Hello all, thank you for your time. I recently had to replace the head gasket on my new-to-me 998cc 77 Mini. When I took the head off, I noticed there were no valve guide seals, but the guides were the newer bullet type. So I took the valves and springs off to put new hat-type-seals in.
All went slow but steady, and the other day I finally reassembled the head, but back on the manifolds, carb, etc.
The engine is now running VERY rough and noisy. both during idle and acceleration. Here is a video to show the issues and sounds Im hearing:
Here are some of the things that I did make sure and check before that video was taken:
- Valve clearances are at .012 thou
- All head bolts are torqued, even after heating the engine up a couple times
- New spark plugs, gapped accordingly
- Compression test resultes are as follows
cyl 1: 135
cyl2: 135
cyl 3: 120
cyl 4: 135
(this was my first ever attempt at a compression test, if these values seem off, I can try it again)
I am curious if there is a misfire, which might pertain to my valve job. But there are other suspicious areas too, let me explain:
MANIFOLD
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- When I took the exhaust manifold off I discovered one of the 3 pipes (nearest to the radiator) was sheared off at the area where it joins with the other pipe. Photo here: http://imgur.com/N4ALisc
- That might be the source of the fluttering when I let off the accelerator, and the engine winds down. But I am not sure. I don't think this is the cause of the rough idle/acceleration, because it's just a pipe that heads to the back, shouldnt matter a whole lot, what do you guys think?
CARB
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- A lot of people on the forums suspect carbs as the source of misfiring. The thing is that I basically took it off and put it on again, and the car was running OK before this, so I didn't really do much to the carb aside from jostling it around a bit, and keeping it in a bin while I did the work.
- The mixture was very rich when I got the car, and I'm trying to tune & adjust it right, but weather I lean it out or richen it up, these symptoms and sounds still persist.
- Is it worth looking at the jet/needle/etc?
- I did open up and look at the float chamber, and the pin that the float presses against, all is well in there
TIMING
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- Again, so many people talk about the distributor, rotor, and leads/plugs, but I didn't touch this during the head project, so I am very suspicious that the timing could have all of a sudden went wrong. Should the timing be something I check anyways after doing a project like this?
Other notes
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- At the same time of doing this project, I took out my Smiths gauges to do some cleaning & restoration work. They are about 50% hooked back up. I don't think that there are any electric governers on this engine that would affect this stuff, but I thought it worth mentioning in cause you guys know more than I
- I've heard talk about a vacuum advance tube. The car doesn't appear to have one on it. I do see where it would attach to the carb (it's currently capped off) but I don't see a place on the distributor where it would go.
Conclusions
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This all brings me back to the head, and Im wondering if there are valve seating issues, bent valves, or sticky guides. I think that at least 3 of the 4 cylinders are ok in terms of the valves, since I am getting consistent compression readings. Cyl 3 is suspicious at 90. Perhaps the lower reading is an indication of valve seating issues, and therefore misfiring?
Any help, advice, or direction would be greatly appreciated. Thank you for your time.
Edited by mattaebersold, 25 May 2013 - 11:49 PM.
