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Username Post: Holley Dual Sync distributor        (Topic#352187)
hulsinc 
Contributor
Posts: 105

Loc: Illinois
Reg: 04-02-10
07-25-18 01:05 PM - Post#2741145    

I installed Holley EFI and Dual Sync distributor and ever since I have had trouble with very little oil pressure in the lifter oil galleys resulting in very little oil at the rockers. On idle I can hold a rocker down by thumb. Installed on a 396 big block Chevy. Thinking maybe something to do with oil partially blocked or leaking around the distributor shaft. Has anyone seen or heard of this? Block came from a 69 Chevelle. Ever since I installed the two, it seemed like it had a slight miss in the engine which I've never been able to figure out. Ran it in the '18' tour until it died on the interstate. Not fun and games thereafter. EFI monitor shows 35 AFR. Runs when cold. Runs poorly when hot but will settle down when changing to open loop. Thinking valves not opening all the way making EFI think low on fuel at oxygen sensor and flooding the engine out. Stupid thinking? I'm not a mechanic. Electrical contractor by trade. What do you think?



 




Rick_L 
Honored Member
Posts: 27645
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
07-25-18 04:54 PM - Post#2741162    
    In response to hulsinc

There is (or at least supposed to be) a groove on all Chevy distributor housings where the oil to the lifters passes through. Compare your dual synch to a stock distributor to see if it's there and in the same place. Actually I can't imagine it wouldn't be. Also if the distributor has an adjustable collar it must be set at the right height. Also an aftermarket intake manifold needs to have the top of the distributor hole at the correct height. Usually only a problem if the manifold has been seriously milled down, or sometimes a fabricated manifold can have this too tall or too short.

As for your other problems, an AFR of 35 is way lean, not rich. Shouldn't even run at 35 AFR.

Low oil pressure to the lifters should make it clatter like crazy, but shouldn't affect valve lift unless you've wiped every lobe out due to no oiling.




 
5Larry7 
"16th Year" Gold Supporting Member
Posts: 1965
5Larry7
Loc: Dallas, TX
Reg: 05-17-04
07-25-18 08:13 PM - Post#2741175    
    In response to hulsinc

I have Holley Dual Sync distributors in both of my Holley HP equipped cars and they both function great. Have you posed this question on the Holley Performance products forum? If not, I highly recommend it. https://forums.holley.com/ There is a great deal of knowledge there on the Holley EFI.

'57 210, 327 cid, Holley MPFI, 700R4, A/C & more.
'51 Studebaker Starlite coupe, 350, TH400, GV OD.
'96 Replica of a 1950's Teardrop Trailer.


 
rcr3 
"15th Year" Silver Supporting Member
Posts: 3170
rcr3
Age: 67
Loc: MANHEIM PA. U.S.A.
Reg: 11-24-02
07-26-18 02:46 AM - Post#2741188    
    In response to 5Larry7

Thanks for that link!

Was wondering for a long time where Danny Cabral had gone.

'67 Camaro survivor
'06 Z71 Sierra Ex Cab
'37 Chevy cp.SOLD!!6/7/14
'74 Nova Custom cp.
'73 Nova pro-street project
'17 Chevy Trax LT
'00 S10 Ex cab






 
hulsinc 
Contributor
Posts: 105

Loc: Illinois
Reg: 04-02-10
07-29-18 08:36 AM - Post#2741392    
    In response to Rick_L

Back when the engine was hot and we were trying to figure out what was wrong it would barely run on a idle or when giving it a little gas. When changing the EFI to open loop it would clear up and run normally. Holley suspects a defective sensor and they are sending me a new one, but I have to solve the no oil at rockers on both sides first. At this point I suspect rear cam bearing.



 
hulsinc 
Contributor
Posts: 105

Loc: Illinois
Reg: 04-02-10
07-29-18 08:45 AM - Post#2741393    
    In response to Rick_L

Big thanks to all who replied. Since I have no oil on both sides I'm ruling out the dist shaft being the problem. I was told by the block seller it came from a 69 Chevelle, but wondering if it is a 65 or 66 with 3 holes in the block at the rear cam bearing. Can't read serial number on front of block because they were partially removed when decking the block. Can't get to the date code on the back of block because it is about a 1/2 inch off the fire wall and can't get a mirror in there much less read it if I could. Is there any way to check oil passage from filter to rear bearing for blockage? could air pressure be applied at the block above filter to check this? Really grabbing for straws here now!



 
Rick_L 
Honored Member
Posts: 27645
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
07-29-18 10:04 AM - Post#2741399    
    In response to hulsinc

You're right, if you have a 65-66 block, it requires a groove in the rear camshaft journal, and the rear camshaft bearing must be the 65-66 one with 3 holes instead of one, and a groove connecting the 3 holes.

If you don't have this, you won't have oil to the lifters. I would think though that the lifters would clatter like crazy and would fail in a short time.

I don't know of any way to check this with the engine assembled and in the car.

The date code is on the back of the block near the bellhousing flange.



 
hulsinc 
Contributor
Posts: 105

Loc: Illinois
Reg: 04-02-10
08-07-18 05:25 AM - Post#2742191    
    In response to Rick_L

Thanks much. In the process of cam removal now. Having trouble removing balancer. Used Auto Zone cheap-0 puller but gave up for fear of breaking it. Getting a better one today to put the crank to it. Kill or cure. Lifters did clatter and I did have a little oil at some time cause it wasn't completely dry. Must have got a little at high rpm. Did have 1 bent exhaust push rod. That must have been the slight miss I thought I heard?



 
hulsinc 
Contributor
Posts: 105

Loc: Illinois
Reg: 04-02-10
08-10-18 02:53 PM - Post#2742634    
    In response to hulsinc

Update. The block is in fact a 66-67 (found it on the back of block on the casting). Pulled the cam and as suspected it has 3 holes in the bearing but the cam was not grooved blocking oil from getting to the lifter galleys. The engine builder screwed up on this one.



 




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