DIY Engine Rebuild Costs

Messages
519
Location
Australia
Thread starter
Hi everyone, I've always wanted to do a DIY engine rebuild and have come across a project I am interested in. This is covering the short block only and only machine shop costs. If the engine being rebuilt is in tact (i.e., did not suffer catastrophic damage) would measuring the journals etc and doing a standard rebuild with just a hone be sufficient? Or will the crank journal need to be honed? Also how difficult/costly would oversize bore be by 0.5mm? I would attempt to take most measurements myself however there are things that perhaps the machine shop might need to do for me
 
Messages
519
Location
Australia
Thread starter
It'll be to a 6A13 Mitsubishi short block. Just a standard rebuild with potentially oversized pistons.
 
Messages
285
Location
Central Texas
The problem with DIY rebuild is finding a shop that does good work. I stopped rebuilding engines my self because I walked into the machine shop and realized they had the same old equipment they had when I was young. I could get about 80,000 miles on my Datsun rebuild before it began using oil. I wound up ordering a reman from Nissan in Japan (not a 30,000 mile used one from Japan) I would get close to 200,000 miles on one of those. That's driving driving flat out most of the way at for 160 miles and 100 miles late at night. I ordered a ford engine rebuilt in the USA (not by Ford). Was not impressed with what I got. If you can not get a reman by Mitsubishi, Don't have the crank turned under ten thousands. Do have the cylinder bored by a shop. Just doing a ring job and only reaming the top of the cylinder will only last so long.
 
Messages
284
Location
WA
Crank journals don't get 'honed', that is for cylinder walls. They do get cut for undersized bearings & they can be simply polished if they have no damage.
 
Messages
3,025
Location
Ca.
How much if any crosshatch is left should give you at least an idea of wether you should bore or hone. If you bore have the shop use a torque plate or you'll end up with an oil burner pretty quick. Overbore will cost new pistons, rings, and likely a trip to the balance shop - mostly likely new wrist pins If you are lucky the crank can be polished.
 
Messages
5,410
Location
Baltimore, Maryland, USA
I've always wanted to do a DIY engine rebuild... Start out with something small, like a weed whacker or lawn mower, and work your way up to a car. In fact, your first car engine rebuild should probably be a small 4 cylinder car where you can do an in the car partial rebuild (meaning that you don't even remove the engine block from the car).
 
Messages
24,629
Location
Upstate NY
I did this on a Ford 289 Mustang engine. Bored with pop up pistons. Crank cut. Engine hot tanked to clean it. I put it back together. 3/4 grind cam. Lots of help from my Dad as I was 17 I think. Learned a lot. With my Jeep engine failure, I bought a reman engine.
 
Messages
11,711
Location
North Carolina
Depends on what you are starting with. It its an engine you bought, everything has to be checked. Probably by a machine shop is best. If its an engine in a car you've owned since new and its been maintained with good oil service and not overrevved, you could check things yourself. Look at the bearings as you tear down. Send the head to the shop. Check the freeze plugs for corrosion. Make sure everything is really clean on reassembly. I'd use a bore brush to hone if you go that route. Wash the block out good afterwards. Use a brush to clean the bores with soap. Wash until you can wipe the bore with a paper towel and stays clean. Get a good torque wrench, not an HF one.
 
Messages
1,387
Location
RI
The cost will widely vary depending on what kit you use and what it needs for machine work. With boring the cylinders and line honing the mains (or at least checking it) would be the only way I would want to do it IMO. What's going on with the engine?
 
Messages
9,805
Location
Jupiter, Florida
The one major mistake DIY overhauls often have is the failure to clean all oil passages with a bristle brush. Including inside the crankshaft.
 
Messages
4,299
Location
Southeast
Agree with the issue finding a good machine shop. I did a DIY a while back, chevy 283. I was taking my time and waited a while for another shop to rebuild the trans while it was all out. Only after final assembly and startup did I find the hairline crack caused by rushed machining right on the oil pump's output journal. Leaked 1 quart per hour. Went back to work with them and the doors and windows were shuttered. Very disappointing.
 
Messages
328
Location
VA
Good machine shops are a PITA to deal with because they are super busy and usually have commercial accounts that will bump you right out of the rotation. Be prepared to wait.
 
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