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Blown head gasket and compression test
https://auszookers.com/forum/viewtopic.php?f=5&t=18827		 Page 1 of 1
Author:  Jasen [ Fri Feb 04, 2011 7:08 am ]
Post subject:  Blown head gasket and compression test
Hey all,

About 4-6 months ago I replaced my head gasket (G13A) after it blew between cyls 2 & 3. Did all the usual stuff when replacing it - ie: oil and coolant flushes, kero soaked sump and rocker cover to get rid of all the gunk and also adjusted the valve clearances while I was at it. Went great for a bout 3-4 months after that but over the last month or so I've been having overheating troubles. I'm pretty sure the head gasket has let go again as it's heating up to normal temps then just keeps goin to just under the redline. I've flushed my cooling system again (system pressurises fine with no external leaks) and manually tested my thermostat to rule those out. (I'm thinking a warped head may be the cause :oops: )

My question is would a blown head gasket show up on a compression test? I've been burning thru about 2l of oil every month or so (no external leaks) and figured maybe rings have gone too. Compression results on the warmish engine were 162 150 160 162 - which i think is still alright (170psi is what it should be right?) While cyls 2 & 3 are a bit lower i would have thought it would show less with the head gasket gone.

Might be G16 time.... (got a quote for a g13a from a wreckers run and comp tested 3 months warranty inlet/exhaust manifolds and carby - $1100!!!! 8O )
Author:  Teracis [ Fri Feb 04, 2011 7:36 am ]
Post subject:  Re: Blown head gasket and compression test
I just got a g13ba from someone on az for $350

We will find out tomorrow whether it works or not!
Author:  Jasen [ Fri Feb 04, 2011 7:41 am ]
Post subject:  Re: Blown head gasket and compression test
Haha yeah that's the sort of price i was thinkin when i started lookin for a straight 1.3 replacement - at least for that price i could spend the extra $$$ rebuilding my old engine myself (but am a little dubious about re-using my head if it's been warped or softened)

.... doesn't help that my cash flow is like a 90yr old with a prostate problem atm :\
Author:  Teracis [ Fri Feb 04, 2011 7:45 am ]
Post subject:  Re: Blown head gasket and compression test
I have a basically brand new head on the engine I'm taking out, I was told it had been replaced a few thousand k's before I bought the car.

Mine burns oil around the 50:1 ratio at the moment...
Author:  steak_knife [ Fri Feb 04, 2011 7:48 am ]
Post subject:  Re: Blown head gasket and compression test
Teracis wrote:
I have a basically brand new head on the engine I'm taking out, I was told it had been replaced a few thousand k's before I bought the car.

Mine burns oil around the 50:1 ratio at the moment...


Sell him your head... :roll:
Author:  Jasen [ Fri Feb 04, 2011 7:54 am ]
Post subject:  Re: Blown head gasket and compression test
I refuse to pay for that sorta stuff Stekky..... oh the head off his car.....
Author:  steak_knife [ Fri Feb 04, 2011 7:54 am ]
Post subject:  Re: Blown head gasket and compression test
:lol: :lol:
Author:  skyman [ Fri Feb 04, 2011 9:38 am ]
Post subject:  Re: Blown head gasket and compression test
ROFL


The 1.3 should have 199 PSI when it's fresh, the service limit is 170. The max difference should be about 15 psi across them.

Usually when all the pistons have the same compression you;re good (with low power) till about 160ish. If any of them hit 150 its time for a rebuild for sure. :?
Author:  Teracis [ Fri Feb 04, 2011 11:20 am ]
Post subject:  Re: Blown head gasket and compression test
skyman wrote:
ROFL


The 1.3 should have 199 PSI when it's fresh, the service limit is 170. The max difference should be about 15 psi across them.

Usually when all the pistons have the same compression you;re good (with low power) till about 160ish. If any of them hit 150 its time for a rebuild for sure. :?


I should do this once I've replaced the motor (if it runs...)
Author:  Jasen [ Fri Feb 04, 2011 10:48 pm ]
Post subject:  Re: Blown head gasket and compression test
skyman wrote:
ROFL


The 1.3 should have 199 PSI when it's fresh, the service limit is 170. The max difference should be about 15 psi across them.

Usually when all the pistons have the same compression you;re good (with low power) till about 160ish. If any of them hit 150 its time for a rebuild for sure. :?



Thanks mate - i was thinkin the fresh psi was 170, but yeah I rly think it's time for a rebuild. Just gotta work out if it's worth it or whether i should see if i can find a carby g16a for the same price as rebuild (i'm rly runnin on a very tight budget atm and this is my daily so can't have any significant downtime)

Don't wanna reuse this head as i've had trouble with alloy heads softening on a couple of CA18DET's i've had to fix and figure the alloy zook head - while not under the same thermal stresses as the CA's - would prob have the same issues after being overheated a few times.

PS: Teracis if u find that u have a good head to sell me 8O send us a PM - ur on the Goldie right? Would be happy to come down to pick it up - good excuse to get down for a surf anyaways lol :D
Author:  skyman [ Fri Feb 04, 2011 11:21 pm ]
Post subject:  Re: Blown head gasket and compression test
Ya know depending on what you can find you got a few options.

If you are really on the cheap, you can pull it down, stuff some new bearings and rings in, hone the block, and check the head (maybe just stuff it back on with a new gasket). That;s not a costly adventure, but it does take some time, especially if you find you need machining.

If your looking at the same $, or even cheaper ya can look around for a complete used 1.3 with everyone upgrading to 1.6's they are out there. There should be a lot of them in good condition with good compression but ya gotta be picky. I have seen good 1,3's here go for $50 to $350 with everything attached including the carb! Just bolt in and go, hey? it;s one that wan't have much downtime too.

The you have the 1.6's, a 8 valve is a tad easier on the wiring side, but near 20 horse less. A 16v is the ultimate, but you will need to figure the wiring conversion.

These install can be quick too, if you get everything done ahead of time, you can have it done in a weekend.

If I were you/ If I was not worried about more than a stock engine for power, and on a real tight budget, (or not keeping the Sierra). I'd find a used 1.3 and stuff it in,. The harder you look the better you can find.

If I wanted to upgrade the Sierra sooner or later anyways, or I was going to keep it, the 1.6 would be the only way to go. I would be upgrading to a 1.6 sooner or later anyways, so why not replace the engine once. I;d just limp it along until I had all the 1,6 stuff together. I'd buy the kit piece at a time to save money.

Hoping that helps.

--Sky
Author:  shep [ Fri Feb 04, 2011 11:30 pm ]
Post subject:  Re: Blown head gasket and compression test
is your radiator clean on the outside? give everything a good clean and
put some morays in the motor and some chemiweld in the radator.
and while ya save up for a new motor, drive it until it stops.
Author:  bohuler [ Sat Feb 05, 2011 12:17 am ]
Post subject:  Re: Blown head gasket and compression test
I have a 1.3 you can have for $300. Im in melbourne if you wanted to work out freight :D Came out of my donor car i bought for the windscreen :D
Author:  skyman [ Sat Feb 05, 2011 1:21 am ]
Post subject:  Re: Blown head gasket and compression test
Quote:
"and while ya save up for a new motor, drive it until it stops"


X elleventy-billion. Drive it tha' piss out of it until it dies, but get the overheating taken care of first. If the compression is down, it just means you have to rev it higher to git where you're going. :mrgreen:

These . will go forever + a few years, my buddies was smoking when he got it from the rings. He changed the plugs a little more often, but he drove that thing for 3 or four years? Daily until he found a 1.6

As for your first question I didn't cover. The head gasket could be the cause of your low compression, or a bad valve too. You'd have to do a leak down test and listen to find out exactly what the problem is. Leak down tests are just as easy as a compression test, but tell ya lot more.
Author:  Damo [ Sat Feb 05, 2011 1:25 am ]
Post subject:  Re: Blown head gasket and compression test
Just a FYI with head gasket problems.

When you are replacing a head gasket you should check the "flatness" of the head with a straight edge and feeler gauges. Also, don't forget to check the block the same way. I looked at a 1600 once that was always blowing head gaskets. Gasket changed, same thing. Head was reco'd, same thing. Turned out the block was the culprit, had to have the top of it faced.
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