Corsa piston build with throttle bodies

OP
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pork

pork

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So engine is trashed.....

All good though as I’ve just picked up a cga3de block and crank from dave shaw (thanks mate)






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Last edited:
OP
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pork

pork

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Well hopefully this time with a cga block it’ll go better

New pistons abs rings on order too


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OP
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pork

pork

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Just got my cga3de block back, bored out and honed.....had to buy 4 new pistons too

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Almost done polishing the head up, then il send that of to have the cr12 valves put in


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OP
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pork

pork

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Gotta get a move on now to finish the micra.......me and the old man are gunna build one of these now

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Had a look round the factory today, amazing cars!

Gunna stick the ls3 engine in it too


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Haven't been on here for a while, shame about the engine but at least your still at it.

However those LS engines are incredible for their size etc
 
OP
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pork

pork

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Cheers dude.

Gotta see it through

Should be sending the head off for the valves to be fitted this week, got a tiny bit more polishing to do


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OP
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pork

pork

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Head and valves sent off
Gave them the crank and rods too, all the bearings got trashed as well,so new bearings ordered and crank polishing


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OP
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pork

pork

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Right......got all my bits back

Cga block re-bored/honed 3mm off the deck
New corsa pistons/rings
New main/big end bearings
Crank polished
Head diy port/polish, longer cr12 valves cut in, 2mm skim

I’ve got some cat cam springs coming too

Big dent in bank account

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OP
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pork

pork

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Got my valve springs through, so can rebuild the head

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Longer valves so I don’t have to double up the shims, plus they’re under Cr12 buckets, so no chance of spitting them out

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New cg13 clutch, fitted to cg10 spline.......should stop the grinding noise whilst engaging gear

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...........and because I’m a ****ing idiot, and didn’t check the cc in the head correctly before skimming it, I’ve had to get a de-comp plate from Ferriday Engineering to bring the c/r back down to 12:1

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It was nearly 17:1

If it don’t work, then I’ve wasted all that time and effort polishing that head


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OP
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pork

pork

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Well it’s dead again, after 15 miles

Comp test showed 5 bar on all cylinders

Taken head off



Have some pics........

Pistons as I found them

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Block to gasket face

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Head to Decomp plate face

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Gasket to Decomp plate face

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Gasket to Decomp plate face

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Cleaned up the pistons and can’t see any cracks/ damage

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Is there any way of telling if the rings are trashed without taking the block apart (can’t be ****ed......again)



I’ve sprayed some brake cleaner until it pooled on the pistons....it didn’t drain away, if this means anything


Opinions, suggestions........criticism, all accepted and appreciated


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OP
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pork

pork

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Used some wellseal jointing compound between plate and head as per instructions


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OP
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pork

pork

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Well it looks a lot cleaner from when I put it on, the wellseal is red colour.

And the plate in pic was as I found it.


You reckon new head and just a gasket theb


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frank

Club Member
i would try 2 old gaskets and see how it ran i guess mate, and if the compressions are back to normal then decide which way to go
 
OP
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pork

pork

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i would try 2 old gaskets and see how it ran i guess mate, and if the compressions are back to normal then decide which way to go

2 gaskets ain’t enough to bring the cr down. That’s why I git the plate

You think if I rebuilt it with a new head gasket and resealed the plate then over over torque it, it’ll at least let me do a comp test again


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frank

Club Member
try that then eh, i would use proper screen bonding sealer personally, and let it tack off for an hr or so before fitting
 
OP
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pork

pork

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Had a closer look at the head and plate today

I can see sort of faint ‘blast’ marks coming from the combustion chamber parts

I’ve cleaned up and re-sealed and put it all back together,

Hope get to comp test tomorrow, got called out so couldn’t try today


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OP
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pork

pork

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Had a quick go before work.

All cylinders went to 7bar

Put a smidge of oil down there, and went right up

Cylinder 1- 10bar

2-3-4 - 12bar

What does this mean then?

Cylinder 1 is trashed.

Or is it because I’ve only done 15miles on this fresh pistons/rings


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Had a quick go before work.

All cylinders went to 7bar

Put a smidge of oil down there, and went right up

Cylinder 1- 10bar

2-3-4 - 12bar

What does this mean then?

Cylinder 1 is trashed.

Or is it because I’ve only done 15miles on this fresh pistons/rings


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Doesn't necessarily mean the cylinders trashed. Could be a worn cam or a bad set of rings. Edit: or a leaking valve.
 
OP
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pork

pork

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Well I’ve tried it again.........



Won’t start, compression gone down to 7ish bar


**** it !!!


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OP
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pork

pork

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Had a spare hour today.

With old stuff I had:

Cylinder 1- 5 bar
Cylinder 2/3/4 - 7 bar

Tried a new head .......

Same results

Pulled out piston 1.......rings intact, bores look fine, hone marks still there,no signs of damage

Gunna pull engine apart, rebuild, start again


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OP
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pork

pork

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After 15 miles

Hope not, what’s symptoms would I get with that?

All I’ve got so far is low compression and smoke from the breathers


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OP
OP
pork

pork

Club Member
the overbore might have made them too thin maybe ? then they crack and leak compression into the crankcase

Thought beings I’ve used a cga3de this time, it’ll be ok, it’s only 0.5mm

Would of thought I’d if done the gasket or rings before the liners gave out

Il take a look once it’s in pieces again


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