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My M20 engine has 20-30% leakdown. It’s probably good for this year as I’m still doing HPDEs and not yet racing. But I’d like a stronger engine for next year.
Looking at it from a financial perspective, how much does it typically cost to rebuild (top and bottom) an M20 engine vs buying a strong-running (e.g., low-leakdown) junkyard one? Thanks for any info.
who’s doing the labor?
uh60fixer wrote:
[quote]My M20 engine has 20-30% leakdown. It’s probably good for this year as I’m still doing HPDEs and not yet racing. But I’d like a stronger engine for next year.
Looking at it from a financial perspective, how much does it typically cost to rebuild (top and bottom) an M20 engine vs buying a strong-running (e.g., low-leakdown) junkyard one? Thanks for any info.[/quote]
leggwork wrote:
[quote]who’s doing the labor?
[/quote]
Professional engine builder. This is way above my ability :ohmy:
uh60fixer wrote:
[quote]leggwork wrote:
[quote]who’s doing the labor?
[/quote]
Professional engine builder. This is way above my ability :ohmy:[/quote]
What?? :ohmy: Above your ability? Nah, You can handle it. Wes
a salvage engine will be a fourth of the cost of a professionally built engine. The problem is you have no guarantee of what you are getting from the junkyard. You might find a running donor car with a strong engine for less than $1000. There are lots of M20 autos for sale.
http://www.car-part.com/
A quick search reveals they run $500-1200 depending on mileage and how greedy the owner is.
If parts prices are similar to my old Audi 5 cylinder, then expect a rebuild with parts and machine work to be $2000-$3000. That is a standard size rebuild without boring or new pistons.
If you can get the head off and drop the pan you can rebuild the motor yourself, at that point you’re half way there to begin with. Since the rule stipulate OE equivalent parts its makes for a pretty inexpensive rebuild, I think I spent about $350-500 for parts (rings bearing, oil pump and master gasket set, new head bolts) the expensive part was the head, I got a rebuilt head (new valves rockers cam, valve seals, etc…) for about $500-600 dropped it on there and called it a day. Car runs nice and strong. Didn’t even bother with a hone on the cylinders @ 250k there was virtually no scuffing, factory cross hatch hone and no ridge. Same with the bearings (rods and mains, just R&R with factory replacements, you don’t have to drop the crank; just slip the bearings up and around (use plenty of assembly lube on the bearing face). Just make sure you clean up the pistons pretty well, there’s probably a fair amount of carbon build up on them that you want to get off, that and it makes it tough to slip the rings in (scotch brite works great for the piston tops, a piece of the old ring works well for cleaning out the ring grove). The only speciality tools you’ll need is a torque wrench (which I hope you have already) and a ring compressor to get the pistons back in the bores. Also I’d label your con rod halfs so you make sure you get the parts matched up (same ones go in the same bores). Also if you want (I didn’t know I could do this w/o a press) the wrist pins are floating so you can replace them on your own (just need some cir clip pliers).
I got lucky. I found a guy parting out a 88 and got the engine, complete pan to intake for $250. I’ve got my old bottom end that I will rebuild eventualy. I’ve done enough research to know that it will be more costly than a Ford 302, but still manageable if you do it yourself. I have not called any places for a complete motor. Maybe try NAPA or an engine rebuild shop.
rpob5t wrote:
Is that it? From the bentley looks a lot more difficult.
I whish I had somebody like you nearby to help me out.
BETO wrote:
[quote]rpob5t wrote:
Is that it? From the bentley looks a lot more difficult.
I whish I had somebody like you nearby to help me out.[/quote]
I left the crank in so I didn’t spend the extra time to take the trans out (I did the rear main seal when I did the clutch) I may be over simplifying things (I did leave off taking accessories off to get the timing belt off, but you do that when you take the head off anyway), don’t get me wrong it was a lot of work but, as long as you have a helper good weekend should get done (maybe 2 if you don’t want to thrash) I peorsonally found taking the trans out (damn starter bolts) way more frustrating even though it took me less time. With the crank in once you have the pan dropped you just un-bolt the con rods and push the pistons out the top (tap them in/out with a wooden dowel so you don’t accidentally score or mar anything), re-ring them and new bearings and drop them back in, same goes for the mains, just slip the top portion around the crank journal and you don’t have to drop the crank.
I’m not saying I’m the best mechanic in the world (heck I make my living as an accountant for christ sakes 
) but if you have a basic mechanical understanding (granted my father was an ASE master tech so I spent a ton of time helping him as a kid and learned a ton, plus I have a nice collection on Snap-on’s at my disposal when I do the work @ his place and if I really get stuck he’ll lend a hand, so that does give me a little more confidence) it can be done, it just takes some time and hard work (that and make sure you keep everything clean while working on an open motor.
FYI (at least in the SoCal area):
Pro engine build using high-quality parts: $1800-$2000
Decent used engine: $500-$1000 (& hope for the best!)
Engine removal & install: $450-$1000 (depending on the shop)
I am in the process of a rebuild right now.
I am using a decent bottom end from another car, and the head from my current car. Parts so far are about 400-ish for bearings, seals, gasket sets, new clutch kit, etc.
I have the bottom end assembled, and am getting ready to start pulling the top end and accessories and assembling the whole kit and caboodle.
Adding to it is the fact that I am putting all of this into a different chassis.
Helping me out is the fact that I am friends with a guy who owns a shop and I am using his equipment including his hoist and lift.
The added bonus is that the same guy is building an x50 engine to swap into his e30, and I am planning an taking his good M20 off of his hands as a backup for my car.
Local yards will give you a running M20 for 4-600 or so without accessories.