timing belt problems

[swedge]

finally got my 20seh running today on r1 carbs and megajolt

all running fine untill the alternator belt came off for some reason

i put it back on and it came off again this time getting stuck behind the lower timing belt pulley i ended up cutting the old alternator belt off as it was all twisted by now

before i fitted the new one i checked the timing, it was bang on when the engine was put in

i put piston 1 to tdc and the cam shaft is now sitting here



a good few teeth out, the engine still turns over by hand find and can still hear compression while turning it by hand

something isnt sitting right though to make the alternator belt come off, ive took a few pictures of how i have things set up

bottom timing belt pulley, as you can see its not sitting right





water pump


cam pulley


the way i have the bottom pulley set up is i put the big washer on first, then the woodruff key, then the pulley them the main bolt and thick washer

is that correct?

[Joker]

Hi mate something is very wrong there, Don't the 8v's have a backing plate of some sort to keep them inline? Did you say you put a washer before the bottom pulley? Is it possible to fit the pulley with out the washer?

[swedge]

yeah there is a washer on the rear of the bottom pulley, thinner bit bigger in damater than the front pulley

i dont think it would make a difference with the washer there or not as the bottom pulley has a recess in it where the washer sits

its as if somethings not sitting straight and throwing everything off

[Joker]

There isn't really much to not be straight though, Does everything look straight? I cant think what would do it to be honest, the crank cant be bent as it just wouldn't work if it was, What have you done to it before fitting the belt.

[swedge]

yeah everything looks fine apart from it all being shifted closer to the engine

[Joker]

it looks like you have too much gap between the bottom pulley that the belt sits on and the oil pump mate.

[swedge]

yeah you could be right, i dont think i can get it on any further though, anyone know if there should be a washer there?

[neilb1798]

they do two different types of belts make sure you have the right one ones 111 teeth and other one is more wont make a difference with backing plate mines has nothing on and its fine they also do two different sizes of top pullys and if your doesnt have pre tentioner on adjust the water pump to tighten the belt up that will sort it

[neilb1798]

oh and dont worry about head when timings off there none contact i found out that when i had belt snap a while ago took the head offand realised i only needed to take rocker off oh well

[swedge]

yeah i know about the cam pulleys as i needed a replacement and bought the wrong one to start with, mines is from a mk2 cav not a mk3

i think the timing belt is at the right tension, i can just twist it and no more 90 degrees

anyone have epc to check if there should be a washer behind the lower pulley?

[lee303]

i thought you only had the washer on the 16 valve? not saying that for definite as its been a while since i have looked at a big block, but the bottom pulley will dictate the belt position for everything else so if you can fit the pulley without and it still goes up tight on the bolt, i would try that

[lee303]

infact looking at the pics doe the crank pulley not look to be sitting off the crank a little? is that a recess in it before the crank nose?

[Joker]

lee303 you see what I see, it looks like it should go flat up against the pump, try it with out the washer mate unless someone can say otherwise.

[swedge]

ill see what it is like without the washer tomorrow, the thing is i bought the engine already have removed from the engine bay and it had no belt on it at the time and i cant remember if the washer was in there or not

the washer is actualy slightly smaller in diameter than the recess inside the pulley so you guys could be right

if the bottom pulley was too far out wouldnt that pull the rest of the belt outwards instead of into the engine?

[lee303]

no because the effect of having the belt hanging off the edge of the crank pulley will be for that edge to fold and pull the belt further off, @Joker, yup, i think the front of pulley needs to be up against the nose of the crank with no recess

[Joker]

it would mess the whole thing up m8 try it see how u get on

[lee303]

also if the crank cog is too far off the nose then the alternator bely pulley will also be out, explaining the alt belt coming off, does that belt run look straight?

[swedge]

yeah it looks straight but it will do as everything has been pulled to the side, ill take the washer off tomorrow and see what its like then

i have epc on my pc but its playing up atm so cant check if it should actually be there

[swedge]

sorry thought you meant the timing belt, i never actualy noticed if it was straight i was just too excited to have it running lol

[swedge]

my images wont enlarge on epc but looking at it there shouldnt be a washer behind it

[lee303]

it all adds up tbh

[swedge]

yeah, ill post back tomorrow and let you know

[swedge]

washer removed

[vectra640]

that looks a whole lot better

[swedge]

ive turned it over a few times by hand but it still seems to move towards the engine when going round the cam pulley it over hangs by maybe 1-2mm