Engine Build Questions
Turbo Mini Forums

Hi

Just a couple general ones really:

1) What torque do the strap bolts on the flywheel need doing up to?

2) Do I need plates to sit on top of the rockers before the bolts go on, I seem to remember taking some off?

3) I have been told to double check my cam timing after the head is bolted on, how do i find TDC of number 1 with the head off accurately?

Thanks

Jon

All these questions will be answered by reading a haines manual...

1 - Haynes manual

2 - Usually only the pedestal with the shaft retaining pin, the metal plate has a rectangular hole that goes over the pin and stops it unscrewing. The others are normally just washers.

3 - with a DTI (clock guage). Do it carefully reading angles at say 10 thou BTDC and ATDC, rotating both ways, and split the difference - trying to just find the zero point is too vague.

EDIT - typo

Edited by Rod S on 22nd Oct, 2009.

Schrödinger's cat - so which one am I ???

O.K!

Questions 1 and 2 have been sorted - I am going to re-check the cam timing with the head on. What I would like to know is what is they best way to get the DTI through the spark plug hole?

I have one with a needed on, so I think I may have to borrow one which has the plunger on to get it through, is this right?

Also where abouts do I have to put the DTI on the top of the rockers? Is this on the adjusting screw at the back?

Thanks

Jon

what i have done is use a dead stop to get tdc,

basically get an old plug, smash the ceramic out and cut the electrode off then put a bolt through it so it stops the piston from comiming all the way to tdc, with the protractor on turn the crank one way until the piston lightly touches the "dead stop" note the degrees on the prottractor, then turn the crank the other way until it stops and note the degrees, adjust the protractor untill you get the same reading at each end. sorted

put the dti on the valve retainer cap, try to keep it as upright as possible so it gives an acurate reading.

Very difficult to do TDC on the A series with the head on because of the angle of the spark plug hole, an improvised extension to the plunger type DTI would be required, kept as near vertical as possible.

BUT, I wouldn't trust the cam readings with the head on, not unless you completely slacken off all the adjusting screws to the point where none of the valves actually move - if indeed this is possible - because otherwise the load of the valve springs could easily overcome the load of the chain tensioner when you are turning the engine backwards (as well as forwards) to average the readings.
When running at speed, the chain tensioner keeps the slack on one side only - when rotating the engine backwards and forwards to get an average reading (as you should) on the cam, the chain tensioner may be overcome by the valve springs when rotating backwards.

Schrödinger's cat - so which one am I ???

Hi

I can just put a bolt in the spark plug hole to act as a stop.

When the DTI is on the valve retainer cap, do i just do it say .005 before and after the top then set it to the centre value of degrees.

Is that the best way?

Thanks

Jon

the bolt in the spark plug hole will need to be tight, ie be the right thread and have a lock nut, or it will not be accurate enough.

with the dti on the valve cap take the degree reading .005 before and .005 after, add them together, then divide them by two and you will get the reading.

Just to double check:

Its a 14mm thread for the spark plug hole, I can get a nut and bolt from work?

Thanks

Jon

Edited by jonb_5 on 26th Oct, 2009.

you might find that the threads do not match, IIRC plugs are fine pitch