Gaz 66 Tuning challenge 2010

[zoltan]

Haymish and I have been mulling over the best ways to tune the Gaz 66 ZMZ engine for a short while now and so we have decided to have a light hearted but highly competitive tuning challenge.

There are four criteria to be met

More power
Better economy
Better reliability
Cost

Now my chosen route will involve fuel injecting the Gaz engine amongst other options using the Megasquirt MS1 V3 ECU and a Ford EDIS ignition unit. Haymish, the traditionalist scorns this high tech approach so I will let him lay out his own plans in due course.

We are both looking at having some cams made, probably using a Rover V8 mild road profile. I will do these.
I was looking at having some longer conrods made to raise compression that way but it seems that skimming the heads will get us to 8.5:1 without too many problems so I might leave the rods for the time being (I will be getting hammered on cost already anyway)
Haymish is very kindly donating an inlet manifold to my effort so that I can butcher this with fuel injectors, a fuel rail and then sort out some kind of throttle body, preferably robbed from something kicking around at work.

The way I see this working is that the current distributor is really a weak random spark generator with a very fixed range of ignition options and the Russian carb a very inefficient fuel tap that spends most of its time pouring fuel into the engine. My thinking is if I can use a 3D ignition map tuned for best torque at each combination of rpm and manifold vacuum (or throttle angle) and accurately calibrated fuel injection I should be able to whop him on points 1,2 and 3. Even without touching the internals I'm sure I can achieve substantial improvements just by junking the carb and dizzy.

On cost I reckon with a bit of careful scrounging I can get my cost down to about £750 for the engine management. The ECU is £300 and Ebay USA will provide V8 EDIS ignition module, two coils and plug leads for about £100 shipped. It is quite easy to set up and tune once you have managed to filter down on the masses of information available on Megasquirt. It requires only a Windows laptop and an RS232 serial port lead and most of the software is open source.

Over to you Haymish ;)

[haymish]

as you should all be aware i am a luddite as regards gizzmos'-and zoltan has already almost conceeded defeat in one area -COST-now i do more miles than most but the maths of spending the best part of 1000quid to put squiggly thing on to get marginally better fuel consumption[hopefully] just doesn't add up-even for the mileage i do-the thought of spending that much for occasional use is just plain stupid .
reliability-well i dont feel that they are that unreliable but the dizzy and carb are not exactly the best in the world so undoubtedly could be improved-the dizzy actually has a huge range compared to most western ones of its era-but zoltan is blinded to that cos he suffers from the delusion that new must be best and if it doesn't have lots of little circuit things in it can't be good-to me lots of little circuit thingys just means more money and more things to potentially go wrong-however as one of the criteria is money and i will have an enormous head start in that direction then i might just see if the dizzy can be upgraded[wouldn't bother normally cos i dont think the dizzy at all bad-just the quality of most points interesting.but seeing its a challenge then it might just turn into a twin point set up-advantages for those unaware are less stress on points-last longer etc and incredible accurate set up/dwell angles ,bigger range of advance/retard
etc and despite all the alledged advantages of squiggly things are in use all over the world in exceedingly fast road and race vehicles.
yes i will be using a carb but havn't decided just on which one yet-but lots of tricks available to make their performance better
power-well hopefully the two cams will be identical so a level playing field so we should get a reasoneable comparison of old school engine tuning to gizzmology-i'm somewhat outgunned in terms of available workshop toys but that dont worry me in the slightest cos i've spent over 30 years making engines go quicker than manufacturers intended and will be drawing up a masterplan to beat zoltans efforts-and that dont cost money-just time
p.s. convinced my approach will be best cos of the nature of the beast-crude ,basic , and simple-high techy gizzmos just not very compatable with that-5 million different fuelling maps pretty irrelevant if it just likes lots of fuel dumped in it etc.

[portamurda1]

i'm hoping it still has to perform as intended...ie with any old shit going in the tank/s....anyone considered mechanical fuel injection, twin twin or quad discharge coils?

I await the results with ;) baited breath.....

[haymish]

coil upgrade allready penciled in cos i'm so far ahead on the cost criteria

[KarlJ]

I think we'll need independent testing and judging of the results of this exercise otherwise the arguments will drag on and there will be fighting

How about bringing them both to next year's forum meet? - we can do some tests and testing there. Interestingly you are both roughly the same distance from the meet location (give or take 20 miles and depending on the route you take).

[haymish]

best doughnut contest for one

[KarlJ]

I was thinking more of measured fuel efficiency, pulling power etc - but doughnuts will do. Will be interesting in a field and 4WD!

I still think the Sainsbury's shopping trolley towed behind a diesel Zil would win that one

[haymish]

trouble with lots of tests is the other variables-like a pulling power test-can you factor in wt of vehicle,type of tyres etc-cos i will weigh in a good ton lighter than zoltan-which causes chaos in speed tests,fuel efficiency etc-so the tests have to be more creative than functional-like doughnuts more along the lines of driveability and fun factor methinks

[haymish]

tug of war would be good

[Cable Leics]

I'm interested to see the results of this...

Though I'm usually a fan of 'gizmology', I think I'd go (theoretically as I don't have a truck yet) a similiar route as Haymish, purely for cost.

[zoltan]

-well hopefully the two cams will be identical so a level playing field so we should get a reasoneable comparison of old school engine tuning to gizzmology-

Cams will be identical and will be drawn like FA Cup numbers by a visiting celebrity from a 24" deep hat!

[zoltan]

tug of war would be good

Hopefully we can have our own version of tractor pulling if the Militant is there again

[Andy_l]

I think we'll need independent testing and judging of the results of this exercise otherwise the arguments will drag on and there will be fighting

Invite The Stig to the next forum meet ;)

[Rob Reznik]

Dont forget boys you need torque as well as HP

[haymish]

that's why a mid range rover v8 cam profile being possibly used-the ones for autobox v8's put out most of their torque in a very wide useable band comparatively low down the rev range unlike the more sporty cams that release oomph way higher up the rev range.also aiming at 8.5 to 8.7ish compression which also helps mid range torque.certainly not intending to create a fire breathing monster cos woul prefere it to hold together for more than a week or so-just want lots more oomph and a bit more get up and go[and it would be nice to get a bit more of a 101 nasty rasp to the exhaust tone -including a bit of popping and flames on the overrun-but zoltans squiggly thing probably frowns on that as a waste of fuel WRONG

[haymish]

i sent a gaz 66 cam down to zoltan a bit ago so he could see about reproducing a replacement with a bit more ooph-well he has measured it up and the cam lift is stunningly terrible.its 0.217 inches -which if not in your range of knowledge-is about half the cam lift of a 1970's rover v8[and a low tune one at that,not an sd1 .]a just standard cam out of a rover 3.9 is around .415 inches and a mild kent/piper road cam is in the region of .440 inches.that extra 0.025 gives you about an extra 20 bhp-so i'm smiling at the thought of an extra lift of 0.220ish inches-that gaz engine will just come alive -however i've measured up the valve springs and if they get put back in there would be nasty crunchy noises followed by silence and tears/tantrums cos nearly double the cam lift means the springs will get coil bound just about as the valve is fully open-so next job is find some decent valve springs with one less coil in them so the power of the new cam can be liberated[once zoltan and kent have made them between them ]

[zoltan]

You might be able to tell which lobe I measured from, whether an inlet or exhaust:

http://flickr.com/photos/[email protected]/4822044950

[haymish]

presuming right hand end of picture is dizzy end.
at dizzy end the passenger side bank is set back by a spacing of one valve and starts with an exhaust -while the drivers side bank starts with an inlet
so eighth valve in will be an exhaust valve on the drivers side

[zoltan]

Yes, right hand end is dizzy end. As luck would have it, the hole in the protractor was exactly the right size for the Gaz cam, no blue tack required

[haymish]

just been comparing a R 3.5 v8 standard cam with your photo-and just grinned.