Bmw r75/5 microsquirt project for a newbie

[slow_hemi6]

If that gouge is as deep as it looks, I would say the crank is beyond economical repair.

[fefenin]

Thank you very much for the answer

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[R100RT]

Hello Jeremey, I see you found you way over to the forums @ ADV and some specific engine advice coming your way.
I guess you will go through the process of measurement, or decide on the fate of your engine (my hunch at this time - it is toast and you need another runner).
I have had a gentleman contact me back at the beginning of your inspections - who offers a free engine but is in Northern BC Canada. Shipping on that might be high - but still much lower than the costs of the various parts you are likely to require (crank, all bearings, rods?, oil pump, rings and valve job - it goes on and gets higher being a BMW)
Let me know what you decide to do.

Lorne

[fefenin]

I really would be happy if that engine could come in here. That would be wonderful! ;)

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[R100RT]

Please read your PM messages, I've sent you another one

[fefenin]

Hi, I did answer it

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[R100RT]

hi Jeremy, I have sent you another PM (today, Wednesday March 22)

[fefenin]

Ok so I decided to clean everything on Lorne advise and buy the cheapest crank I can get. Have a look at it and give a try .
Plus I would like to paint the frame while I can remove everything. Maybe redo the wiring as well. So it'll be a near complete rebuild.

Have a question in regards for microsquirt use.
I know now my injection overflood the engine.
The values in cc and displacement is for the full size engine right? Not only one cylinder?

For example : one injector is 310 cc /minutes and my engine 750cc.

Otherwise if I put the right values and it is flooded I don't know how to do except by cheating the injector values... 500cc for example.

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[R100RT]

The fuel calculation is based on the total displacement, not just one jug.
Why don't you post your last msq that seemed to allow over fueling for you (lots of time with mechanical work going on). There are numerous things that all come into play for the final fuel delivery.
And good for you for doing up a restoration. It will be critical to observe any and every little clue as you are cleaning things and measuring parts. You have to be able to say "this is why the bottom end failed" - because they are very robust and don't often fail like this.
Even a flaky oil pressure sender that may not have advised you the pressure was low at an idle/ low oil level/ poorly fit internal oil filter with its delicate shimming/ or something else.

[fefenin]

here you go ...
not sure witch one i was running lastly.

ok
got a new crankshaft
got second hands heads from a 80 g/s
got second hands rocker arms with roller bearing for my heads

plan to rebuild valves , guides and seats for those new heads
check pistons and cylinders

camshaft oil pump keys is busted ... not sure what to do maybe solder in and macine out again the metal...or find a new one
it is gettiçng expansive now

[R100RT]

Use care on which valves, guides, and perhaps seats that are used, as certain parts don't seem to work as well (Motobins sells BMW valves at a very reasonable price - they are actually TRW but authentic) Are you certain your heads were not suitable to freshen up? and replacement of the seats is not that common and being an aluminum head requires top level shop procedures - otherwise they are rattling out and initiating a whole new round of greif for you. But perhaps you got a good deal on the spare heads?
If your oil pump drive key is sheared off - did that happen during disassembly or was it sheared when you checked it? Perhaps that has something to do with the bottom end failure - if so then your oil pressure warning circuit requires a close inspection - or add a mechanical gauge for peace of mind.
I looked at both those templates, and the following might be creating rich fueling:
- not sure what kind of injectors you have, but the dead time setting of 1.0 may be a bit high. If you haven't ran the test to prove the setting (actual fuel pumped and numbers recorded for the Xcel file) then you might be able to prove it by the "number of squirts" method that can be read about here.
- on your afr target table, you should keep in mind that our boxer engine spends the majority of its map time at or above 70kpa, as well the engine likes to be between 3100-5000 but really does best up high, so your targets are rather rich. I'd be keeping those closer to 14.7 in many of the bins down low etc.
- how is the seeming accuracy of your Wide Band readings? If you have a dedicated gauge that you can compare to TS, are they similar readings. Where is your sensor mounted and at what angle from vertical?
- is your fuel regulator vacume referenced, or one pressure throughout?
- you mention above that you have 310cc injectors, but both those files have 290 listed?
- I have much lower VE bin numbers (until boost), but again it is important what your wide band is saying is happening and if its accurate. (however, my fuel regulator is 43.5, and is boost referenced so goes up as boost does).
- the enrichment tables are all areas that may create some rich running, but best thing is to establish proper running for a warmed up engine, then return to those (start up, warm up, etc.) to gain good starting and initial running from cold. Again, you have to be able to trust your WB. If plug readings are vastly different then its probably inaccurate.
A couple of other things that don't relate to afr, but why have on your "Gauge Settings Limits, the rpm warning down at 3000? Also, you might find it better and easier on the starter to reduce those ignition timing settings down low and for cranking.
Lots to go over, lots of time.
Regards, Lorne.

[fefenin]

OK
first of all , my rocker arms were quite dammage, and you had to center them very accuretly so the valves could turn to be . my heads were good but the r80 G/S i found were nearly free and i had to buy the rocker arms assembly from ebay ...

for the valves i things i needed to change the guide and valves anyways on my genuine r75/5 heads. so it it the same to do it on the r80 G/S ones ...
the rockers will be in place it no risqk of doing it wrong.
i think the seats don't look so good so i'll see with the machiniste nearby (looks like he knows thoses engines) if it not safe i'll ask if we can only ground them

the oil pump key sheard off a bit but i heard it is a common problem on early machines cause it was design too weak. it was like that before i openned everything that is for sure. the pump was still driven for sure.
i didn't have any oil pressure switch before i installed microsquirt. and i guess failure is just because when i was tennager i didn't put any oil either change the filter
every holes looks clean inside the engine case.didn't check the oil pressure releaf valve yet.

injector is green injector from ducati 748 on a thread i found : IWP724 = 308cc/min on some others 300cc not pressure...

how can i test the dead time? with a seringe for exemple and few pulses??

for the afr i'll have a look to it to be closer to 14.7 for bin down low

the accuracy of the wide band is very sharp according to datasheet there is a software that is used to calibrate the sensor with microsquirt at start up so it is the exact same reading as the gauge.
the sensor is mounted as recommended in the datasheet : 2ft away from exaust port on left side tube about 30 deg from vertical and it is just after after left cylinder and before my feets ;) noi much room for gear switching.

my fuel regulator is a cheap one from ali express , but it seams to do the job it is set to 3bars and i didn't connect the vacumm port cause it looks like pressure is not dropping even under load. i guess not referenced then

yes i mention it just randomly, i did put 290 because i found that somwhere on internet, 308cc at 3 bar should be more proper, my mistake.

wide bande was going of scale while running so i did'nt know what hapenned. and i guess the engine was not running smothly when warm because of the huge knocking of the crankshaft.

i guess i did try to limit at 3000 rpm when cold to prevent the knocking ? not sure about that or maybe to try some features can't remember.


today i did clean the case and oil holes...
remove the posts from the r80 g/s head so i can fit the last /7 series rockers when they arrive.
redo the threads on one exaust head ports.

check the oil pump mesurements and they looks ok .

so i guess i just have to wait for the new crank and go to the machiniste for that the rods and the valves guides.
then find the main bearings size i need

it is going on step by step, to slow for me but still...

[LAV1000]

Getting dead time from injectors right.
I did use a kitchen scale and measured the weight.

[fefenin]

Could you tell me more about the way to do that please?

found this by the way (again different values) : IW-724 285cc 2.25bar 15.4ohn EV1 connector

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[R100RT]

The proper way to calculate dead time is on this "U" tube video, but a bit more involved and dangerous if you're using gasoline.
https://www.youtube.com/watch?v=lJgi8l-2XG4

The cheat method is outlined from a post below - perhaps not the best description but all I can quickly find this morning (need to get back to work):

The way to check dead time in the car is to change the number of squirts per cycle. What you want to do is let your project idle and take note of the AFR. Then change the number of squirts per cycle (either more or less depending on where you were) and observe the AFR again. It should be the same. If you get richer with more squirts / cycle, then the extra fuel is coming from extra dead time every squirt. If you get leaner with more squirts, then you have not enough dead time. It's an iterative process. Make sure you never idle the engine at a very low PW because it may throw you off if you're near the non-linear part of the injector PW. I used 1 squirt, and 2 squirts, cycle key between changes there.

This however is way ahead of the cart and the mechanical work underway should be the thing you are most concerned with.
Regards,

Lorne

[fefenin]

Thanks for that. It is just do I can prepare myself and do it when everything is back together.

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[fefenin]

It has been a long time. Ok so I had the engine case checked and the camshaft bearing that is aluminum at the back behind the oil pump is of values ... Don't know what to do. Front bearing of the camshaft is limit. And I don't know how it is possible cause it is screwed in. Maybe this can be mounted with glue. The rest of the engine is fine , even good.

Have nice day

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[R100RT]

The bearings used on the mono block, their installation, and certain retention methods are rather unique to this engine. You will probably gain best advice on that over on your post @ ADV - lots of guys there that have worked on this engine many times and can save you the greif of a small mistake, plus how to solve wear problems. Not sure if you are saying your rear cam journal is over spec for wear? Some machine shop expenses may start to develop here salvaging the block then.

[fefenin]

Yes the rear cam journal is over spec from wear. I will post there then! Thanks

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[fefenin]

Ok it's been a long time but I had my engine block checked with the crankshaft and few other parts. And a lot of things were wrecked. I had a hard time to find an engine block with the camshaft and front bearing in my budget... I am now on for a new rebuild adventure ... Change all the bearings front back and main crank bearings... Would like to be very accurate with that so the engine can last long. Need to rebuild the valves as well. I also realized that when microsquirt died last time I had the Aled and Wled lightly lit even when the software had the led off so I wonder if I did wired it wrong ? Need resistor or something maybe or the grounding was wrong. So looks like I am back in business for a while.
Wants to make a part to hold a new sensor for camshaft also so I can go full sequencial this time. I had an issue with the bike being probably way to rich and I have to read again how to manage that. I remember someone saying that it could be my injectors being to big. Could someone comfirme that I can make it work like this? Or else I would go for a r80r injectors body so I would be closer to the specs of my bike but need more money and mods then. Thanks in advance . It is late and I hope to be clear enough.
Good to be with you again

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