M20B27 bottom end tear down and rebuild question

[jc1000]

I am about to pull my M20B27 engine out, remove the head, then tear down and (hopefully) reuse the bottom end components (block, pistons, crank). I have an 885 head that I will be putting on it, then turbo. This is my first engine build.

My question is:

As a newbie, should I have the shop tear down the bottom end (I will remove the head first), inspect and measure everything, the TELL ME what can and can't be re-used? (After which I would clean/prep/assemble everything)

Or, do I need to go buy all the measuring tools and do the inspection/measuring myself?

I am hoping for the first option, so that I can count on their expertise and wouldn't need to buy and learn to use the precision measuring tools for my first build, but want to make sure that this is a somewhat common procedure.

Is that something machine shops often do (tear down, inspect, measure, advise, then hand back over to customer) or will they look at me funny?

I just want to make sure I am approaching this the best way possible. Thanks!

[82eye]

I am about to pull my M20B27 engine out, remove the head, then tear down and (hopefully) reuse the bottom end components (block, pistons, crank). I have an 885 head that I will be putting on it, then turbo. This is my first engine build.

My question is:

As a newbie, should I have the shop tear down the bottom end (I will remove the head first), inspect and measure everything, the TELL ME what can and can't be re-used? (After which I would clean/prep/assemble everything)

Or, do I need to go buy all the measuring tools and do the inspection/measuring myself?

I am hoping for the first option, so that I can count on their expertise and wouldn't need to buy and learn to use the precision measuring tools for my first build, but want to make sure that this is a somewhat common procedure.

Is that something machine shops often do (tear down, inspect, measure, advise, then hand back over to customer) or will they look at me funny?

I just want to make sure I am approaching this the best way possible. Thanks!

a good shop can easily do that. it's the route i took on my i engine. i had them replace the rings and bearings, clean the block, inspect the crank, and rebalance the crank and bottom end.

i let them advise on whether to replace pistons or connecting rods, they weren't necessary for my build. wherever you go make sure they don't hot tank the block unless you plan on replacing the intermediate shaft bearings. not all shops are up to that part of the job. it can be done without damaging them, but you can't tank it. the intermediate bearings are hard to source. they are a babbitt bearing, and are specialized.

[digger]

my first question is why rebuild it at all?

[jc1000]

my first question is why rebuild it at all?

Good question.

I bought the car non-running so I have no idea what shape it is in, and since I am going a new direction with the build, I didn't want to put in a lot of work to get it running "stock". (For one thing, part of the original intake manifold cracked off so I would have to JB-weld it or something in the meantime.)

I figured since I am swapping out the head for a rebuilt one, I may as well open up the bottom end and see what shape it is in. That way I am starting with a clean slate.

I am totally new to this, though. Does that logic make sense to you? I suppose I could slap on the new head and see how it runs? Is there anyway to diagnose the health of the bottom end without the car running?

[82eye]

Good question.

I bought the car non-running so I have no idea what shape it is in, and since I am going a new direction with the build, I didn't want to put in a lot of work to get it running "stock". (For one thing, part of the original intake manifold cracked off so I would have to JB-weld it or something in the meantime.)

I figured since I am swapping out the head for a rebuilt one, I may as well open up the bottom end and see what shape it is in. That way I am starting with a clean slate.

I am totally new to this, though. Does that logic make sense to you? I suppose I could slap on the new head and see how it runs? Is there anyway to diagnose the health of the bottom end without the car running?

if you're gonna turbo it would go best on new rings. gaps on turbo rings are different than on n/a. i'd make sure of a healthy bottom on a turbo build.

[digger]

Good question.

I bought the car non-running so I have no idea what shape it is in, and since I am going a new direction with the build, I didn't want to put in a lot of work to get it running "stock". (For one thing, part of the original intake manifold cracked off so I would have to JB-weld it or something in the meantime.)

I figured since I am swapping out the head for a rebuilt one, I may as well open up the bottom end and see what shape it is in. That way I am starting with a clean slate.

I am totally new to this, though. Does that logic make sense to you? I suppose I could slap on the new head and see how it runs? Is there anyway to diagnose the health of the bottom end without the car running?

It does for a NA engine but for a turbo engine you need to think about how much power/boost you are going to want and perhaps potentially future proof the pistons and rods a bit.

[jc1000]

if you're gonna turbo it would go best on new rings. gaps on turbo rings are different than on n/a. i'd make sure of a healthy bottom on a turbo build.

Thanks, 82eye

[jc1000]

It does for a NA engine but for a turbo engine you need to think about how much power/boost you are going to want and perhaps potentially future proof the pistons and rods a bit.

Thanks, digger . Can you expand on that last bit: "potentially future proof the pistons and rods a bit." What would this look like?

My understanding based on limited research is that a stock 885 head with a stock B27 bottom end is a pretty good recipe for a moderate turbo (nothing crazy). But I am all ears if you have any input here. My goal is to hit 300 hp with this build.

[digger]

Thanks, digger . Can you expand on that last bit: "potentially future proof the pistons and rods a bit." What would this look like?

My understanding based on limited research is that a stock 885 head with a stock B27 bottom end is a pretty good recipe for a moderate turbo (nothing crazy). But I am all ears if you have any input here. My goal is to hit 300 hp with this build.

Better rods e.g from 24V and /or better pistons which would likely be aftermarket. It depends what the goals are as stock stuff will be ok with mild boost if tuned correctly