The Oil Pump Changes Main Bearing Clearance?
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- Опубликовано: 15 сен 2024
- Does a torqued oil pump change the rear bearing clearance? By How much? let's find out!
Small Block Chevy
This will show you why a block should be line honed with the a oil pump or dummy pump bolt on
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This is why the oil pump or a dummy pump needs to be installed and torqued if the block is line bored. It not only increases the clearance but it pulls the main cap out of round. Using a dummy pump for just the bolt boss area while checking clearance let’s you get at the bolts on the mains with out the actual pump being in the way. If you have a bore gauge like this and don’t have a dummy pump. Check the difference before/after... just like this video. Subtract that from your plasti gauge reading. Thanks for posting this video. Great info about the details so many overlook or never knew about to begin with. 👍
Good point! I don't use plastigauge often but for the guys that do a oil pump with the top cut off would work for a dummy pump
Absolutely. It's funny I'm 61 I've been building motors since before way before internet. Or videos. Have learned so much from good sources like piss cutter. Your awesome. Thanks again for all those kick ass videos!!
That is WHY, when you have the block (Line Honed), you bolt on a Oil Pump mount base.
HOT ROD 1983
Exactly!
I wonder what the difference would be at 15 degrees from vertical. I'll try it next time. I'm thinking with the width of #5 an extra .001 doesn't hurt anybody if you're running typical clearances.
A plastigager could register the cap then hand-tighten the main bolts, torque the oil pump then torque the main bolts
That a good little squeeze right there 😮
Did you check the clearance at 90° to the oil pump? I'm betting the clearance may have actually decreased there, probably not by a full thousandth, though.
Never even considered this! I will now thanks
Wow. I've heard this in the past. Thanks for the video. I've got a block sitting here. I'm gonna try it
It makes sense, I`ve not measured it before but I bolt a cut off oil pump pedestal on. I would assume the distortion is localized around the bolt hole as it is on the cylinders with a torque plate. I`ve seen as much as .00075 near the bolt holes for about an inch down the wall usually in the corners. couldn`t see any difference at the bottom of the cylinder with or without main caps on. The aftermarket blocks hardly move if at all. Yes attention to detail is important.
I have noticed on small blocks with some miles the rear bearing will have a low not worn spot in the middle I figured it was from the oil pump bolt .
Good tech tip. I’d often wondered if it made a difference to the bearing clearance.
Good stuff Cutter, that is very interesting, a good way to spin a main if you not careful. Thanks for the RnD keep it up
You will never spin a bearing with MORE clearance.
Be surprised how many people never even think about this
The ones that don't actually build engines, yes. Those of us that do, know, and also know that on a bigger surface area, and being the thrust, doesn't matter. It's actually better.
Is that at just 12 o'clock? Does the clearance change at 10 and 2?
Interesting. I never really thought about it.
Wow. Over the years in various shop I've wrenched at I've seen Tech's zip on oil pumps with their 3/8 impact guns when doing oil pump replacement. Also with hot engine temps the clearance would probably be more.
The old ugga chuga torque haha
Congratulations on taking the time to measure and then discover the many forces involved to produce precision machined parts. Your machinist should of course be aware of the effects of clamping pressure. and you should ask what torque numbers he used so you can duplicate these pressures upon assembly. You should probably ask before dropping off the block. If he tells you it’s not that important - find another machinist. What you saw in the rear main is exactly what happens when bolting on a set of heads. Which is why you should ALWAYS bore/hone with a torque plate. BTW, plastigage is a poor substitute for a bore gauge. Plastigage is suitable if you were buying a used engine and wanted to verify that the crank wasn’t cut.Beyond that it’s of little value. I would encourage you to purchase a dial indicator that reads in “tenths” or .0001. A .0005 ( half a thousandth) reading indicator at a minimum.
Remain inquisitive and pay attention to details. You have something for this field. Best wishes for your success.
Thanks for the comment! Good info!
I don't use plastigauge but I do believe it works well enough for the average guy putting his engine together in his garage with a new rotating assembly and a professionally machined block but you are right its not replacement for a bore gauge.
Cheers!
Btw calryan how does plastigage tell you If the crank was cut lol .. it only tells you What the bearing clearance is. The only way you can tell if it’s been cut is by measuring it with a micrometer Or Caliper etc. etc.
Note to self, buy a bore gauge
I usually see about a half thou.. on my starrett dial bore gauge
Now I know why I've always heard the rear cap can afford a hair more clearance then the rest of the mains! I've always been told that but never a believable reason why, this is clearly a good reason
Is this test done with the factory GM oil pump bolt, or are you using an aftermarket oil pump stud su h as ARP 230-7003? I can see how a bolt would distort the cap by pulling up on the threads as it is torqued, but a stud should produce a different result.
ARP stud in this test but believe it or not a bolt is basically the same result
That's very surprising. I guess I learn something new everyday
@@cuttersperformance im guess your right on that, I couldn't imagine it making a difference either way and I believe the torque spec is the same for both but could be wrong. I know Arp has higher torque specs sometimes but im thinking the oil pump was about the same
Just subbed today as I saw your EFI V carb on Nicks Garage. only ever saw one of your vids before. Like your content. Are you also a Canuck? Cheers from Calgary.
Thanks for the subb and yes im a Canuck!
So does the rear main bore get narrower where the cap meets the block....?
Is the stud bottomed out in the cap, or left out a thread or 2 to see if that makes a difference?
Stud screwing into bearing!
If you have a crank that has been polished and not turned don't worry.. If you're running super tight clearances on stuff this aint the only problem you're going to run into Race engines are built slightly loose Higher oil pressure and Heat Will take care of that problem You need the room for expansion
At the track, if an engine is 0.001” loose nobody will know. If it is 0.001” tight everyone will know
I like that! Haha
An oldy but a goldy…
Most would want a .002 clearance on all the mains, on the thrust i would go .003, allows a better "BUFFER" of oil film plus you can do the "notch trick" on the front of the thrust face to allow oil to go into the thrust area more efficiently..
You can buy those STDX that is .001" thinner or thicker for customizing clearance, i recommend whatever brand ya get preferable King Bi-Metal Aluminum, that you also get a set of "X" versions as well. A "MUST HAVE" for a serious engine builder...
Factory LSX engines uses the Aluminum silicon Bi-Metal and King is the only MFG i know of that makes a serious performance oriented type like that... Those bronze tri layer is bullshit, no thank you, seen them get eat up wayy too many times.
So is the key to have the block and caps line bored with an oil pump installed?
Yes! If the block is getting a line hone make sure they bolt a oil pump on
@@cuttersperformance would most competent machine shops know to do this?? Hopefully 😅
@@jimmy_olds you would think so if they're doing it for a living but im willing to bet there's some that don't lol, u will definitely make a point to ask from here on out lol
great video, what do we do with this information tho(I am new). Does this mean you actually need a thicker bearing?
Two things haha
1)check your clearances with the pump on
2) of your getting the block line honed ask if they install a oil pump or suitable replacement to give it the proper pull on the cap.
At the same time most guys haven't been checking this for years and most have no issues.
The use the information as you will
Cheers! Thanks for checking out my video
What bore gauge do you suggest for someone that will be building an engine maybe 1-2 times every few years in a garage ?
Fowler 52-646-400-0
@@cuttersperformance awesome thanks 👍🏻
Do you normally run the m155hv oil pump on your vortec engines?
Most street engines I will use an HV pump, but usually, it's not necessary
👍
blew my mind, i thought it would be only a couple tenths
Wow. Good info
Piss cutter What do you usually run for a rear bearing clearance for street strip When the oil pump is on And torqued?
.0025 to .003 ideally
@@cuttersperformance Hey Piss I have a question maybe you can answer What causes rear main bearing to wear un-even more wear on closer to the seal side? Plastigage Shows 2 Thousands towards the end 3000 at the beginning why?
Can you send me a picture?
Pcperformance1@outlook.com
@@cuttersperformance I emailed you the photos
Haven't gotten anything?
the suspense was killing me. i was not able to finish watching.
Run a high volume and you will never know
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Didn't the gauge go down? That would tighten the bearing on the crank. If it changes at one point it must at another.
Its the opposite dial movement with bore gauge than you would think. The journal got larger with the pump being torqued. The pump pulls on the top of the bearing cap
@@cuttersperformance I see, have you checked at say 45°one way or the other? I can see the reason to mount the oil pump when line honing, and I thank you for bringing it to my attention. I worked for a machine shop in the 90s, and I don't remember if they did it or not.
After thinking about my bore gauge, your totally right. I bow to your knowledge.
looks like it was getting tighter,not looser
Dial bore gauge goes the opposite direction on the indicator
holey shit...
Doesn't seem to make sense. That can be an issue
What doesn't make sense? That it changes that much?
No issue at all.