New crate engine oil priming/ ignition timing impact if the distributor is mis-installed

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.

BlazerBill

Full Access Member
Joined
Mar 24, 2023
Posts
74
Reaction score
62
Location
Texas
First Name
Billy
Truck Year
1983
Truck Model
Chevy K5 Blazer
Engine Size
350
I’ll be installing a new GM crate 350 into my ‘83 Blazer soon. While the engine is on the stand, I’ll need to pull the distributor to prime the oil system. I’ve not done this before although I’ve watched videos of the process. I’m just curious how the engine will operate in the truck if I don’t get the distributor reinstalled in the same position. Will I be able to correct the timing with just turning the cap after the engine is installed and running or will I need to pull the distributor back out and reposition it? Is there a different way to oil prime the engine that doesn’t require pulling the distributor? Thanks!
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
1,629
Reaction score
2,207
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
Easiest way is driving oil pump through distributor hole. There are tools made or can modify old distributor.

Engine doesn't care where the distributor is positioned as long as the firing order and timing are correct. That being said putting it in correctly isn't hard.

With engine on top dead center [#1 firing] install distributor with rotor pointed at #1 distributor cap tower. May not drop all the way and require turning oil pump shaft to line up with slot in distributor. Advance unit will be on the passenger side. #1 tower should be positioned in the front to right [passenger side] of center.
 

85K304SPD

Full Access Member
Joined
Mar 29, 2022
Posts
396
Reaction score
591
Location
Las Cruces, NM
First Name
Richard
Truck Year
1985
Truck Model
K30
Engine Size
383
Make sure that you are at TDC on the #1 piston and the timing mark on 0. Mark the housing and the block and mark where the rotor is pointing before you pull it out and after you pull it out. Look down the hole and note the position of the slot on pump drive. After you prime the motor, just do all of that in reverse order. The engine doesnt care where #1 is, but plug wires might not reach if not in correct position. You want the distributor to be straight across the top when the timing is set. If its too far off after you get it running, you can always pull it back out and turn the pump drive back or forward with a long screwdriver and re install it so that it is straight across. It may take several times of taking it in and out before you get it to seat all the way down, engaged in the pump drive, straight across.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
4,068
Reaction score
5,921
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Here',s the best advice I can give you.Before you pull the distributor turn the engine,by hand until the rotor is pointing straight back,if it was in the car it would be pointing straight at the firewall. Now take a nail set,scribe what ever and make a match mark on the distributor base and intake manifold. When you go back together point the rotor straight back and line up your match marks. I always point the rotor at the firewall before I pull it. I can come back in 20 years and still stab the distributor first try.. pay attention to the oil pump drive position you may have to reach in with a screw driver and rotate it..
 
Last edited:

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,042
Reaction score
1,459
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
All of the above is great advice and I always just point the rotor straight back and use a sharpie to mark...

To answer your question about if there is another way..there is and that is with a pressurized pre-luber. You can install temprarily or buy a system that pressurizes the oil system before you crank everytime. While its been awhile I used to use them on the dyno and we would even pre-heat the oil to protect the engines more and get the engines up to operating temperature quicker for less wear.

You must be registered for see images attach
 

SirRobyn0

Full Access Member
Joined
Dec 6, 2019
Posts
6,742
Reaction score
11,319
Location
In the woods in Western Washington
First Name
Rob
Truck Year
1984
Truck Model
C20
Engine Size
305
All good advise and priming the pump though the distributor hole is the standard way.

Getting the timing right on the first try is really great and you have been given good advise on that, but I also want to say that if you mess it up and it either back fires or refuses to start the engine isn't going to turn into a pumpkin. Just take the time to figure out what went wrong and try a second time.

Don't forget to break the camshaft in the way the manufacture recommends!
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
1,629
Reaction score
2,207
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
If distributor and intake are original most of the time there is a chisel mark across the parting line. Align those marks timing will be very close. It is on the rear.
 

chevytech87

Full Access Member
Joined
Dec 6, 2022
Posts
94
Reaction score
210
Location
Tomball, TX
First Name
Brandon
Truck Year
1987
Truck Model
GMC R1500
Engine Size
305
All of the above is great advice and I always just point the rotor straight back and use a sharpie to mark...

To answer your question about if there is another way..there is and that is with a pressurized pre-luber. You can install temprarily or buy a system that pressurizes the oil system before you crank everytime. While its been awhile I used to use them on the dyno and we would even pre-heat the oil to protect the engines more and get the engines up to operating temperature quicker for less wear.

You must be registered for see images attach
Used one of these for my 383 I just installed, can confirm it works quite well. Shop bought one and we’ve never had the chance to use it, figured I’d try it out.
 

BlazerBill

Full Access Member
Joined
Mar 24, 2023
Posts
74
Reaction score
62
Location
Texas
First Name
Billy
Truck Year
1983
Truck Model
Chevy K5 Blazer
Engine Size
350
Great advice! Thank you all so much!
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,038
Reaction score
1,833
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
Does your new engine have a a flat tappet cam or a roller cam? Flat tappet cams require break-in, and if you have never done it before it can make you very uncomfortable.
Standing next to an engine that is running at 2500 rpm for 20 minutes to break in the cam is really noisy, and it feels like there is a risk that you could break something. However, it has to be done.

Also, if you haven’t got the distributor in the right position and the fuel flowing properly, it may be hard to start the engine. If it takes a while to find and correct your error it will cause you even more stress. Did I just screw up my brand new cam because the engine wouldn’t start right away? (Probably not.)
 
Last edited:

RanchWelder

Full Access Member
Joined
Jan 14, 2023
Posts
631
Reaction score
916
Location
Earth
First Name
--------
Truck Year
87
Truck Model
Blazer
Engine Size
355ci

sidschev

Full Access Member
Joined
Oct 2, 2023
Posts
279
Reaction score
495
Location
Arkansas
First Name
sidney
Truck Year
1984
Truck Model
c1500
Engine Size
350
WHY would you need to prime a new engine ???? it should have assembly lube on everything so lube at startup would be a non issue...
 

justhorns

Full Access Member
Joined
Jun 1, 2022
Posts
237
Reaction score
610
Location
Denver
First Name
Lee
Truck Year
81
Truck Model
C10
Engine Size
250
WHY would you need to prime a new engine ???? it should have assembly lube on everything so lube at startup would be a non issue...
Because it’s easy. Just make sure on any new engine start that you immediately have oil pressure. No gauge? Don’t do it!
 

ali_c20

Full Access Member
Joined
Sep 20, 2016
Posts
1,026
Reaction score
1,388
Location
Austria
First Name
Alexander
Truck Year
1974, 1979
Truck Model
C20, K5
Engine Size
350, 350
I prime it to check if I have oil pressure, no matter if roller or flat tapped cam. No oil pressure no bueno.
When I have to pull the distributor I set the engine on tdc, then rotate it to the desired degree mark on the balancer and put the distributor back in with the finger aligned to #1 contact. If your balancer doesn't have degree marks you can measure the circumference and calculate the distance. Works great and no more worries about timing being far off.
 

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
743
Reaction score
3,015
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
I don't know if your supplier provided you with instructions prior to start up, but I would advise you to use a quality oil, not any off the shelf 10W30.
If anything, use at least an additive designed for older motors and break ins; something with an elevated level of ZDDP. Amsoil Z Rod, Castrol Hi Mileage Classic are two that come to mind, or Lucas Hot Rod & Classic.
 
Top