Why are rebuilt motors garbage?

Jackstand Queen · 02-16-2009, 10:42 PM

Generally speaking rebuilt motors are garbage. An ordinary rebuilt motor might run for 50,000 miles before starting to burn a couple quarts of oil per tank of gas, or throwing a rod through the side of the block.

The reason why ordinary rebuilds don't last is the high bearing tolerances that most machine shops use. Typically, a machine shop uses tolerances of 500% larger (read this as looser) than what comes out of the Toyota factory. Larger bearing clearances mean lower oil pressure, which in turn causes higher bearing wear. Which in turn causes short engine life expectancy.

At the Toyota factory, the engine assembler has a bank of dozens of sizes of bearings for the crankshaft and rods. He measures the rotating part, and then hand picks the correct size bearing for a tight fit.

At the local machine shop, time is money. They can choose 5,000th inch oversized bearing, or 10,000 oversized. Then they slap it together and call it good.

If you have a real quality machine shop, they could "Blueprint" your motor and build it like you'd want them to. But Blueprinting costs a lot more.

I really don't trust any of my local machine shops to properly weigh and balance the rods and pistons. I don't trust them to ream out the journals so that an oversized bearing has a clearance of 1000th inch.

As long as there are Jspec used engines being imported . . . I'd much rather take my chances on one of them, than have a local shop touch the insides of my dead or dying engine.

GENESIS · 02-17-2009, 12:30 AM

I somewhat what agree with that,most machine shops i know cuts corners there piston rings are lower quality than the oem also they try to knurl the valve guides instead of replacing them with tighter clearances,They just want their quotas, unlike places like Rebello or flying miata they take pride in what they do.

HoLun · 02-17-2009, 09:50 AM

thats why, if you want quality or performance, you either learn it real good and do it yourself, or pay the money to do it right.

"regular" rebuild is for regular people who want to get a little more out of their grocery getters.

Jackstand Queen · 02-17-2009, 11:27 AM

Blueprinting an engine requires tooling, training, experience, and a mindset that most small machine shops don't possess. Due to expense of tools, workspace requirements, and years of needed training and experience: Blueprinting is not a DYI endeavor.

mr220v · 02-17-2009, 12:29 PM

It's also why you don't want to rebuild a clean used motor just for the heck of it.

HoLun · 02-17-2009, 01:33 PM

Quote:

Originally Posted by Jackstand Queen

Blueprinting an engine requires tooling, training, experience, and a mindset that most small machine shops don't possess. Due to expense of tools, workspace requirements, and years of needed training and experience: Blueprinting is not a DYI endeavor.

If you are DIY rebuilder you should already have all the tools for measurement, bore gauge, calipers, dial indicator, micrometer, maybe even a CCing setup. I really don't see how this cant be for DIY.

Unless you are talking about having a bridgeport and assorted attachment, boring machine, and all that stuff to DIY....

all you got to do is measure, and then take it to a competent machine shop and tell them how much to cut.

grizzy225 · 02-17-2009, 01:57 PM

question!!!!! i am on the track of having my engine rebuilt as some of you may know...

i got a lot of useful information reading this post and was wondering what are the most IMPORTANT THINGS TO REMEMBER when going through with it... the guy that i have in mind has worked with my dealership for years and only uses toyota parts... am i safe to go ahead with it?

janice

Sang · 02-17-2009, 04:23 PM

I'll always rebuild my own engine as opposed to buying a used, unknown condition JDM import. I have to be in a desperate situation to buy a used longblock to swap in and go. And you're right, most mom and pop shops wont do a rebuild correctly. But there are also many good shops will. If one of the good ones happens to be local to you, great. If not, i'll spend the couple hundred bucks to ship a block.

Jackstand Queen · 02-17-2009, 08:24 PM

You know the theme music to the Movie "Deliverance"? "Dueling Banjo's" I believe its called. Well in my local machine shops that's what's playing whenever they are open.

The people that work in my local machine shops are like characters right out of the movie "The Hills have eyes".

I would not leave them alone in a room with my dog!

Much less, let them touch my engine.

But this thread has been illuminating. There are good machine shops out there somewhere other than where I live. Buying a used Jspec is definitely a crapshoot. But having one of my local machine shops help me with a rebuild is garanteed to produce garbage.

Of the tools Holun listed, I have one of them . . . a caliper. I don't want to own tools that I will use only a few times say in the next ten years. I'd rather pay someone who knows how to use a dail indicator, rather than buy one. And not know how to use it.

como · 02-17-2009, 10:43 PM

As a newbie, nobody informed me that rebuilt motors aren't as good as originals.
I'm looking for a 1986 mr2, and many of the ones I find on craigslist come up with the seller saying something like "rebuilt motor with only 40,000 miles on it" like it's a good thing, and I never questioned it.

Thank you.

Sang · 02-17-2009, 11:08 PM

If you want a stock engine, get an assembled shortblock from toyota. That will ensure that it was built properly, to toyota specs, with toyota's expensive ass equipment.

And if it wasn't built properly, they come with a limited warranty.

nikn · 02-17-2009, 11:13 PM

yea this has been an eye opening thread for me too. I thought if an engine was rebuilt that automatically meant it's more reliable!

...****

M.Bailey · 02-17-2009, 11:47 PM

When I had my motor machined I had it doen by Archie Somers at Somers racing engines in battle ground washington and I had my dad who has been building high performance engine for 20 years build my engine. Archie is the best machinest that I know and probly one of the top five builders and machinests on the west coast I would highly recomend him for people who are looking at rebuilding there engines or looking to build any highperformnace or street motor. my tolerances are are tigher than factory on everything and he hand fits everything. I know for most of you it is quite a drive but it is worth it I dont know what the prices are because the machine work was a present from my dad but we dont have a lot of money so it cant be to extreme. Archie does all of my dads block machine work and has been doing so for 20 years

MR_mean2 · 02-17-2009, 11:51 PM

Anybody else that can recommend reputable builders?

Bak@EMSPowered · 02-18-2009, 01:46 AM

ATS Racing does great work. I've had 2 motors from them, and have recommended them to countless other customers of ours, all of which have been happy with the quailty of their work.

XJoshua · 02-28-2009, 12:51 AM

Quote:

Originally Posted by MR_mean2

Anybody else that can recommend reputable builders?

Over in the midwest area. Colorado Springs, CO to be exact. McCabe Motorsports. I had him machine my Jeep AMC 4.0L into a 4.7L Stroker. He uses laser guided equiptment, sits you down and talk about wants and needs, expenses you are willing to use. All around a nice guy. A local machine shop fubar'd, my connecting rods and other parts. He fixed the connecting rods, and measures every part for straightness. Paid him $1300 to fix problems. He quotes me $2000 if I had gone to him in the first place. He has several awards for cleanliness, and other junk. Also has alot of out of state customers.

5/5 Review for him.

MANDALAY · 02-28-2009, 09:31 PM

Do the above comments also hold true in building an engine ?
I built my beams new will new parts from Toyota but used their Short Block.
Soon im going to upgrade it due to SC . now if i buy a new block, new pistons forged, eagle rods turbo and crank. will it all go together with the right tolerances ie using OEM bearings etc.

Jackstand Queen · 02-28-2009, 11:46 PM

Mandalay . . . crikey mate . . . you are getting your Americanish language mixed up.

Building an engine in Austrailia is the same as rebuilding one in the USA!

If I understand correctly, you did not buy a pre-assembled short block from Toyota. But you bought some new engine parts, and are using the old (used) crankshaft and used block right? With the right machinist and machine shop, your setup could be assembled really as good as it can get.

As to your engine's situation . . it depends on who is doing the work. The machine shops I'm putting down are the one's who throw crap together good enough for the engine to run a short while. Because the work goes faster that way, and they can make more money by taking on more work.

Blimey, I'd love to go out busting Dingo's and Roo's in the Outback!

MANDALAY · 03-01-2009, 08:58 AM

Holly crap your getting yor Aussieish language correct

Nah i bought a brand new short block from toyota and also everything else.
What i want to do is buy a new block only then new forged pistons, turbo eagle rods and OEM crank to make another short block. Stronger so as to up the PSI.
Can i just buy OEM bearings and just put it together or do they have to be sized ?
Thats the question.
Personally i would never rebuild a used block, thats me .

Jackstand Queen · 03-01-2009, 01:43 PM

Stuffing those new parts in the block would require correct sizing of the bearings and journals. Its often called a "blueprinting" standard of rebuilding. However the Slop Shops I am vilifying could easily just say their junk is "blueprinted".

I will outline the opposite qualities and characteristics of a Slop Shop:

Younger owner and employees.
New shiny Digital (CNC) computer network controlled machines.
Clean floor, office, workspaces, tools, and machines.
Good personal hygiene and grooming of owner and employees
Good lighting inside the workspace
Lack of mouse and rat droppings and clouds of verminous insects.
Blah, blah blah . . . . . .

02-16-2009, 10:42 PM	#1 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	Why are rebuilt motors garbage? Generally speaking rebuilt motors are garbage. An ordinary rebuilt motor might run for 50,000 miles before starting to burn a couple quarts of oil per tank of gas, or throwing a rod through the side of the block. The reason why ordinary rebuilds don't last is the high bearing tolerances that most machine shops use. Typically, a machine shop uses tolerances of 500% larger (read this as looser) than what comes out of the Toyota factory. Larger bearing clearances mean lower oil pressure, which in turn causes higher bearing wear. Which in turn causes short engine life expectancy. At the Toyota factory, the engine assembler has a bank of dozens of sizes of bearings for the crankshaft and rods. He measures the rotating part, and then hand picks the correct size bearing for a tight fit. At the local machine shop, time is money. They can choose 5,000th inch oversized bearing, or 10,000 oversized. Then they slap it together and call it good. If you have a real quality machine shop, they could "Blueprint" your motor and build it like you'd want them to. But Blueprinting costs a lot more. I really don't trust any of my local machine shops to properly weigh and balance the rods and pistons. I don't trust them to ream out the journals so that an oversized bearing has a clearance of 1000th inch. As long as there are Jspec used engines being imported . . . I'd much rather take my chances on one of them, than have a local shop touch the insides of my dead or dying engine.

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02-17-2009, 12:30 AM	#2 (permalink)
GENESIS Gate keeper of Redwood rd Join Date: Feb 2009 Location: dublin,ca Posts: 778 Thanks: 4 Thanked 23 Times in 24 Posts iTrader Rating: (4/100% )	I somewhat what agree with that,most machine shops i know cuts corners there piston rings are lower quality than the oem also they try to knurl the valve guides instead of replacing them with tighter clearances,They just want their quotas, unlike places like Rebello or flying miata they take pride in what they do.

02-17-2009, 09:50 AM	#3 (permalink)
HoLun ASE Master tech Join Date: Jan 2009 Location: Austin, TX Posts: 79 Thanks: 0 Thanked 5 Times in 5 Posts iTrader Rating: (0/0% )	thats why, if you want quality or performance, you either learn it real good and do it yourself, or pay the money to do it right. "regular" rebuild is for regular people who want to get a little more out of their grocery getters.

02-17-2009, 11:27 AM	#4 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	Blueprinting an engine requires tooling, training, experience, and a mindset that most small machine shops don't possess. Due to expense of tools, workspace requirements, and years of needed training and experience: Blueprinting is not a DYI endeavor.

02-17-2009, 12:29 PM	#5 (permalink)
mr220v Beams Owners Group Join Date: Mar 2006 Posts: 2,529 Thanks: 13 Thanked 176 Times in 147 Posts iTrader Rating: (11/100% )	It's also why you don't want to rebuild a clean used motor just for the heck of it.

02-17-2009, 01:57 PM	#7 (permalink)
grizzy225 just because.... Join Date: Feb 2008 Location: CT Posts: 641 Thanks: 48 Thanked 9 Times in 9 Posts iTrader Rating: (3/100% )	question!!!!! i am on the track of having my engine rebuilt as some of you may know... i got a lot of useful information reading this post and was wondering what are the most IMPORTANT THINGS TO REMEMBER when going through with it... the guy that i have in mind has worked with my dealership for years and only uses toyota parts... am i safe to go ahead with it? janice

02-17-2009, 04:23 PM	#8 (permalink)
Sang Turtle Join Date: Jul 2006 Location: FL Posts: 4,096 Thanks: 18 Thanked 267 Times in 246 Posts iTrader Rating: (5/100% )	I'll always rebuild my own engine as opposed to buying a used, unknown condition JDM import. I have to be in a desperate situation to buy a used longblock to swap in and go. And you're right, most mom and pop shops wont do a rebuild correctly. But there are also many good shops will. If one of the good ones happens to be local to you, great. If not, i'll spend the couple hundred bucks to ship a block.

02-17-2009, 08:24 PM	#9 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	You know the theme music to the Movie "Deliverance"? "Dueling Banjo's" I believe its called. Well in my local machine shops that's what's playing whenever they are open. The people that work in my local machine shops are like characters right out of the movie "The Hills have eyes". I would not leave them alone in a room with my dog! Much less, let them touch my engine. But this thread has been illuminating. There are good machine shops out there somewhere other than where I live. Buying a used Jspec is definitely a crapshoot. But having one of my local machine shops help me with a rebuild is garanteed to produce garbage. Of the tools Holun listed, I have one of them . . . a caliper. I don't want to own tools that I will use only a few times say in the next ten years. I'd rather pay someone who knows how to use a dail indicator, rather than buy one. And not know how to use it.

02-17-2009, 10:43 PM	#10 (permalink)
como Road Warrior Join Date: Jan 2009 Location: Southern Maine Posts: 652 Thanks: 13 Thanked 10 Times in 9 Posts iTrader Rating: (2/100% )	As a newbie, nobody informed me that rebuilt motors aren't as good as originals. I'm looking for a 1986 mr2, and many of the ones I find on craigslist come up with the seller saying something like "rebuilt motor with only 40,000 miles on it" like it's a good thing, and I never questioned it. Thank you.

02-17-2009, 11:08 PM	#11 (permalink)
Sang Turtle Join Date: Jul 2006 Location: FL Posts: 4,096 Thanks: 18 Thanked 267 Times in 246 Posts iTrader Rating: (5/100% )	If you want a stock engine, get an assembled shortblock from toyota. That will ensure that it was built properly, to toyota specs, with toyota's expensive ass equipment. And if it wasn't built properly, they come with a limited warranty.

02-17-2009, 11:13 PM	#12 (permalink)
nikn Cage Fighter Join Date: Jan 2007 Location: dirty jerzey Posts: 201 Thanks: 12 Thanked 3 Times in 3 Posts iTrader Rating: (5/100% )	yea this has been an eye opening thread for me too. I thought if an engine was rebuilt that automatically meant it's more reliable! ...****

02-17-2009, 11:47 PM	#13 (permalink)
M.Bailey wrenching skills Join Date: Aug 2008 Posts: 118 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0% )	When I had my motor machined I had it doen by Archie Somers at Somers racing engines in battle ground washington and I had my dad who has been building high performance engine for 20 years build my engine. Archie is the best machinest that I know and probly one of the top five builders and machinests on the west coast I would highly recomend him for people who are looking at rebuilding there engines or looking to build any highperformnace or street motor. my tolerances are are tigher than factory on everything and he hand fits everything. I know for most of you it is quite a drive but it is worth it I dont know what the prices are because the machine work was a present from my dad but we dont have a lot of money so it cant be to extreme. Archie does all of my dads block machine work and has been doing so for 20 years

02-17-2009, 11:51 PM	#14 (permalink)
MR_mean2 No Skills Join Date: Nov 2007 Posts: 34 Thanks: 4 Thanked 1 Time in 1 Post iTrader Rating: (0/0% )	Anybody else that can recommend reputable builders?

02-18-2009, 01:46 AM	#15 (permalink)
Bak@EMSPowered Banned Seller Join Date: Oct 2005 Location: Austin, TX Posts: 5,925 Thanks: 30 Thanked 193 Times in 165 Posts My Google Map iTrader Rating: (49/93% )	ATS Racing does great work. I've had 2 motors from them, and have recommended them to countless other customers of ours, all of which have been happy with the quailty of their work.

02-28-2009, 09:31 PM	#17 (permalink)
MANDALAY Beams Owners Group Join Date: Feb 2007 Location: victoria AUSTRALIA Posts: 4,210 Thanks: 136 Thanked 112 Times in 107 Posts My Google Map iTrader Rating: (6/100% )	Do the above comments also hold true in building an engine ? I built my beams new will new parts from Toyota but used their Short Block. Soon im going to upgrade it due to SC . now if i buy a new block, new pistons forged, eagle rods turbo and crank. will it all go together with the right tolerances ie using OEM bearings etc.

02-28-2009, 11:46 PM	#18 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	Mandalay . . . crikey mate . . . you are getting your Americanish language mixed up. Building an engine in Austrailia is the same as rebuilding one in the USA! If I understand correctly, you did not buy a pre-assembled short block from Toyota. But you bought some new engine parts, and are using the old (used) crankshaft and used block right? With the right machinist and machine shop, your setup could be assembled really as good as it can get. As to your engine's situation . . it depends on who is doing the work. The machine shops I'm putting down are the one's who throw crap together good enough for the engine to run a short while. Because the work goes faster that way, and they can make more money by taking on more work. Blimey, I'd love to go out busting Dingo's and Roo's in the Outback!

03-01-2009, 08:58 AM	#19 (permalink)
MANDALAY Beams Owners Group Join Date: Feb 2007 Location: victoria AUSTRALIA Posts: 4,210 Thanks: 136 Thanked 112 Times in 107 Posts My Google Map iTrader Rating: (6/100% )	Holly crap your getting yor Aussieish language correct Nah i bought a brand new short block from toyota and also everything else. What i want to do is buy a new block only then new forged pistons, turbo eagle rods and OEM crank to make another short block. Stronger so as to up the PSI. Can i just buy OEM bearings and just put it together or do they have to be sized ? Thats the question. Personally i would never rebuild a used block, thats me .

03-01-2009, 01:43 PM	#20 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	Stuffing those new parts in the block would require correct sizing of the bearings and journals. Its often called a "blueprinting" standard of rebuilding. However the Slop Shops I am vilifying could easily just say their junk is "blueprinted". I will outline the opposite qualities and characteristics of a Slop Shop: Younger owner and employees. New shiny Digital (CNC) computer network controlled machines. Clean floor, office, workspaces, tools, and machines. Good personal hygiene and grooming of owner and employees Good lighting inside the workspace Lack of mouse and rat droppings and clouds of verminous insects. Blah, blah blah . . . . . .