8 replies to this topic

[_Dan_]

Hi All!

 

Been a few years since I was last active on here, the VX has been nicely tucked up in the garage most of that time, doing an embarrassingly low annual mileage!

 

Anyway, I recently picked up a Z22SE from a non-starting vectra with the aim to slowly build up a spare engine for the VX, incorporating the eagle rods I have had lying around for ages and doing jobs like a balance shaft delete etc.

On investigation of why there was no compression I found 7 out of 8 of the inlet followers randomly scattered around the head and a load of bent inlet valves!

 

The pistons are marked from the contact with the valves but the bores look/feel fine, the followers all look OK, as do the cams apart from one small scratch on one of the inlet lobes. 

Intestetingly the chain was intact so I don't know how it happened, skipped a tooth maybe?

 

The question is, how much of it is likely to be salvageable? Are the valve guides likely to have survived? Could the pistons be re-used? Anything else that is vital to check?

Your collective wisdom on this is much appreciated!    

 

Cheers,

 

Dan

[Nev]

I'd say the valve guides that struck the pistons would be highly suspect. You could slide a valve in and out and see, but even then they might be weakened by the leverage of the valves that took the hits.

 

The pistons might be ok if they have enough meat on the crowns. I think 6mm + might be acceptable if you need to grind them, but is it really worth the risk as they are cast items and might crack later on?

[KurtVerbose]

Intestetingly the chain was intact so I don't know how it happened, skipped a tooth maybe?

 

My guess is it's probably been over rev-ed then.

[Madmitch]

Had a little bit of this when I was racing half a century ago!  Agree 100% with Nev about the guides, I would just get on and replace them.  If the valves slide nicely then a grind to get everything seating nicely should suffice.  I would have a good look at the pistons though, especially around the ring grooves.  In one of my internal failures one piston had been struck on the edge of the crown and still slid up and down the bore nicely but, when we took it out we realised that the side of the piston had collapsed just enough to close the ring grooves on that side jamming the rings solid.  Had we run it like that it would probably seized.  One other thing, change the oil filter in case there are bits of metal in it! 

[vocky]

the chain(s) will have jumped a couple of teeth, due to excessive wear caused by old age or high mileage or a cheap pattern chain kit failing.

 

The inlet hydraulic lifters will all be scrap, so must be replaced and you should check the roller rockers for any signs of stress cracks.

 

The inlet valve guides will need to be inspected and if cracked replaced - very easy to see the cracks with a torch, just remove the valve and look inside the port.

 

The pistons will need replacing, as they are very weak on the z22se and you will get excessive oil useage.

 

I probably have some standard z22se pistons you can have for the cost of shipping. I will have some hydraulic lifters and valves if you need any spares.

[vocky]

ps: do not be tempted to buy any pattern chain kits, there are many threads of them failing on the z22se site.

[_Dan_]

Vocky - you are a hero as always

 

If you have some pistons going spare that would be great, let me know shipping cost etc & I will get payment sorted out (drop me a PM). I will definitely need 8x inlet valves, if you have any available please let me know.

 

I'll check out the valve guides and roller rockers - what is the process for replacing valve guides?

Also - the tech info makes a point of making sure the same roller rockers go back in the same positions - how important is this (it's impossible to tell where they all came form as they fell out!)

 

Cheers,

 

Dan

[Bargi]

chuck a Saab head on with some uprated springs, done

Edited by Bargi, 14 March 2016 - 10:00 PM.

[oakmere]

I got my valve guides replace for approx £120.00 including the guides by an engine rebuilding place so it won't break the bank.