JowettTalk

Putting aside compatibility issues of ethanol on rubber etc.... Comments above re matching your octane to your compression is correct... more correct is matching the octane to the dynamic compression ratio of the cam profile of the engine is what is critical....or more accurately the cylinder pressu...

Forget reading plugs to set mixture with modern fuels.....only reliable way now is invest in O2 sensors and a data logger (like a Innovate LM 1 or LM2 or DIGITAL AFR meter There is really nothing one can do when traveling between say snow line and sea level.. if tuned for sea level and getting up cl...

Ideally higher the compression.. and thats the Dynamic compression ratio... or in basic terms, the max cylinder pressure at a given loan and rpm....the higher the octane of the fuel require for efficient burn. So if u have an old veteran/ vintage car that was designed to run on British Pool fuels be...

Having played about with and built my own electronic ignitions over about 50 years, I have given them up! For me, it's back to straight-forward points. Put that into the context of the obsoleting of the points system for HEI by manufactures around the world it was NOT an upgrade made in the early t...

u should really dial the curve in rather than simply estimate the values you require as tuning specs....Forget any factory settings... our engines have been re bored, different compressions and the fuels are very different from the old British pool fuels...very different time from spark to max cycli...

Im not too sure how well these old cases with such high Alumium content would weld up with our modern alloy sticks. If going to get welded, ask if they have to pre heat the the whole item before welding...Cast Al is like cast iron, a very high heat expansion co efficient, and appling heat in certain...

If timing on a road u dont need great distance... a steep hill 100 yrs or so in a lower gear, and a passenger with atop watch.. just hit that 1st spot at the same speed/ rpms each time... an ave of 3 runs per setting gets one damn near spot on As to chassis dynos... 99% of shop dynos havnt been re c...

Been a buysy day , back Couple comments above So the question is what has changed since then? Petrol certainly, wear on engine and I must try to remember what I have done to it since then! If u go back to my orginal post I think... Compression will change timing... a so called "worn " engi...

the things we can do are: 1. Open up the hole for the max advance stop 2. Alter the springs (wire diameter, number of coils and length) 3. Possibly change the weights (although as far as I know they were always the same). 4. Play around with spring or slackness of the vacuum unit (If someone can fi...

Your point 3/ lowest advance at the idle rpms u want... On a Jav/Jup engine the idle rpm is about 850 rpm although some will idle at 500rpm. So when you say 'lowest advance' would you turn distributor (or micrometer adjustment) clockwise to retard until the idle was unstable, or what? I assume here...

We have a similar Dizzie specialist near us, excelent reputaion in the automotive industry, and hosted a club rech evening a while back. He will rebuild any dizzy , VA what ever...."to the specs the customer requires" or put another way..the specs the customer establishes for his vechile, ...

Now I am on the hunt for programmable distributor but first need to understand what I am doing. Do modern petrols need more max advance than the pool petrol used when the DM2 40317 curve was chosen? Does a balanced Jowett with ported heads that can rev up to 6000rpm need a different curve? Does the...

"Considerable" indicates excessive blow by past the rings... Which is likely to be combined with the filter/ valve type system between the crankcase vent tube and crankcase being dirty of faulty. Start with the filter/ valve, clean, check vanes etc 1st. Check cyclinder compression, blow by...

Perhaps I should try buying a top of the range fuel, rather than the cheaper brands? Well u could try that, maybe go to the States, try their fuel, or Aussie... end of the day, it is the volitile parts of the modern fuel that permiate and evaporate , and it it those that the engine relies on to fir...

It's interesting to hear that you support David Morris' statement about stale petrol. look, there is only one way I can put this. Hell yeah. And several threads here on hard start......after winter storage. Im not around just jowetts, but hot roads, classic Aussie and American cars, and also on suc...