My take on the oiling system crossover tube for the small block
- Thread starter Jadaharabi
- Start date
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anitrowarrior9
Well-Known Member
Thanks for the information. It seemed to me if I was going through all this to make sure the oiling was better, I may as well have full time oil up top also. Just fyi this is a street/strip pump gas 408 build.
Duane
Well-Known Member
Just some friendly advice. Keep in mind that these are full on race modifications. More better oiling does not hurt but we also do not want to ruin a perfectly good block. Take some time and study the block and make sure you understand the circulation of the oiling.
Pro charger has been brave enough to share with us his mistakes so that others can learn not to make them.
I have a member wanting to talk with me on the phone who burned up all his rockers on one side of his motor after doing these mods.
Obviously a mistake was made, and I am glad to help as is Jada and others, but the individual has to understand how the circulation works. Be careful and have a plan. And ask questions. Good luck to you.
Duane
Well-Known Member
Also are you sure you understand what you need to do with the cam bearings to do the jumper tube mod?
Duane
Well-Known Member
Jada please remember that I ran my crossover line from the passenger side to the drivers side differently because I have an X block that can front oil so I am using that feature. The main galley will be fed from both ends and the galley is plugged at the front as well so there should not be a velocity problem with two opposing oil feeds. Just an FYI. This is the Charles Sanborn method.
Duane
Well-Known Member
Pretty big chamfers at the top of those lifter bores, I heard those type bores leak huge.
anitrowarrior9
Well-Known Member
The way I read it was to drill 1/8" holes in the cam bearings and rotate the bearings so these new holes line up, thus blocking off the stock holes feeding the heads.
Duane
Well-Known Member
That's is correct. Make sure your engine machinist or whoever is installing the cam bearings understand that as well.
Marcohotrod
Well-Known Member
is there a problem with getting full time rocker oiling with a groove in the 2 and 4 cam journal like Crane and others did? and my flat solid lifter 340 has been going since 1995 with no full time oiling (Hughes said he did testing and at speed the cam spinning fast gives like a steady flow) and I blocked oil to the drivers side with a plug in the front driver side passage. no crossover tube, enlarging passages at filter and from cam to mains per old Dick Landy
Duane
Well-Known Member
I ran a grooved comp cam in my last motor to get full time oiling that way, and I lost the spread on the 2&4 main bearings after 40 runs.
It was pointed out to me by another member that the mistake I made was not using a restrictor at the deck to reduce the flow.
Charles Sanborn oiling guru(rest in peace) said on another board that trying to get full time oiling by increasing volume through the cam bearings was later found to fail main and rod bearings.
The new Chrysler approved method is to turn the cam bearings to completely cut flow to the rocker feed passage and use a jumper tube directly from the main galley.
Now if the pulsing on and off were to look like a steady stream of oil flow at higher rpm, the engineers at Chrysler would not be telling everyone to not restrict flow to the 2&4 cam bearings for many many years. In the stroker small block book they are still saying there is not enough oil getting to the rockers and they were the first to put in print to run a jumper tube.
Would you care to explain how you control the leakage at your cam bearing to the rest of us. I mentioned earlier in this thread that you made that claim many months ago, but never explained how this would be done.
Marcohotrod
Well-Known Member
leakage at cam bearing? I guess it is controlled by the tight cam to bearing clearance. A mistake many make, that restricts oil with a stock block, where oil up to the rockers goes up around the 2 and 4 .450" head bolt, is using a .500" stud
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They sure are. Someday I may bush them. This is my expermental block. I still have to have it fitted with new main caps and bored.
Plus I want to do the block side watering to it.
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Marcohotrod
Well-Known Member
the large chamfer leak problem depends on type of lifter and amount of cam lift, may be a problem, maybe not
Duane
Well-Known Member
Allow me to refresh your memory.
In another oiling thread on the board many months ago you claimed that restricting the oil to the cam bearings from the main bearings was not required on your motor because you carefully controlled the clearance with your cam bearings.
That post was mentioned in this thread by procharged.
What I would like you to explain is how you adjust or control this cam bearing clearance as you stated.
Duane
Well-Known Member
The type of leakage that you are talking about is the type where the oil band may uncover the large oil feed passage in the lifter bore and drop the main oil pressure. This would as you say vary with the type or design of the lifter. That is not what I am talking about.
Those blocks with the large chamfer even with a stock lifter have less precision surface contact because the large chamfer has machined it away. This leaves less surface contact and allows the oil to leak by easier. IMHO those blocks leak more.
Pittsburgh racer has mentioned in another thread that he would never build another small block without tubing the block because he had oil pressure problems from all the leakage around the lifter bores.
This was with a flat tappet cam. He said the lifter nearest the back of the block were leaking the most. To figure out why it was low on oil pressure he pulled the intake while pre oiling the motor and said he could not believe the amount of oil leaking around the bore.
Those big chamfer blocks are even worse for that. IMHO
Alex5280
74' Duster
Dropped my block off at the machine shop for bushings to be installed. Happy Thanksgiving to you guys!
Marcohotrod
Well-Known Member
I also measure every lifter bore diameter
Happy Thanksgiving Everbody
Duane
Well-Known Member
Implying what ???
Duane
Well-Known Member
I know lol, I wanted him to say it instead of making blank statements with no follow up dialog. But apparently he does that.
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What did you find on the burnt tips?
My guess is turned cam bearing and no oil fed to the driver side head.
nm9stheham
Well-Known Member
FWIW, for a data point on the chamfers leaking: My son's 340 was a virgin block, with the chamfers, and the lifter bores were unworn. (A couple were so tight that we had to get Crane to send us a few extra HFT lifters with OD on the small end of the range, so we could fit them in some of those tight lifter bores.)
Fired it up with the drill to pre-oil and check oil to the rockers (since I had added some rocker oiling holes), and did not see any real oil flowing/oozing out of the chamfered bores at all. So, from that, I wold suspect excess oiling there simply has to do with bore wear. (Test conditions: Oil was 1W30 at room temp, with a drill at 600 RPM, which corresponds to 1200 engine RPM. Pressure was a bit over 70 psi at the usual pressure sensor location.)
Marcohotrod
Well-Known Member
I measure lifter bores in a discussion about oil pressure is not a blank statement, it is common sense to me, and good engine building-measure as many clearances as you can-and if you can't-pay someone to
nm9stheham
Well-Known Member
And if any asks me about a rusty SBM block, I try to remember to mention that the lifter bores will need to be honed out to clean them up, and that might cause excess leakage there. Some of the rusty 340 blocks you run across on eBay and Craigslist are all set up for this problem to happen.
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