brief history - changed carbs, engine management devise (renix?), all pipes and hT cables, new cambelt, idle solenoid etc. Even rebuilt the carb with new gaskets and things. Emmission levels are good.
The motor is running fine and will initially tick over just fine at about 800 rpm However, it hunts/searches a bit as the tickover is not as smooth as it should be. It eccelerates well and the motor will spin up to the redline in fine stile in 2nd and 3rd. (I don't do that in 4th or top so as to stay in touch with my licence.
However, following a run at a decent speed (65 plus) as I slow up or stop at junctions, the revs rise to 16/1800 rpm and then fluctuate between that and 10K. On the over-run with reduced throttle it's snatchy and I often need to drop a gear to keep the revs up in line with the speed i.e. above 18k rpm.
So the only thing I haven't done anything with is the inlet manifold. Do you reckon the problem is there?
The idle solenoid is the same thing. You might want to consider the fuel cut off box though, its located in the engine bay attached to the passenger side wing just in front of the strut tower.
Cheers Adam
Is this a 1.7? If so I reckon you've got the classic warped carb base. There isn't a relay for the cut off solenoid on these ones, they're on all the time. When the car starts running funny, in a well ventilated area, run an unlit blowlamp round the carb baseplate, or spray WD-40 round it, the manifold vacuum will draw the fumes in and the car should start running correctly again.
If this is the case, only cure is a new carb, and the inlet manifold flange will be warped slightly too so when you take the carb off, stuff a greasy rag down the hole to prevent any shavings getting into the engine and file it CAREFULLY flat. I suppose there's nothing to be lost in trying the same trick with the carb base but I've never heard of anybody successfully doing it because its so difficult judge the flatness, but you've got a machine shop near you they might be able to skim it for you. The reason it only does it when hot is probably because the rubber gasket is strong enough to seal when cold and hard but when it gets a bit hot, the rubber gets soft and can't resist any more.
I totally agree on the cause of this problem;
but please dont try to take a file at the manifold... it will be ruined!
if it is really crooked you may apply the same procedure as the one below, for the carb base;
- dismantle carb, until you only have the lower part with as few as possible parts sticking out.
- file off the extending part at the side of the base, so you can put it flat down on a surface.
- take a piece of thick glass, and a sheet of _NEW_ sanding paper, grain 400 or 800.
- put the carb base on the glass with the sanding paper between. with a very light pressure, move around the carb in the figure of an eight - and at each movement, rotate the axis of the 8 a bit clockwise, so that the angle at which you are moving it is different all the time.
keep at this until the whole base is sanded (in the beginning, only the edges will be sanded)
clean, reassemble (check the float's weight to be 6 grammes, and not a gramme more - or else replace!!!) and adjust everything according to the haynes instructions. Fit a new gasket between the carb and the manifold.
Final important step: torque the carb. base nuts up carefully ACCORDING TO SPEC!! (this is very important to prevent yourself from a 'go back to start' experience...)
what you should check also is the nuts with wich the manifolds are attached to the cilinder head. these are of a very flimsy construction, so they are prone to run loose. with a few of them missing you might get the strangest results as well....
(check together with the other leak spot, same procedure)
i'm starting to feel a little better already! Can it be fixed with any gasket goo?
I'll check the manifold bolts asap and order a new gasket just in case. The replacement carb came off a donor car that was running sweet as a nut.
Would be worth getting the manifold off the sweet running car too, and a present of a new manifold to head gasket. Haven't had the experience of the manifold nuts loosening off TBH. The torque of the carb bolts is 14nM be anal and do it properly with a torque wrench, its worth it for these, too tight and it pulls everything out of shape, too loose and they'll rattle off too easily.
I've had the 1.7 manifold off many a time. The nuts do undo with ease normaly. Use a 10mm flat sided socket on the recessed nuts and a normal spanner on the others. Be worned there are two nuts underneath that can be tricky to get your hand to. This confused me the fist time as the B20 volvo engine only has one.
when my carb came loose the car was fine except when you went to slow down for roundabouts , junctions etc ( it would just die ) but could be sorted by temporarily pulling the choke out a tad , luckily the first time (and only time) it happened was on the way to the Gaydon meet and Francois showed me what was wrong and tightened it up , It has been fine ever since and no sign of warping , this may be because I am running a weber replacement carb and the build quality is much better than the standard carb
this may be because I am running a weber replacement carb and the build quality is much better than the standard carb
pictures/info please!!
PS have been thinking about monopoint renault injection (F3N) but don't know yet if the manifold needs to be exchanged etc. Would be a great investment in reliability..
Can it be fixed with any gasket goo?
