[engine_work] Xu9j4 Mi-16 Rebuild

[kyepan 291]

she's been getting a thorough seeing to of late, dirty slut. I gave her a wash and then resealed her leaky dip stick, we shall see where the leak returns from. In the mean time, she'll get some more of what's good for her.

 

Needless to say there was oil in the block webbing around the dipstick, and over the gear box.. which would lead me to think cracked breather and or venting from the dipstick.

 

My catch tank doesn't appear to be catching anything.

 

Amazingly she doesn't have a leaky sump.

Edited August 3, 2012 by kyepan

[kyepan 291]

update - misfire, which i thought was from oil everywhere, is not from oil everywhere, as i have cleaned it up and it's still doing it at very low throttle openings.

Also it was definitely coming out of the dipstick, as opposed to breathing through the catch tank, it breathed through the dipstick.

 

Need to figure out a way of sealing the dipstick more effectively, and check that the bodies are still in balance, tps still correct.

Small low mid range flat spot at WOT..

 

will investigate this evening and report.

[DanteICE 72]

This is without a shadow of a doubt the most uninteresting and dull thread I've ever read.

 

Trollollolllol

 

On a serious note, brilliant stuff and you should be really proud of that; I've been gripped. Although if I get in trouble at work for not doing my work I'm going to point my boss in your direction.

[Batfink 201]

can you get a new dip stick and tube? Would that solve things....

[kyepan 291]

I looked for a month and didn't manage to find anywhere that would sell me one it's been bodged for the time being.

 

 

On the misfire - it's getting worse, slightly more throttle required to clear it, and it's sounding distinctly hoarse at light cruise and over-run exhaust note has. It runs clear when given lots of throttle.

 

We've located it to a cylinder, it would appear that cylinder 1 (cam belt end) is misfiring at idle and under light throttle loads. When we removed the plug lead for that cylinder it made no difference. It is sparking to the lead, the coil will cross a gap of an inch or more as you try to plug it on but it's clearly not happy somewhere. Perhaps a break in the lead, perhaps something up with the plug

 

The car is also smelling of fuel at idle, which tells me it's not really combusting properly.

 

I checked:

The throttle pot settings and they are fine

re-balanced the bodies to 5 (what sandy set them to) as one was at 4 and one at 3

Lifted a plug out of the offending cylinder, looked normal light brown colour.

 

Plan

Swap two of the leads over and see if the misfire moves to another cylinder, are the wasted sparks on the diagonal?

Put in the spare set of plugs and see if it's a cracked plug.

 

Buy a spare coil pack to keep in the car, buy a spare set of leads to keep in the car..

Fit leads and coil pack to make sure...

 

Compression test.

[welshpug 1,675]

1+4 and 3+2, usually paired top and bottom, most marked to show thst, unlimely to be a coil though, two would be down if it was, check injector wiring and try new plugs

[kyepan 291]

right, fiddled with the leads but they seemed to spark and it seemed to run clean at wider throttle angles, then i heard it.

 

Hang on a minute, Listen to this..I know that sound, but where on earth is it coming from, surely an air leak on bodies isn't possible. sounds localised too, funnily enough, around cylinder one, the one that is not happy.

 

found it!

 

Now fixed, nothing to do with electrics at all, the silicone between the bodies and manifold had deteriorated.

 

1) Took the top plate that holds the two together off

2) Resealed all of them, even though it was only 1 cylinder.

3) Checked balance, and sure enough it was out, so i rebalanced the cylinders with my gauge.

 

4) BRAP is back.

 

Quiet as a mouse under the bonnet though.

[welshpug 1,675]

WIN! WANT!

[DanteICE 72]

Very impressive...good bit of hunting there!!!

 

Geoff

[kyepan 291]

A quick update, mostly fuel delivery related.

 

I had previously shown you all the bodge, however it needed fixing, so here is the tapped and threaded fix, i wasn't happy that the engineer didn't get it totally true to vertical.

 

 

 

But he assured me it had enough thread in contact to prevent any sort of leak. He said i could have the keys to his workshop if it did.

 

 

Secondly, the new routing of the fuel hoses to feed both fuel rails met a slight snag, in so far as my lack of securing caused some very slight rubbing on the goodridge fitting from the alternator fan.

 

As you can see it's worn away the screw on connector, and the hose end.

 

Once apart you can see that it wasn't that near to penetrating and looked worse than it was.

 

 

 

 

Bought a new t piece and 3 hose ends, so a fitting fitted and everything carefully cable tied and protected with anti rub corrugated sleeving. Lesson learned prior to fireball. I also bought an MSA spec fire extinguisher to go in the cabin, lest anything untoward happen. Where do people usually mount these?

[welshpug 1,675]

Extinguisher usually goes under the passengers knees

[kyepan 291]

Extinguisher usually goes under the passengers knees

do you screw it straight up into their knees to mount it? what happens when they aren't in the car?

[guffe 2]

do you screw it straight up into their knees to mount it? what happens when they aren't in the car?

Of course you have to secure the passanger to the car permanently. Stupid.

[kyepan 291]

For some reason it won't rev when you first start it from cold, for the first five or so seconds, and there appears to be some kind of air leak again, making a squealing noise.

 

It's definitly not running right at very small throttle openings, all sandy's good work on the cruise ignition seems to be wasted currently as it needs a hefty bit more to go, and goes with a jerk, behaving a bit like jetronic...

 

I'm going to pull the inlet and bodies off completely, to look at the flare on the bodies fuel rail inlet pipe, and re-seal the bodies to the manifold in a more belt and braces style way, making sure that the correct type of silicone sealant is used.

 

Cheers

J

[dcc 855]

from my own memory, mine didnt have any 'sealant'. although they were jenveys, they had an oring. the gasket (when sandy fitted it) was a generic pattern one from a motorfactors and was applied with grease rubbed into it. he said this is the best way to get it to seal to both surfaces. I had no complaints as after 6-7 hours of fettlign and mapping, the car then felt like it was a rocket.

[kaich 6 1 Cars]

really awesome job mate

[Batfink 201]

Could you fit some jenveys or similar instead? Maybe using a bolt on flange plate with the right hole spacing. I might be able to get a hold of some rather cheap tb's.

[kyepan 291]

i would probably need a new manifold in that case, but lets discuss it, thanks.

[welshpug 1,675]

I have a DCOE pattern manifiold that Colin made for Pete (MadProf) its no use for my engine bay but might work on an ally block in a 205...

[Paul_13 212 1 Cars]

[welshpug 1,675]

a wee bit small Paul

 

hmm, see what you're trying to do there, its broken!

 

 

http://i1224.photobu...1027-WA0000.jpg

Edited November 9, 2012 by welshpug

[Paul_13 212 1 Cars]

[kyepan 291]

it seems to be trying it's hardest to empty it's oil out of the dipstick... my patience is wearing thin. and the catch tank doesn't seem to be catching anything. Although that said, it's still rapid and sounds lovely, handles like a kart.

 

Took a mate out in it last night, he was giggling like a little girl and said it had masses of grip.

[kyepan 291]

so - a little update

 

The car seems to have a waterleak - or at least it's using water, the header tank was empty at ace the other week, so either the head is going or i have a waterleak from the bbm hoses, or the cap is not working or the thermostat is not working properly.. all will become clear in good time.

 

Fixed the o rings on the bodies for a second time, this time the o-rings i purchased were not thick enough in cross section, i had 3mm and got 2mm.. the difference seems to be important, it started leaking again with the tell tail phutting noise. So will be ordering some 2.5mm cross section o rings of the correct diameter to fix the air leak in the bodies once and for all. Once the hand is out of plaster and the wrist works.

 

Next - more camshaft.

 

Now i need to ask a couple of silly questions as i'm trying to figure out my static compression ratio.

 

The head has been skimmed on it's initial rebuild, then welded and skimmed again on this rebuild.

The liner seats have been recut, and the block deck refaced.

 

Now if i correctly recall, Paul Gardias said the absolute minimum he could take off when skimming or refacing was 4 thou, or 0.004 inches / 0.1016mm, what he did take off i'm not sure.

 

So the question - what would be considered an average skim? is there such a thing? there was a reasonable amount of pitting.

 

firstly based on the minimum of 0.004 inches 2 x skims = 0.008 inches /0.234 mm off the combustion chamber height

which gives a 1.08 cc reduction in combustion chamber capacity. down from 40 to 38.92

 

Secondly if we take that he just refaced the liners, liner seats and block deck, we can reduce the deck height above the pistons by 0.004 inches / 0.1016mm too. Which would take it from 0.4mm / 0.0157480315 down the bore to 0.0117 inches deck height.

 

All of this adds up to 10.72 static compression ratio.

 

Please advise if my 4 thou skims are a bit on the pessimistic side, and is there any way of measuring the head height in situe.

[petert 607]

If he took 0.4mm off the block and the head has been skimmed to its maximum (approx. 0.5mm), you'd be around 11:1. Were the valve pockets deepened at the same time? If not, I wouldn't get too excited about bigger cams without taking some measurements.