Low conpression after engine build vvti ?

[ilovejapcrap]

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 !

[Carolyn]

yes several times.

[Carolyn]

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).

[Carolyn]

You're not going to like this:  Are you sure your compression test was accurate?  Had to ask.

[ilovejapcrap]

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 !

[jonbill]

Lucky it's a non interference engine! [emoji12]

[ilovejapcrap]

Hehe

[SteveJ]

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.

[Carolyn]

Lucky it's a non interference engine! [emoji12]

Your subtlety is only exceeded by your forbearance.

[ilovejapcrap]

Well without the cams on valves are shut anyway

Anyway taking head for checking and skimming tomorrow.

What gaskets has everyone used ?

[jonbill]

I used the standard mls gasket from the MAG rebuild lit.

[ilovejapcrap]

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

[jvanzyl]

Good luck!

[smarty72]

Fingers crossed for you...

[ilovejapcrap]

It runs !

Looking very strongly that the headgasket was my main issue allowing venting between bores

[ilovejapcrap]

 m https://youtu.be/yGNOdvMkFbM m

[shnazzle]

Sweet! Well done

[smarty72]

Hooray

[jonbill]

Well done - reward for perseverance!

[Carolyn]

Got there!  Good show.

[cabbydave]

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