MGA breathing heavily
Discussion
I asked the following question in the classics section and was pointed overvher:
Hoping someone can help here - we've got an MGA with a motor that's been freshly rebuilt. It seems to run well but is losing a fair amount of oil out of the breather. Also seems to be heading toward overheating when run round town but no issue when out of town.
Many thanks in advance!
Hoping someone can help here - we've got an MGA with a motor that's been freshly rebuilt. It seems to run well but is losing a fair amount of oil out of the breather. Also seems to be heading toward overheating when run round town but no issue when out of town.
Many thanks in advance!
Thanks both, only issues pre rebuild were a bottom end knock as as result of wear. Turned out the bottom end had never been apart. It had the crank ground, new pistons, reciprocating mass lightened and balanced, rebored block, all new bearings throughout, new camshaft, new rocker assembly, new oil pump, new water pump, head refurbed etc.
Haven't done any further investigation yet but mainly wondering how heavily these engines should breath when freshly built?
Haven't done any further investigation yet but mainly wondering how heavily these engines should breath when freshly built?
Thanks guys, I got to take a look at it this evening and I think I've found the issue, let me run this past you:
Standard breather system for those of you that don't know is like an upside down hockey stick which vents via a 90 degree elbow from a hole in the tappet chest cover. The high point of the curve is above the hole in cover - I assume this is to stop liquid oil from escaping out of the breather. What has happened is that the elbow has popped out of the hole and oil is then free to escape directly from the hole. Not sure how much oil there is generally splashing around the tappet chest area? So possibly it's not breathing heavily at all and is just leaking oil. Unfortunately I can't get the elbow back in position so will have to remove the manifolds and make sure it's very well seated this time.
As for the overheating, it was definitely low on water so maybe there was an air lock or we have a leak - will have to investigate further on a dry day.
Peter - you're clearly an expert on these engines having checked out your website. Not to far away either as we are in Stafford. Car runs pretty well but obviously needs setting up properly - assuming of course we get the breather and cooling issue sorted what sort of mileage would you say is sensible to get it properly tuned? Not looking to extract the maximum possible power, just a smooth running, easy starting nicely idling motor.
Standard breather system for those of you that don't know is like an upside down hockey stick which vents via a 90 degree elbow from a hole in the tappet chest cover. The high point of the curve is above the hole in cover - I assume this is to stop liquid oil from escaping out of the breather. What has happened is that the elbow has popped out of the hole and oil is then free to escape directly from the hole. Not sure how much oil there is generally splashing around the tappet chest area? So possibly it's not breathing heavily at all and is just leaking oil. Unfortunately I can't get the elbow back in position so will have to remove the manifolds and make sure it's very well seated this time.
As for the overheating, it was definitely low on water so maybe there was an air lock or we have a leak - will have to investigate further on a dry day.
Peter - you're clearly an expert on these engines having checked out your website. Not to far away either as we are in Stafford. Car runs pretty well but obviously needs setting up properly - assuming of course we get the breather and cooling issue sorted what sort of mileage would you say is sensible to get it properly tuned? Not looking to extract the maximum possible power, just a smooth running, easy starting nicely idling motor.
Thanks Peter, will see what they recommend. They suggested a 500 mile break in period. Fortunately it didn't actually overheat but started to climb and so was shut down and allowed to cool (I wasn't with the car at the time and only had chance to take a look at it this evening.
Does my hypothesis on the breather sound sensible?
Does my hypothesis on the breather sound sensible?
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