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Found 5 results

  1. I am trying to time my series (petrol 2.25), workshop manual says TDC with 90 octane or 3deg with 83 octane, modern petrol is 95 octane or above anyone have an ideas of where I should set the timing?
  2. Hello, This is my first post on here so please be gentle and admins, by all means move delete as appropriate. Like a lot of people starting with megasquirt I've been through Nigels (HFH's) comprehensive posting as req'd to try and get round various issues. Having finally got my 3.9 started and running with base maps (again provided by Nigel) and the installation effectively 'finished' i've been having the following issues whilst trialling: 1. Flat at WOT and feeling bogged down in the middle rpms 2. Lag from idle before picking up revs 3. Significant lag at idle and throttle is blipped (almost an impulse step) 4. Slow response to regain revs when starting large electrical loads (fans) I spoke to a mechanic friend of mine and his opinion was a lack of advance in the ignition (issue 1) and a poor ignition map for the others. Initial test was to up the trim angle to force in more advance across the range, not a very refined method i'll admit, but results sat in the garage was an instant improvement in response whilst up to temperature (away from dreaded zone of warm up enrichment). So with the evidence of my ears and a small amount of knowledge (dangerous i know) I set out to re-write a starting point map that would work, and yet remain safe and not damage the engine. So my brief had 4 requirements: 1. Find a way of modelling a known distibutor, but not a lucas if possible. 2. Generate a new table that would be "safe" 3. Be able to model both vacuum and mechanical advance. 4. Manually adjust to put a "Valley" outside the bottom of my known rev range to assist in stablising the idle The starting point was to try and find a generator that would allow me to understand what it was generating and how it was doing it, and allow me to model a known working solution within the 12x12 map. As a mechanical engineer I decided it was easier to use someone elses solution and reverse engineer understanding than make my own. Luckily after a few hours of searching i came across this thread on another forum: http://www.msextra.com/forums/viewtopic.php?f=94&t=29033 which contained the following spreadsheet (of unknown origin i'll admit please do not follow if you are concerned about the security implications of unknown excel spreadsheets): http://home.comcast.net/~whaussmann/MS_MGBGT/MGB_Ignition_map.xls This will generate a table based on both a vacuum advance and up to 2 spring rates for mechanical advance (not quite as refined as a 12x12 table, but please remember I am trying to create something that works and refine in the future). This allows the modelling of a magnecor type dual spring distributor with vacuum (fulfilling the requirement of a "known" solution). This can then produce a mechanical response (advance) that will look something like the two stage graphs at the bottom of the following link. This can be adjusted to fulfil what appears to be a fairly standard "bring in quite a lot of advance early" approach (the spreadsheet can only do linear response, but you could manually input figures to give a more refined match): http://www.britishv8.org/Articles/Curving-Rover-Dizzy.htm So as a compromise between the various curves i chose to have the initial spring coming in between 900 and 1700 rpm with an advance of 15 degrees and the second spring operating from 1800 to 3300 rpm with a advance of 10 degrees. This gives a total of 25 degrees of mechanical advance across the rev range with it all in by 3300 rpm. The next challenge was to find the characteristics of a vacuum system that would work on this engine, a few more hours and another tank of juice on the e-cigarette yielded: http://www.distributordoctor.com/vacuum_units.html This gave me the data needed to produce a vacuum response of 5 inHg start 17inHg with a total vacuum advance of 8 degrees across the range. The final stage was to input the static advance, the book says 2-3 degrees for a 3.9 high compression, so I used 6, as it looks better at 0 vacuum and i can adjust as required. Once the table had been generated i adjusted the 500rpm bin to be 800rpm bin +1 degree, uploaded to the ecu. The result, a stable idle at 750rpm and 35-40 kPa, no lag on revving and a big grin in anticipation of the next competion. Having looked around this forum, I have concerns about this as it appears to have a lot of advance, similar in areas to Nige's 'extreme' tables. However, having looked into the theory I think this is quite an accurate modelling of a magnecor distibutor (with the advance limited towards the top end) fitted with a Lucas vacuum advance module (admittedly one for an MGBGT) and represents what would be happening on a dizzy driven ignition system. Hopefully someone may find this useful. Comments please...
  3. I know I can google this and find lots of info, mainly timing, head gasket or de-laminated hose. But mine was fine until I did the following 1. Changed oil and filter 2. Changed diesel filter 3. Bypassed the EGR So which of these caused this (am thinking the egr removal) and is this likely to clear after a few starts or a run? OR Is it just a coincidence and I have one of the faults mentioned at the start of this post?
  4. Hi Everyone, I've got a 1985 Ex Mod 110 with a 2.5 NA diesel. I brought it to my mechanic last week to change the timing belt and check the valve clearances, and there are now some new issues with the engine. When he checked the clearances, he told me instead of the 0.010 of an inch the manual calls for, my clearances were all out of whack, with some gaps as large as 0.050 of an inch. After the adjustment, the engine seems to generally run more smoothly, however, I'm having the following problems: - When trying to start, the starter begins to crank but then "whines" almost as if there is no resistance on the engine. Almost as if its skipping. Before getting it back from my mechanic, the truck would instantly start if the engine was hot, now it struggles to start when it is up to running temp. - Significant amount of white smoke upon startup - When idling, there is an intermittent "chugging" sound, almost as if the engine is not getting enough air, and sounds as if it is close to stalling out. In fact on a cold start, if I don't rev the engine for a 20 seconds or so, it will stall. - Intermittent clicking/rattling from what seems to come from under the rocker cover under medium to high revs - very pronounced after a cold start during higher revs in 2nd and 3rd gear. Oddly enough the noise is non-existent doing 65 in 5th gear on the highway. The mechanic I brought this to is not a diesel mechanic, but took on the job because the engine seems "simple enough." Along with all the parts to do the timing (including the timing tool kit I'm almost positive he didn't use), I gave him the diesel Defender workshop manual and Haynes manual, so that is what he went off of to do both the timing and the valves. I' Any idea what is going on here? Thanks in advance for your help!
  5. Guys, After swappng my SU's for an EFI (flapper) top end controlled by MS tihngs have been good. Petrol was running well but LPG was pinging slightly initially. MS (MJ before) has been running ignition for some time now and i have not changed my spark maps for a year or more. I originally put this pinging down to the fact that I still had the old round style rockers and had simply piped the crankcase vent connections from the rockers, via flame traps and a y-piece into the plenum. My thoughts were that the larger diameter port on the plenum (compared to the SU's) was drawing in more oil vapour and causing the pinging. I thought perhaps the cooling effect of petrol was inhibiting the symptoms when not running on LPG. This was not initially a problem as I was busy hooning around tuning for petrol. Anyhow at the start of the week I fitted "proper" Efi style rockers with the foam filter on one side and the brillo pad filled outlet on the other that goes to the plenum. Still the same. Pinging on gas. This happens on medium to hard acceleration. I have tried running uber rich at all times (like 13:1 or better)- no effect.. I have cut timing so that LPG is now the same spakr map as petrol - still pinging. Worst of all it now seems to be pinging on petrol too. So what else could it be? My thoughts are: 1- Soot from tuning petrol causing detonation - things were a little rich when I started out tuning the MS 2- My wideband is lying to me and I am not running as rich as I think I am 3- My air intake is now above the drivers exhaust manifold and hot air in may be contributing. (MS reports 30-35degree air tems when cruising on a hot day - i would not have thought that was too high) 4- I had initially thought a weeping petrol injector, but now it is pinging on petrol too I think this is pretty much ruled out. 5- My trigger wheel has moved. My plan of action is to check base timing, then recalibrate the wideband, check the plugs and then the injectors. So does anyone have any further suggestions on causes or things to check? The noise sounds like a cross between a bunch of keys or a couple of marbles rattling around in a jam jar. It is definitely load related and backing out of throttle ior shifting down a gear instantly stops it
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