nimrodTT

ok, i just dropped my new streetport motor in this week, but it wont start for some reason. i think i checked over everything and im starting to drive myself nuts - just spins and spins without so much as wanting to start. its got compression, fuel, and spark. i even tried push starting, and nothing worked. any ideas?

hanman

My first thought would be timing. Make sure that the distributor is in correctly, if not, it will never start. Make sure the main pulley was installed in the correct place, again if not, it's not going to run.
hanman

MIKE-P-28

iTrader: (1)

Sounds like the first time I streetported or tried to Needless to say I ground it too far and I got it to run once by putting ATF in it, but the porting was done wrong by me So no one to blame but myself ...

nimrodTT

its a very mild streetport, i didnt touch the inside or outside edges. as for the timing, ive restabed the dizzy about 30 times and im doing it the same way ive always done it. and the main pulley is the racing beat underdrive, theres no way i could possibly install it wrong.

after looking more closely at the spark it seems weaker than before, any ideas what would cause a weak spark? im running a wasted spark on the leading off a accel dual post coil and the stock ignition on the trail. i could go for some expert advise right about now.

hanman

Weak coil, bad dizzy cap, bad rotor, bad plug wires, bad coil wires, fouled plugs.
hanman

MIKE-P-28

iTrader: (1)

If you ground any of the port towards the inner edge (towards the eccentric shaft) , you got a worthless motor. Thats what I did, just smoothed the edge and raised the top and that was my problem.

nimrodTT

weak coil ruled out because both are doing it, leading doesnt even go through dizzy so that rules out rotor and cap, plug wires are brand new and spark is weak before them anyway, fouled plugs ruled out because i just cleaned them. still no start.


i didnt touch those edges.

MIKE-P-28

iTrader: (1)

Dude I bet you messed up... Better ask peejay...

hanman

Nimrod,
I don't mean to be an *******, but the reality is, if it has spark, compression and mixture in the right quantities at the right time then it is running.
So, obviously one of these is not coming together correctly. Is the timing spot on?

hanman

Just a thought, Mike is concerned on the porting. Have you done an accurate compression test? I don't mean the three Pffft's and it's ok type either.
hanman

MIKE-P-28

iTrader: (1)

Yeah porting a motor is more than grinding some metal away. Thats like having a valve in a piston motor open too long, no opening up at the right time.. Got a picture of the porting?

REVHED

It could be something as simple as the accelerator pump not working. It could be gummed up due to not being in use for awhile. That's what happened to me when I put my new engine in. Just poured a few drops of fuel down the carb throats and she started right up. I seriously doubt that it's anything to do with the porting since it's mild and you didn't touch the inside edge. You'd really have to **** it up in a big way for it to cause your engine not to start.

nimrodTT

got it started for about three seconds maybe five times, it kept dying because the rear carb isnt pulling as much vacuum as the front and so there must be a leak somewhere. I found a shoulder of a bolt that was holding up the intake manifold from mating perfectly straight but it only helped it; no cure yet. Both rotors hit in the 50psi range (remember that the motor is cold and has not been broken in). here's two pics of the rear ports.

MIKE-P-28

iTrader: (1)

Doesnt look bad, of course the difference between one that runs and one that dont, is very very subtle. I screwed mine up, but you need someone that has done porting succesfully, that would be best.. Good luck man, I hope you dont have to take it apart again

hanman

Well, at least we can rule out spark now.
Are you running Webers?
50 psi is low, but you have a good point about cold and new engine. Are you sure that you have a good seal on the intake manifold now?
Have you tried starting fluid or pouring a little fuel down the barrels?
hanman

nimrodTT

yeah, 36DCDs. found the vacuum leak - a carb gasket fell off its landing just a hair - so i made new gaskets and the leak was gone. Now it starts up, but wont run for more than about 30 seconds and will not idle at all. Some ether and a little throttle has to be applied to get it to start, and when it does it just wants to shut itself back down. I think it might be that the mix is off, but im not sure if it needs to lean out or richen up. Then again it could be something completely different.

hanman

Based upon what you are saying, I would try going rich on the mixture.
Good news at least we have probably narrowed this down to fuel mixture problems.
hanman