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MG Midget and Sprite Technical - Cam follower problem ?
|1974 Mk3 1275 rebuilt engine 6000 miles ago in 1994.|
The Car had just been fully serviced and was running beautifully.
My son drove home 80 miles probably fairly hard. Engine was running on 3 cylinders. Tappets more noisy than normal. No 8 exhaust no clearance. Removed head fitted and cut new silicon seats and 8 new valves all lapped in etc. Everything refitted as by book. Hot Compression 180 across all cylinders. Timed properly carbs set and balanced new points condenser etc. But car still running rough and tappets very noisy. Anyone have a view whether cam followers are prone to failure. At rebuild new cam bearings were fitted but not cam or followers. Anything I might have missed before I take out the engine for strip down. Thanks Mike
|how is the rocker gear?|
worn shaft or rocker pads can cause adjustment issues and noise
if you have a dial gauge on a magnetic base you can measure the lift on each push rod and check for disastrous wear
Easy to check before you tear down the engine
|Im with onno. |
To ansewer your question on the followers
The Followers can be an issue, esp if you have the ones that have the little hole drilled in them for oil seepage, as those have a solid history of fracturing....see picture below
But Id go the path that Onno laid out 1st, as it could well be the rocker gear is worn, Id lean towards this before the fractured lifters
|>>>>1974 Mk3 1275 rebuilt engine 6000 miles ago in 1994.<<<<<<<|
(16 years ago the engine was rebuilt)... curious is that 6000 miles ago a typo? and meant to say 60,000 miles ago
370 miles a year isnt exactly to church
|Hey Prop, in the UK it isn't more than a couple of miles from anywhere to anywhere else!|
|Dave O'Neill 2|
|Prop yes it is only 6000 in 16 years with annual service each year. Very occasional use.|
Ono thanks for the advice I do have the Gauge and will go that route first.
I keep forgeting that.
9 miles just to the grocery store one way for me. It must be nice having everything so close.
|in the UK, "100 miles" is far|
in the US, "100 years" is old
|LOL thats so true norm, |
I was astonded several weeks ago that people in the Uk live in homes older then the age of our nation...That just seems wrong some how. LOL
|I think it's odd that our cousins live in houses made of wood when we live in houses made of brick.|
Me, I'm not scared of the Big Bad Wolf!
|Me, I'm not scared of the Big Bad Wolf! |
there used to be a popular hippy type of house that uses mud and straw for the walls, luckly the local building inspector put an end to that real fast
Prop... brick, wood, staw, huh! they all blow up in a F5 tornado
|Noisy tappets due to wear usually quieten as the valve train gets warm, so I would expect the cyclic clatter to reduce considerably after about 5 minutes at idle. You can remove the rocker assembly - and replace it without pulling the head. The engine wants to be cold with radiator cap and plugs removed. Keep the rockers in order as you remove them from the shaft, and check the wear on the bottom half of the bush and corresponding area on the shaft. The wear is typically worst on the rockers furthest from the oil feed. Sometimes you can get away with just replacing the shaft and rebushing and reaming the rockers, but for the small extra cost it's usually best to replace with new.|
I live in a house made of mud and straw. It's stood there since 1470, with some of the original mud and straw still in place.
They don't make mud and straw like they used to!
|Well we have now established that we are only getting about 0.2" lift on number 8 Valve instead of 0.32" on the rest on the valves so the midget is up on axel stands awaiting an engine out and new Cam shaft and followers. any comments on the replacement cam MD266 or 731 are curent thoughts for every day use.|
|I used a Kent 276 and thought it made a great fast-road cam. I thought about a 266 first, but then realised how annoyed I'd be if it turned out a tad too mild... hence the 276!|
|I ran an MD266 in a fairly std 1275 for a long time. Even with 1:1.5 rockers it never felt like a non-std cam - always very well behaved but happy to rev all the way to 6250ish|
|Dean Smith ('73 RWA)|
This thread was discussed between 02/07/2010 and 20/07/2010
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.