2T-G/3T Hybrid Compression Problems

**Rodger** · 31-01-2006, 03:48 PM

Born-Enthusiast,

The size of the carbies is a measure of the bore at the the throttle plate/engine end of the carby.

Also a 40mm Mikuni/Solex has #165 stamped on the throttle plate.

A 44mm Mikuni/Solex has a #175 stamped on the throttle plate.

To recognise the model of Solex go to this web page (thanks to September Squall):

http://www.wolfcreekracing.com/carbid.html.

Regards

Rodger

**sillycar chick** · 31-01-2006, 04:24 PM

Thanks for your info on Solex's, Rodger! I too had been pondering the same question, but hadnt been bothered to ask the question ;-) And when the engine is up and running, if the need arises to play with the carbies i'll shoot you off a PM. Thanks!

**Born-Enthusiast** · 31-01-2006, 04:28 PM

thanks rodger im just checking what i've got now. . . it took a bit of running back and forth but i have s5 40mm thanks for the help

**mynameisrodney** · 31-01-2006, 05:33 PM

Originally Posted by Rodger

Also a 40mm Mikuni/Solex has #165 stamped on the throttle plate.

A 44mm Mikuni/Solex has a #175 stamped on the throttle plate.

thanks for that mate. Are 40's fine for a hybrid? i have a set of what i now know to be 40mm solexs and a set of 45mm webbers. if the 40's are fine i'll fit them and sell the webbers to help pay for my respray.

chris

**tricky** · 31-01-2006, 08:30 PM

Rejetted 40's are fine, especially for a regularly driven car. 45DCOE's are gret for top end though... But if you sell them, they are worth a mint, and will definitely be a good start on saving for a respray!

**Rodger** · 01-02-2006, 09:37 AM

Thanks Tricky,

Exactly as you say.

There are several things we can change on the Solexes depending on how the car is to be used.

There are also several things to check if you can before bolting them on. The operation of the pump circuit, the inner venturis if they are loose and the state of the idle mixture screws are just three things.

If anyone needs parts or jets or more help please ask.

Regards

Rodger.

**3T-GTE** · 01-02-2006, 01:59 PM

Yes interesting reading...

I've also noticed that there are several formulas used around the place.

Just wondering if your figures look the same using these 2 calculators:
http://www.turbofast.com.au/Tfcomp.html

http://www.kb-silvolite.com/calc.php?action=comp

This second site also allows you to calculte the dynamic compression ratio if you can work out where your Intake Closing Point is.

Were you able to do the quick check that Jason(YellowRolla) reccomended?

quick check - wind no 1 to TDC compression (dial gauge down the bore), check that number 4 valves are open about the same amount. While the cam cover is off check all of the valve clearances

If so, what did you find?
Cheers,
3T-GTE

**sillycar chick** · 01-02-2006, 04:52 PM

3T-GTE,

Thanks! I tried the calculators but they didnt work out to what I got. And you have to convert to imperial, bugger. I used the formulas to calculate it manually:

Comp. Ratio = ( Vol. bore@BDC + Vol. head chamber – Vol. piston dome + Vol. @ head gasket ) ÷ ( Vol. bore@TDC + Vol. head chamber – Vol. piston dome + Vol. @ head gasket )

And I havent had a chance to measure anything on my engine yet, but I do recall when I was assembling it, when no1 piston was at TDC, the valve lobes were pointing horizontally towards the rocker cover (if that makes sense) therefore the valves were closed.

**YelloRolla** · 04-02-2006, 01:57 AM

Originally Posted by sillycar chick

3T-GTE,

Thanks! I tried the calculators but they didnt work out to what I got. And you have to convert to imperial, bugger. I used the formulas to calculate it manually:

Comp. Ratio = ( Vol. bore@BDC + Vol. head chamber – Vol. piston dome + Vol. @ head gasket ) ÷ ( Vol. bore@TDC + Vol. head chamber – Vol. piston dome + Vol. @ head gasket )

And I havent had a chance to measure anything on my engine yet, but I do recall when I was assembling it, when no1 piston was at TDC, the valve lobes were pointing horizontally towards the rocker cover (if that makes sense) therefore the valves were closed.

They didn't need converting to imperial. At the top there is a number 1 for imperial OR choose number 2 for metric.

**sillycar chick** · 04-02-2006, 08:14 AM

YellowRolla,

I wasnt referring to your link to a calculator, but the links 3T-GTE gave me both required you to input data in inches.

Follow his links and you will see what I mean...

**YelloRolla** · 05-02-2006, 12:04 PM

Okey doke. The carfor site is very useful and I thought that you had overlooked that part of the calculator. Obviously though you are smarter than that.