Discussion in 'Mech Tech' started by willster, Jan 9, 2018.
@72devon I’ll give up now. I don’t think we’re talking about the same thing.
I run a 1776 with 044 heads and 284 duration cam shaft (Empi 110) and JK stainless with twin ICTs. And SDVA dizzy.
Full flowed next To crank pulley, but no oil cooler.
Currently on 52 idles and 145 mains. Can't rememeber the airs.
The engine runs nicely at idle with no flat spots. Engine is running cool even at a cruise of 70mph with a 6 rib gearbox.
Pulls from 1K rpm, but much happier 2.5K rpm and above.
The engine even returns 30 mpg on a motorway run!
However a word of warning. I paid out £1.6K to have my engine bored out to 90.5mm and the new cam. However the engine builder cut many corners and the springs snapped shortly after break in due to not using new uprated springs.
Then I took the engine apart myself and discovered the heads were poorly bored and had cracks all over the show and loosing compression. Basically they guy decided what I could not see would not harm me.
After my rebuild I have done 5K faultless miles and not a drop of oil.
My advice is weld a full range air fuel meter and do your own jetting as so many garages have forgotten the art of jetting and it is time consuming especially with ICTs.
Is it safe to come out yet ?
I feel bad, it all kicked off after I posted about compression ratios.....& I don't even understand them!
Don’t feel bad but I’m sorry I couldn’t explain it very well. Perhaps John Maher would have more success. http://johnmaherracing.com/tech-talk/what-effect-does-compression-ratio-have-on-bhp/
Now I see what you mean,as much as it does not change compression,on paper it can.
I'm not even trying to understand it!
It’s not just on paper, the cam specification determines the required CR and the engine builder adjusts the deck height and/or combustion chamber volume to obtain the CR the cam needs for good engine efficiency.
So how do you put that into the John mayer compression calculation?.
The John Maher compression calculator tells you what the CR is, not what it is supposed to be.
Once you know what CR you require input the data into John’s calculator.
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