MG T-ABC

OK, hopefully just one more question before the start attempt for this engine that was rebuild decades ago but not yet run:

Thanks to Duncan and Steve for their excellent advise on the bendix needing cleaned; Its now turning over (with the plugs out) and I do see oil making its way out the rockers and even the end of the OP gauge line. I changed the oil previously and prefilled the new spin-on adapter filter, as well as forced oil under pressure via the gauge fitting until I saw oil coming out the rockers.

I did puff some oil via syringe pressure into the gauge (and the gauge moves), and I do have oil making its way out of the end of the oil gauge line (dribbling not shooting)...

I am not seeing OP on the gauge during the cranking.....should I?

Or would it require the engine RPM to start to register at the gauge?

Thanks-
Mark TC8126

If you crank long enough, you should get pressure. If not then most likely the pump hasn't primed yet. I wouldn't worry too much, since you know oil is everywhere it needs to be. Running a few seconds without full pressure won't do any harm, in my opinion. There is virtually no load on the bearings, etc at idle. One simple trick to priming the pump is to take the top fitting off and pour oil into it just before cranking.

Good luck!

For good luck on something like that, I would give a squirt of oil around each tappet and along the rocker shaft.

I am hoping the attached video got attached; it was shot by the Mrs. as I started the engine for the first time.

It started relatively quickly, ran very well, no smoke, and my oil pressure was climbing as I checked the gauge.
It was reading 50psi when this whirring clatter started. I though the bendix must gotten hung up, but that wasnt it.

My neighbor thought it might be the water pump, so I added more coolant and restarted it, and after a few seconds, the noise vanished. Then after a few seconds, it returned.

And very concerning is my oil pressure is back to zero at startup; This clattery whirring starts with the engine, and seems to be the front/top end. There is plenty of oil under the valve cover, and is is visible coming out the rockers. The lifter cover when removed shows lots of oil moving around...

It soubds like something is making a partial contact with something, and I can feel it when holding the top of the vavle cover....

Any thought greatly appreciated, this is a huge letdown after it stats and runs so well.

If the attachment isnt there, Steve, please advise how to send.

Thanks
Mark

Best way is to upload it to YouTube and then post the link. If you put the YouTube brackets around it, the video will show right here in the forum. Link this: ...where the link is to your actual video, not just to YouTube.

The noise sounds like it might be the rockers hitting the valve cover. Try leaving the cover loose so you can slide it around while running and see if the noise comes and goes.

As for the oil pressure, that's a mystery.

Thanks, Steve-

To that end, my engine came with an aftermorket (likely Arnolt) aluminum valve cover, so....

I do have an original that I will clean up and install in the morning and report back.

~Mark

That's a common and disconcerning, but not serious clatter with Arnolt covers - if you inspect the inside of the cover you will most likely see where the rockers have been making contact with the side of the cover. As Steve wisely suggests (as always), shifting the cover with the bakelite nuts loose will generally silence the offending rockers.

Tom Lange
MGT Repair

Well, Unfortunately, I still have a noise...Maybe a different noise, This sounds like a rapid chatter / very light knock that is present even with the valve cover off. Also present with the fan belt removed.

Whatever it is, I can feel it with my hand on the left side of the sump, all the while with 40+ PSI oil pressure at idle. Oil is welling out of the rockers as well. I'm stumped and hope I didnt damage a rod bearing, but its only run (5) times about one minute each (I'm running just on filled carb bowls at this point).

This AM before I started it, I ran the starter without plugs to check OP (my gauge seems pretty slow to react, and holds the pressure for about 30 seconds after the spinning stops, strange) and there was no noise; Its only present when it actually starts and runs, even at idle speed.

Any additional thoughts welcomed. I guess I can pull the sump but its not even leaking oil, so hate to disrupt all that if its something else.

Thanks for any inputs to check-
Mark

Does it sound like it happens with every cylinder, or just one? Do you feel it elsewhere also? If so then one thought... did you check valve to block clearance? If the clearance is extremely tight, you can get no contact while turning over slowly, but when running it will make a sound like you describe. Did you skim the head and/or go with an aggressive cam or other mods?

Not sure what mods were or could have been done; the engine was built by an scca racer so it could be a little hottened up back in the sixties...

Where would I check for valve to block clearance as I am not following what this mod would entail?

Thanks
Mark

I suppose if there was a wear ridge at the top of a cylinder that didn't get removed then it could be a piston ring hitting it.

Another possibility might be if the cir clip was left off the end of the camshaft allowing it to move about.?

Does the sound stop when you depress the clutch? If so, it could be crankshaft end float.

There are so many possibilities.....

If the engine was intended for racing it may have extra baffles added which may have come loose?

Unfortunately I don't know of a way to check valve clearance without removing the head.

The camshaft circlip is only to aid installation. Location is determined by the thrust plate behind the timing gear.

There are so many possibilities that it's difficult to diagnose remotely. Possibly something unrelated like the generator? A video or even a sound recording might help.

Mark, did you have a chance to inspect the 2-piece push rods, and tappet fit? Some replacement tappets are slightly oversized, which can cause them to hang up. If you have a real long screwdriver it can make a good mechanics stethascope for finding noises.

Bob Grunau was extremely helpful and generous with his knowledge, and pointed to the possibility that the circlip was missing on the end of the oil pump driving shaft. Sure enough, when I removed the oil pump end cap, the shaft had no circlip (which originally was a formed clip and not available) and had walked inward on the gear until it was being ticked by a connecting rod. I'll see more when I pull the whole pump.

So does the engine really need to be jacked up to pull the pump body? I think if the end cap is off, the body would have clearance to come off, but there there room to pull both pump shafts out?

Thoughts on pulling those shafts welcomed..

Thanks!
Mark

You cannot usually pull the pump body off as it will not clear the chassis by time that the drive shaft comes out of the block. Due to the closeness of the fit between the shaft and the engine block you will not have any wiggle room until it's quite a long way out. Assuming that the shaft has the woodruff key and that's not missing as well you will not simply be able to slide the pump body off the shaft. You have to kind of walk the pump cog off the shaft by gradually packing between it and the bottom of the pump body. You can then remove the woodruff key so that you can separate the drive shaft and the pump body. I've not tried it with the engine in the car, but I would imaging that it's a lot trickier than lifting the engine a bit so that you can get the whole pump off in one go.

Thanks, Steve W and all-

Jacking the engine up was simple enough; I removed the bottom nuts from the two main bolts that go thru the front rubber mounts (removing the pair of small bolts did not free it up) and instead of draining the radiator, I removed the bottom rad nuts and rubbers and using a bock of wood under the rad saddle, jacked it up with a separate jack at the same time. It only needed a little more than an inch to gain the needed clearance for the pump removal. I found the TABC thread about removing the idle gear spindle via an 8mm x 1.0 bolt with a socket and washers over it, pulled right out, and rotated the oil pump while pulling and it came right off.

So, following my previous post:
I found the very end of drive gear at the end of the pump shaft had been bumped by the crank bobweight just enough to cause the noise; there was no metal removed or deformed from the gear end (it looked polished in two spots by the rubbing). It appears the key in the drive gear had kept the shaft from moving any further in...holy cow. The gears were held in the same configuration and there was always solid flow at the rockers.

Doug Pelton offers the correct circlip for the driven gear shaft to keep it in place, which apparently was previously unavailable (particularly back in the 60's when this engine was done) and a much more correct type than a lesser version that is out there. This also gives me the chance to verify the gear clearances and properly pack it with vaseline when done.

So I highly recommend checking that circlip in rebuilt engines.

Boy was that lucky!

You were definitely lucky…I wasn’t. I had a Moss replacement circlip on my shaft, it broke and the shaft was pulled down into the engine. It damaged one of my balanced rods and cracked the end of the oil pump…about $800 in damages.

Hi, Gene-

Sorry to hear that. Yes, I was very lucky, aided by this was the first start up so I never had the revs over 1K and only ran it for a minute. The tight fit of the gear and key on the shaft helped as well.

FTFU offers a ring that is not a circlip but more like a miniature closed-ended piston ring; It looks like a very positive solution.

Butch Taras also has the proper clips, and for the record he does proper rebuilds including surface grinding the lid.