nicrguy1966
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Posts posted by nicrguy1966
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6 minutes ago, johny said:
Cant see it as complete waste of time as valve timing was wrong wasnt it? How much do you think it was out in the end?
I flipped the sprocket, so I'm assuming a 1/4 of a tooth, but honestly, even with measuring everything several times, that could easily have been user error!
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20 hours ago, Iain T said:
To continue this topic I have advanced my timing from around 11 degrees to 17. I had to adjust the tickover as it was a little high at this setting. Took the car out for an hours drive of slow, medium and er sorry 'orficer fast driving with no pinking under load. Tickover is more stable and revs and pulls very nicely. On listening to the engine my high and low advance range is around 8 to 24 degrees so I set about the middle.
I'm leaving the advance there and will give it a longer term test as it seems a pretty safe setting.
Iain
I'm still making minor changes to my ignition timing. Yesterday I advanced it slightly, and went for an hour's drive. Still no pinking, so I'll advance it a bit more before my next drive.
I've packed the strobe away and decided to just set the ignition timing so the car runs its best. Out of curiosity, I might check what that setting is once I've found it (I'm actually expecting it to be exactly where it was when I wrote post #1, and all the work I did on the cam timing was a total waste of time, but let's see!)
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33 minutes ago, Pete Lewis said:
whilst the max centrifugal advance is around 3000rpm with a around 28/32 degs advance
do READ the test data in the WSM as this is mostly done DECELERATING
remember the only triumph ignition timing specification is ......static
moving away from spec for all the above reasons is fine if you have good ears and no worries about melting a crown
if you dont know , then its best not to mess with the unknown
happy christmas
Pete
My car only runs smoothly when it's way off spec (hence starting this thread). I've given up all hope of ever setting it to spec. I just want it to run well across a wide rev range.
It's better now than before I started meddling, but I'm sure there are a few more horses hiding somewhere. A year ago I had no power at high revs and struggled to go above 70 mph in top gear, now it feels keen even at higher speeds than I'm allowed to drive. Low revs aren't quite right yet, hill starts are not my friend.
Setting the ignition by ear (or for peak revs) seems to give me far better results than a strobe and any target 'correct' setting.
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7 minutes ago, johny said:
garage will soon warm up with the engine running at 3000rpm😁
To avoid carbon monoxide poisoning, I'll have the exhaust pipes facing the open garage doors, although I should get a nice warm glow from the engine.
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5 minutes ago, johny said:
You havent got one of these on the carburettor end of your throttle cable?
I can't remember. I'll have a good look and decide on a solution once the weather is warmer.
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7 minutes ago, johny said:
And wait till the neighbours go on holiday?
Luckily there's a good 2 metre air gap between my garage and the neighbours, so as long as I don't start at 7am on a Sunday, it shouldn't be too bad, no worse than mowing the lawn hopefully.
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4 minutes ago, johny said:
yes but the linkage isnt prefectly rigid, well mine isnt, so I can change each carb individually even with all the connections fully tightened up. This doesnt matter when operating the carbs with the throttle cable but might make a difference in this case especially as its running at no load...
I'll have a good look at the linkage and see if there is a better solution, maybe a bulldog clip or similar on the accelerator cable. I'm not doing anything until it's at least 15 degrees outside, so a few months away.
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3 minutes ago, Wagger said:
Beware, the linkage can slip unless the clamps are really tight.
Hopefully not as it would also be slipping when I drive, which it doesn't seem to do.
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34 minutes ago, johny said:
well as theres one on each carb its possible to get out of balance...
Yes, but the two carbs are linked by a common throttle control (unless you deliberately loosen the link between them), so adjusting the idle on one the accelerator cable is connected to should affect both (exactly like pushing the accelerator pedal)
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1 minute ago, johny said:
Yes ear plugs recommended and might be able to do it without an assistant by using the throttle cable adjustment - screw it out to hold the right revs and then youre sure any increase when moving the dizzy isnt from their foot wobble...
I was planning on screwing down the idle adjustment on the carbs. Bad idea?
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On 11/12/2023 at 21:23, Wagger said:
This thread is going on and on. The most sensible suggestions have come from PeteL and JohnD who has raced his Vitesse.
I am repeating myself now.
Run the engine at 2500 to 3000 rpm. Adjust the advance or rotate the dizzy (after slackening the clamp just enough) for max rpm and back it off a tad.
I have used this method since the 1970's and never suffered pinking, burned out valves, melted pistons or burned spark plugs.
You can play all you like and never better this method. A pal raced Minis using this method and wasted less time than others in the pits. He won most of the time too.
I'll be setting my ignition timing at 2500rpm as soon as the weather warms up a little.
One scary thing is how loud the engine sounds at higher revs inside the garage. I know it must be even louder at >4k rpm on the road, but it doesn't sound as scary without all the echo and with (some) sound proofing between engine bay and cabin
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4 minutes ago, johny said:
Now I think I'll be progressively advancing my timing in search of those extra 10 horses😁
That's what I'm currently doing.
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44 minutes ago, Firefly said:
Yes it`s staying at 17 Deg BTDC, I`ve been around engine over 50 years and know when an engine is happy or not, including working at Triumph all thro` the 1970`s. Indeed an engine can be damaged, particularly by pinking which is suggesting the fuel isn`t being burnt properly. So I`ll let you know when the heads blown off. 😀
Even after all my messing about, I'm pretty sure my engine is back at around 20 degrees BTDC. I've adjusted the timing 'by ear' a couple of times since changing the cam timing, each time slightly advancing the timing. With each adjustment, low rev power has improved, without power loss at high revs or pinking.
I'll dig the strobe out again once the weather warms up.
My current thoughts are around a new distributor in the new year.
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6 hours ago, Cookie said:
if anything the ignition needs to be retarded with modern fuels. I have a late GT^ MK3 engine and timing is supposed to be 10 deg BTDC according to the manual. However, although it tickover smoothly at that setting it pinks badly up hills. I've found that it needs to be set at about 6 deg BTDC to avoid pinking on modern fuels (and that's using 99 Ron super unleaded E5), at 7 deg or more it pinks badly, but at 6 deg it only pinks very occasionally. Of course using e10 normal unleaded would need even more retardation to avoid pinking, but then GT6s were designed to run on 5 start leaded 100 Ron back in the day so that's not surprising.
I think as has been said that your pulley harmonic rubber damping has shifted and the scale on there is now way out. Quite a common issue on the pulleys on 6 cylinder cars when the pulleys get old and the rubber damping starts to break down.
Thanks for the suggestion, and I wish life were that simple, but I don't think the timing mark is incorrect for several reasons.
1) I felt the position of piston #1 and it matched the timing mark
2) I removed the crank pulley and inspected it, there's no sign of any issue with the rubber and it wasn't possible to move the mark.
3) The timing of the cam shaft was wrong in the opposite direction to the problem with the ignition (cam was too much ATDC, ignition is too much BTDC)
4) I've set the cam timing based on the TDC mark, and if it was as wrong as the ignition timing, I doubt the car would even start, but it runs well.
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2 hours ago, Wagger said:
25 years back at a Minor meet, I saw a Minor van with a Toyota MR2 engine and transmission in the rear. Held the back down better than the conventional set up. Others had Fiat Twin cam engines installed. We chose to keep ours as original looking as possible. BIL sold it in 2005 for over £5k.
Apologies to all for the diversion. It is a shame that the Vitesse is so nose heavy, I do not like chuckng mine around anything like as much as the minor.
Getting back on topic, my car only runs really well when fully warmed up. No good messing with anything until it has run for about 20 minutes. Best done in warmer weather too.
I'm very happy to wait for warmer weather! My garage isn't heated and I tend to damage my fingers much more working on a car in the freezing cold.
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1 hour ago, Pete Lewis said:
500 is too slow target is generally 800ish
500 is ok for strobe ign timing check so no advance is produced by the centrifugal weights in the dizzy but a bit on the slow side for a normal idle
Pete
I know a 500 rpm idle is lower than standard, but the car used to be perfectly drivable at that setting.
Now I have to really rev it and slip the clutch to pull away, and on one occasion when I needed to do a hill start, I was reving up to about 3000 rpm to pull away, otherwise as soon as the clutch bit, the car felt like it was going to stall. Once moving, the car is a better drive than before I changed the cam timing.
Until I've tried a few different ignition timing settings I'm quite relaxed about this issue. It might be a very easy fix.
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On 31/10/2023 at 19:14, johny said:
Any conclusion on the patient yet?
Given the sudden drop in temperature, I've not spent much time working on the car for a couple of weeks.
Things still to do:
1) Recheck the cam timing now the cars done a few hundred miles (using balance point of 1 & 2 rockers)
2) Try various slight adjustments of the ignition timing to see if I can increase power at <1500 rpm without hurting the power at >1500 rpm. If not, increase idle speed from 500 rpm to 850 rpm.
If I find the cam timing isn't perfect, I'm happy that I can repeat the process of adjustment without the 10 pages of help I needed last time!
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31 minutes ago, Ian Foster said:
In case it helps, here is the ignition side of my GT6 engine, which also has a Delco distributor.
#1 plug lead at 6 o'clock position using a Pertronix electronic ignition.
If you are using electronic ignition, the distributor will probably be in a slightly different position compared to a points set-up.
Post engine rebuild I discovered that the distributor drive was 180 deg out (slot towards the right), now corrected.
I set the timing at 12deg BTDC using a strobe, which is 10 deg BTDC static.
Ian
PS Nic, perhaps you can give us a summary of exactly where you are with this, as I'm a bit confused reading recent posts.
So clean! Do you ever drive your car? 😁
I'm sure I could rearrange the leads to match yours if I wanted (and twist the dizzy body), but I'm not sure how it would make any difference to the running of the engine.
Where I am is that I have changed the cam timing, and things seem a little better than before, but I still have a little fine-tuning to do before I'm finished.
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Today's installment:
- Fixed the leaky hose
- Adjusted all tappets so there's no rattle
- Got the strobe out and found that my "roadside" setting was way off and retarded the ignition to around 16 degrees BTDC (any less than this and the engine started to sound unstable)
- Went for a drive. A nice smooth tickover at 500 rpm. Lacking a bit of power at low revs, but not as bad as it used to be when set to 13 degrees BTDC. A blip on the accelerator and I could pull away with no problem. At 2000 to 3000 rpm it felt like I had more power than before. I took it to a stretch of motorway and pushed it up above the speed limit without any issues. The lack of power I used to have above 3000 rpm seems to have gone, so nice acceleration in 4th gear from 70 to XX mph (just in case the police are watching!)
I need to use the car Friday so I'll probably leave it as it is until after that, but I suspect I'll be playing with the ignition timing again in the next couple of weeks (and might even double-check the cam timing now I know how "easy" it is!). As an experiment, I plan to set the ignition to 13 degrees BTDC to see how it drives, but not until after Friday.
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On 05/10/2023 at 20:03, RedRooster said:
While you are there have you thought about a high level brake light, most modern cars tower above the GT and the light is more visible.
I like that idea a lot!
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17 minutes ago, Iain T said:
The suspense!! Do tell.....
Dizzy drive slot orientation can't be the problem it only makes the body in an odd or unable to rotate position.
Iain
I'll be playing with it again after lunch. I'll first check the rocker gaps and replace a bad hose clip while the engine is cold, then fire her up and check/adjust the ignition timing.
I know it needs to be retarded as there was pinking when I had a drive yesterday. I never had pinking before, as the engine seemed to like a stupid amount of advance, so something has already changed.
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31 minutes ago, JohnD said:
Your pic from above, niceguy, and it shows the distributor rotated clockwise from the normal position, which is with No.1 lead at 'six o'clock'. This I presume is the "Very advanced timing" that you have found necessary. But why, everyone cries!
The legbone's connected to the ... kneebone, or in this case the dizzie drive shaft is connected to the distributor drive gear and thereby to the cam shaft, and to the oil pump. The pump has a 'dog' on the end of its shaft that connects to the drive gear. But when assembling these parts, the pump must go in long before the others. Then when inserting the drive gear, the pump shaft must be rotated so that the dogs match, AND the gear must be inserted several degrees away from this orientation, as the hypoid cogs between camshaft and drive gear rotate the gear as it descends into place. The objective of this fiddly manoeuvre is to orientate the drive slot in the face of the gear to match the peg in the end of the Dizzie drive shaft, so that the dizzie is then in the correct orientation, with 1 at six o'clock.
Phew! A picture is worth a thousand words, but I can't find a diagram of all three (Pump, drive gear, dizzie) as they are always in different sections of the parts catalogue!
What I'm saying is that it is possible to assemble these parts in as many positions as there are cogs on the drive gear! That's 16, I think, so the possible error is in multiples of 20 degrees.
I suggest that is your problem, nice guy! Your cam mistiming is trivial, carb tuning likewise, neither could account for the advance you need to use. It's the Distributor! Take it out, look at the slot in the face of the drive gear. It should be in a "five past seven" position , but note, the slot is slightly offset, which should be to the left, thusly:
Alternatively, just move all your ignition plug leads one place counter-clockwise! Then re-time!
Simples!
John
I agree with Johny.
I have full adjustment of the distributor from firing at TDC to 20 BTDC just by twisting the body. I could do everything you described, but to get it to run smoothly, the spark would be at exactly the same time as it is now.
Edit: I haven't actually checked the ignition timing since adjusting the cam timing, so it might already be "fixed" (wishful thinking).
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6 minutes ago, Pete Lewis said:
Think Dave picked this up when i did Twiddle days at club HQ
good fun but cant do it now cant hold spanners zimmer frame and iron lung and ball cock all at the same time Ha !
maybe we organise one for the spring
Pete
Holding a feeler gauge, screwdriver and 1/2 ring spanner all at the same time is enough of a challenge for me!
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13 hours ago, daverclasper said:
I don't know how flat your rocker pads are, the valve tips can wear an indent and setting with feelers leaves too large a gap. there are ways around this
To identify a noisy rocker, then when idling, push a thinner gauge old feeler in the gap and the rogue one should quieten down
So far nothing has been badly warn on the engine. I had a reconditioned engine fitted about 15 years ago and do fairly low mileage (3-4k per year).
GT6 Mk3 only runs well with VERY advanced timing. Any ideas why?
in Electrical System
Posted
I'm advancing the timing and going for a drive to see how it performs in various conditions, from low rev hill starts to acceleration from 50-70 on the motorway.
Even after adjusting the cam timing, with the ignition timing set to 'standard' low rev power was very poor. So far, each time I've advanced the ignition, overall performance has improved.
Trial and error will continue through the winter months, with maybe another play with the cam timing when the weather warms up.