firing order... hmm...

[Euphoric306]

well im trying to put in an o2 sensor, which didnt work out... another story

anyway, a couple weeks ago i changed wires n cap, before that it was spark plugs. i never noticed before, but my firing order is that of a non-HO engine (1-5-something), but on my emissions label under my hood AND in my haynes manual it says that HO motors have 1-3-something firing order. SO, before i bought the car, the engine must have been swapped out for some reason.

this angers me a bit because now i have no idea whats under that intake manifold. (roller this, hydraulic that). although, it could be a good thing. ANYWAY, the manual says the engine tags r on the front of the valve cover (no where to be found) so where are some other good places to pull the numbers off this engine and find out what i got here.

in case u didnt understand that, my VECI Label shows a different firing order than what is set up on my motor, and since the crankshaft, camshaft, and other things maybe, must be changed out in order to change firing order, this must be a whole non-HO engine swapped into my car.


oh yea, assuming i do get some numbers off the engine, how can i use those to discover its meaning?

 

[Rick 91GT]

The cam determines the firing order...

Easiest way to tell is put the HO firing order on the car and see if it runs great, if it does it needs it.

The 2 firing orders are close enought that the a car that needs a HO firing order will run with the old NON HO firing order, it will be a little lazy down low but rip up top. I did it by accident a few years ago..lol

 

[jrichker]

FYI:

HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8

I wouldn't think that an engine with the wrong firing order would run very good. I would expect to find lots of poping and backfiring.

 

[Rick 91GT]

FYI:

HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8

I wouldn't think that an engine with the wrong firing order would run very good. I would expect to find lots of poping and backfiring.

Actaully it ran and idled like a 600" Pro stocker, sounded pretty mean. HAd no low end but ran very good up top....shocked me as well.

 

[PNY PWR]

Someone probably put a regular 302 cam in it, if so you need to time it as a 302. i timed an HO like a regular 302 once, it wasn't pretty.

 

[PNY PWR]

Someone probably put a regular 302 cam in it, if so you need to time it as a 302. i timed an HO like a regular 302 once, it wasn't pretty.

Even if it's a non-HO motor totally I wouldn't be too worried. Any 302 is a good motor and can be built well.

 

[Euphoric306]

id rather not switch it back without doing some research first... last thing i need is some busted journals or osmething