seeking help:installed timing belt and covers - now misfiring?
 

Hi all,

I need some advice, I have so many different ideas going through my head right now, I need some expert opinion.

Yesterday and today, We replaced the timing belt and covers and now the car misfires and inst drivable..idles perfect thought..

Basically, a huge misfire/backfire on acceleration somewhere between 1500 and 4000..

The engine is a 2.1 stroker with jun 272 cams + Jun cam gears and has been tuned and running for about 5000kms.

The cam gears have been adjusted, i wonder if we need to reset that before trying to install the timing belt? Then set the cam gears again?? Will this affect the tune again if we set it like not 100% as it was before..

Also, since there was no covers around the cam sensors and now they're fully covers, I wonder if this could affect the tune?

Frustrated user right now.. like i said, please any advice would be appreciated.

Regards,

David

With the JUN cams and gears it would have been dialed in when installed.... this may make the timing marks uselss for actually knowing whats whats now !@
Why are you screwing with the belt if its only done 5K ? Those cams are good cams...quiet large and its possible to bend valves pretty easy by getting the belt wrong a tooth or so.

You could re-set wheels to 0 and then install belt at marks, should run but it may not be timed that well...

Your tune will be miles out with-out the cams being back to where they were set-up and car was tuned.

Engine out job to degree cams correctly.

Wasn`t a wise move screwing with it with-out knowing what you were in for...there are ways of replacing belt in your situation with-out screwing things up... but its too late for that now.

^^WHS

Cam timing is out - I hope you haven't bent any valves.....

Do your adjustable pulleys have the belt alignment marks on them?

Yes Rocoo they do, cam timing has been dialed in before the tune.

We didn't use these when lining up the timing belt.. should have?

So if I reset the cam gear timing to 0 degrees and align these accordingly when doing the timing once again. will the timing be right?

If I do the above, will this throw my tune?

then readjust the cam Timing to what it was prior- tune will be fixed?

Compression test on driver side is good, haven't done the passenger side yet

and yes fair enough gtlegacy. Btw are you sure the engine needs to come out to adjust the cam gears?

There is plenty of room for a small ratchet and hex bit to make the minor adjustments on the cam gear.

To dial cams the valve covers need to come off so a dial gauge can feel the cam buckets to find lift@degree...

The cam gear timing is adjusted on the front of the cam gear.

This is what I mean?

You need a dial gauge reading off the valve bucket to dial in the cams static timing with any sort of accuracy. Just moving the adjustable wheel blindly may result in valve clash and fuck your motor.

It's the one reason why I never fitted them during my build.

Do your cam wheels have the lines and dots to align the belt?

Like this:

[IMG]http://img.photobucket.com/albums/v499/mick24/CamTiming.jpg[/IMG]

hang on, forgive me if this sounds stupid.. i don't understand why the cams need to be dialled internally? This was never done previously... we installed the cams, buckets etc, checked cam to valve clearance 0.20mm and 0.25mm int/ext.. then fitted the cam gears redid the timing belt, then adjusted the cam gears as per the tuner and then got it tuned.. I am listening to what you're saying thought , do you have a DIY or fsm guide that you recommend?

p.s the standard timing marks all line up.. we turned the motor over by hand to check everything was lining up as per the manual.. was about to start counting teeth..

The cam gears line up perfectly but what I mean is the inside dials, is there a different procedure for changing timing belt when you have adjustable cam gears?

p ps. Roccoo i used your build as the platform for mine, but ya 2.1 lol..

yes Rocoo they do, we used that to align it? The cam gears have markings just like the standard cams.

1 line and 2 lines and a side line on the bottom cam gears