3TJ Timing with no rotor

[Drunkn Munky]

Ive come to installing the camshafts on my race motor and the manual says turn the crankshaft until the "T" mark aligns with the mark on the casings but i have no rotor on this engine so no "T" mark to align. How else can i ensure the crank is in the right position to install the cams?

I do have a BDK ignition advancer but theres no timing marks on this either

[Evilchicken0]

That's a good one.
What about the dot on the flywheel at 11 o'clock on your picture ?

OK take the plugs out and use a pencil or long thing down the plughole of number one cylinder. And rotate the engine until no1 piston is at the top of its stroke. That's either TDC on no1 or no4. Have a look at the dot on your flywheel and see if it lines up with the crankcase joint at the front of the engine, if so its probably TDC. If it lines with the joint at the rear its TDC no4 so rotate the engine another 180 degrees
Lay the cams in and look at the lobes. Tdc is the ignition so the lobes for no1 should be pointing at each other with the cam timing marks corresponding to the dots on the journals.

Have a look at my 660 thread on the last page there's a pics of the flywheel you might be able to work out TDC from the cranks keyway

[Drunkn Munky]

Nice one ec thats another one I owe ya

[KIYOSHI]

If it's a race engine you are building don't trust the original timing mark or go by the guessing method of popping something down the plug hole (sorry evil).

You need a dti gauge fixed to the cylinder head or on a magnetic stand. The tip will need extending so it touches the piston crown (in the center) at what you guess should be tdc.

Then fit a degree wheel to the end of the crank with a pointer fixed to the crank cases.

Now rotate the crank backwards/forwards through tdc. You will notice a period of rest on the dti when it stops rising and falling. Take note of the degree the crank rotates through whilst this happens. The central point of this period of rotation is the exact point of tdc.

Sounds hard work but it's easy in practice and in a race engine will gain horsepower and reliability.

What's the spec on the engine? I might have a few tricks up my sleeve that will be of interest to you. We have run and tuned/setup 3tj engines at genuine 85bhp + for years so know a few helpful tips.

[Drunkn Munky]

It is a race motor yes, SP spec, was told it puts out 72bhp but ive yet to have it running. It came to me with a stripped plug thread but whilst i had the head off i noticed the rear cam chain guide was on its last legs so had to split the cases to replace that. It runs a ram air type setup but ports are stock so weather it makes 72bhp i dont know.
Ive always fancied one of those fancy gauges to set TDC, you have any links to all the kit id need? Always interested in tips for more power.

[Evilchicken0]

I guess you could it that way

[KIYOSHI]

If the ports are untouched i can't see it doing much more than stock. I'll PM you a very good setup when I get a moment. It will require the cams dialing in and a bit if stripping/rebuilding but will give you a very strong motor with power output below 140000rpm.

You should also pre-load the valve springs by installing washers below the spring seat, keep the valve from jumping into bed with the pistons :-)

[Drunkn Munky]

Nice one i'll look forward to it

[Wraith]

When I used to ride RDs, I used to use a Dial Gauge and Spark Plug Adapter.

Setting the points via the marks were just not accurate enough.

Some people used to use a disk on the end of the crank when they converted to electronic to set it up.

[Ant142]

If the ports are untouched i can't see it doing much more than stock. I'll PM you a very good setup when I get a moment. It will require the cams dialing in and a bit if stripping/rebuilding but will give you a very strong motor with power output below 140000rpm.

You should also pre-load the valve springs by installing washers below the spring seat, keep the valve from jumping into bed with the pistons :-)

I know this is an old post but I’d be very interested in any set up advise you can send me, especially regarding cam timing. I’m a bit late to the party it just getting into racing an fzr.