Look at my plugs! They have been oil fouled and I'm not sure how big the culprit is... :-/

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[1987 GMC Jimmy]

Summit sells the 73-87 truck steel fuel line if you need a new one.

 

[maxtwms]

Summit sells the 73-87 truck steel fuel line if you need a new one.

Any benefit in getting a braided ss one?

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[1987 GMC Jimmy]

I’m sure there is for ease of installation, and it’s probably not bad. I know that the solid one isn’t going to succumb to vapor lock issues because there’s only one routing for it, and it’s a tried and true setup. That’s why I’d go with that one.

 

[maxtwms]

New tag should help

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[maxtwms]

Is this the one you're referring to?
https://www.summitracing.com/parts/cst-cvc1038-ss/overview/year/1985/make/chevrolet/model/k10
$45 seems kind of pricey and I'm not sure this is the current design I have on there now. I'm trying to imagine this connecting to the pump and carb and I just don't see it. Probably because I'm using a Holley instead of the Quadrajet??
Can you explain the vapor lock scenario? I'm not familiar...

 

[74 Shortbed]

I just run a braided line in it's place, it don't have anything to do with vapor lock, you should have a return of the pump anyways..

 

[maxtwms]

Maybe it's this one?
https://www.ebay.com/itm/1981-87-2w...ash=item3f48620247:g:ojgAAOSweW5U-iKS&vxp=mtr

Except this is for a 350 2WD. Can't see how that would matter....

 

[maxtwms]

I just run a braided line in it's place, it don't have anything to do with vapor lock, you should have a return of the pump anyways..

I like the look of a braided one and it seems easier to install so Im on your side. The only reason Id justify another solid line is that I dont intend to take the carb on and off and wouldnt mind saving $20. I welcome part suggestions.. maybe even with a filter/gage combo.. I like to make sure all my bases are covered if Im going to take the time to replace all this stuff.