mightyboy F5A timing.

[Psi_Wagon]

ok before i start, i have searched high and low about this topic with no success :S

ive read everything Brayden has said on the topic, but to no avail. (not saying its not right though! i will explain later)

anywho, decided my boy needed a new timing belt, its done almost 310,000k's, and who knows how long since it been changed. so i ordered a replacment belt kit online(not knowing there was 2 types).

it got here, i pulled the boy apart to find it had the square belt, and the new one is the round type...
so i decided to put it back together until i got the right belt, and heres where my problem lies.

after all my stuffing around, ive moved the cam & crank gears, ive tried everything to line them up correctly, even followed the procedure from the 550cc Hatch service manual. i get to the point where its all together, lined up as per the manual, i try to turn the crank gear 2 revolutions as it says but i only get about 1/4 turn when the valves hit the #1 piston.

its got me stuffed.

now i dont know if this is related or nut But, i have a 2nd mightyboy for parts that i thought ide compare, and it has the round type belt gears (its also been sitting in a paddock for 12 years...)
Now the thing that i found strange was, both mightyboys have the F5A motors, BUT they are stamped "F5A" in different positions on the block? (pics below)

i need to get my boy back on the road asap, even with the original parts for now. if anyone could help that would be great!

Pics;
note the white one is the one i am having trouble with.





on my white boy the marking 'F5A' on the block is underneath the intake manifold, just above that oil pressure sender, whereas the red on has it just behind the oil dipstick :S





help!

on an unrelated topic, i found my long lost 14mm socket

[Psi_Wagon]

anyone ?

[Brayden]

I'm confused about why you need to turn the crank 2 revolutions. 1 revolution will bring it back to the same point, albeit on a different stroke cycle.

What you need to figure out is where your cam is sitting. The easiest way to do that it to check against the distributor. Firstly move the crank to a point where all the pistons are clear of valves, then if you rotate the camshaft to the point where the rotor is firing number 1, that will give you roughly TDC for cylinder 1. (Cam alignment markings should also line up at this point)

From there you can follow the advice of the workshop manual to offset the cam to a point where all the valves are closed, move the crankshaft to TDC cylinder 1 (woodruff key pointing up) and then set the cam back against the alignment markings.

Fit your belt and away you go.

[Ralf the RR]

I'm confused about why you need to turn the crank 2 revolutions. 1 revolution will bring it back to the same point, albeit on a different stroke cycle.

This is a final check to ensure all the marks line up after complete assembly.



Here's a tip if changing the belt only:

While the old bet is still attached, mark each gear and the corresponding point of the belt with liquid paper.

Then remove the belt, and lay it over the new belt.
Mark the new belt in exactly the same positions as the old.

Fit the new belt so the marks line up.

One thing though. This relies on the old belt being in the correct position!
It's always wise to check the marks as per the manual.

[Trevor]

I used to think that the crankshaft keyways were always up but some of the cars I have done lately this doesn't apply any more

[Al_Zhiemer]

Just a quick question.

When you put the belt back on, do you keep tension on the belt opposite side to the tensioner pulley??

You want the belt to be slack on the tensioner side of the belt, so when you put tension on the belt it pulls tight from here. if you have slack on the side where you have no tensioner this could be your problem. Having slack on the side opposite to the tensioner will effectively put your timing out by a couple of teeth once it is rotated as it has to take up this slack befor the cam gears move.

Cheers.

[Trevor]

Yes

[Psi_Wagon]

ok i worked it out, and not the way the manual says how to do it!

but whats with the different F5A blocks ?