this head is definately not 27ccs i`m sorry to say

looks pretty stock to me,,, even slightly smaller than stock cause it looks to have been shaven a tad

so definately ot 27cc`s

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Yeah it was only a quick test to see if the old head was substantially different. I'm just going to put the new head on and check compression. I don't really think I have any other choices

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If its yours, customize it !

You really should work out your compression ratio before you put the head on. Because your engine is a 1380 and that head with stock looking chambers, if your pistons come to the top of the block your going to have some pretty high compression which is going to be a really bad thing.

You are much better off taking the time to setup a way of measuring the head and block cc's then putting the head on and having continuous problems

11:1 then u got to start using 104 octane once u get into 12:1 and higher

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A good friend will come and bail you out of jail...but a true friend will be sitting next to you saying "Damn...that was fun!"

Doing a compression test will not tell you anything about your CR and how your engine will run with a particular head.....

Dicko.

Yeah, that's probably the case in a lot of bigger motors These little ones with their crappy flowing heads actually don't mind running high comp. My blue mini in my avatar is running a 11.2:1 on 98 and loves it The standard Metro HLE runs 10.3:1 from the factory. A major contributing factor is also the cam, higher lifitng longer duration cams have lower dynamic compression so they actually NEED higer static compression ratios to make any kind of decent power

Good point though, with a 1380, it's easy to end up running a stupidly high compression ratio with the wrong piston and head combination
[edit]


Too true dicko, and that comes back to what I just mentioned about static v's dynamic compression ratios (also the condition of your rings, how well your valves are sealing etc)

Take the time and work out what you're running before you assemble it, its not worth rushing these things

[end edit]

looks like about 5 or 6-ish cc`s difference to me

so if your old comp ratio was 10.2:1,,, then your new comp ratio will be upwards of about 11.3 or 11.4:1

ish

a bit high for pump fuel

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I guess i trusted the guy that i bought the head off too much. I asked if this head would be fine for a 1380 running high compression and he said that it would be more than comfortable to handle it. The heads on now. Not sure what my best option is now. By the sounds of it people believe that the combustion chambers need to be bigger. Just really un sure of where to go from here.

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If its yours, customize it !

That "Done up head" you are showing seems to me that the valves especially the exhausts are a bit too far down in the seats. Might be better off going up a size in the valve to bring the valve seating higher in the seat.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

The guy you bought it off of might have been meaning that the head will work well on your engine (which is running a high compression ratio). Not necessarily meaning anything about how this head might change your compression ratio. Just a thought.

The chambers might not need to be bigger, that depends on how the pistons sit in the block. The piston crown might sit down from the deck of the block enough to lower the compression to a suitable level. The pistons might have a large dish.
Or the pistons might have a small dish, and be flush with the deck, in which case that head will probably make it too high compression.

That is why you should measure these things. It is better to be safe then sorry.

Yeah ive screwed up pretty bad. Not sure if its of any help but i did take photo's of the pistons before i put the head on. They are dish but not sure if it is standard dish or not.
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If its yours, customize it !

Nah, haven't screwed up yet... haven't screwed up till you assemble it and find out that you should have checked all these things before hand.

Doesn't matter if your pistons are standard or not, you should stilll measure them the same way we got you to with your head, using a CD, like the doc suggested, or a sheet of acrylic with two holes like I do and a burette or syringe

So remove the head,Measure the compression chambers and the piston dish and work out the compression ratio ? Thats my first step? then modify if the ratio is too high?

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If its yours, customize it !

You could do it the way motorbikes do, with head on, it's easier. More accurate too.
1. Face car uphill.
2. Remove the spark plugs.
3. Position #1 or #4 piston at TDC, compression stroke (both rockers loose), TDC timing marks in line.
4. Fill a syringe with light oil of some sort. I suggest ATF, it's thin and cheap.
5. Fill the cylinder through the plug hole until ~1/2 way up the threads.
6. Read off the amount you put in, this is the total CV from my formula above. Calculate the C/R, `displacement' being engine size/4.
7. Put a bunch of rags in front of the motor, crank for a few secs with plugs out. There's only about 36cc or so in there, not too much mess.
8. Refit plugs, hose any ATF off the front of car and you are good to go.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Cheers dr mini ill do that

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If its yours, customize it !