Should i get my block resurfaced

[Slybeanx]

I just bought a M52 with 140k miles on it, supposedly was running and everything. I'm just wondering since it makes sense to pull it apart and replace the gaskets etc should i get it resurfaced and checked over by a machine shop? I don't know anything about rebuilding/ resurfacing an engine so I'm mostly asking for any tips on what to do or when to know its needed for future reference. thanks!

[efficient]

just do it for the peace of mind

[MR E30 325is]

just do it for the peace of mind

Agree with this.

[TobyB]

You won't know until you pull the head.
The condition of the surfaces will dictate whether to skim the head,
the block, or both.

As I get older, I tend to not pull the head unless there's cause...

t

[jbontke]

You are aware that resurfacing a block means pulling and disassembling the engine, right? If you are that far in, may as well rebuild as needed. You have to pull the head to check if the block surface is flat for the cyl head.

[nrubenstein]

If you take it apart, you’re going to spend at least a grand on machining. The machine shop will almost certainly tell you that the exhaust valves are out of tolerance, and you’ll pay a decent amount of money for the cleaning and checking process.

Given how cheap an M52 is, it’s hard to justify. Notwithstanding that lots of people here like to tear the engines down, doing that proactively is just expensive. And you’ll get no credit for it if you’re like most folks and sell the car/engine in a couple years.

[e30davie]

How long since it was running?

Id suggest, do a compression test. and see what its like. You can do it out of the car, just make sure it has oil. and put it on an old tyre or something. Done it many times. comp test gives you a reasonable indication of the condition of the motor. rings, valves etc, if you get reasonable comp results then its a runner.

I have previously done a compression test on a 4age, results were great, put it in car, headgasket blew. seems the engine had sat for years and once it got coolant and oil in it the gasket degraded almost immediately. unlucky. pulled the head, $500 later on the head at the machine shop due to leaky valves....and that engine lasted a few yrs without issue.

I have also done a comp tested an m20 which also came up great, but because i wasnt ready to put engine in yet i pulled the head anyway and gave it a once over. Turns out all the exhaust valve guides needed replacing, turned into an expensive exercise but the engine has given great service the last few yrs.

What i am getting at is, if you pull that head off and you want to do things properly, be prepared to spend money, but also be prepared for an engine that will give good service. If you start removing cranks, pistons, rings, bearings....you are in for thousands $$ before you get it back together to do it all properly.

[CaptiveComp]

Agree with this.

Agreed

[Slybeanx]

Thanks for all the help! Since its going to be a project while I'm in school I'm going to take it apart and get it surfaced and checked over. I already pulled it so its not too bad!