fuel additives

[Keithver]

I am running my S2 1,3 on normal (in ZA) 95 octane fuel. I have just replaced the plugs (champion N9Y) and the engine still stutters at around 2000 RPM
A carb specialist has advised me to add about 200ml of diesel to a full tank.
He reasoned that the fuel today (without the lead) is less able to lubricate properly and the diesel in the fuel should lubricate better.
My understanding is, that adding diesel to the tank will slightly reduce the octane rating.
As i said, I run 95 octane which is one point lower than the recommended (handbook) 96 octane.
Is this a good idea or not?
I heard somewhere else that one could add kerosene (paraffin) alternatively, with the same results.
The same guy said that I should run a hotter plug and suggested the Bosch WR7DC+ for our warmer climate.
Should I worry about additives or not?
Any thoughts would be appreciated

[lancialulu]

Stuttering at c 2000 is caused by poor valve timing in my experience. I would not add diesel.... Octane values are to guide for preignition conditions. Does your Fulvia engine pink under load (at 2000-3000 rpm)?

[neil-yaj396]

My Beta used to run fine on the old 95 octane E5, but since it was upped to E10 it hasn't run well, especially on hot days. I've always added the odd glug of Millers VSPe and have now moved to Super E5. Diesel and Kerosene are definitely not suitable additives. The latter would actually reduce both the octane and the lubricity of the petrol. It can cause overheating and is in any case illegal as you are technically 'extending' the fuel.

Unlikely, but HMRC could seize your car if they found kerosene in your fuel.

[nistri]

The current method to measure octane rating is different from the past one, hence 95 is the old 96.

[Keithver]

Stuttering at c 2000 is caused by poor valve timing in my experience. I would not add diesel.... Octane values are to guide for preignition conditions. Does your Fulvia engine pink under load (at 2000-3000 rpm)?

I'm pretty sure that the timing is correct. All three timing marks line up perfectly.
I haven't noticed any pinking. The problem seems worse at low revs in low gears. She runs better as the revs increase

[lancialulu]

Stuttering at c 2000 is caused by poor valve timing in my experience. I would not add diesel.... Octane values are to guide for preignition conditions. Does your Fulvia engine pink under load (at 2000-3000 rpm)?

I'm pretty sure that the timing is correct. All three timing marks line up perfectly.
I haven't noticed any pinking. The problem seems worse at low revs in low gears. She runs better as the revs increase

The "timing marks" are to initially set the cams so the valves do not touch the piston when turning over the engine totime the cams..... I use a crankshaft protractor (download and print one) a dial gauge on inlet /exhaust #1 valves set to a "setting" clearance of .4mm. Depending on the cam you look for the opening and closing position of the valves. Depending on the camshaft (I assume 303) you calculate the MOP (max opening position) from these measurements and set the cam to 109 ATDC for inlet and 109 BTDC for exhaust (303 cam - others may be different). I have a car that hesitated badly and after trying everything looked at the cam timing and it was 20 retarded on the inlet....

[davidwheeler]

I would have thought that 95 octane is a bit low.  I run my SII 1600 on 99 octane from Sainsbury's.   (or Tesco)  Worth a try perhaps, especially as it is E5.

[Keithver]

Tim Thanks - It is a 303 engine. I presume the cams are standard. I am notoriously bad at understanding things. I need to draw them before I might understand. The photo below shows my crank protractor. With help from the workshop manual I note that your 109deg bisects the obtuse angels of opening and closing angles given in the manual. The first bit of sense!
I have written a description of your process below. Would you be kind enough to let me know if it is correct before I climb under the bonnet, Please

Use a crankshaft protractor (download and print one).  Set the gap to 0.4mm for inlet and exhaust valves of #1. (where does the 0,4mm come from)
Look for the opening and closing position of the valves using a dial gauge.

Check when inlet valve #1 begins to open and set the dial gauge to zero.
When it closes completely, note the gauge measurement.
Calculate the MOP (max opening position) from these measurements (halfway between the two).
Turn the crank so that the inlet cam is at MOP according to the dial gauge calculation. Remove the inlet Vernier pin and turn the crank so that the protractor reads 109 ATDC for inlet valve #1. 
Re-insert the Vernier pin.
Repeat the same process for the exhaust cam, but so that the exhaust cam is set to 109 BTDC for exhaust.

As I say, it takes me a while to understand these, for me, complicated things

Unfortunately, Here in ZA, we only get 95 octane at the coast. Its only 93 upcountry. 99 is not available

[nistri]

For the 303 engine the maximum valve lift is 2.2 mm. Harry used to sell a custom made feeler gauge of 2.2 mm to set the camshaft timing.

[lancialulu]

Hi Keith
Sent you a pm

[jimbo64]

I use this online may help these are your details you supplied

[Jaydub]

All good advice on the cam timing, but no use at all until you have set a true TDC, because the manufacturing tolerances mean the standard TDC marks could be quite a few degrees out, and therefore so will your cam timing!
Look at BURTON PERFORMANCE CENTRE website. Top right of their opening page, it says "tuning Guides". Click on that and then click on "Cam timing" It will explain how to get a true TDC.  Once you have that you can then set cam timing, but not before.

Good Luck.

[lancialulu]

All good advice on the cam timing, but no use at all until you have set a true TDC, because the manufacturing tolerances mean the standard TDC marks could be quite a few degrees out, and therefore so will your cam timing!
Look at BURTON PERFORMANCE CENTRE website. Top right of their opening page, it says "tuning Guides". Click on that and then click on "Cam timing" It will explain how to get a true TDC.  Once you have that you can then set cam timing, but not before.

Good Luck.

also if someone has changed the flywheel ……

[Keithver]

Thanks Jim for the very useful adjustable degree wheel. What a great tool.

Thanks for the TDC tip John. I checked and the flywheel mark lines up almost exactly. The marks are maybe the width of the stamped lines out.

Tim, I set the cams up with your MOP method. I see why you say, check, check and check again.  Both cams look as if they were out by about 5 or 6 degrees.
 As you can see from the photos, at TDC the inlet cam mark (photo 1) is slight past the mark now and the outlet slightly more than that.
The engine starts and I took it for a very short run. All seems fine. I will take it for a good run on the weekend to test it properly.
Thanks again for all the help and information

[jimbo64]

This is where mine ended up slightly advanced  inlet,  spot on exhaust