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Post by boggissimo on Apr 17, 2024 9:49:07 GMT
Compression test results, engine warmed up first and all plugs out:
| Cylinder 1
| Cylinder 2
| Cylinder 3
| Cylinder 4
| | Dry | 150
| 140
| 135
| 140
| | Wet | 170
| 165
| 160
| 180
|
Minimum compression according to the Haynes manual is 9 bar, so about 130 psi. So none of the cylinders are officially below spec, but quite a long way off the ~190-200 psi that would be expected if it were factory fresh.
Not much difference between the dry and wet tests, and the plugs were very oily, so I think the dry test was not very dry! At least they are all within 10% of each other so head gasket looks OK (I only fitted a new one last autumn). Which leaves piston rings and valve stem seals as potential contributors (or scored bores I suppose).
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Post by boggissimo on May 1, 2024 11:21:14 GMT
Was a bit cheesed off after the MOT and had seen the local club bike MX5 'Ron', a well used H reg 1.6, was up for sale at a great price for club members. I messaged the current custodian and it had already sold (within a few hours) but he said one of our other clubmates had done welding on Ron and it was mint, so I got in touch. He was happy to pick up the car, sort out the rear sills and bring it back for a proper bargain price, so off it went last week. As usually happens with these things, it was worse than it looked from the outside, and the front sills needed doing too, but he sorted them out too and I got the car back yesterday. |
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Post by boggissimo on May 1, 2024 11:23:25 GMT
The front wings were rotten on the surface skin too, so I'm painting up the OEM replacements I picked up in recent MX5parts sales and will fit them before it gets tested again.
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Post by boggissimo on May 8, 2024 10:13:52 GMT
Plenty of progress to report: - Extended wiring from original fan switch, to reach new switch in coolant reroute spacer (it had a different thread size, and I couldn't find a single-pin switch that fitted, so got a 1/8NPT switch and an adaptor from 1/8NPT to the M12x1.5 thread in the port)
- Removed original exhaust manifold, and was about to fit a spare OEM one when I was offered a Mazdaspeed manifold nearby, and got a used Cobalt setup for the rest of the system, so I now have a fully fitted (and not bent) exhaust again
- Removed both front wings, they were in quite a state and it was a real pain to get the bolts off at the front where they meet the bumper. The bracket that holds them together had rusted away so there was no way of holding the bolts still to try to undo the nuts, so in the end I had to tin-snip through the wings to get them out of the way and then cut/grind the bolts off. Have got a pair of Jass stainless steel brackets to replace them with
- Painted new front wings, just need to paint the black part at the bottom and then I can try to fit them later
- Returned the rear third brake light wiring to be a brake light, as I'm fitting the rear reversing/fog light bar to the new bumper (tonight's job)
- Booked an MOT for Friday...
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Post by boggissimo on May 10, 2024 14:32:43 GMT
FAILED AGAIN - just on emissions this time, CO of 4.49%, limit is 3.5%. Going to dump the old fuel (into the lawnmower), fill up with the posh stuff and chuck a load of injector/fuel system cleaners at it, then go for a retest tomorrow.
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Post by dickie on May 11, 2024 15:20:51 GMT
You need to do an Italian Tune Up.
Load up the engine lights fan etc then get it very hot and drive straight in for the emmisions test.
Might even have to load it on the brakes to get it really hot ( Good Left foot braking practice )
I used to have a freindly garage that would let me take the car out and drive it to the bottom of a local hill then rag it up the hill and staight into the test bay.
A lot of garages dont get the car hot enough for the cat to work.
Most Cats dont work around town when they are needed and only get up to temperature at motorway speeds
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Post by boggissimo on May 13, 2024 8:55:08 GMT
You need to do an Italian Tune Up. Load up the engine lights fan etc then get it very hot and drive straight in for the emmisions test. Might even have to load it on the brakes to get it really hot ( Good Left foot braking practice ) I used to have a freindly garage that would let me take the car out and drive it to the bottom of a local hill then rag it up the hill and staight into the test bay. A lot of garages dont get the car hot enough for the cat to work. Most Cats dont work around town when they are needed and only get up to temperature at motorway speeds It's got a decat pipe in it now, though I do have the old cat I could have fitted, but the tester said it probably wouldn't make any difference to the CO reading. Anyway I pumped out the old fuel, put in some Esso 99, some fuel system cleaner and some Redex, thrashed it all the way to the testing station, and it passed!
So I loaded up and went to Debden yesterday, and despite the oil smoke still coming out, I won the class 
Now need to work out what to do with the engine. In the autumn I changed the valve stem seals, but something I did caused the intake camshaft to get jammed up, which snapped the lug and bolt of the cam pulley as the belt was still turning it. I changed the head over with a used one, but couldn't face doing the stem seals on it before fitting it. Since the oil smoke problem is just as bad with the new head, I think it's probably piston rings that need sorting. So the options as I see it: - Take the engine out, rebuild it, put it back in
- Leave the engine in, drop the gearbox and sump pan, access the internals while it's still in the car and just change the rings
- Take the engine out and fit the used NB engine (with NA intake cam and CAS)
- Run it as is for this season, check (and if necessary rebuild) the NB engine before swapping them over later in the year
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Post by atlex on May 13, 2024 9:24:12 GMT
or do my bizarre piston soak fun time thing ^
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Post by boggissimo on May 13, 2024 13:33:33 GMT
Yeah I saw that, was going to try some more solvent stuff while I work out what else to do. Will see if I have a suitable fitting to add some air pressure to the cylinders and push the solvent through.
At least it might help work out which cylinders are better/worse so I can concentrate on the bad ones. Presume it'll match up with the compression test, with the middle two cylinders being the worst.
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Post by atlex on May 13, 2024 15:39:56 GMT
Yeah I saw that, was going to try some more solvent stuff while I work out what else to do. Will see if I have a suitable fitting to add some air pressure to the cylinders and push the solvent through. At least it might help work out which cylinders are better/worse so I can concentrate on the bad ones. Presume it'll match up with the compression test, with the middle two cylinders being the worst. a compression tester fitting is what you want, hooked up to an air line or .. tyre pump ?  |
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Post by boggissimo on May 20, 2024 13:43:51 GMT
Yeah I saw that, was going to try some more solvent stuff while I work out what else to do. Will see if I have a suitable fitting to add some air pressure to the cylinders and push the solvent through. At least it might help work out which cylinders are better/worse so I can concentrate on the bad ones. Presume it'll match up with the compression test, with the middle two cylinders being the worst. a compression tester fitting is what you want, hooked up to an air line or .. tyre pump ? Got one of those, but it's a different size fitting to my compressor hose 
Also need to work out where to get the chemicals from...
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Post by boggissimo on May 20, 2024 13:45:35 GMT
Fitted a pair of front wheel bearings/hubs the other day, since that was an advisory on the MOT. One of them was noisy, the other one wasn't, but I changed it anyway.
Now thinking about fitting the ECU, got an intake air temperature sensor so have all the bits, will see what I can get done...
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Post by atlex on May 20, 2024 14:39:53 GMT
a compression tester fitting is what you want, hooked up to an air line or .. tyre pump ? Got one of those, but it's a different size fitting to my compressor hose
Also need to work out where to get the chemicals from...
pure xylene or toluene from a wicks/b&q ? |
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Post by boggissimo on May 31, 2024 15:21:48 GMT
Got my Megasquirt (MS2PnP) ECU fitted up, including an intake air temp sensor stuck into the air crossover pipe and a new lambda/wideband sensor going into an AEM gauge/controller. Can't get the bleddy thing to speak to my laptop though!
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Post by Zed. on Jun 1, 2024 20:49:21 GMT
comms issues are great fun, I bought 3 cables before I could get a dta ecu to speak with my c raptop  Rich. |
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le sigh