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MG Midget and Sprite Technical - Cam and lifter wear

As I have posted on previous threads, I am rebuilding my 1275 at almost 250,000.

Crank is going back STD, only polishing required. Cylinders will be bored to .020 and one valve requires replacement. Basically, almost everything was immaculate.

But the lifters and cam are trashed! The consensus is that there is an essential zinc based additive that was in older motor oils that is no longer present as it fouled catalytic converters. I have been using straight 30W, Valvoline racing since 1972.

Any suggestions for additives or old style motor oil that would have a formulation appropriate for this engine? The flat cam and worn bores apparently accounted for the power loss.
Glenn Mallory

I'd expect the cam and lifters to be trashed at 250,000. Get the lifters from APTfast.com .. and maybe the cam too. I think you'll be fine using a true racing oil (Brad Penn is a brand name recently thrown about). However, be prepared to change it more frequently than modern oils.
Trevor Jessie

Theres alot of "ZDDP" additives on the market, check with your local chain auto parts store, (Advance, autozone, ect.) they will have 5-6 to choose from.

Prop
Props Black Hole

BTW.

I got alot of advice to avoid the lifters with the hole drilled in the side, this creates a weak spot and the lifter will fracture at the drilled hole.


Prop...How does that hole vent oil agian...Prop
Props Black Hole

7 out of 8 of the lifters were very badly pitted. Oddly enough, one was not. I have been advised to use the ZDDP type additive. Valvoline racing + STP oil treatment (since the car was new) seem adequate.

I change oil and filter about every 3K - 5K miles. The lack of wear on the crank and valve train and the minimal wear in the bore would indicate that the oil change frequency is sufficient. The oil in the engine was normal color, not the black that is typical of high blow-by engines.

Interesting that oil additive formulation became obsolete before the engine did.
Glenn Mallory

Look here:
http://classiccarmotoroil.com/
Also, Valvoline is good too if it's Valvoline VR-1 (I know that it still has ZDDP in it).
Jon Saylor

Hi Glenn
You mention 7 out of 8 lifters trashed and one ok and also one valve needed replacing. You should have a thorough inspection of you valve springs-- measure their length and strength as I suspect you have a soft one there and at that age they all probably need replacing anyway. Theory #1-- The soft valve spring has reduced the load on the lifter allowing it to survive but in doing that has reduced valve seat pressure and burnt the valve It is very important to have the springs at the correct fitted length/pressure for performance and durability,
Interesting that you can get away with the Valvoline race oil on the road -- I used to run 50 weight Valvoline race oil in a hot MGB years ago and had to pull the head off after about every 10000/15000 kilometers and give the bores a light hone as they kept glazing up. I've heard of others with the same problem as well. But if it works for you that's all that matters.
Good luck with the rebuild but I would get them springs checked Cheers Willy
WilliamRevit

Check out this web site: Cam-Shield.com...good info.

I'm using Lucas Oil Stabilizer and it sure helps quieten the valve train, but no ZDDP in it. I use Valvoline VR1 (some ZDDP), but may soon change after learning more about the pitfalls of using racing oil in a street engine.

I think I'll also try the Cam Shield.

Dave
DL Rhine

I would probably replace all valves, springs, and guides after this many miles. The springs can fatigue and with a new cam and lifters, the springs might get stressed a little more and break. Been there, done that... Not a pretty picture when you have a valve spring break and drop a valve. When you get done with your rebuild, use a non-sythetic for break in. Our Porsche engine builder uses Rotella T 15-40. Lots of zinc and non-synthetic. He says he gets a lot of strange looks when he tells people what to use, but it does work. Amsoil has a racing oil, Series 2000 synthetic with extra zinc in it. A little expensive, but a 40-50 dollar oil change every 5000 miles is a lot cheaper than an engine rebuild. HTH
Tim Michnay

Hey glenn,

Both Kent and Swiftune have kits with the camshafts that have springs and lifters, as well as various othe add ons, I got to agree if the srings are original, they gots ta go...just to many miles, dont forget to get a new oil pump, always a good idea to roll those out during a rebuild.

Prop
Props Black Hole

I guess you can get Penrite oils in the USA?

http://www.penriteoil.com/uk/nextpage.php?navlink=penworldwide

If so I would recommend Penrite Classic 20/50 for a street motor or Penrite HPR30 20/60 for a tuned motor.

Both contain ZDTP and both are excellent in my experience.
Deborah Evans

Deborah Evans, Cambridgeshire, United Kingdom
I guess you can get Penrite oils in the USA? """

Hard to find in the Colonies.


""""Our Porsche engine builder uses Rotella T 15-40. Lots of zinc and non-synthetic.""""

Sorry Charlie..........Rotella is formulated for Diesel motors.....WRONG additive package.


"""DL Rhine, South Carolina, USA
Check out this web site: Cam-Shield.com...good info."""

There you go!!!!!!!!!


""""Posted 29 August 2009 at 19:57:21 UK time
Glenn Mallory, New Mexico, USA, gmall18073@aol.com
7 out of 8 of the lifters were very badly pitted. Oddly enough, one was not.""""""

Light pitting is normal in very high milage motors.

""" I have been advised to use the ZDDP type additive. Valvoline racing + STP oil treatment (since the car was new) seem adequate.""""

Valvoline racing = WRONG additive package. BUT with frequent oil changes it might be ok.


""""""Prop...How does that hole vent oil agian...Prop"""

The hole allows the oil colleted in the shell lifter to drain out and not have 20 grams of oil in each lifter.








M. Who

"Valvoline racing = WRONG additive package. BUT with frequent oil changes it might be ok."

Valvoline VR1 20/50 racing contains ZDDP and is recommended for flat tappet (OHV) applications.

I've been using Valvoline products for 25+ years both on my race motors (A Series 1380cc, Triumph 4-pots (both running 8000 rpm red lines), Coventry Climax motors (9500 rpm redline), Lotus 'Twinks', Triumph 'Sixes', Ford 'Kents' as well as on street motors with absolutely no issues.

Quote the Valvoline site for VR1 20/50 Racing:

Valvoline VR-1 Racing Motor Oil is recommended for engines burning gasoline and full or partial alcohol fuels in track and street service.....

....ZDDP additive provides tough anti-wear protection.....
Deborah Evans

<Sorry Charlie..........Rotella is formulated for Diesel motors.....WRONG additive package.>
He uses this for break in or dyno time. 30+ years as an racing engine builder (some as factory)is good enough for me.
Also after a little research, Mobil 1 15-50 actually has the minimum amount of ZDDP in it as recommended by cam-shield. https://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf I might switch back just because of availability, but will probably stick with the Amsoil since it seems to do a good job in btoh race cars.(2L Porsche and Bugeye)
Tim Michnay

The Rotella-T used to be fine, but as I understand it, about a year and a half ago they took most of the ZDDP out of the diesel rated oils also.

Charley
C R Huff

Frankly and Surly,

Why risk it, I dont...just buy the ZDDP additive and pour it in at the time of the oil change and use what ever oil you like, and call it a day, Thats what I do, After all there just arnt any oils left over the counter that have the ZDDP...No point fretting over it. Just the way life is.

Prop...Adapt and Semprfi, uoowha...Prop
Props Black Hole

...there is such a thing as too much of a "good" thing.
Trevor Jessie

I go to my local GM dealer and purchase a bottle of E.O.S. Engine oil supplement. I have used it for 20 years and have never had a cam/lifter failure on a multitude of engines.
Sandy
SANDY SANDERS

Glen
Just interested----Did you get them valve springs measured up---- result? Willy
WilliamRevit

Glenn

I'm new to this Spridget stuff lately...I worked on them back in the 70's. My daily driver back then was a Triumph GT6 and I co-owned a '60 Bugeye race car (autocross special and many a trophy). Back in the day we used Valvoline oil exclusively...but back then ANY oil had the ZDDP that our engines needed.

Just recently purchased a '78 1500. When I first bought the car it sounded like a small diesel...went right to the rocker arms and adjusted valve clearances, dumped the oil and filled with Castrol GTX 20/50...not much change in the noise.

Since then I've read many threads on this sight, read info on many other sites about flat tappet engines and zinc/phosphorous and came up with this combination: Valvoline High Mileage 20/50 (a synthetic blend), Lucas Oil Stabilizer and Cam-Shield...the difference in the valve train noise is amazing....believe me, it's night and day.

I know you're rebuilding, so you won't need high mileage oil, but definitely look at Valvoline (maybe Dura Blend), Lucas and Cam Shield.

Good luck and with a little research I think we'll be able to keep these old cars going for quite awhile yet.

I love my little car and have 2 grandsons who'll probably fight over it after I'm gone...just had an impromptu race with the wife coming back from the lake, she in her Toyota with one kid and me in the midget with the other...took us at the stop light ...but then came the twisties!

Think I'll have a victory beer,

Dave

DL Rhine

<<Just interested----Did you get them valve springs measured up---- result? Willy>>

Machine shop measured the springs and found them within tolerance. Maybe the worn cam and lifters wasn't exerting enough pressure.
Glenn Mallory

Hi Glenn

Most billet A series cams now come with a lube hole drilled in the base of the cam lobe,original cams are only splash fed, maybe you have always been gentle on your engine and not enough splash to oil the lobes? Just thinking that your springs are un-worn so maybe you do not push the engine hard? Mind you, 250000 miles is pretty good in any language.

I get the feeling the oils Stateside aren't as 'good' as over this side of the pond, we will, no doubt, end up with the same restrictions on additives.

I haven't used Penrite since I had some de-nature in a hot Rover V8, low oil pressure after a hard track day( hard by my non skilled driving standards anyway:) ), dropped oil and first half came out like paraffin, second half came out like stp. Engine wouldn't crank up pressure with new oil so I had to strip pump and pack it with grease. I then used Silkolene Pro4 semi until they stopped making it.recently I have had some good reports from customers using Castrol 10-60 edge.

Peter
peter burgess

This thread was discussed between 29/08/2009 and 14/09/2009

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