Honda Prelude Forum - PreludeDriver.com

My daughter's 1990 2056cc - B21A1? I guess, engine 197000Km has no compression in one cylinder. Other 3 work fine and I drove car back from Vancouver, with revs in the 3000rpm range was able to get reasonable power and coast at 100km/hr - and have parked it at home in the Okanagan. She can't afford to get a mechanic to do the job of rebuilding the engine - probably up in the $1200 - $1600 range.
What do you think about getting an engine from the wreckers and which engines would fit the car - and in the end would it be any cheaper.
The car did use oil about 1litre or 2l per fill up seemed heavy use but not dripping when parked and no evident clouds of blue when running, before the compression in the cylinder went.
Is rebuilding engine or swapping used engine something I could tackle - I know thats a hard one to answer - I can use mechanical tools and have done maintenance, oil changes, front disc brake replacements, water pump, radiator replacements on own vehicles and have helped/watched engine and clutch removal - and I can read and follow repair manual instructions - and have a good understanding of engine and system functions but don't know if pulling an engine is feasible - I do have a mechanic friend that I could call on to help if I ran into a major problem.
I guess I don't know where to start - and what to look for in a used motor at the wreckers or what the going rate is - I think if I found one in the $500 - 600 range and did most of the work myself, and replaced a few other things like clutch, timing belt - it is due close to 100K since last changed, water pump - and total cost was $1000 - 1200 - so that she could get a couple of years of no major repairs - then it would be worth it. I guess the only other thing that could go then is the transmission but no issues at present so would take my chances.
Basically could anyone give me some feedback - if my cost of used engine and some of the other parts to replace are possible in the total cost of up to $1200 and secondly - what you think about used from wreckers or trying to rebuild the engine - how much and what is involved in the one cylinder compression problem. Sorry for the long post - I haven't done this before and don't know what the compression problem involves so I don't know what specifics to ask. Thanks for any help or suggestions.
Or what could I sell it for " as is" and then add $1200 - 1400 to the sale price and buy a Prelude in reasonable shape that she could drive for a couple of years and not do all the labour and possible problems of fixing it.

Since your engine is losing so much oil, the piston rings are probably to blame for your bad compression and oil loss problems.

Changing piston rings isn't terribly hard, but it does require a bit of knowledge to complete. The basic procedure is that you take the cylinder head off the top of the engine (requires slipping off the timing belt) and drop the oil pan and girdle off the bottom. Then you can remove the lower rod bearing caps and push each cylinder out the top of the engine, replace the rings, and then reassemble everything. Reassembly will involve setting the timing again, since you will have to remove the timing belt to get the cylinder head off.

Cylinder rings aren't that expensive (make sure you get ones from Honda). You'll also need some engine assembly lube, cylinder ring compressor, cylinder ring spreaders, a torque wrench and a fresh load of engine oil.

A few notes if you go this route:
-Since you have a B21A1 which has FRM (Fiber Reinforced Metal) cylinder walls to don't need to de-glaze the cylinder walls when you change the rings. Take the pistons out, swap the rings, put them back in, that's all.
-Make sure to number each rod cap and piston. They must all go back into the exact same location that they came out of. If you mismatch a rod cap you risk a mismatched bearing and that's a great way to do a whole mess of damage to your engine.
-Use ONLY Honda rings. They're worth the money.
-When you remove the head, you'll have to slip the timing belt off the cam gears (usually accomplished by removing the cam gears themselves). The timing belt will want to droop out the bottom of the engine. Make sure you mark the position of the belt on the main belt cog connected to the crankshaft and the cam gears. You have to be very careful to now mess up the timing when you do this procedure.

As far as engine swaps, the B21A1 is really your only option. The B20A5 will fit just fine, but the ECU in your car is an OBD1 ecu where as the B20A5 uses a OBD0 ECU. Rather than mess with swapping out the ECU set and wires, just try to find a B21A1. They are around in the wreckers. I picked up a full B21A1 engine once (with tranny) for about $200 from my local self-serve wrecker. The hardest thing will be finding a good one.

Don't forget that you'll need an engine hoist if you decide to swap the engine.

If I were you, I would probably go try to switch out the rings. It'll be less expensive and the procedure isn't too complex. Swapping the engine isn't impossible, but it requires a lot more labor to complete, and then you're still left with the challenge of finding a decent engine to swap in. However, this is only my opinion, and above all I encourage you to do what you are comfortable with. If this is your first time doing something this involved on a car, don't be afraid. Just take it slow, make notes, take pictures and know your material. If you learn about what you're doing up front, you'll see just how easy these cars are to work on.

I'm not sure if this reply gets to you hope it does, since this is my first reply post. - I want to thank you for the detailed and very knowledgeable reply to my problem. It is very encouraging that you take the time to be so helpful with your expertise and you write it in a very understandable way and tell me the things I need to get started or make a better choice. From what I have read you are absolutely right about the engine losing so much oil that the piston rings are the problem for the oil loss and as you say it is FRM in the B21A1 from what I have read - and I think that loss of oil and lower compression across all cylinders has been an issue for a while - but in addition - the car started idling very rough and when I got it home I took it to my friend mechanic and one of the cylinders has virtually zero compression - so it is likely that a burnt valve is also a problem for that cylinder - and it is working on 3 cylinders which have even compression - but as you say the rings need replacing since I have read that the FRM does cause or add to worn rings.
I have got a Chilton Honda Accord/Prelude 1984 to 95 manual so I will have a look at it to see if I can follow it enough to make sense out of it and feel confident enough to do the job - however, you post has been so helpful because it told me how to do some of the things and what to look out for - in understandable language - that the manuals do not always give in their point form.
I will start checking prices of rings at Honda, getting or renting an engine hoist, cylinder compressor, cylinder ring spreaders, torque wrench, engine assembly lube - I would not have know what I even needed to get - so thanks again. My daughter goes back to school in September - so the good thing is I have a few week ends and evenings to do this - So I will look into parts and Chilton manual and the info you have provide - and see if I have the courage to try this - I guess I should give it a go otherwise the car is just parked and I would like to get it fixed for her. It is a red prelude that looks very similar to your - but not as nice a shape - although everything works - cruise, cold ac, sunroof - but if you do come by a good or happen to know where I could pick one up let me know. Thanks

It is rare but you can get oil loss through the valves.

When you did the compression test did you do a wet and dry test ?

Happy to help.

Crash_Control makes a good point. You can lose oil through the valves, but the rings are the more likely route. Sounds like you may have issues with your valves in at least one cylinder though.

Feel free to ask more questions if you need any additional help. There are a lot of knowledgeable people that read these posts.

Just to clarify, you talked about renting an engine hoist: An engine hoist will only be needed if you decide to swap the engine. You won't need it to do the rings.