Author Topic: 73 Mini Innocenti 1300 Export  (Read 49045 times)

Offline Vikram

Re: 73 Mini Innocenti 1300 Export
« Reply #475 on: April 26, 2019, 09:22:45 AM »
 Ok interesting, probably won't find anything on mine then

Offline Jimini II

Re: 73 Mini Innocenti 1300 Export
« Reply #476 on: April 26, 2019, 05:20:40 PM »
I have had an acquaintance ask about checking the VIN of an Inno Mini.

I know the VIN on an Inno is stamped/tagged differently than regular Minis with a prefix stamped directly into body metal somewhere - usually a prefix is something like B38/??

Can Dan post a picture of the location(s) of the stamped prefix and any tag(s) from this Inno as a reference point I can pass along?

Thanks.

I worked on one a while back Michael a 66 or 67 and the vin was stamped into the inner fender on the brake booster side just above where the solenoid would mount on an early car

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #477 on: April 26, 2019, 05:32:28 PM »
I got the crank back today from the cranky guy and have started some basic assembly. Before I go there I took some pics of where he had to take metal off the crank to get it balanced. One of the rods was considerably heavier than the others and it took quite a bit of metal off to get it balanced out. I also made a little video of checking the thrust bearing clearance.....the clearance spec is 3-5 thou, we have 4.

1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #478 on: April 27, 2019, 03:07:16 PM »
Today I put the pistons back on the rods, and put one in the block so I could establish TDC. My pointer lined up perfectly with the TDC notch in the front pulley.

Next I've started dialing in the camshaft, but I need to find the specs on this particular cam....nothing came with it. I think I figured out why I had so much trouble getting the cam timing set on Dan's engine. I think the first time I set it I may have been using the exhaust valve instead of the intake...but I figured it out in the end...…  :-[ ::) 8.gif
« Last Edit: April 27, 2019, 03:09:36 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #479 on: April 28, 2019, 03:21:35 PM »
Setting the cam timing - the standard woodruff key gives 104, and the offset that was in there gives nearly 115, since what we're after is 106, maybe I'll just leave it alone. I doubt I can buy an offset key from any of the local auto parts stores, but I can call the engine builder nearby and see if he has any. I'm doubtful tho…..I can get them from MiniSpares in sizes from 1-10* offset, but at this time I don't need anything else so......
« Last Edit: April 28, 2019, 03:30:27 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #480 on: April 30, 2019, 11:35:47 AM »
11/32 - 24 rod nuts?

I bought some new rod nuts for this engine from MiniSpares - they're 3/8-24 like every other Mini I've ever seen - and they don't fit. So I tried a 5/16-24 - too small and 3/8 is too big. WTF?

Anyone ever run across this? If so, where did you get some new rod nuts this size? What part number are they?

I have the original rod nuts which do fit, but MS does not indicate in their listings what size they are, and I bought what they claim are the correct new updated nuts - but they're 3/8-24...…

I may be whistling past the cemetery but I've never had a rod nut come loose or fail in all the engines I've built.

Edit: Summit Racing carries 11/32-24 rod nuts, they were used on the very first Chevy V-8's in '55
« Last Edit: April 30, 2019, 12:54:29 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #481 on: May 01, 2019, 02:56:58 PM »
I got the pistons all ready to install, all the rings in, bearings cleaned and ready to install. I put a couple of short pieces of fuel line on the rod bolts so they wouldn't nick the crank when I pushed the pistons home. I found my smaller ring compressor and slid everything in and tightened and torqued the rod bolts. I'm still looking for the right torque spec for the rod nuts,, normally it would be 35-40, but that's for 3/8" rods bolts - these are slightly smaller at 11/32.
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #482 on: May 01, 2019, 03:07:23 PM »
That gap from the top of the piston to the deck gives me pause.....wonder if the rod length is different between the rods for the 1 3/4' journals and 1 5/8" journals? I haven't found a spec yet....

In the teardown pic they look closer to the deck height.
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #483 on: May 02, 2019, 10:51:51 AM »
Almost have a completed rear end.  This light was fiddly, especially when a stud broke when I had took it off initially.

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #484 on: May 02, 2019, 11:34:56 AM »
Well, seems the original crank was stroked, and the pistons modified to work with the stroked crank and that's why when I went back to a std crank the pistons are sitting so far below the deck.

So, mulling choices at this point.....

1) Go back to the original crank and rods - to do that I'll have to have the damaged end machined - to fix THAT, I can buy the 998 primary gear which has a smaller bushed end, and machine the old crank to fit - that will fix the damage. Then use the original crank, rods and pistons - that will get the pistons flush and give us a 1410cc displacement - Big motor! I'll also have to buy new rod and main bearings as they're different than those for this crank. I'll also have it all rebalanced.

2) Carry on with what we have, and machine the block down to get the pistons flush and the compression ratio we want - probably the least expensive way to go. Displacement will go down slightly - back to 1380. And I'll need to cc the chambers to find out how far to go - we don't want to get the CR too high cause then it will need race gas to run and not ping itself to death. This choice won't require rebalancing

3) New pistons with the same crank and rods we now have. We think when the crank is stroked the piston tops are cut down so they don't go over the top of the block. New 1380 pistons should bring us flush again. That will require rebalancing.

Many things to consider......but first I'll get the head cc'd to find out what we have, then we can make a decision and get parts on order....or take the block up to have it decked.
« Last Edit: May 02, 2019, 11:37:30 AM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline Jimini II

Re: 73 Mini Innocenti 1300 Export
« Reply #485 on: May 02, 2019, 12:17:08 PM »
I vote deck the block seems the easiest and cheapest option at this point. Or depending on the CC's measurement maybe skim the head but with as low as that dished piston looks to be in the bore i am thinking that might not be a viable option with the amount of material that needs to be removed.

Always something to throw a spanner in the works.

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #486 on: May 02, 2019, 01:05:20 PM »
"Always something to throw a spanner in the works."

Ain't that the truth! And when it's not even remotely stock and you have no paperwork to tell what it does have, you're on a voyage of discovery.

The pistons are down 75 thou altogether at TDC.....once we have the chamber cc then we can calculate how much we'd need to deck the block to get he compression ration we're after. Then I can decide the best route. The easiest and cheapest and quickest would be to deck the block.
« Last Edit: May 02, 2019, 01:10:16 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #487 on: May 02, 2019, 01:30:50 PM »
Easiest is #2 and probably what we should do, then again it's tempting to have a 1410cc.  4.gif 

Tank restore under way.  Thought I was done sanding and could prime and slap some paint on, but after a coat of primer realized how ugly the one is.

Offline Vikram

Re: 73 Mini Innocenti 1300 Export
« Reply #488 on: May 02, 2019, 03:28:11 PM »
Dave, I saw your picture on Facebook and wow its thin between the cylinders! Didn't realise it would be so close, some serious over bore!

Not saying its a bad thing, simply observing.

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #489 on: May 02, 2019, 03:33:08 PM »
yes, but the head gasket seems to have held OK, no evidence that it's not going to work.
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline Jimini II

Re: 73 Mini Innocenti 1300 Export
« Reply #490 on: May 02, 2019, 06:14:03 PM »
yes, but the head gasket seems to have held OK, no evidence that it's not going to work.

I am not questioning you Dave far from it but looking at the pre tear down picture of the block you posted there looks to be the start of possible head gasket failure between 2 and 3 especially when you compare them with the sealing patterns between cylinders 1 and 2 and between cylinders 3 and 4.
You are doing the build and know what you have seen i am just looking at one picture.

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #491 on: May 02, 2019, 06:31:21 PM »
I do see that…..not much we can do about it now tho, is there?  I mean, the bores are done and all....  ::)  8.gif

I had the head skimmed, and if we have the block decked at least we'll know that we have two flat, accurate and smooth surfaces to hold a gasket - that's about all we can do. I know that a lot of guys bore these things to 1380 and don't have gasket problems, and we have no idea if they retorqued the head or anything. We'll just have to see what happens I guess.

BTW, a stock 1275 head gasket fits these bores perfectly.
« Last Edit: May 02, 2019, 06:34:26 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline Jimini II

Re: 73 Mini Innocenti 1300 Export
« Reply #492 on: May 03, 2019, 01:17:34 PM »
I am still amazed the engine ran as well as it did with the issues it has had, apart from the piston height of course as you are using a different crankshaft.
It should theoretically be better with both surfaces new and flat and maybe some quality hardware to hold the head in place that's all you can do and hope for the best.

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #493 on: May 03, 2019, 02:38:09 PM »
Dave will post more details as he's the engine guy but looks like we may be going the stroked route.  Head chambers are 26cc which are rather large vs 21.4cc stock on a 1275 head.  That combined with the 1.9mm deck  puts compression down to 8:3:1 territory.  Doing the math having 0 deck height puts us at 9:8:1, and with a sliver of deck at 0.25mm gives a 9:6:1 compression.  To get 10:3:1 the block deck would need to be 0 and 2cc off the head skimmed.  But, going back to a stroked crank of around 83mm vs stock 81.4 puts it all back to 10:1 compression without shaving anything.  Also gives us a 1410cc torque monster.

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #494 on: May 03, 2019, 03:11:23 PM »
Once I get the crank back and can measure how far we are below the deck height, I may have them take a fine cut off both the head and block to make sure we have perfect flat surfaces.

Dan has a set of new, high performance head studs and nuts I'm going to use, it's good that it's already drilled for the extra stud and bolt....the bolt hole has been helicoiled too. All the holes were nicely chamfered too, so it's clear someone knew what they were doing when they built this mill.
« Last Edit: May 03, 2019, 03:15:06 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #495 on: May 05, 2019, 06:09:03 AM »
I've been reading up on stroked cranks and 1380s.  Found one dyno from a street 1380 with a stroked crank.  This is roughly what we can expect to see. 

Peak BHP: 105.7bhp @ 5500rpm ATW
Peak Torque: 105 lbft from 2500-5500rpm atw (3 cheers for long stroke)

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #496 on: May 05, 2019, 10:04:21 AM »
Dang, you gave it away!
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #497 on: May 05, 2019, 10:11:51 AM »
Couldn't resist!  Regarding stroked cranks, I'm realizing a huge benefit is an ideal powerband for everyday use.  Most 1275-1380s making the same power require huge cams that only hit big numbers at 7k or up.  You'd get a slug down low and have to wind the engine out, whereas this setup everything is right where you want a street car.  The example figures posted were on a "big" 286 cam, which typically isn't the best option but the stroke fixes that and then some.  Off topic but 7 port heads do better with larger cams too.  If I get around to my 7 port build and do a stroked motor, no telling how big I can go and still make insane power off idle.
« Last Edit: May 05, 2019, 10:14:18 AM by 94touring »

Offline MiniDave

Re: 73 Mini Innocenti 1300 Export
« Reply #498 on: May 06, 2019, 11:15:02 AM »
Went back to the machine shop and we rechecked the cc on the head.....we did a different cylinder this time and it still checked out at 26cc. I also took over an unmodified 12G940 head and it came out at almost 24cc. I'm going to have him skim the head very slightly to clean it up more and it may take us down to 25.5 cc

I'm also going to build my own CC equipment, it's a good bit of info to have on future builds.

The pistons came out at 8cc, they were supposed to be 9 so that backs up the thought that the tops were skimmed slightly for clearance to the top of the block. As I'm going to have a couple of thou taken off the top of the block too - to make sure it's dead flat and smooth - we might wind up taking another couple thou off the tops so we don't go over the top of the block. There's no problem if they do, as long as there's clearance between the valves and pistons when it's all done.

Once it's all back I'll do another dry assembly and measure everything out before we cut anything more.
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: 73 Mini Innocenti 1300 Export
« Reply #499 on: May 06, 2019, 11:27:31 AM »
Ran the updated numbers and it gives us a 1413cc at 10:27:1.