What to do?

Wed Jun 15, 2016 1:14 am

I'm at a bit of a crossroads regarding what to do with my 325.
It has 160k miles on the clock, doesn't run very well and is noisy on the top end. The way I see it I can either m52 it or recon/overhaul the m20. The car isn't my daily driver but I do take it all over Europe every year so I need reliability more than performance. I know the 52 is a much better lump but tbh I don't know which would be the better engine choice for me. Can anyone tell me the approx costs of both options? Parts cost in the case of the 52 swap and a rough estimate for a machine shop to restore the m20.

TIA

Wed Jun 15, 2016 8:59 am

given you take it all over Europe I would be minded to invest in an M52 conversion and have it done by know zoner, DanThe is know for his conversions and qualify.

Can help you on prices but im budgeting for about £2K plus the donnor for a quality conversion.

Wed Jun 15, 2016 9:40 am

I can handle the spanner work it's fabrication that I fail hard on. I'm surprised there isn't a Zoner offering a package tbh. Sump/mounts/wiring etc. £2k was more than I wanted to spend and I'd also need to bear in mind that sticking with the m20 would give me what is effectively a new engine whereas going donor m52 involves fitting a 100k plus lump......unless your budget allows for an engine refresh is belts/water pump etc.

Wed Jun 15, 2016 9:46 am

if you want to stick with the m20 then why not go for a 2.8?? like you say, it offers an "as new" m20 not a 100K+ M5x lump,

just don't see thew appeal in the M5x swap as to me the engine is soulless, if done right for the same sort of outlay you get a "new" engine.

thats the way i see it.

Wed Jun 15, 2016 11:21 am

steve_k wrote:if you want to stick with the m20 then why not go for a 2.8?? like you say, it offers an "as new" m20 not a 100K+ M5x lump,

just don't see thew appeal in the M5x swap as to me the engine is soulless, if done right for the same sort of outlay you get a "new" engine.

thats the way i see it.

If the 52 swap is going to be 2k I may as well overhaul the m20 already in it. I know DanThe does already to go wiring solution (but I'm not sure how much that costs) and I think he also offers an exhaust option.....again no idea of that cost. Other than that a parts list already exists in the wiki leaving only labour as an unknown and the amount of labour you do yourself can make a huge difference in the cost of the conversion. The power/economy/driveability of the m52 would be nice but not necessary.

Wed Jun 15, 2016 1:04 pm

N00b wrote:
steve_k wrote:if you want to stick with the m20 then why not go for a 2.8?? like you say, it offers an "as new" m20 not a 100K+ M5x lump,

just don't see thew appeal in the M5x swap as to me the engine is soulless, if done right for the same sort of outlay you get a "new" engine.

thats the way i see it.
If the 52 swap is going to be 2k I may as well overhaul the m20 already in it. I know DanThe does already to go wiring solution (but I'm not sure how much that costs) and I think he also offers an exhaust option.....again no idea of that cost. Other than that a parts list already exists in the wiki leaving only labour as an unknown and the amount of labour you do yourself can make a huge difference in the cost of the conversion. The power/economy/driveability of the m52 would be nice but not necessary.

thats what i mean, at that cost minimum i would rebuild the m20 instead.

Wed Jun 15, 2016 1:51 pm

I would stick with m20 it is a good engine and simple to work on

Wed Jun 15, 2016 9:11 pm

If the bottom end is good could you get away with a just reconditioned head?

New injectors and new breather hoses and you should have an engine that will do another 100,000 miles.

Thu Jun 16, 2016 9:51 am

DHFiS wrote:If the bottom end is good could you get away with a just reconditioned head?

New injectors and new breather hoses and you should have an engine that will do another 100,000 miles.

The car doesn't get used much and to the best of my knowledge it doesn't use/ burn/leak any fluids. If this is true then how can i check the bottom end with or without the head in situ? I was thinking a compression test wouldn't work as i could have a valve leaking. I've seen people pull a head then pour a little fuel onto each piston to check for leakdown but a)I don't know if this is conclusive and b)I don't know how to check the crank bearings. Is it simply a case of the bottom end is either good or it's not? There's definitely something not perfect in the head as it sounds "tappety". It actually sounded worse after it had been in to have the clearances done???

Are there any relatively inexpensive upgrades worth doing while the engine is in bits? A lightened flywheel seems to be a must. Does anyone make a crank scraper? Are there any head mods worth doing? I wouldn't change the cam unless the original is worn and as i said earlier reliability is my main goal here but if i could pickup a few extra ponies here and there for minimal outlay then why not?

Thu Jun 16, 2016 10:27 am

N00b wrote:
DHFiS wrote:If the bottom end is good could you get away with a just reconditioned head?

New injectors and new breather hoses and you should have an engine that will do another 100,000 miles.
The car doesn't get used much and to the best of my knowledge it doesn't use/ burn/leak any fluids. If this is true then how can i check the bottom end with or without the head in situ? I was thinking a compression test wouldn't work as i could have a valve leaking. I've seen people pull a head then pour a little fuel onto each piston to check for leakdown but a)I don't know if this is conclusive and b)I don't know how to check the crank bearings. Is it simply a case of the bottom end is either good or it's not? There's definitely something not perfect in the head as it sounds "tappety". It actually sounded worse after it had been in to have the clearances done???

Are there any relatively inexpensive upgrades worth doing while the engine is in bits? A lightened flywheel seems to be a must. Does anyone make a crank scraper? Are there any head mods worth doing? I wouldn't change the cam unless the original is worn and as i said earlier reliability is my main goal here but if i could pickup a few extra ponies here and there for minimal outlay then why not?

yes you could do a compression test, just to be on the safe side,

as for the bottom end, you could get the sump off & check the bearings etc.

crank scraper? US only it seems though they do pop up on ebay from time to time.
best bet in that case would be a sump baffle extension plate, mainly from the US but if you know any machine shps in your area i can send you the .PDF file to get one made,

i got mine made up through maxfield & it only cost me £20 insread of $50+ intl p&p from the states.

Thu Jun 16, 2016 10:29 am

nearly forgot, head mods?? if you want to go down that route i;e port polish, gas flow, 3 angle valve seats, port matching, etc you need to find some one who knows & understands how to do it properly.

for that i would suggest maggspower.

Thu Jun 16, 2016 10:31 am

Unless its been seriously neglected or abused, a M20 short engine with just 160k on it, should be as good as new.

Thu Jun 16, 2016 1:54 pm

Who ever did your clearances should have noticed if cam was worn but it is easy to remove valve cover and check it for yourself.

P.s. Look for wear on rockers too

Thu Jun 16, 2016 2:01 pm

Brianmoooore wrote:Unless its been seriously neglected or abused, a M20 short engine with just 160k on it, should be as good as new.

Hard to say. It had 140k on it when I bought it.

Thu Jun 16, 2016 2:03 pm

steve_k wrote:nearly forgot, head mods?? if you want to go down that route i;e port polish, gas flow, 3 angle valve seats, port matching, etc you need to find some one who knows & understands how to do it properly.

for that i would suggest maggspower.

I just wondered if there was anything worth doing while it's apart. As I'm not chasing more power triple angle seats would be an unnecessary expense for me.

Thu Jun 16, 2016 2:11 pm

Exhaust valve guides are the bit that wears on the top end.
On a 'normal' M20B25 at 160k, I'd expect everything else, after a bit of valve refacing and seating, to be within original factory tolerances.

Thu Jun 16, 2016 5:10 pm

Brianmoooore wrote:Exhaust valve guides are the bit that wears on the top end.
On a 'normal' M20B25 at 160k, I'd expect everything else, after a bit of valve refacing and seating, to be within original factory tolerances.

Knowing you're the zones version of macgyver, I realise you may not be able to answer this but could you give me an idea how much it should cost to do such a refresh and, if possible, recommend someone/somewhere to do it. I realise you can do this kinda thing with a rusty spoon and two kitkat wrappers but I haven't done a head disassembly before and as I'm still mid house renovation I don't have anywhere to do so.