MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: ilovejapcrap on July 11, 2017, 10:46

Title: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 10:46
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 !
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 11, 2017, 11:11
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....
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 13:58
ive measured the compression got 100 , 130, 70 and 70.

I'm well annoyed at moment

hey ho
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 11, 2017, 14:10
Oh dear.  When you've regained your composure.... check your valve clearances while you've got the cam cover off.  Fingers crossed.
Title: Re: Low conpression after engine build vvti ?
Post by: Essex2Visuvesi on July 11, 2017, 15:28
Have you done a wet compression test?
May help to pinpoint where the loss of compression is coming from
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 11, 2017, 16:17
i would caution against spinning that engine until the valve timing is checked/sorted.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 18:52
Anyone know valve clearances ? Thanks
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 11, 2017, 19:02
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.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 19:22
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
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 19:23
Or would it still run but lumpy ?
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 11, 2017, 19:29
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.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 19:39
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?
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on July 11, 2017, 19:48
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.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 19:56
Biggest I can get on one of the exhaust for example is 0.10 and it should be .25 at least
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on July 11, 2017, 21:54
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?
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 11, 2017, 22:01
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
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on July 11, 2017, 22:41
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.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 13, 2017, 10:06
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
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on July 13, 2017, 10:15
 m https://www.youtube.com/watch?v=9c1YSic7ejs (https://www.youtube.com/watch?v=9c1YSic7ejs) m

anyone had IAC cause my issues ?
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on July 13, 2017, 10:47
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!!
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on July 13, 2017, 13:12
+1, although a wet compression test might be worthwhile before you pull it.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 2, 2017, 11:39
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.
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 2, 2017, 12:11
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
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 2, 2017, 15:09
Hi yes done that seems good

Any idea what my internal bores should measure at ?
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 2, 2017, 15:30
check your email
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 2, 2017, 17:15
Well they seem ok

I'm so annoyed at moment can't seem to find an issue !

I'm assuming others have used after market head gasket with no issues !
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 2, 2017, 17:23
yes several times.
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 2, 2017, 17:39
Yes several times.  I doubt a dodgy head gasket would give such massive low compression on its own, (You might get a coolant leak, or some other problem that may surface in a running engine) but not 70 psi in two cylinders. Either: The valves weren't sealing, the rings aren't doing their job, one of the surfaces (head or block) isn't flat, or the head was not bolted down properly.  
Is a liner sticking up??
Were the very low readings in adjacent cylinders?
Are the rings phased correctly?  (Though I doubt that would cause your symptoms).
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 2, 2017, 18:15
You're not going to like this:  Are you sure your compression test was accurate?  Had to ask.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 6, 2017, 20:03
Hello all

The original test was 100 130 70 70 for compression.

I then leak down tested it at like 1.5 bar and all came back as ok in that test. Odd not sure how good a leak down is.

I took the head off and checked it all out and could find nowt wrong.

I then put head back in using old bolts and gasket for a check and had 0 compression on test

So I figured oh gaskets not re sealed but thinking now after a major break from it I did not have all timing chain back on so it would not open valves to allow air in to them compress !

Anyway I have removed head again and measured the internal bore. They seem ok.

In order to try and prevent taking bottom half of engine back to bits I've ordered a set of RIK pistons same as ones I installed.

So I can do rig gap test without taking it to bits ( assuming they are same as what Ive installed ) should be.

If that comes back ok I'm checking top of block for flatness.

If that comes back ok I'm sending head off for a full rebuild new gasket and bolts and putting back together.

Fingers crossed it's a warped head of faulty gasket !
Title: Low conpression after engine build vvti ?
Post by: jonbill on August 6, 2017, 20:28
Lucky it's a non interference engine! [emoji12]
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 6, 2017, 21:40
Hehe
Title: Re: Low conpression after engine build vvti ?
Post by: SteveJ on August 6, 2017, 21:47
Don't assume that's correct - several people have reported the last gen (8-hole) pistons did in fact hit the valves when tested.

For the record Toyota specify the 1ZZ IS an interference engine design.
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 7, 2017, 07:48
Quote from: "jonbill"Lucky it's a non interference engine! [emoji12]

Your subtlety is only exceeded by your forbearance.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 7, 2017, 22:25
Well without the cams on valves are shut anyway

Anyway taking head for checking and skimming tomorrow.

What gaskets has everyone used ?
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on August 7, 2017, 22:48
I used the standard mls gasket from the MAG rebuild lit.
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 10, 2017, 18:54
Hello all.

Quick update I have had full rebuild on head re skimmed valves lapped again and shins ( or whatever you call them) checked.

They say it had a few minor issues but doubt it would cause my issue.

I have also checked the spate rings in bite and all are well within tolerance.

The gasket I used was a Certain make and the head shop says they have had a couple of issues with them. I have got a different make that they advised !

So time will tell
Title: Re: Low conpression after engine build vvti ?
Post by: jvanzyl on August 10, 2017, 18:56
Good luck!
Title: Re: Low conpression after engine build vvti ?
Post by: smarty72 on August 10, 2017, 18:57
Fingers crossed for you...
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 20, 2017, 09:50
It runs !

Looking very strongly that the headgasket was my main issue allowing venting between bores
Title: Re: Low conpression after engine build vvti ?
Post by: ilovejapcrap on August 20, 2017, 09:54
 m https://youtu.be/yGNOdvMkFbM (https://youtu.be/yGNOdvMkFbM) m
Title: Re: Low conpression after engine build vvti ?
Post by: shnazzle on August 20, 2017, 09:58
Sweet! Well done
Title: Re: Low conpression after engine build vvti ?
Post by: smarty72 on August 20, 2017, 10:58
Hooray
Title: Re: Low conpression after engine build vvti ?
Post by: jonbill on August 20, 2017, 11:10
Well done - reward for perseverance!
Title: Re: Low conpression after engine build vvti ?
Post by: Carolyn on August 20, 2017, 11:19
Got there!  Good show.
Title: Re: Low conpression after engine build vvti ?
Post by: cabbydave on August 20, 2017, 18:56
I would only use genuine head gasketson Toyotas. I learnt that one back in the days I was running a mk. Come to think about it I still have one