Compression Ratio Too High?

[Multi69s]

I just got my heads back from Headflow Masters (dropped seat). They did a full rebuild and installed larger valves. So the heads are 1700 based, but now they have 40 x 36 valves. The heads also have extensive porting and the combustion chambers have been reworked to the Porsche 2.0 shape. Since the heads were "decked", I had to re-CC them. The chambers came out at 50CCs, and the pistons are 7CCs, for a total of 57CCs. My deck height is 0.045", so my compression will be 8.6:1.

The rest of the engine specs: It is a 2L, with a Scat C25 cam (Lift - 0.455", Duration – 272, Duration @ 0.50 - 234), 72-74 heater boxes with thunderbird header, Suzuki Hayabusa muffler, dual Weber 40DCNFs (30mm vents) and a slightly modified Type 1 028 distributer.

The motor is actually in a Squareback, with an automatic transaxle. I usually run 92 Oct. fuel, so is the 8.6:1 compression going to be too high. or is it doable?

Also, I have noticed that on some T4 engines, the owners have a flexible hose that screws into the oil switch location on the block. They then screw in their sending units into this hose. Does anyone know where to get this hose?
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69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[raygreenwood]

I got 8.587:1.....cool!

That will be no problem with either the carbs or with the original D-jet.

The hose people are using is a brake hose with teflon lining. There is a thread about it in the bay forum about a month or so ago. Ray

[jaxdream]

Using the brake hose is a great way to do the oil press mod. You will have to come up with a ground for the sensor because when it's mounted in the block that is where it gets it's ground. Being you want do the hose mod why not spring for the dual idiot light / electric pressure sender and related pressure gauge if you don't already have them . You will need to seal the hose being that the thread is straight walled , same as the sending unit ( 10mm X 1.0 thread ) , not tapered as in NPT . Also mount the sending unit to the fan case out of the way of moving parts and run a separate ground to the mounting also for the sender to work . This would give an indication of oil pressure another critical engine spec . Keep posting , your particular engine setup is a little different , but not bad . You got the port velocity from using 1700 heads as opposed to using 2.0 heads , this will change a little , not a clue as to how much ,because of the valve redo , but shouldn't be troublesome .

Jack

[Lars S]

Have one of theese in my 412.. works great.

http://m.ebay.co.uk/itm/Remote-Oil-Pressure-Gauge-...1889696288



Lars S
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