White smoke and low compression between 2 and 3 sounds like head gasket to me?
Burning oil would be blue smoke and smelly.
Hey guys,
I recently installed a smallport 4AGE to use temporarily whist waiting for an engine rebuild.
It was sold as a "running engine", with the ad saying 150psi across all cylinders - sounded a little low, but I was only planning on using it till the end of the year.
However after I installed the motor, I found that this was not the case. It feels and sounds like its running on 3 cylinders, and is blowing white smoke.
Here are the results of the dry compression test after warming the engine to operating temp:
1 - 190
2 - 60 and did not hold pressure
3 - 60 and did not hold pressure
4 - 210
It's weird that the gauge looses pressure on cyls 2 and 3 after maxing out at 60psi when cranking. I don't think it's something I am doing wrong, as I immediately swapped the gauge back to cyls 1 and 4, which held pressure until I pressed the release valve, as did the results on cyls 2 and 3 below VVVV
I then did a wet compression test on cyls 2 and 3, with about 1/2 tablespoon of oil:
2 - 205
3 - 220
There is also a reasonable amount of pressure coming out of the dipstick hole, but there is NO oil in my catch can, so it sounds like its probably rings?
It was suggested that I do a leakdown test, however I don't have an air compressor etc.
Where would the issue likely be?? Bottom end or head gasket/top end? The later I can fix with spares I have lying around.
Cheers,
Andrew.
White smoke and low compression between 2 and 3 sounds like head gasket to me?
Burning oil would be blue smoke and smelly.
if you oil them, noramlly help the rings seal, put a vacume guage on it see how still the needle is (can show sign of valve issues) my 4a has a ring (pos piston) it fills a medium milo can with oil in like 5 mins, and covers engine bay in oil(rear muffler is dripping with oil)
Last edited by lolwat; 16th September 2012 at 11:14 PM.
As "Azz" has said above, sounds like a HG blow between two cyls. Has actually happened to me before, with simular symptoms....
Ie; This -
Last edited by maxhag; 17th September 2012 at 03:17 AM.
1974 MX22 MARK II CORONA HARDTOP COUPE - Awaiting a full restoration
Those compression numbers on 1 and 4 are relatively low. When I did a compression test on my smallport it was 225 on all four. As everyone said it seems to be a blown HG, take the head off and have a look, worse case is you need to pull the motor out anyway.
I'd put money on the head gasket being gone as well
Thanks for the replies lads. I'm hoping it's the head gasket or even the head as I have spares of both lying around. I'll start pulling the head off tonight.
timbo - my compression gauge is just an el-cheapo of ebay, so I am not too worried about the exact numbers. The engine I recently pulled out of the car had around 200-215 across all cyls and it still pulled strong!
Ah righto, they are never foolproof but give you an idea. Good luck with it, HG is easy, rings will be easy because you've already taken the head off!
if you think its between cyclinders, put a plug in 2 and test 3 see if ti changes at all
Thanks Michael, I'll give it a go.
Need to recharge the battery first