What carb needles are in it? I would try Ms to start with...
If it dies when warm and won't restart until cool, check the valve clearances are not closed up.
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| New motor - bad vibration https://www.ausmini.com/forums/viewtopic.php?f=2&t=9164 |
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| Author: | Matt68 [ Mon Jul 18, 2005 10:07 am ] |
| Post subject: | New motor - bad vibration |
OK, I really need lots of help and advice. Problem; new 1275 motor, freshly rebuilt. In car again. (twin hs2 SUs, cooper s style extractors, custom steel maniflow inlet manifold, electronic ignition, cooper S cam profile, electric fuel pump.) Takes lots of choke to get started. When it is going, it sends a really bad vibration through the entire car. Not a violent one, but a fairly urgent buzz. Like the whole motor is vibrating at a high frequency. The motor dies once the motor is warm, won't start again. Mixture seems to be weak (lift pin on underneath of carb, motor stalls) even though i have wound down the mixture nuts 4 complete turns. Idle is set at 1000 rpm, static ignition timing at 6 degrees BTDC, new plugs, new leads, new dizzy cap & rotor (new dizzy). Please Help, I have just poured my heart soul and many $0000's into this car and I'm a little heart broken at the moment... Ideas anyone??? Matt |
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| Author: | drmini in aust [ Mon Jul 18, 2005 10:20 am ] |
| Post subject: | |
What carb needles are in it? I would try Ms to start with... If it dies when warm and won't restart until cool, check the valve clearances are not closed up.
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| Author: | FatMaserati [ Mon Jul 18, 2005 10:26 am ] |
| Post subject: | |
It definately sounds lean. And yeah, as the Doc says, check valve clearances. When you put the engine back in, were the engine steady bars rebushed and tightened properly? (Though I don't think this is why your engine is vibrating as such, still, better to eliminate possibilities) |
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| Author: | Circus_Maximus [ Mon Jul 18, 2005 10:28 am ] |
| Post subject: | |
G'Day Matt, Make sure you don't have an air leak in the intake manifold. Two possible sources, Manifold not located properly when you no longer have the locating rings fitted in the head (due to a bit too much inlet porting - In my opinion), what I had once when the extractors were fitted (they were expensive crap) the bends from the head were not tight enough so the inlet manifold bolted up firmly BUT interfered against the exhaust manifold and could not seal both ports at the same time OR secondly an air leak from the brake booster or dizzy vacuum advance (If you have either). |
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| Author: | drmini in aust [ Mon Jul 18, 2005 10:30 am ] |
| Post subject: | |
A guy on MM forum had this vibe problem- turned out he had not bolted the straps to the flywheel properly, so the diaphragm cover and backplate were running in orbit. 
You can check this by looking thru the starter hole (minus starter)- jack one front wheel up , put in 4th & turn wheel..
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| Author: | Matt68 [ Mon Jul 18, 2005 10:52 am ] |
| Post subject: | |
drmini in aust wrote: What carb needles are in it? I would try Ms to start with...
If it dies when warm and won't restart until cool, check the valve clearances are not closed up. Thanks Doc, I have M needles in there now, with red springs. I'll check the valve clearances, hadn't thought of that one, They were set to 15 thou cold, by the 'longer' rule of nine method in the manuals...
I'll check the flywheel straps too. I could've sworn i did them up right but....  .... I have been known to make mistakes. (at least I learn from them tho')
Circus_Maximus; There are no locating rings, as it is a maniflow manifold, but when fitted it locates on the studs. Looking down the ports, it is a perfect match!! No servo takeoff, and the vac advance line is good. There is some play in the carb spindle bushes, so maybe there is a vac leak here? i'll get them sorted soon too. FatMaserati; Yeh, the engine mounts & steady bushes all new. It doesn't move at all, (it's not visible vibration, like where the steady rubbers are gone, I got that on my 78 van  ) it vibrates. like you put your hand on an .. um.. vibrator? But a big one!! Kind of like when holding an angle grinder.
Thanks all, I'll check up on these ideas this weekend, & if you have any more keep em comin! I'll let you know how I go Matt |
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| Author: | 9YaTaH [ Mon Jul 18, 2005 12:35 pm ] |
| Post subject: | New Engine |
Just remember also that a remanufactured engine may be tight and overheat for the first couple of hundered miles....need to take that into account as well. |
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| Author: | Matt68 [ Mon Jul 18, 2005 12:43 pm ] |
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Yep, should have mentioned, when it got warmed up (10 minutes of running) it sat at about 80 degrees celcius. (i have a 74 degree thermostat and an auxillary radiator.) is this a bit high or OK? Matt |
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| Author: | poeee [ Mon Jul 18, 2005 12:47 pm ] |
| Post subject: | |
80deg C is normal running temp. |
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| Author: | Matt68 [ Mon Jul 18, 2005 1:07 pm ] |
| Post subject: | |
Thanks Poeee!! Thought it was OK, but wasn't sure. Matt |
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| Author: | scotty [ Mon Jul 18, 2005 2:46 pm ] |
| Post subject: | |
Circus_Maximus wrote: G'Day Matt,
Make sure you don't have an air leak in the intake manifold. Check this by spraying a bit of carby cleaner or wd40 around the gaskets. If the revs rise - there is a leak  .
Correct me if I am wrong anyone 
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| Author: | MiNi MuLiShA [ Mon Jul 18, 2005 4:07 pm ] |
| Post subject: | |
scotty wrote: Circus_Maximus wrote: G'Day Matt, Make sure you don't have an air leak in the intake manifold. Check this by spraying a bit of carby cleaner or wd40 around the gaskets. If the revs rise - there is a leak .Correct me if I am wrong anyone only correction i can see that has to be made is.... do it on a cool or cold motor... not a hot one 
sure does make life interesting.. but its a great idea! -Cam
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| Author: | Matt68 [ Mon Jul 18, 2005 4:12 pm ] |
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I have also heard that if you drip some oil on the gasket/manifold face and see bubbles that's where the leak is. Bu tMy bro told me and he's usually full of it so anyone out there know of the best way to check for vac leaks? Cheers matt |
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| Author: | FatMaserati [ Mon Jul 18, 2005 4:19 pm ] |
| Post subject: | |
Just following on this, and it may be related to your problem, but after a crappy morning (car wouldn't start - got RAC to come have a look - crappy battery pretty much), I was driving my Mini around and noticing that when I put my foot down reasonably hard, the engine would vibrate horribly and make this bad "nasty fluttering" sound. I let the car idle as I popped the bonnet and had a look. The rubber gaskets around the screws that hold the main jets in place (on my 40 DCOE Weber), had perished, and fuel was pissing out of there when it idled, as well as air being sucked in when revved hard. I made new gaskets myself, and boy, she is a fast sonnuvvabeyutch now. After experiencing a leak in my carby/inlet manifold this morning, you can probably bet that this is your problem (most likely, and most hopefully!). Do the aforementioned trick to see where your leak may be. |
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| Author: | Matt68 [ Mon Jul 18, 2005 4:34 pm ] |
| Post subject: | |
aforementioned trick? Fuel (yours)
Oil (mine - sort of) WD40 or carb cleaner ( Cam)
Matt
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