Guest jeff1216 Posted November 11, 2003 Share Posted November 11, 2003 1978 280Z F54 block with flat top pistons E88 head Ported polished oversized valves Wild cam (stage III) Arizona intake Holley 390cfm A little more info........................I was suprised to find that my 78 had an F54 block.....when I pulled the head off the pistons looked new...very little carbon. I do not know if it has been bored over or not. E88 head was a lucky find.........I bought all new 280Z valves for it.............the machine shop had me come by...The head looked to be race prepped................Huge intake and exhaust valves.....much larger and thinner than the stock 280 valves. Installed the stage III cam and heavy springs. We can get the car to fire when hard and the gas and will run when pumping the gas and keeping the rpm's high. It still sputters un-burned gas thru the carb and will not idle. Fuel leaking from the intake problem fixed. I am now curious ..... is it possible that the car is making more power and compression than I thought......Maybe need 110 octane to run? (I say this because I have no idea what has been done to the bottom end. OR With the hot cam and HUGE valves....Do I need to re-curve the timing? If so how do I recurve the timing? I can tell you this............when turning the motor over the compression is so strong that it will almost stop a fully charged battery from spinning the motor on the compression stroke. Jeff Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted November 11, 2003 Share Posted November 11, 2003 I'd avoid higher octane until you know that is what is needed. Higher octane is going to make it even harder to run. With the problems you have mentioned and the problems with backfiring through the carb that you mentioned in another thread, I would say that the timing might be off or be getting too advanced. Have you disconnected your vacuum advance? You should, until you can get it running. Try setting your idle higher and lean out the idle mixture some, this will help it idle with that cam. What do you have your timing set at? Also, I have never heard of compression being so great that it would make it difficult to start. I am not sure you could build an L28 to get super-high compression anyways. Have you tried a compression test to see what you are running at and to confirm everything is even? Quote Link to comment Share on other sites More sharing options...
Guest jeff1216 Posted November 11, 2003 Share Posted November 11, 2003 Cam timing is set by the book..................dizzy has been turned to bring her between 10 and 20 advance and will not smooth out in any of that area. Will do a compression test tonight and post results. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.