Low conpression after engine build vvti ?

[ilovejapcrap]

So I've rebuilt my engine and can't get it to start

It had a new timin chain kit I'm wondering if my timing is out

I've read about unlocking the vvti pully would this cause issue with my timing I just bolted new one on !

[Carolyn]

So you're happy that the injectors are working properly?  Your 'low compression' header:  is that a guess, or have you measured it?
The VVTI hub shouldn't be a problem, especially if it's a new one. As the engine hasn't run, there will be no oil in the VVTI hub, so it won't have operated.
As for the valve timing, you can find out.  Pull the cam cover.  Wind the engine round manually until the mark in the main pulley lines up with the TDC mark on the timing cover. Remember the engine might have to go round twice to get the marks where you want them. Look at the timing marks on the two cam sprockets -they should be lined up horizontally.
If it's out, remove the chain tensioner, then you can take off the exhaust cam pulley and adjust the inlet cam position until the mark on the VVTI pulley is in the right place (lined up with the top of the head).  You have to use a wrench on the hexagonal on the cam to get it to sit where you want (the valves will try to push it out of position)  Once that's positioned, slip the sprocket onto the end of the exhaust cam (without the bolt, so you can play around with it) and get that mark in the right place.  Put the bolt back in.  Tensioner back in, turn the engine to release the tensioner and check the marks again.  Don't attempt to rotate the engine backwards, as the chain can jump.
Sorry to see you're having such a battle.  I'm trying to help....

[ilovejapcrap]

ive measured the compression got 100 , 130, 70 and 70.

I'm well annoyed at moment

hey ho

[Carolyn]

Oh dear.  When you've regained your composure.... check your valve clearances while you've got the cam cover off.  Fingers crossed.

[Essex2Visuvesi]

Have you done a wet compression test?
May help to pinpoint where the loss of compression is coming from

[Carolyn]

i would caution against spinning that engine until the valve timing is checked/sorted.

[ilovejapcrap]

Anyone know valve clearances ? Thanks

[Carolyn]

Intake 0.15 – 0.25 mm (0.006 – 0.010 in.)
Exhaust 0.25 – 0.35 mm (0.010 – 0.014 in.)

If you find some of them a lot bigger, let us know.

[ilovejapcrap]

Right done one of the exhausts and can't get a 0.20  between cam and follower.

So I'm guessing messed them up ? Would this by my issue

[ilovejapcrap]

Or would it still run but lumpy ?

[Carolyn]

Check them all.  Measure them accurately.  See what will fit with a little drag.  Have you checked the valve timing?  Slow down and be methodical. Guessing won't help.

Edit:  Check your email.

[ilovejapcrap]

Timing is good.

I'm going to check them all but don't have the time tonight ( going to work) the two that had less than 70 psi on pressure test don't seem to even get a 0.20 under them when the stats state 0.25 to 0.35.

I'm just checking I'm going down the right path.

It's all new to me but I'm guessing with wrong clearance the valve opens too soon causing bad compression?

[jonbill]

Whats the biggest you can get between cam and follower? Unless it's being held open on the base circle, I don't think it's the reason for  your no-fire or low compression. But you should get it right before going onto the next problem.

[ilovejapcrap]

Biggest I can get on one of the exhaust for example is 0.10 and it should be .25 at least

[jonbill]

Well it's not ideal, but really that's not going to kill your compression or stop it running.
I would expect some other valves have comparably too much clearance - have you measured them all?

[ilovejapcrap]

not as yet jonbill I had to go to work

I'm going to do Thursday

does it sound like it could cause my issue or am  barking up wrong tree

[jonbill]

I'd say if none are tighter than .1mm and none looser than 0.5mm, then it's not the main problem.
So lets see how they measure up on thurs, and maybe do a wet compression test and take it from there.
Fingers crossed.

[ilovejapcrap]

well jonbill / carolyn the worst one is 0.10 on exhaust when it should be 0.25 min

the rest are within min tolerance so its not looking like its that.

I had the block honed and correct rings fitted.

My mechanic friend is adamant the piston and rings are put together right.

so I'm getting rather concerned.

the only bits to do with timing (assuming timing is right and I think it is) are the vvti solenoid (I broke mine and got a second hand one) and the cam phaser (new one came with timing kit)

I have read about unlocking phasers, if it was wrong would it knock timing out and stop it starting / cause low pressure.

my mechanic friend says he has had issues starting cars with the phaser before all be it not on vvti engine.

could / would the phaser or new vvti solenoid being incorrect stop starting / cause low comp ?

hanks

[ilovejapcrap]

 m https://www.youtube.com/watch?v=9c1YSic7ejs m

anyone had IAC cause my issues ?

[Carolyn]

Well, if it's not valve clearances or valve timing...  I don't think the VVTI hub would give your symptoms.  After all, the engine will give full compression no matter how advanced the VVTI is, or the system wouldn't work.   If you pull the VVTI valve, that should release the oil pressure inside the hub (if there is any, since the engine hasn't run).  The engine should start with the VVTI disconnected (electrically).  So you can try that.  Or you could put the old VVTI hub back on (they are pretty reliable so both won't be bad).

However, the give-away is that the compression problem is not even across all cylinders.  Something like the hub would give consistent symptoms.
Such a massive loss of compression has to be in the valves or rings.  It's a very 'mechanical' issue.  Either valves are not sealing properly or the the rings are wrong.
I'm afraid you're clutching at straws.  I would open that engine up and see what the issue is.
I know you don't want to have to go through it all again, but it's hard to see an alternative.

Deep breath!!

[jonbill]

+1, although a wet compression test might be worthwhile before you pull it.

[ilovejapcrap]

Hello all!

Yes this is still going on !

I've taken the head. Ack off done some tests on it and. Any find anything really wrong !

So I'm starting to think piston / rings

I've just picked up a bore gauge to measure the internal bore.

Can anyone say what it should be ? Tolerance etc.

[Carolyn]

Have you placed the head upside down and flat, with the plugs in and filled the combustion chambers with petrol?  Do the valves leak?

Sent you an email.... the end-gaps for the rings are worth a look...(once you've ruled out leaky valves).

c

[ilovejapcrap]

Hi yes done that seems good

Any idea what my internal bores should measure at ?

[Carolyn]

check your email