price of rebuilding the engine

[timothymoore]

i was wonder if one of the guys on here could help me out with this. at school we did compression tests on the D and 2 of the cylinders only had 75 and 80 psi. thinking that it may be a stuck valve, next quarter at school, we are taking the heads off and doing valve jobs on them. we also found a ring of rust around the top of one of the cylinder walls. my question is : if my engine needs a total rebuild, what could i look to be spending in the rebuild or would it be smarter to buy another engine and put in.

[Kenny_Z]

Most of the time it is cheaper to rebuild what you have. Even if you found a donor engine it'd need an inspection and possibly a rebuild as well. You can expect to need gaskets and it is a smart idea to change out the bearings if you're in there. Odds are the piston rings are toast especially if you have low compression.

I'd love to pull and rebuild my engine. I'd put in the performance cams and higher compression forged pistons.

[David T]

Before planning on rebuilding the motor there are a lot of things you can do first. Do another compression test and then repeat after squirting in some oil into each cylinder. If the compression goes up that would mean leaky rings. Do a leak-down test. That will tell you if it is valves or a head gasket. You can adjust the valves, one or more may be a little too tight and not seating properly and leaking. If you can get the motor to run you can do a combustion leak test on the cooling system to verify a head gasket leak, especially if the two low cylinders are next to each other. Unless the motor was overheated you should not need to do anything more than a valve adjustment. Check the plastic screen in the oil fill. If it is melted or missing there is a good chance the motor was cooked. If so, replacement may be the smarter option.
David Teitelbaum

[dmc6960]

You can do a strait up rebuild for less than $1000, excluding labor if someone else does it. But when the $400 cost of new rings somehow convinces you to buy $1100 new pistons, then while your at it getting new camshafts and a high quality head job, then you might as well port/polish it as well, along with a new exhaust to go with it. Wow, suddenly your engine rebuild has turned into a home-built Stage II or II.5, for a little less than the cost of a Stage II from DMC.

[Grover]

You can do a strait up rebuild for less than $1000, excluding labor if someone else does it. But when the $400 cost of new rings somehow convinces you to buy $1100 new pistons, then while your at it getting new camshafts and a high quality head job, then you might as well port/polish it as well, along with a new exhaust to go with it. Wow, suddenly your engine rebuild has turned into a home-built Stage II or II.5, for a little less than the cost of a Stage II from DMC.

My project this winter... 8)

[timothymoore]

Most of the time it is cheaper to rebuild what you have. Even if you found a donor engine it'd need an inspection and possibly a rebuild as well. You can expect to need gaskets and it is a smart idea to change out the bearings if you're in there. Odds are the piston rings are toast especially if you have low compression.

I'd love to pull and rebuild my engine. I'd put in the performance cams and higher compression forged pistons.

i didnt know they made forged pistons for the D.

[Kenny_Z]

I think they have to be custom made but I'm not absolutely positive on that.

[Grover]

i didnt know they made forged pistons for the D.

DMC Europe sells them in either High Compression or Low Compression (for forced induction)

[DMC1983]

Yeah the biggest cause of low compression in engines that have been sitting are stuck rings. You can easily see if it is by throwing some marvel mystery oil in each cylinder and cracking it over (by hand, with a wrench). Let it sit there and they should pop back out. It's better to just replace the rings, but you can easily find if that's the issue. I'd just take it apart. What do you got to lose?

[David T]

Just taking the motor apart and reassembling it will cost you a set of gaskets at least and a lot of time. Before planning on mechanical work at least do *some* diagnostic tests. The simplest would be another round of compression tests, first "dry" and then squirt some oil into the cylinders. Why take it all apart when it could be something as simple as a valve adjustment? Or maybe just a "top end" clean-up valve job (unlikely).
David Teitelbaum

[DMC1983]

Just taking the motor apart and reassembling it will cost you a set of gaskets at least and a lot of time. Before planning on mechanical work at least do *some* diagnostic tests. The simplest would be another round of compression tests, first "dry" and then squirt some oil into the cylinders. Why take it all apart when it could be something as simple as a valve adjustment? Or maybe just a "top end" clean-up valve job (unlikely).
David Teitelbaum

As far as valves go, couldn't they take on a bit of corrosion after 22 years? I'm sure the oil film would degrade after that long and seeing how there are ways for moisture to get trapped in the top end, it seems likely

if the car was driven up to the point of storage and the PO never properly prepared the car for storage, I'm curious as to the condition of the cylinder sleeves and jackets. Now, I know the antifreeze contains corrosion inhibits but what state are they in after a period of time?

[David T]

In my experience, if the engine turns over freely there is a lot of hope for it short of taking it all apart. That said, it *could* have had a problem BEFORE it was stored. I still think doing some diagnostic testing won't take much time or cost anything. I have seen where an engine had some low cylinders and after running it a short time and retesting the low cylinders improved. Could be stuck rings, maybe some carbon on a valve seat, who knows? Certainly worth trying before all of the time it will take to take it out, all apart, reassemble (maybe making some mistakes, broken bolts, etc) and then reinstalling. Always safer to do the least you have to do to fix something. Just because you *can* take it all apart doesn't mean you have to or should.
David Teitelbaum