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Discussion Starter #1
I'm wondering how many guys hjave seen a trend with 4-7 swap cams and difficulty getting oil to the #6 and #8 lifters, especially the #8 ex lifter. I'm wondering if there isn't something about the timing of the lifters in their bores that makes this difficult. Dart BigM block, 70# oil pressure, I have oil at every rocker except #8 ex. To get oil to the #8 intake, the #6ex and #8int valves have to be off their seats a couple hundred thou but still, no oil to #8 ex. Been priming and turning for an hour. Had oil in the pushrod, just seems that the oil runs out of steam at the end of that passenger side galley at the rear. I've had this happen before where it took a LONG time to get oil to that last rocker and I think the common denominator seems to be a 4-7 swap firing order, or maybe just the Dart block.
Any input? Thanks.
 

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darts oil feed in the front of block for lifters 8 going to be lonely air lock ? used many of them blocks with 4/7 never seemed to be a big deal
 

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wow thanks for posting this .I have a big m block just got it together and I had the valve covers off for priming and did the same thing number 8 exhaust push rod had little to no oil coming out .I was getting ready to pull the intake and look at the lifter to see if there is some thing wrong ? so is this a common problem I wood like to find out before I take it apart. and it is not a 4/7 cam
 

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Discussion Starter #4
wow thanks for posting this .I have a big m block just got it together and I had the valve covers off for priming and did the same thing number 8 exhaust push rod had little to no oil coming out .I was getting ready to pull the intake and look at the lifter to see if there is some thing wrong ? so is this a common problem I wood like to find out before I take it apart. and it is not a 4/7 cam
I'm sure most of it is due to the fact those lifters are on the very end of the run for the lifter oiling. Lifters are oiled from the back of the block on the driver's side, up to the front, crosses over, then back down the passenger side to the rear. I'm confident that everything will be OK, I just like to see oil on every rocker before I go.
 

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wow thanks for posting this .I have a big m block just got it together and I had the valve covers off for priming and did the same thing number 8 exhaust push rod had little to no oil coming out .I was getting ready to pull the intake and look at the lifter to see if there is some thing wrong ? so is this a common problem I wood like to find out before I take it apart. and it is not a 4/7 cam
Don't take it apart, I bet it's pretty common .... Mine is the same way (non swap), it took quite a long time for some reason to get that oil out that #8. I bet I was priming for a good 4-5 min before I saw oil sign up top, had me worried. I think when the engine actually fires and all the internals are in motion, this gets resolved fairly quick :confused: .... Hope so anyway !!
 

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I have seen a couple priming tools be a little off on alignment for the oil galley and makes it take forever to pre lube.

Just something I have seen.
 

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v
I'm wondering how many guys hjave seen a trend with 4-7 swap cams and difficulty getting oil to the #6 and #8 lifters, especially the #8 ex lifter. I'm wondering if there isn't something about the timing of the lifters in their bores that makes this difficult. Dart BigM block, 70# oil pressure, I have oil at every rocker except #8 ex. To get oil to the #8 intake, the #6ex and #8int valves have to be off their seats a couple hundred thou but still, no oil to #8 ex. Been priming and turning for an hour. Had oil in the pushrod, just seems that the oil runs out of steam at the end of that passenger side galley at the rear. I've had this happen before where it took a LONG time to get oil to that last rocker and I think the common denominator seems to be a 4-7 swap firing order, or maybe just the Dart block.
Any input? Thanks.
Scott I dont believe it is the 7/4 swap...I have experienced this same condition myself...My observation is the rocker arms contribute to this by leaking a ton of oil in there mostly static position relative to our priming efforts. Usually I see a flood of oil coming from 2 and 4...while priming the T&D's on our Big Chiefs...I have spoken with T&D about using a smaller feed hole thru the rocker , they agree but wont change ... smaller pushrod thru holes are not the answerer IMHO... restricting oil in the rocker works well.. helps with oil return issues as too..
 

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Discussion Starter #15
How thick of oil.
JG BR30

joe gibbs break in
Yep.

i never lost a push rod tip from lack of oil on number 8 with the dartM block
I think once the engine is running it's not going to be a problem. Thanks Pat.

Don't take it apart, I bet it's pretty common .... Mine is the same way (non swap), it took quite a long time for some reason to get that oil out that #8. I bet I was priming for a good 4-5 min before I saw oil sign up top, had me worried. I think when the engine actually fires and all the internals are in motion, this gets resolved fairly quick :confused: .... Hope so anyway !!
Hope so too...

I have seen a couple priming tools be a little off on alignment for the oil galley and makes it take forever to pre lube.

Just something I have seen.
Not an issue with the dart block.

did you rotate the crankshaft 180* or more and reprime?
Of course.
 

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Discussion Starter #16
v
Scott I dont believe it is the 7/4 swap...I have experienced this same condition myself...My observation is the rocker arms contribute to this by leaking a ton of oil in there mostly static position relative to our priming efforts. Usually I see a flood of oil coming from 2 and 4...while priming the T&D's on our Big Chiefs...I have spoken with T&D about using a smaller feed hole thru the rocker , they agree but wont change ... smaller pushrod thru holes are not the answerer IMHO... restricting oil in the rocker works well.. helps with oil return issues as too..
It's definitely a volume issue, not a pressure issue. I like Chris's idea of running an auxiliary line.
 

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I just built a 706 for myself but i`m using a merlin block with a 4/7 swap. While priming, cylinders 7 and 8 oiled up first. 1 & 2 took a while to prime.
 
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