is it possible? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TugOwar · 03-13-2005, 05:10 PM

You guys ever tried replacing main bearing/rod bearings in a SBC while it IN the truck? Just curious if its even possible.

1972ChevyCheyenne · 03-13-2005, 05:58 PM

Not sure if it is possible in our trucks, or any that have independant front suspension. I do remember grandpa telling me that cars with a straight axle, you must measure all the bearings in the when doing a rebuild, because they had a tool that were able to grind the mains. I wonder where all the filings went? I know this doesn't help but I thought it would be a neat piece of info.

Sorry about the :hj:

Jamie

krue · 03-13-2005, 05:59 PM

It's way too easy to pull the engine for me to even consider trying to do it in the truck.

Tx Firefighter · 03-13-2005, 06:02 PM

Yes it's fully possible to inframe the bearing change.

Some guys may not be in a position to pull the engine out. When I lived in an apartment years ago, I had to do things like this in the parking lot without the ability to remove an engine.

TugOwar · 03-13-2005, 06:38 PM

Yeah thats my situation TX. Not an apartment but still a rental unit. The landlord don't say much if I can keep things hemmed in under the carport but he'd have a stroke if I start setting up tri-pods in the yard and sh!t, which I don't have one anyway. But if push comes to shove I can borrow one.

My lil 305 has developed a rattle in the bottom end. With limited funds and limited resources it would be easiest, cheapest and quickest if I can do an "in truck" bearing replacement until I can swap the motor completely.

I would really appreciate any tips/thoughts you have before I tackle this job.

**Green Machine** · 03-13-2005, 08:59 PM

Remove distributor cap and loosen fan shroud or remove fan beforen jacking engine. Jack slowly and check for any tight hose,wires or binding on anythng. Put wood blocks between mounts and frame. Pan will clear front counter weight easier if you turn crank to certain postion. Soak everything with Simple Green and get to a carwash and clean the $hit off of everthing on motor and anything near it. Bearing replacement requires absolute cleanliness, replace rear seal while crank is hanging down a bit.

69ride · 03-13-2005, 09:09 PM

Quote:

Originally Posted by Green Machine

Remove distributor cap and loosen fan shroud or remove fan beforen jacking engine. Jack slowly and check for any tight hose,wires or binding on anythng. Put wood blocks between mounts and frame. Pan will clear front counter weight easier if you turn crank to certain postion. Soak everything with Simple Green and get to a carwash and clean the $hit off of everthing on motor and anything near it. Bearing replacement requires absolute cleanliness, replace rear seal while crank is hanging down a bit.

The position is with the timing mark on the damper facing down (or 6 o'clock position looking at it from the front). Good luck

TugOwar · 03-13-2005, 11:01 PM

Ok thanks for the tips. Lemme ask ya this...

Do I plasti-gauge one main and then buy the whole set like that or plasti-gauge each main and buy a set of mix matched bearings to match?

Ratpowerd67 · 03-13-2005, 11:37 PM

i would pull 1 main and rod bearing, check the size, and buy the entire set of that same size. if it has been rebuilt before it should have the size stamped on the backside of the bearing ( +10,+20 etc ). sometimes they will have GM stamped if they are original ( standard size ). considering that you are on a buget, a mixed set of different sizes would be costly, possibly even trippleing the cost for a custom set. i would also consider replaceing the oil pump ( $20) while your there. it would be soo much easyier if you use a one peice pan gasket. hope this helps.....rat

TugOwar · 03-13-2005, 11:55 PM

You bet it helps Rat. Great idea on the oil pump.

Tx Firefighter · 03-14-2005, 07:27 AM

I would consider a high volume oil pump. Melling part number M-55HV. They run 5 bucks more than a stocker or so. It will act as a crutch, as obviously, your crank journals will be worn some and your cam bearings will be worn too. The extra pressure on the pump will compensate for the wear.

TugOwar · 04-09-2005, 05:01 PM

OK, picked up plasti-gauge at autozone this morning and just dropped the oil pan. No jacking necessary but I did have to loosen the starter so the pan would clear it.

I found the torque specs here for later use.

I can see now that cleaning the old oil pan gasket off the block is going to be a PITA, cork gasket.

My question now is this: Is there anything special I need to watch for when removing or installing the oil pump? Are there timing issues involved there?
Any input is appreciated.

P.S. FireFighter I'll follow your advice on the HV pump. thanks

RED72blazer · 04-09-2005, 05:37 PM

I was going to recommend a high volume oil pump too, not that you really need it, But it is good insurance against worn or sloppy bearing clearences.

TugOwar · 04-09-2005, 09:23 PM

Thanks very much Red.

I plasti-gauged the rear main and it mashed it so flat it stuck to the crank. I removed the bearing from the cap and found it already has 10 over in it so thats what I'm going back with.

BurnoutNova · 04-09-2005, 10:53 PM

if you replace the oil pump... make sure you position the pick up tube in the right spot, not to close or to far away from the pan. also would be a good idea to tack weld the pickup tube to the pump.

and i would NOT put a high volume pump in, it will suck the pan dry... maybe it would be ok if its a low reving motor, but with a stock pan, it could be easy to run it out of oil.

TugOwar · 04-09-2005, 11:55 PM

it'll prolly never see 5k rpm.

TugOwar · 04-12-2005, 10:49 PM

Well I sucessfully changed the main bearings and installed new HV oil pump. I pulled the fire wire off the distributor and turned the motor over until the oil pressure picked up, then replaced the fire wire and busted her off.

It sounded really good to start off, it seemed quieter and tighter, but then again it never did have a problem idling while cold. I let it idle until it was at operating temp and then started to bring up the rpm. Still has the same rattle at the same rpm as before, though not quite as severe which is probably due to fresh oil and new pump.

I don't know whether to go back in and attempt to put in new rod bearings or not.
The crank journals have obvious wear, it may still be the crank rattling, not sure...

Ideas? Thoughts? Spare Cursewords?

68C15 · 04-12-2005, 11:01 PM

do the rod bearings. plastigage them & go for odd sizing (+.012, +.015 etc) to get the clearance correct. just get them all the same size instead of a mix-n-match. (go for the average)

sneakysnake · 04-13-2005, 12:00 AM

If the bearings are worn, then the crank is worn.replacing one without the other is a waste of time.Turn the crank buy bearings to match.

TugOwar · 04-13-2005, 01:45 PM

Dang sneakysnake, wish I'd thought of that.

wannabeburbowner · 04-13-2005, 07:18 PM

yeah, and if a rod is starting to knock, then it might be getting out of round too. Might want to have the rod checked also.

03-13-2005, 05:10 PM	#1
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	is it possible? You guys ever tried replacing main bearing/rod bearings in a SBC while it IN the truck? Just curious if its even possible.

03-13-2005, 05:59 PM	#3
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	It's way too easy to pull the engine for me to even consider trying to do it in the truck. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

03-13-2005, 06:02 PM	#4
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Yes it's fully possible to inframe the bearing change. Some guys may not be in a position to pull the engine out. When I lived in an apartment years ago, I had to do things like this in the parking lot without the ability to remove an engine. __________________ I'm on the Instagram- @Gearhead_Kevin

03-13-2005, 06:38 PM	#5
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	Yeah thats my situation TX. Not an apartment but still a rental unit. The landlord don't say much if I can keep things hemmed in under the carport but he'd have a stroke if I start setting up tri-pods in the yard and sh!t, which I don't have one anyway. But if push comes to shove I can borrow one. My lil 305 has developed a rattle in the bottom end. With limited funds and limited resources it would be easiest, cheapest and quickest if I can do an "in truck" bearing replacement until I can swap the motor completely. I would really appreciate any tips/thoughts you have before I tackle this job. Last edited by TugOwar; 03-13-2005 at 06:41 PM.

03-13-2005, 11:37 PM	#9
Ratpowerd67 Registered User Join Date: Aug 2002 Location: Trenton ,Texas Posts: 328	i would pull 1 main and rod bearing, check the size, and buy the entire set of that same size. if it has been rebuilt before it should have the size stamped on the backside of the bearing ( +10,+20 etc ). sometimes they will have GM stamped if they are original ( standard size ). considering that you are on a buget, a mixed set of different sizes would be costly, possibly even trippleing the cost for a custom set. i would also consider replaceing the oil pump ( $20) while your there. it would be soo much easyier if you use a one peice pan gasket. hope this helps.....rat Last edited by Ratpowerd67; 03-13-2005 at 11:40 PM.

03-13-2005, 05:58 PM	#2
1972ChevyCheyenne Registered User Join Date: Sep 2004 Location: Teeswater, Ontario, Canada Posts: 173	Not sure if it is possible in our trucks, or any that have independant front suspension. I do remember grandpa telling me that cars with a straight axle, you must measure all the bearings in the when doing a rebuild, because they had a tool that were able to grind the mains. I wonder where all the filings went? I know this doesn't help but I thought it would be a neat piece of info. Sorry about the :hj: Jamie

03-13-2005, 08:59 PM	#6
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Remove distributor cap and loosen fan shroud or remove fan beforen jacking engine. Jack slowly and check for any tight hose,wires or binding on anythng. Put wood blocks between mounts and frame. Pan will clear front counter weight easier if you turn crank to certain postion. Soak everything with Simple Green and get to a carwash and clean the $hit off of everthing on motor and anything near it. Bearing replacement requires absolute cleanliness, replace rear seal while crank is hanging down a bit.

03-13-2005, 11:01 PM	#8
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	Ok thanks for the tips. Lemme ask ya this... Do I plasti-gauge one main and then buy the whole set like that or plasti-gauge each main and buy a set of mix matched bearings to match?

03-13-2005, 11:55 PM	#10
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	You bet it helps Rat. Great idea on the oil pump.

03-14-2005, 07:27 AM	#11
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	I would consider a high volume oil pump. Melling part number M-55HV. They run 5 bucks more than a stocker or so. It will act as a crutch, as obviously, your crank journals will be worn some and your cam bearings will be worn too. The extra pressure on the pump will compensate for the wear. __________________ I'm on the Instagram- @Gearhead_Kevin

04-09-2005, 05:01 PM	#12
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	OK, picked up plasti-gauge at autozone this morning and just dropped the oil pan. No jacking necessary but I did have to loosen the starter so the pan would clear it. I found the torque specs here for later use. I can see now that cleaning the old oil pan gasket off the block is going to be a PITA, cork gasket. My question now is this: Is there anything special I need to watch for when removing or installing the oil pump? Are there timing issues involved there? Any input is appreciated. P.S. FireFighter I'll follow your advice on the HV pump. thanks

04-09-2005, 05:37 PM	#13
RED72blazer urban fourwheelin Join Date: Aug 2002 Location: Seattle Posts: 1,007	I was going to recommend a high volume oil pump too, not that you really need it, But it is good insurance against worn or sloppy bearing clearences. __________________ 1972 K5 Blazer with Cummins 4BT, NV4500 swap in the parts gathering stage.

04-09-2005, 09:23 PM	#14
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	Thanks very much Red. I plasti-gauged the rear main and it mashed it so flat it stuck to the crank. I removed the bearing from the cap and found it already has 10 over in it so thats what I'm going back with.

04-09-2005, 10:53 PM	#15
BurnoutNova Registered User Join Date: Mar 2004 Location: CA Posts: 2,057	if you replace the oil pump... make sure you position the pick up tube in the right spot, not to close or to far away from the pan. also would be a good idea to tack weld the pickup tube to the pump. and i would NOT put a high volume pump in, it will suck the pan dry... maybe it would be ok if its a low reving motor, but with a stock pan, it could be easy to run it out of oil.

04-09-2005, 11:55 PM	#16
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	it'll prolly never see 5k rpm.



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04-12-2005, 10:49 PM	#17
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	Well I sucessfully changed the main bearings and installed new HV oil pump. I pulled the fire wire off the distributor and turned the motor over until the oil pressure picked up, then replaced the fire wire and busted her off. It sounded really good to start off, it seemed quieter and tighter, but then again it never did have a problem idling while cold. I let it idle until it was at operating temp and then started to bring up the rpm. Still has the same rattle at the same rpm as before, though not quite as severe which is probably due to fresh oil and new pump. I don't know whether to go back in and attempt to put in new rod bearings or not. The crank journals have obvious wear, it may still be the crank rattling, not sure... Ideas? Thoughts? Spare Cursewords?

04-12-2005, 11:01 PM	#18
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	do the rod bearings. plastigage them & go for odd sizing (+.012, +.015 etc) to get the clearance correct. just get them all the same size instead of a mix-n-match. (go for the average) __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

04-13-2005, 12:00 AM	#19
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	If the bearings are worn, then the crank is worn.replacing one without the other is a waste of time.Turn the crank buy bearings to match.

04-13-2005, 01:45 PM	#20
TugOwar Registered User Join Date: Sep 2004 Location: Pleasanton, TX Posts: 1,723	Dang sneakysnake, wish I'd thought of that.

04-13-2005, 07:18 PM	#21
wannabeburbowner Registered User Join Date: Dec 2004 Location: New Philadelphia, Ohio Posts: 253	yeah, and if a rod is starting to knock, then it might be getting out of round too. Might want to have the rod checked also. __________________ 71 Chevy Long Bed (gettin' bagged) 84 GMC K1500 (Sold) 85 Monte Carlo SS white w/gray int. (being a dumba** and totaled it ) 85 Monte Carlo SS clone T-top (Sold) 72 Chevelle-tubbed 64 Buick Sportwagon

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