Engine break in run - rotating engine and filling carb bowls?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

K5_489

Member
Joined
Dec 11, 2019
Posts
41
Reaction score
25
Location
Arizona, USA
First Name
Eric
Truck Year
1986
Truck Model
K5
Engine Size
489 BBC
I'm a day or two away from finally getting to fire my new 489 for the first time....and while this is far from my first engine build, this IS my first "performance" build on a old school carb'ed V8 (been working on small 4 cylinder EFI stuff for most of my life). So I understand the core concepts of first engine fires/break ins, I'm just not 100% sure of a couple specifics as it relates to these engines. I also have legitimate ADHD (doctor diagnosed, with bottles of prescribed happy pills :p), so I've learned to check and recheck things many times before finally "pulling the trigger", so to speak, lol.

I have an electric pump on the truck, feeding an Edelbrock 1406 carb. Is the fuel pump alone enough to get the fuel bowls filled properly, or do I need to manually fill them in some way?

When priming the engine, I know the engine needs to be rotated over to get oil to flow to all the areas...can this be accomplished by bumping the starter with the spark plugs out, or does it need to be done by hand? There's no way I'm going to get the balancer on/off without pulling the radiator, and I know these motors aren't supposed to be turned by the front crank bolt. I suppose I could get under the truck and rotate it with a pry bar wedged up in the converter bosses, but the starter just seems so much easier.

I know lots of people say priming is a waste of time, or going for more than a few seconds past the pump building pressure is a waste, but with that whole ADHD thing, it just makes me feel better knowing I've got oil flowing throughout the motor, and it's a way for me to double check that I didn't forget a galley plug or something during assembly. Getting distracted during important things is a real issue for me due to the ADHD, and it's pretty easy for me to forget one or two of those "little things" during assembly.
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
The electric pump will be sufficient to fill it up, and it will do it relatively fast. I’d always spray a shot or two of starting fluid or a pour a couple ounces of gas down the barrels, after a long sit, new carb, carb rebuild, whatever. I’ve never deviated from mechanical fuel pumps in past carbed setups, which those can’t flow fuel as consistently as electric, but if you give it a few seconds’ prime and don’t flood it, the extra help would still be applicable until fuel’s flowing by itself.

What you can do for the oil priming, which I wholeheartedly believe to be a good idea, is get an old distributor and cut the gear off right above the teeth so it only engages the oil pump. You can either engineer it to be hand cranked or drill operated, but since you want to build pressure to test for leaks, the latter route will be necessary. They also sell them pre-made if used distributors are a scant find near you, but I’d check the reviews on the one you decide to get because I’ve seen where people have had issues. I suppose you could use a long screwdriver, but that seems to me like the worst approach by far.
 

K5_489

Member
Joined
Dec 11, 2019
Posts
41
Reaction score
25
Location
Arizona, USA
First Name
Eric
Truck Year
1986
Truck Model
K5
Engine Size
489 BBC
I've got half a dozen SBC/BBC HEIs sitting on the shelf now, with an Accel unit already gutted and the gear turned down on the lathe for just this occasion :p That distributor came on the SBC when I bought the K5, and I wouldn't normally touch Accel stuff with a 10 foot pole these days (I certainly wouldn't buy it myself), but it seemed to be working OK then...and died about a week after I bought the truck, lol. It got replaced with a MSD Billet, and I immediately marked that Accel to be the pump drive tool donor later.

The electric does flow fuel quite nicely, as it made quick work of draining the 6 month old fuel out of the tank last week. I probably could have ran that fuel without issue now, but it was 87 octane, and I figured having fresh 91 in there was a better idea. The motor is only 9.5:1 compression, and _should_ be OK on 87 in low load situations, but better safe than sorry and all that.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,347
Reaction score
3,591
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
As mentioned, electric pump will fill the carb just fine

Either modify an old distributor, or the engine priming tool is pretty cheap, especially considering the cost to build a engine. Spin the tool with a drill, rotate the engine 90*, prime the engine, rotate another 90*, etc until you have made one complete rotation. The theory is by rotating the engine, all the oil holes in the crank will be filled with oil. Cheap insurance. You don’t want to spin the engine with the starter, especially with a flat tappet cam. The slow rotation wil wipe all the break-in line from the cam lobes.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
29,088
Reaction score
23,899
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Some of the oil primers don't have the machined area at the lower portion, so it bleeds off most of the oil flow before it can circulate.

I like the modified distributor technique. It's basically free, other than some time spent on the bench grinder.
You must be registered for see images attach
 

bft305

Member
Joined
Jun 26, 2017
Posts
44
Reaction score
21
Location
ME
First Name
Ben
Truck Year
1976
Truck Model
K20
Engine Size
350
You can also go to autozone, oriellys, etc and rent for free the oil priming tool, if you don’t have a old distributor to modify. That is what I did a few years ago and it worked fine.
 

PrairieDrifter

Full Access Member
Joined
Dec 28, 2014
Posts
3,453
Reaction score
4,559
Location
North Dakota
First Name
Mason
Truck Year
84,79,77,70,48
Truck Model
Suburban k10, bonanza k10, c30 C&C, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350
Some of the oil primers don't have the machined area at the lower portion, so it bleeds off most of the oil flow before it can circulate.

I like the modified distributor technique. It's basically free, other than some time spent on the bench grinder.
You must be registered for see images attach
This right here!
 

Tonyg123

Junior Member
Joined
Dec 25, 2019
Posts
10
Reaction score
2
Location
Texas
First Name
Tony
Truck Year
1979
Truck Model
Gmc
Engine Size
5.7
Electric fuel pump should be fine for your carb prime. It wont hurt it to put a small amount in the carb. Most definitely prime the oil pump. Rent a tool from auto zone( no charge). Remove the valve covers and prime until u see oil coming out of the pushrods. May take a while but stay with it. You will feel the drill slow when it picks up the oil.
 

Forum statistics

Threads
42,076
Posts
908,540
Members
33,550
Latest member
kurt54
Top