Hi could anyone help me to figure out the compression ratio on my 400m the block was bored and dekked 0.25mm and heads milled 2mm and the intake exhoust runners were ported "heads and mainifolds mached together" im using the edelbrock preformer 400 manifold and the cam is a crane 272 .... i tested nr 1. cilinder with a compression tester and it came out just over 150psi ...... also i installed a Dui hei distributator and im having some isues starting the engine when it starts upp it runs great but is hard to start !! any ideas ?? thanks

 

What starting issues? Slow turning over or not firing? 150 isn't too extreme; what is the initial timing?

 

The distributator is not fyring but i thing the broblem was the ground ... i used a 10 gauge wire and a 12V30A solinoid to bypass the ballast resistor but i messured the voltage to the diss and it read 11.94V or something like that ..... okey 150psi is not so extrime i was just wondering if the engine was in the 9.1 area or something like that i did not remove all the spark plugs just the one and diskonected the fuel hose to the carb so it is not a acurate reding ... and yes sorry about the bad spelling hehe

 

150 is pretty much a 9:1 engine. On your grounding you might need to install new battery cables. If they are kinda green and nasty need to change. Don't be using one of those connection with the two small blts in the battery connector, they will eventually suck. Make sure your grounded from battery to engine and engine to frame and frame to cab. Use a set of battery cables to help troubleshoot your grounding issue for a quick test.

 

Okey will do thanks alot .... i used the old 12.4V hot wire to the realay and then to ground and then the 10 gauge wire from the + side of the battery and throug the relay and to the diss ...

 

These old trucks also have an ignition wire coming off the starter solenoid and going to the coil to provide full volts while starting. Maybe you should look into that also.

 

Okey i took a look at the cables and grounds and wired the two wires that came from the old coil togheter and the got full voltage and the truck fired upp and runs great know i set the timing at 12BTDC like sugested .... also i tried the compression test again with all spark plugs removed and the throttle full open "but engine cold" et came out just under 170PSI .... im not sure how much that is in ratio but thanks alot for the help