flathatmat
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| posted on 4/4/07 at 09:15 PM |
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New pinto engine gremlins
Finished all winter upgrades including rebuilt 2 litre pinto engine including new pistons, bearings unleaded head and new newman PH4 cam.
First time out today and is pinking really badly at 2800rpm upto around 3400rpm!!!
Have now set the timing to 8 degrees BTDC and it is still the same??
Has anyone any ideas???????????
Cam Timing out?? More timing adjustments?? Fuel upgrade??
Any info would be helpful
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jacko
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| posted on 4/4/07 at 09:21 PM |
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i would think the timing shouldbe about 12% --14% is it a modifide cam [ not standard ] the timing wants to be 36 -38 % at 3000-3500 rpm
What carbs do you have fitted ? are you on dizzy or megajolt ?
[Edited on 4/4/07 by jacko]
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flathatmat
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| posted on 4/4/07 at 09:25 PM |
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Wouldnt that make it worse??
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jacko
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| posted on 4/4/07 at 09:26 PM |
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try it and see
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flathatmat
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| posted on 4/4/07 at 09:33 PM |
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I am on twin 40's and dizzy. The timing was initially set at 10 degrees, then 8 and was going to try it at 6 degrees towmorrow. Also the head
was skimmed by 40 thou which i did forget to mention but was a standard head to begin with.
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mookaloid
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| posted on 4/4/07 at 09:40 PM |
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Which fuel are you using? try some optimax or similar to see if that makes any difference - it's the difference between pinking or not pinking
on mine....
"That thing you're thinking - it wont be that."
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nitram38
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| posted on 4/4/07 at 10:41 PM |
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Try setting the engine timing by ear.
Slacken the distributer bolt slightly and adjust it while the engine is running. You will surprise yourself how close you can get it to the correct
setting.
Drive the car hard and if it still pinks, advance it a bit at a time.
Re-check with timing light.
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02GF74
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| posted on 5/4/07 at 07:27 AM |
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quote:
Originally posted by nitram38
Drive the car hard and if it still pinks, advance it a bit at a time.
I thought you were meant to retard it if it pinks?
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russbost
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| posted on 5/4/07 at 08:57 AM |
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Easiest way is Nitrams above, except you retard not advance to get rid of pinking.
It may be caused by the head skim as you now have higher compression, in which case it's worth trying high octane fuel, or an octane booster.
Still use the above method to set the best timing for your engine tho'.
Obviously worth checking & double checking your cam timing, you don't have a vernier pulley I assume?
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nitram38
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| posted on 5/4/07 at 09:24 AM |
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quote:
Originally posted by 02GF74
quote:
Originally posted by nitram38
Drive the car hard and if it still pinks, advance it a bit at a time.
I thought you were meant to retard it if it pinks?
OOPS! 
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flathatmat
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| posted on 9/4/07 at 06:57 PM |
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Ok!! I have now done all the things suggested and the engine is now running at 6 degrees BTDC, super unleaded fuel and thae cam timing is spot on but
the bloody thing still pinks like crazy at 2800rpm???
Anyone have any other thoughts???
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MkIndy7
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| posted on 9/4/07 at 08:26 PM |
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Whats controling the Advance/retard of the Ignition?.
It seems like when the engines on Maximum load the timing is not retarded enough.
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flathatmat
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| posted on 9/4/07 at 08:51 PM |
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The advance/retard is controlled by the centrifugal weights in a standard dizzy.
This is my next job to check the total advance of the dizzy to see how much i have.
If anyone has any info on this it would be helpful.
Thanks for the reply.
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nitram38
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| posted on 9/4/07 at 08:59 PM |
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You should also have a vacuum advance?
It is common to remove the vacuum advance ( and rely purely on the centrifugal advance) if you are running side draughts, but if you have a smaller
carb then you will need more advance.
I bought a crossflow once and it had side draughts removed and replaced with a smaller carb. Unfortunately they didn't put the vacuum advance
back on the distributor.
I didn't know this so when I was thrashing the engine, I melted the two centre pistons!!!
Might be an idea that this is the case with your engine?
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flathatmat
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| posted on 9/4/07 at 09:48 PM |
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The engine runs on twin 40 DCOE carbs so does this mean that the vacuum is not required or doesn't necessarily need it?
The vacuum is not connected. The only other modification that is niggling me is the 40 thou head skim which should be "safe" but is still
playing on my mind. The engine ticks over fine but at 2800 revs it sounds like a box of hammers under load and when you are trying to run the new
engine in is not good
Back to the timing am i right in saying that the distributor is or could be supplying too much advance?? If so how can this be adjusted?/
Thanks again!
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nitram38
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| posted on 9/4/07 at 10:20 PM |
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If the distributor has still got the vacuum actuator attached with those carbs, then remove it (even if the vacuum hose is disconnected). You will
also then need to connect the vacuum advance plate to the centrifugal plate inside the distributor.
This is normally done with a self tapper through both plates.
This will limit the amount of advance only to the small amount by the centrifugal weights.
This maybe your problem.
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gazza285
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| posted on 10/4/07 at 12:20 AM |
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quote:
Originally posted by nitram38
when I was thrashing the engine, I melted the two centre pistons
It was nothing to do with the vacuum advance being disconnected then, the vacuum advance is an emmissions measure to reduce hydrocarbons on overrun,
there is very little vacuum at full throttle.
DO NOT PUT ON KNOB OR BOLLOCKS!
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nitram38
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| posted on 10/4/07 at 06:54 AM |
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quote:
Originally posted by gazza285
quote:
Originally posted by nitram38
when I was thrashing the engine, I melted the two centre pistons
It was nothing to do with the vacuum advance being disconnected then, the vacuum advance is an emmissions measure to reduce hydrocarbons on overrun,
there is very little vacuum at full throttle.
Not having enough advance under loading the engine means the firing the spark too late. This means that most of the fuel in the cylinder is burning
after the exhaust valve has started to open. This is effectively the same as running on a lean mixture. I am talking about a 1600 with 1300gt pistons
(10:5:1 compression) reving to 9000 rpm.
The centre pistons on a crossflow suffer the worst. As the mixture is lean they get too hot.
Pintos tend to be stronger and alot come with steel crowns so don't suffer from distruction so easily as crossflows with aluminium ones.
Trust me when I say that this lack of mod did this to my engine, because it happened twice before the mistake was spotted.
Twice I rebuilt the engine.
After I did the self tapper fix, then no more melted pistons.
[Edited on 10/4/2007 by nitram38]
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david walker
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| posted on 10/4/07 at 09:30 PM |
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1300GT Pistons at 9000 rpm! Pull the other one
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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nitram38
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| posted on 10/4/07 at 09:49 PM |
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I have got a santa pod time of 13.64 in my anglia.
The engine was built by Ron Harris
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