Distributor won't fully engage oil pump??
Thread Starter
Instructor
Joined: Nov 2006
Posts: 197
Likes: 0
From: Detroit
Distributor won't fully engage oil pump??
I stopped by the shop to check on my 86 that is getting the new stroker put in, and the builder informs me that the distributor does not fit. I thought what the hell is this guy smoking all chevy v8 distributors are exactly the same, but he dropped it in and showed me, the gears on the distributor mesh with the cam properly, and the distributor drops all the way in, but it seems like it is not properly engaging the oil pump drive. It almost seems like the distributor shaft is too short below the gears, and it is not enganging the oil pump, and there is a lot of play when it is down. The distributor looks to be the stock and came with the car when i got it, but the car came without an engine and just boxes of parts. I compared the shaft to a brand new msd pro billet for a sbc and it looks the exact same length. I am running out of ideas here i am going to check at the parts store to see if they have a new 86 distributor. The motor is 388 stroker on an old rear main seal type block (two piece?) and the intake is an accel tpi. Any help would be good.
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
I stopped by the shop to check on my 86 that is getting the new stroker put in, and the builder informs me that the distributor does not fit. I thought what the hell is this guy smoking all chevy v8 distributors are exactly the same, but he dropped it in and showed me, the gears on the distributor mesh with the cam properly, and the distributor drops all the way in, but it seems like it is not properly engaging the oil pump drive. It almost seems like the distributor shaft is too short below the gears, and it is not enganging the oil pump, and there is a lot of play when it is down. The distributor looks to be the stock and came with the car when i got it, but the car came without an engine and just boxes of parts. I compared the shaft to a brand new msd pro billet for a sbc and it looks the exact same length. I am running out of ideas here i am going to check at the parts store to see if they have a new 86 distributor. The motor is 388 stroker on an old rear main seal type block (two piece?) and the intake is an accel tpi. Any help would be good.
As far as I know, it is not the oil pump pump engagement that fixes the rotor position. In fact the oil pump drive shaft often needs to be rotated to get the distributor to drop in to the same position it was removed. I have to do this with my distributor becasue of the cam and crank postion sensors in it.
I would have to check the cam gear and the distributor gear. I ran a bronze gear when I should not have and it got chewed up pretty good and the rotor shaft was very loose. This seems to be what you are describing.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
What distance are we talking about?
He could install the distributor, then turn the engine over on the stand, remove the oil pan and see what the distance is.
Here's all I can think of; starting at the bottom and working up:
Rear Main cap is not the correct height (I've never seen this before even after the main bores in the block had been align bored).
Wrong oil pump; (Is it new? Did you verify the part number to be sure the pump is the correct one?)
Wrong/mis-installed distributor gear. (Is it even possible to install the gear upside down?)
Wrong intermediate shaft length (although you posted that it's okay);
Hopefully someone else will have other ideas.
Jake
He could install the distributor, then turn the engine over on the stand, remove the oil pan and see what the distance is.
Here's all I can think of; starting at the bottom and working up:
Rear Main cap is not the correct height (I've never seen this before even after the main bores in the block had been align bored).
Wrong oil pump; (Is it new? Did you verify the part number to be sure the pump is the correct one?)
Wrong/mis-installed distributor gear. (Is it even possible to install the gear upside down?)
Wrong intermediate shaft length (although you posted that it's okay);
Hopefully someone else will have other ideas.
Jake
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
All the parts involved are "standard dimension" parts. From what vantage is the lack of engagement being observed? My bet is on the intake manifold fit. If the block has been decked and the heads milled, the manifold can sit too high in the vee, between the heads. Possibly the intake side of the heads or the head gasket surface of the manifold have to be milled. Also, don't forget the manifold to block gasket surface at the ends of the manifold. Once the manifold and head mating surfaces are properly trimmed. the manifold can hit the "china walls" at the ends of the block, and not allow the manifold to fully drop into the vee.
RACE ON!!!
RACE ON!!!
Thread Starter
Instructor
Joined: Nov 2006
Posts: 197
Likes: 0
From: Detroit
The motor and oil pump ran fine before I changed the heads, intake and distributor. The motor went from a iron vortec heads, edelbrock carb intake, and msd pro billet distributor, to brand new dart pro 1 heads, used accel tpi intake, and stock corvette distrubutor (1103680). The distributor gear looks fine to be and is definitly not on upside down. The distributer will drop down all the way to the intake but isnt engaging the oil pump, he used grease on the distributor gear to check engagement and he said it was fine. I called the guy that built the block before me, and he said oil pressure was good, the only problem he ever had was that the oil pump primer tools would not work, but he never had an oil pressure problem, and when the heads and motor were changed there were no chips or shavings in the pan or block so i assumed everything was good. I will tell the mechanic to check the intake manifold clearance.
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
The motor and oil pump ran fine before I changed the heads, intake and distributor. The motor went from a iron vortec heads, edelbrock carb intake, and msd pro billet distributor, to brand new dart pro 1 heads, used accel tpi intake, and stock corvette distrubutor (1103680). The distributor gear looks fine to be and is definitly not on upside down. The distributer will drop down all the way to the intake but isnt engaging the oil pump, he used grease on the distributor gear to check engagement and he said it was fine. I called the guy that built the block before me, and he said oil pressure was good, the only problem he ever had was that the oil pump primer tools would not work, but he never had an oil pressure problem, and when the heads and motor were changed there were no chips or shavings in the pan or block so i assumed everything was good. I will tell the mechanic to check the intake manifold clearance.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
I still think a decked block and a tolerance stack up in the heads and manifold could be the cause. Anything is possible, but the distributor is the last thing I would suspect. Your clue is in:
However I am curious why, "the oil pump primer tools would not work".
RACE ON!!!
Originally Posted by wingman4rent
The motor and oil pump ran fine before I changed the heads, intake and distributor.
RACE ON!!!
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