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View Full Version : 1500 oil pan is off, what should I look for?



Tipsy
05-10-2011, 01:15 PM
Hi everybody! I removed the oil pan on my 76 midget 1500 engine to clean out any gunk in it. While I have it off can anyone suggest other things I might check? I'm no engine rebuilder but I know most of the parts.
For instance,the connecting rods have a bit of play but I don't know if that's normal? Should I be able to move them back and forth a bit?
The crankshaft sits tight in the mains.
Should I re-torque everything to spec or leave it alone?
Any other suggestions would be great!
Thanks!
Jeff

DrEntropy
05-10-2011, 01:36 PM
Side-to-side movement is fine. Only way to detect bearing wear is to un-do caps and visually check or PlastiGauge 'em. If you had good oil pressure, I'd say leave it alone! Disassembling the thing is an invitation to spend money.

Look for sparkly metal in the bottom of the pan. If you see that, maybe it's time to do the entire bottom end... then the rings, cam bearings, oil pump.

Ya see where this leads.

"Here there be DRAGONS!" :jester:

dklawson
05-10-2011, 01:50 PM
Since this is a 1500, get some plastigauge and check the con-rod bearing clearance to the crank. Do not hesitate to put new rod bearings in. The tri-metal ones from BP Northwest are a good buy.

Take the oil pump off and carefully inspect it. If it is anywhere near the wear limit, replace it. Even if the pump lobes and radial clearance check out OK, be sure to make sure the end plates on the pump are flat. You can dress away the end plate scoring using a piece of glass with wet/dry paper on it. Likewise, you can "shorten" the length of the main pump body so there is almost no axial clearance between the end plates and the pump rotor. That can help restore a bit of the oil flow should you reuse the old pump. It's also acceptable to do these things on a new pump to get the pump tolerances as tight as possible.

Most importantly, check the wear and condition of the thrust bearings. I forget what the acceptable axial play of the crank is, but make sure your thrust bearings get you near the low end of the tolerance and replace them while you are there if necessary. This will also give you access to the rear main seal. I would certainly replace it while you are there. Of course, that means taking off the flywheel and the rear plate.

Be careful when refitting the pan. The saddle block at the front can easily have its tapped holes stripped.

aeronca65t
05-10-2011, 02:15 PM
:yesnod: Agree with the above. Especially the comment on thrust washers.

In my 1500 race car, I was getting about 25 hours of life out of rod bearings. This is on a basically stock engine that I was keeping under 5800 rpm. The engine saw hard use, but it wasn't <span style="text-decoration: underline">that</span> hard. The rod bearings <span style="text-decoration: underline">always</span> came out worn.

The 1500 bottom end is weak, but you can protect it by keeping decent bearings and t.washers in it.

I always changed thrust washers at the same time as rod bearings just as a matter of course.

Tipsy
05-10-2011, 06:30 PM
Thanks everyone! Great advice as always!
Jeff

Tipsy
06-16-2011, 08:31 PM
this project is still in the works with items under consideration. Can thrust washers be replaced without removing the crank? I read recently in British Motoring that thrust washers are notorious for wearing in the 1500 midget.
Thanks!
Jeff

jlaird
06-16-2011, 10:52 PM
Sure can.

Tipsy
06-16-2011, 11:12 PM
Thanks Jack! I've been trying to determine the reason for a rattle sort of noise in my engine for some time now. There aren't any MG mechanics around here as far as I know. So I've been slowly eliminating possible causes by repairing and replacing what I can do myself. I guess I'll do a search here and see what info I can find abouot changing the thrust washers. Size required, removal procedure etc. And also if any other possible problems could be the cause for this rattle, it seems to happen at idle but then goes away when driving.

JPSmit
06-17-2011, 06:19 AM
can you describe the rattle more fully? Is it at the top of the engine or the bottom, does it change when you rev up the engine? have you tried a mechanics stethoscope?

dklawson
06-17-2011, 06:53 AM
Can thrust washers be replaced without removing the crank?

Yes they can but you will find it easier if you remove the flywheel and rear engine plate.

Per the Dr.'s earlier advice, Plastigage the crank journals and put in new bearings if necessary. I think Nial will confirm that the bottom end of any 1500 is a weak area that benefits from more frequent attention.

jlaird
06-17-2011, 11:53 AM
If the engine is out of the car it is time to take it all apart and clean and check and new bearings and rings if nothing else.

Machine shop should not charge much for a dip and a light honeing after mikeing the cylinders.

We just talking about a refresh here.

aeronca65t
06-17-2011, 01:02 PM
Can thrust washers be replaced without removing the crank?

Yes they can but you will find it easier if you remove the flywheel and rear engine plate.

Per the Dr.'s earlier advice, Plastigage the crank journals and put in new bearings if necessary. I think Nial will confirm that the bottom end of any 1500 is a weak area that benefits from more frequent attention.

Just a comment:

It's really just as easy to replace the thrust washers with the engine in the car and the crank, flywheel and rear plate all in place.
There's no reason to remove the engine to do thrust washers....unless there's other stuff that needs attention at the same time.

I've done this job over a dozen times with the engine in the car.
Plus, it's great exercise! :laugh:

dklawson
06-17-2011, 02:06 PM
Nial, I defer to you since I know you've done this a lot more than I have.

Guest
06-17-2011, 06:54 PM
I wouldn't even bother with plastigage. Being a 1500 chances are it need bearings. They are cheap and east to change. A quick compresion test before you pull it down will tell you how the rings are. I spend $500 on my all in-house rering and bottom end job for eveything I needed (hone, crank nut socket, etc). That's without any machine work. I pulled the engine completely apart and was glad I did. I found lots of metal in my oil galleys. All said and done I wish I had the extra money at the time to do a proper complete rebuild but I didn't. Almost 12K and still going strong, out of round crank and all.


I've been trying to determine the reason for a rattle sort of noise in my engine for some time now.

That's easy, it's a 1500. :laugh:

Seriously though, mine rattled especially at start up and is much better now since I freshened it up. It rattled ever since I got it (10K ago) and it doesn't sound like it's about to come apart anymore. Well, at least not like it use to. A bottle of Lucas oil treatment doesn't hurt either.

Have you adjusted your valves lately.

One thing I've always done and still do is build oil pressure before I let it light off. I'd rather change a starter than bearings.

bthompson
06-17-2011, 07:43 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]1500 oil pan is off, what should I look for?[/QUOTE]
A 1275! :jester: :banana:

Actually, for all the bottom-end issues the 1500 has, we Midgeteers have it easy. Being able to pull the pan and get to the crank <span style="font-style: italic">in situ</span> makes doing regular bearing jobs an easy weekend swap. Ya can't do bearings in most other cars without pulling the engine and turning it into a week of major surgery.

I remember there is a site <span style="font-style: italic">somewhere</span> that spells out how to swap MG 1500 thrust, crank, and rod bearings, step-by-step. Seems like it's pretty easy once you're familiar with it. If I run across it I'll shoot it your way.

I've been running Nigel for a few years now and haven't touched the bearings yet...getting to the point that I should start thinking about checking them. I drive it like the old torquey long-stroke mill that it is anyway, rarely take it to 3K.

Guest
06-18-2011, 11:00 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]1500 oil pan is off, what should I look for?
A 1275! :jester: :banana:

I drive it like the old torquey long-stroke mill that it is anyway, rarely take it to 3K.[/QUOTE]

Which is even more reason to check them. Lugging the motor down will wear bearings faster than keeping it spinning below redine. High load and low oil pressure is a bad idea. Dad used to wear out bearings in the Ford 240 and 300 very quickly from doing the same. That's why diesels have really big oil pumps and run a higher pressure.

bthompson
06-20-2011, 11:08 PM
Eep.

<span style="font-style: italic">Now</span> he tells me... :wall:

:wink: Nah, I'm not that bad with luggin' it...just too aware of all the reciprocating mass bangin' around up there, so I keep the revs around the midrange. Too much of a weenie to shift at the redline like our Bugeye brethren can.

I prolly <span style="font-style: italic">will </span>pull the pan this fall to check things out, though.

Guest
06-21-2011, 06:08 PM
Too much of a weenie to shift at the redline like our Bugeye brethren can.

I prolly <span style="font-style: italic">will </span>pull the pan this fall to check things out, though.

Me either. Always a good idea to have a peek IMO.

RichBall
06-21-2011, 06:39 PM
I remember there is a site <span style="font-style: italic">somewhere</span> that spells out how to swap MG 1500 thrust, crank, and rod bearings, step-by-step. Seems like it's pretty easy once you're familiar with it. If I run across it I'll shoot it your way.

Here is the site you where remembering.

https://members.core.com/~ckotting/1500_bearings.html

bthompson
06-22-2011, 09:39 PM
Here is the site you were remembering.

https://members.core.com/~ckotting/1500_bearings.html Bingo! :thankyousign:
I love this forum. <<GRAEMLIN_URL>>/grin.gif

Tipsy
07-06-2011, 04:40 PM
Thanks everybody! You've been a lot of help as usual!
I'll check this site out.
Jeff