# Is Rebuildinga car Engine Worth It? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [November 24, 2015, 5:12pm UTC](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449 "2015-11-24T17:12:09Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Flyer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/flyer/32/7298_2.png) [@Flyer](https://boards.straightdope.com/u/Flyer)\ **Post date:** [November 25, 2015, 3:04pm UTC](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449/21 "2015-11-25T15:04:18Z")
> [@leftfield6](#): > > Back 20 years ago, the engine would wear out long before the rest of the car did, so rebuilding the engine often made sense. An engine with 120K miles was on it’s last legs. > > Today, a modern engine made to the more exacting tolerances, can easily last much longer. My Lexus is300 with 115K is just getting broken in. > > So, unless you have a collectible car, I just don’t see an engine rebuild making sense for most instances. > [@jz78817](#): > > no it isn’t. it was “broken in” at 1500 miles. now, it’s just an old engine. 115k miles is middle-aged, but it probably isn’t old. As others have said, modern engines tend to last much longer than other parts of a car. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [November 25, 2015, 3:20pm UTC](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449/22 "2015-11-25T15:20:46Z")
“short block” = engine block, crankshaft, rods/pistons/pins/rings, bearings, camshaft/timing set (if pushrod engine) “long block” = short block + assembled cylinder heads. no brackets, covers, oil pan, etc. ---
**Author:** ![Razncain](https://avatars.discourse-cdn.com/v4/letter/r/9d8465/32.png) [@Razncain](https://boards.straightdope.com/u/Razncain)\ **Post date:** [November 25, 2015, 3:29pm UTC](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449/23 "2015-11-25T15:29:15Z")
> [@botsgotme](#): > > Suppose i have a car that i wish to keep. I decide to buy a junkyard engine, rebuild it, and keep it-when the present engine conks out, I drop my rebuilt engine into it-so i have a new car. > My question: any junkyard engine is liable to have a lot of miles, so, what should i plan on replacing? for example, new piston rings, crankshaft, new valves (or head recondition), new water pump, etc.-the cost of parts mounts up. of course, the labor is free. > Is this a economical way to keep an older car running? Probably not. I did this before in my younger and dumber years. You’re really not saving any money, just because your labor is free, you’re going to need to buy a hell of a lot of tools and equipment, and even then, you’d still come up short of what a good machine shop would have, so still would have to spend plenty by contracting a lot of it out. And doing it yourself, you just don’t get the tolerances you should be getting when others in a properly equipped machine shop could. You might consider buying from some reputable engine builder that can rebuild to original manufacturers specs. Those could probably go the distance. Crate seems to have a good reputation, there are others I’d consider, but honestly haven’t done that much serious research into any of them. Generally when you’ve went the full life on a car’s engine, the transmission, rear-end, front-end, are probably not too far behind either in needing replacement either if it hasn’t already been replaced. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 25, 2015, 3:35pm UTC](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449/24 "2015-11-25T15:35:59Z")
> [@usedtobe](#): > > Japan used to (at least) have a law requiring the engine to be replaced at 40,000 miles or so (producing an artificial market for the industry). The discarded engines were, after some effort, available in the US. Still applies. Couple years ago I secured a Japanese Domestic Market motor for my ailing '87 MR2. Nice 50% bump in power for basically the same cost as a total rebuild of the OEM engine. Of course…all you know is it’s the correct engine. You have no idea what kind of care it received, if any. So a lot of folks rebuild them anyway. > [@botsgotme](#): > > I just checked with a local shop-they want $500 to rebuild the head alone (Saturn 1.9 l SOHC). This is ridiculous-I can do it for about $110.00 in parts). Springs go boing boing and send parts all over the garage. Seriously, if you’re good at it and have the right tools it can be a challenging but fun experience. But there is still the matter of giving it a nice hot salt bath, some resurfacing, and verification of various tolerances on the head itself as well as the cam that a dedicated mechanic is just better at than most folks. For the assurance alone it’s totally worth the $390 your quote provides. Reassembling the block is much harder to muff up and better suited to DIY (but still–knock out the freeze plugs and get the block dipped and at least measured out as well). [Previous page](https://boards.straightdope.com/t/is-rebuildinga-car-engine-worth-it/738449.md?page=1)