badly ping ONLY at over 4.000rpms if wide open throttle
Discussion
griffith 500 model year '96: i've setted timing at 29 deg at 4.000rpm, the engine pulls well until 4.000 rpms but badly ping if just press throttle at around that rpm level, with and without vacuum connected...could it be that the timing get loose at this rpm level because the distributor is worn out (stock '96 distributor)?
...and sorry to bother all of you with all these griffith pains
...and sorry to bother all of you with all these griffith pains
Might want to try backing it off a little, 28deg. is the recommended if the cam is dialed in correctly and the timing mark is in the correct position(has been known for them not to be).
Mine was pinking at 28 Deg. so we backed it off another 2 Degs. and it put out better numbers on the RR.
Mine was pinking at 28 Deg. so we backed it off another 2 Degs. and it put out better numbers on the RR.
As Mr Bluebottle says try checking the accuracy of the pulley timing marks with a probe down no.1 plug hole.
Also dizzy's aren't the most accurate device even when they're new, might be worth pulling it out and checking the condition of the drive gear and make sure there's a minimum of slack in the advance mech.
Also worth making sure that your fuelling isn't lean and that the air intake is as cold as it can be
Matt
Also dizzy's aren't the most accurate device even when they're new, might be worth pulling it out and checking the condition of the drive gear and make sure there's a minimum of slack in the advance mech.
Also worth making sure that your fuelling isn't lean and that the air intake is as cold as it can be
Matt
If the air fuel ratio is around 13:1, then the timing is a bit optimistic, so should be backed off. (For info, mine with a 404 cam running on 95 RON fuel seems to like around 26 degrees here.)
If the fuelling is leaner than 13:1 then this is likely to be a contributing factor so needs to be sorted out.
If the fuelling is leaner than 13:1 then this is likely to be a contributing factor so needs to be sorted out.
Following up on the 'lean' suggestions that others have already made, I suggest you get the fuel pressure checked and also take the plugs out and see whether they're coked up. Running lean can cause detonation, but if it's running rich and forming carbon deposits that can cause it too.
GreenV8S said:
Following up on the 'lean' suggestions that others have already made, I suggest you get the fuel pressure checked and also take the plugs out and see whether they're coked up. Running lean can cause detonation, but if it's running rich and forming carbon deposits that can cause it too.
today i've changed chip with another mark adams, the car goes smooth and crispy now, it even holds the idle and still do not ping BUT only withing 4.000 rpms. Over that edge it ping and stalls. My final idea is: the car runs extremely lean at 4.000rpms+ and this is the reason for pinging, so i'll review the fuel pressure BUT i will have to turn the regulator simply guessing because i have a tripple act carbon plenum that covers it...question: on your opinion of how much should i turn the reg to rise the pressure enough, and clockwise or the opposite?
i know it's quite a lot of guessing but it's the only way to do it tomorrow or monday...thanks for your infos
Giuseppe
Edited by panic on Friday 7th September 21:43
Edited by panic on Friday 7th September 21:44
Changing the fuel pressure at the regulator will change fuelling everywhere else. 4000 rpm's is probably where peak torque is hence the ping at that point. I'd double check timing and plugs before playing with the fuel. Also check fuel lines for leaks, kinks etc and is the vacuum pipe connected to the fuel pressure regulator?
Are you sure it is ping and not blowing exhaust gaskets?
Boosted.
Are you sure it is ping and not blowing exhaust gaskets?
Boosted.
Boosted LS1 said:
Changing the fuel pressure at the regulator will change fuelling everywhere else. 4000 rpm's is probably where peak torque is hence the ping at that point. I'd double check timing and plugs before playing with the fuel. Also check fuel lines for leaks, kinks etc and is the vacuum pipe connected to the fuel pressure regulator?
Are you sure it is ping and not blowing exhaust gaskets?
Boosted.
timing is well fixed at 29 g - 4.000rpms, i've been told that for a car with the mods i have it could arrive to 32 g...so i thought 29 wa within a secure edge, am i wrong? also, retarding it more, won't i kill its performance?Are you sure it is ping and not blowing exhaust gaskets?
Boosted.
vacuum is disconnected.
its a clear pinging, and of the worst type, continuos knocking and engine stalling won't go further 4.500rpms, useless to insist it won't take any further throttle and i dont want to damage it.
the very funny thing is that the engine really is crispy WITHIN 4.000 rpms! usually is an engine is too much advanced or retarded or 'ill' for some reason it will be rough also from 1.000rpms, i can notice when something wrong in my engine even when it idles...how come this gremlin right now?
Edited by panic on Friday 7th September 21:53
Edited by panic on Friday 7th September 21:55
Not an avid fan of mods without a proper RR set up myself. Where are you in the country as a quick diagnostic run on a RR is only going to cost you an hours labour at most 
.
My old RV8 used to only like about 26degs at peak torque, which was one of the reasons mapped ignition came in handy as it allowed more advance to be used elsewhere to get the power higher up the range
.
. My old RV8 used to only like about 26degs at peak torque, which was one of the reasons mapped ignition came in handy as it allowed more advance to be used elsewhere to get the power higher up the range
. HarryW said:
Not an avid fan of mods without a proper RR set up myself. Where are you in the country as a quick diagnostic run on a RR is only going to cost you an hours labour at most .
My old RV8 used to only like about 26degs at peak torque, which was one of the reasons mapped ignition came in handy as it allowed more advance to be used elsewhere to get the power higher up the range.
i live in northern spain and i dont know any around the town of Vigo who uses a RR...i'm like a fish outside water around here.... My old RV8 used to only like about 26degs at peak torque, which was one of the reasons mapped ignition came in handy as it allowed more advance to be used elsewhere to get the power higher up the range
. Pinking *and* won't rev? There's something severely wrong, you need to check the basics or get somebody to check it for you. Is the spark OK, is the fuel pressure consistent, is the injector duty cycle looking about right, EGTs looking consistent and lambda readings showing the right mixture. From the sound of it at least one of these will be out which could be due to knackered cam, ignition fault, fuel fault, you name it. You need to investigate it methodically and you can't do that over the internet.
...you're right, with the engine in these 'apparent' conditions i would quickly run to the first pro around BUT, for example, the car went like a lightning and sounded like a thunder, today! ok the weather was much fresher, i've disconnected the vacuum too but is that posible that it goes well today and it might go tomorrow bad like last friday? could it be a switch? a loose connector to the coil for example? or some other jack? If a car goes that bad like i told you members a couple of days ago it shouldnt go quick and not ping 2 days after! sorry to drive all of you crazy, maybe it's better you just forget about...thanks anyway/Giuseppe
It's probably going well when the airs denser and then in's not pinking. On a hotter day it'll pink and behave like a dog. Got any air leaks after the hot wire meter or around the plenum base. These would let air into the engine which hasn't been measured by the efi, in otherwords, false air.
Boosted
Boosted
You can find air leaks by running the engine and spraying lighter gas around every joint, if the engine rev's up you've found your leak.
It does sound like the igntion system is at fault tho'.
Also worth checking the position of the rotor arm relative to the cap, it may be that you're one post out on the plug leads and the rotor is arm is set between the posts so its only firing off one edge. As it advances you pick up the next cylinder.
Set the engine at TDC no. 1 on the pulley and do a few visual checks by popping the dizzy cap off it should line up with the no. 1 plug lead post to start with.
Then set the advance with a light
Matt
It does sound like the igntion system is at fault tho'.
Also worth checking the position of the rotor arm relative to the cap, it may be that you're one post out on the plug leads and the rotor is arm is set between the posts so its only firing off one edge. As it advances you pick up the next cylinder.
Set the engine at TDC no. 1 on the pulley and do a few visual checks by popping the dizzy cap off it should line up with the no. 1 plug lead post to start with.
Then set the advance with a light
Matt
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