to build this eng,I followed a jack merckel build up story in a magizine.In it he said to enlarge the #2 and #3 main oil holes in the block to 3/8",which I did.This is the 1st buick eng Ive ever built,and now I know this was a mistake.The oil pressure has always been marginal,10 at idle,35 at 3K rpm,45 at 4k rpm etc,and I`d like to get that hi-volume oil pump out of there(I think my front cam bearing is wearing and losing oil) I`m thinking of ways to reverse this,like taping and inst long set screws,then re-drilling em to the correct hole size,or install a tube in the big hole to the correct factory ID size.Has anbody on these boards "been there,done that" that has some input on this for me.I hate to start over w/another block.Mine has been machined for the girddle and everything else,this stuff aint cheap,,,any ideas out there?
enlarged oil mains,want to go back stock
- Thread starter turbojack
- Start date
Nasty Wendy
Perverted Lurker
- Joined
- May 24, 2001
Maybe you could press-fit a tube in there that would bring it back to the stock size. You may have to drill it out even larger first though.
I had no problems with the enlarged oil mains. My oil pressure was 25-30 idle and around 70 when I hit throttle. Yes, you have to run a hi volume pump with the enlarged mains.
I think your problem is else where. Did you drill out the main bearings to match?
Billy T.
gnxtc2@aol.com
I think your problem is else where. Did you drill out the main bearings to match?
Billy T.
gnxtc2@aol.com
mikestertwo
Well-Known Member
- Joined
- Sep 13, 2006
+1 I have done this mod on both Oldsmobile and Buick engines with no issues. What are your bearing clearances? Pump clearances?
+2
Did you just modify the mains and nothing else or did you do all the oiling mods? If all you did was the mains you'll have an oiling issue. I did the
mods well before the boards were avalible and cold at ide I'd peg the gauge and warm I'd have 45psi at idle. You may also have the cam bearings improperly installed or the wron bearings.I hate to say it but tear into it and see what's up before you condem the mods as your problems.
- Joined
- May 26, 2001
To me one of the best solutions would be to tap the holes, and loctite a set screw, or something similar, and then drill it to the stock size.
Also, I agree, enlarging these holes is a mistake and not necessary. In the hundreds of Buick V-6 engines we have built, none had the mains drilled, or did we use HV pump gears.
Even the first 109 block in the 8's used a stock oil pump/cover set up by Zimmerman Racing!
I dont see how the main oil feeds size would matter if the bearing oil feed was not opened up to the same size. The f'in things could be opened up to .5inches and unless the bearing hole size was increased to at least that size it would be regulated by it. Fwiw all mine have had stock size feeds and i always used stock length gears with no oil pressure problems.
dr_frankenstein
Mad Scientist
- Joined
- Mar 17, 2008
+3
I dont think the idea is nessacarily for an increase in oil pressure or volume, but to provide access to the 90* turns internally to allow you to clean these areas upand to clean the passage itself up. Ruggles talked about this in his Stage 1 guide.
However I dont think these mods could create any drop in oil pressure if it was all done right.
A.j.
I dont think the idea is nessacarily for an increase in oil pressure or volume, but to provide access to the 90* turns internally to allow you to clean these areas upand to clean the passage itself up. Ruggles talked about this in his Stage 1 guide.
However I dont think these mods could create any drop in oil pressure if it was all done right.
A.j.
m233roller
Banned
- Joined
- Jan 25, 2002
I agree with Bison 100%
I dont see how the main oil feeds size would matter if the bearing oil feed was not opened up to the same size.
I dont see how the main oil feeds size would matter if the bearing oil feed was not opened up to the same size.
I've got opened up mains (with bearing holes to match) and no oil pressure problems, with stock length gears. I don't think that is your problem.
On the other hand, I have definitely had low oil pressure problems from a worn #1 cam bearing! Swap that out if it is worn. I've swapped the #1 bearing with the block in the car. Use a hard bearing, such as the TA Perf cam bearings. Regular parts store bearings can wear out fast, especially when using an aftermarket cam that has a groove in the #1 journal. I got a grooveless cam from Comp to help stop that wear as well.
I'd also verify bearing clearances, oil pump clearances, and recommend doing all the porting mods to the timing chain cover. Plus the biggie oil filter adapter and a good high flow oil filter, bigger than stock size.
John
On the other hand, I have definitely had low oil pressure problems from a worn #1 cam bearing! Swap that out if it is worn. I've swapped the #1 bearing with the block in the car. Use a hard bearing, such as the TA Perf cam bearings. Regular parts store bearings can wear out fast, especially when using an aftermarket cam that has a groove in the #1 journal. I got a grooveless cam from Comp to help stop that wear as well.
I'd also verify bearing clearances, oil pump clearances, and recommend doing all the porting mods to the timing chain cover. Plus the biggie oil filter adapter and a good high flow oil filter, bigger than stock size.
John
Nick, if you've never done it, how can you say the enlarged mains is a "mistake"? "Not necessary" I'll certainly buy, but from your statement it doesn't seem that you can prove it is a mistake.
Or have you actually done it before and found it to make things worse? Buick said it makes things better in the Power Source guide. I note that they never recommended the HV gears either, with or without the enlarged mains.
John
Yeah,I drilled out the brngs to match
main and rod clearances were set at 1 1/5 thou,rear brng was at 1 thou,I pulled eng apart at 2k to re ck it,and it was right where I set em 1 1/5 thou main and rod,rear main brng at 1 thou,,I set pump clearance at 2 thou (I did this twice) and even inst a kenne belle oil pressure booster pump plate kit that I had that was new,still,no help----eng now has 5k on it and its getting worse,now at hot idle,goes dn to bout 6-8 and bearly keeps up w/the 2krpm= 20psi,3k rpm=30psi,etc,etc
went w/the bigge from the get go,ported my used stock cover,then went to a new cover w/ port job,,still no help,lousey oil pressure
To me one of the best solutions would be to tap the holes, and loctite a set screw, or something similar, and then drill it to the stock size.
Also, I agree, enlarging these holes is a mistake and not necessary. In the hundreds of Buick V-6 engines we have built, none had the mains drilled, or did we use HV pump gears.
Even the first 109 block in the 8's used a stock oil pump/cover set up by Zimmerman Racing!
nick,I`m with you on this,if nothing else,I dont like the idea of the hi volume oil pump pulling down on my cam brng,and I think the drill/tap a long set screw,IS the best idea.I live out here in the desert (like you) and the heat out here is brutal on engines .I`ve heard to many bad things bout enlarged main holes verses a stock holed engine,and a lot of bad things on those hi volume pumps to boot--------
You can change the main bearings out with non-drilled ones.
Did you check you oil gallery plugs, is the passenger side driven in too far? How are your lifter bores, are they hemmoraging?
I still think your problem is elsewhere and is not related to the mains enlarged.
Billy T.
gnxtc2@aol.com
Did you check you oil gallery plugs, is the passenger side driven in too far? How are your lifter bores, are they hemmoraging?
I still think your problem is elsewhere and is not related to the mains enlarged.
Billy T.
gnxtc2@aol.com
I agree. Maybe a cam bearing problem. The front one will be a big problem if worn. It will piss out a lot of oil if its ****. HV pumps and cold oil will kick the chit out of the front bearing especially with the grooved cams.
I never have ckd the lifter bores,I used comp cam lifters and never really thought bout it.What should they be,that is ,the clearance between the lifters and bores---havent looked at the oil galley plug,explain this to me
Why do the grooved cams tend to be harder on the bearing,and what bearing do you use.Another guy on this thread suggested using the TA cam bearings.I used the one that the eng machinest suggested (cant remember the brand,but not federal mogal,or any of those "big" brand names)--
They are harder on the bearing because the cam has less surface area to spread the load on the bearing. Ive been using a Clevite aluminum bearing on the #1 location whenever i put a grooved cam in an engine. I have a driver thats works perfectly for installing the new bearing. The engine in my sig is an example. Over 150k on it and oil pressure is 80+ psi at 6k rpm with stock pump gears and hot 30w oils.
