MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Timing Chain Oil Thrower

I have the timing chain cover off to renew its oil seal and I am confused.

I have the 18V engine with the timing marks on top of the cover (best thing they ever did) and the improved oil seal. It is a double chain system inside.

The MGB manual states: "Refit the oil thrower to the crankshaft nose, concave side forward or the letter F forward (ie away from the engine)......" However, the thrower has the F on the convex side! So it seems a bit contradictory. Trial fit with the F forward gives 20 thou clearance with the chain. Putting it the other way round gives plenty of clearance with the chain but obviously closer to the cover (I cannot get a measure on that at the moment as I am waiting for the cover paint job to dry. Which way round is correct?

Steve



Steve Gyles

"F" definitely goes to front, placing the flat flange very close to the timing chain. n That arrangement goes with the later timing cover design with oil seal on the inside.

Early production 3-main bearing engines had different design with thicker (deeper) timing cover with oil seal on the outside. Those covers used a oil thrower ring similar to the MGA with cup shape and the sharp edge forward.

If you install the early thrower ring with the later style cover, it will rub and cut a nice round slot through the cover, and that will leak like crazy.
Barney Gaylord

Thanks Barney. Technical authors never make it easy.

Steve
Steve Gyles

Front end oil seal all done, cover and ancillaries painted and up and running. I had zeroed into that area because of oil that had generally moistened the engine front end and on the electrics side. Went for a run and noticed drips on the driveway when I returned. Closer inspection revealed what appears to be a split in the stainless steel armoured flexible pipe from the engine to the oil pressure gauge. Certainly the whole pipe is wet and oil sprayed on to engine side; the distributer cap and terminals; and starter motor plus terminals. Seems I had 2 leaks. Is flexible pipe failure common? Mind you I think it's been there since my rebuild in 1997.

Steve
Steve Gyles

Steve

This happened to me about 5 years ago. My son had been away for the weekend in the car and it started to leak about half a mile from my house. I doubt he would have noticed until the oil pressure dropped a lot with dire consequences as he rarely drives the car. Subsequently, the flexi hose between the carbs also started to leak so I think there is a real quality problem with some of those flexi hoses. I keep my original hoses as spares as they still work fine, but don't look so smart. John
John Francis

This failure is fairly common. If you don't know the history of the oil pressure gauge hose, you had better change it. The consequences of failure are rather dire (and can be very expensive) when you lose all the oil.

My OP Gauge hose an two fuel hoses at the carburetors have been in service since 1986, almost 450,000 miles by now, and still going strong. They are the Teflon lined hoses from Moss Motors, had a lifetime warranty from new. Very good parts.

I'm not going to change them, as I don't know if the current parts are same quality. But I do carry a spare OP Gauge hose (and almost anything else that keeps the engine running).



Barney Gaylord

New pipe arrived from Moss. Looks pretty much the same as the one I fitted 20+ years ago. It is the same length despite apparent difference in photo.

Damage found on cover. See next post.


Steve





Steve Gyles

I cut the ends off and removed the sheath. Damage obvious a few inches from the engine union. The flexible pipe ran close to the distributer vacuum unit at that point. However, no abrasion marks visible on it.

Second photo shows interesting marks to the inner at that point including what seems to be a small lateral split when viewed under a magnifying glass.

Please note that the hole in the covering is how it came out of the car. No fiddling on my part.

Steve





Steve Gyles

Looks like I am going to have buy another oil pressure hose, I do carry a spare new OP hose but it has been stored in the boot for very many years in my spares stash.

Probably sensible to fit a new one before it fails on me.

Cheers
Colyn
Colyn Firth

All up and running. Removed dizzy for access so that was a bonus cleanup. New pipe is no where near the dizzy nor steering column (RHD) so a bit stumped how the old braiding got in that state. I even thought about shorting out and melting but even that does not make sense. Certainly an item I will be watching more frequently.

I could have perhaps spotted it earlier had it not been for the engine front oil seal weeping and the leak from the brake light switch. Oil well spread and took time to isolate.

Not sure where Colyn will be locating yet another spare part.

Steve
Steve Gyles

Best not ask Steve! :^)
Colyn Firth

I puzzled how a 60psi leak could fracture the mesh. On investigation I noticed that the flexible pipe ran very close to the No.4 HT lead on the distributer. I am guessing that the leakage onto that HT lead created a short and melted the mesh.

Steve
Steve Gyles

Steve

On both my failures there was no sign of damage to the external braid. The internal pipe just sprung a leak.
John Francis

This is exactly the reason I am no fan of braided hoses - you cannot see the state of the rubber hose underneath. The originals were not braided but had a spiral spring around them. (see photo of said hose in a TD)

It's also a reminder that *all* hoses are service items and need to be inspected and renewed as required.

I once snapped brake hoses like twigs when the car had been driven on the highway to me for work. The coolant hoses just crumbled when squeezed too.....

Greetings from rainy Thailand



Dominic Clancy

This thread was discussed between 07/08/2022 and 15/08/2022

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.