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MG MGB Technical - Next rebuild issue - what piston

I never knew there were such differences between reputable machine shops on what parts to use in an MGB Rebuild.

Todays issue, what pistons to us.

In the US, apparently the choice is A&E or County pistons.

Machine shop says get A&E. I am using Hap Waldrop's MGB rebuild kit. Hap runs Acme Speed Shop in South Carolina and builds MG racing engines, but he also puts together rebuild kits for street engines.

Hap says that he likes County. This piston uses Grant rings which have a three piece oil ring. Hap says the A&E use a one piece oil ring and this has caused some issues in racing engines he has build.

Machine shop said that the issues they have with County is that they tend to be larger in their tolerance and this has caused issues.

I would appreciate input from folks that have used either of these brands and their thoughts.
Bruce Cunha

Sorry, that should be JE pistons.
Bruce Cunha

Wow my typing is off AE Pistons
Bruce Cunha

Depends on how deep your pockets are and what type of engine you are building. JE pistons are made in the US and are excellent, but not cheap...you get what you pay for!
I K Jackson

Bruce, when I rebuilt my GB engine back in '93, I went with .040" oversize County pistons. After all these years, including over ten with a supercharger, they're still going strong. I had a friend that was rebuilding an AH 3000. He ordered a set of oversize pistons from JE and they turned out to have been made to the wrong specifications. They were no where near what he had specified when he ordered them. They flat refused to help him in any way whatsoever. He died a few months later and the engine was sold in pieces, along with the car. I've avoided doing any business with them based on this experience alone. RAY
rjm RAY

Bruce I have been a mechanic all my life (which is a long time) I have also dealt with Hap and I would say to go with his recommendations. Either of those products will do the job and although you need to be more careful installing the three piece oil ring it does do a good job. Denis
Denis4

County are a reasonably good standard type of piston at the busget end of the market, some people even race on them.
They do sometimes vary from the nominal size by a thou or two, which some machine shops don't like as modern pistons are now much closer. However old school machinists can remember when such variation was normal, and you had to size each bore to suit each piston individually and get the specified clearance. If this is doen then there are no problems.
Paul Walbran

Any decent engine builder worth their salt would frown at having to do each bore size to a different bore due to poor pistons...!
I K Jackson

Perfection is a goal, not a reality.Piston sizes will vary, no matter who manufactures them. This is why machinists ask for the pistons in advance so that they can measure each piston and size each cylinder accordingly. Over forty years of building engines and dealing with machine shops have taught me this. RAY
rjm RAY

Thought I would give an update. We decided to go with the AE piston. Unfortunately they are currently out of stock on mg pistons except for 60 over.
Machinist does not want to go 60 over when the engine is not in need of going out that far, so he is going to try the county pistons.
Bruce Cunha

Hi Bruce

We find County pistons are very close in size the same as AE, however, we do find AE pistons vary a large amount by weight in a box of 4. The County ones are within 2g straight out of the box as they have obviously been graded. We had issues many years ago with no oil holes drilled in the gudgeon pin bosses of AE ones which AE said didnt matter (why bother drilling a gudgeon pin boss if it doesnt need the lube?). The only problem we have had with County pistons is some were marked with the arrow for front facing rear not front, is obvious if you check offset :)

The three piece oil control ring on the County pistons needs careful assembly on the piston, if they are installed wrong, which can be easy to do, the engine will consume amazing quantities of oil!

Peter
Peter Burgess Tuning

I've also had good luck using County pistons. The ones in my '67 B have seen their share of abuse and they show excellent compression numbers and consume no oil whatsoever. RAY
rjm RAY

Thanks all. Will do an update as the rebuild continues.

Not being a machinist or having knowledge if the various parts available, the input from this group is very helpful.

Peter. Thanks for the heads up on the three piece oil ring. I will triple check these.

If I can ask another one of those questions that will probably have multiple favorites, which engine lube would be recommended?

Used to use STP, back in my younger days. Used GM assembly lube on my TD, but that was when it had high ZDDP levels. I believe they have changed it since.
Bruce Cunha

Hi Bruce

I use a spray white grease with ptfe on bearings and engine oil on the bores and pistons, I use a molydisuphide grease on the cam and followers. Suzuki still sell a moly grease 99000-25140.

http://www.suzukicycles.com/Accessories/suzuki%20oil%20_%20chemicals/99000-25140.aspx

A good bearing grease is
http://www.lubriplate.com/Products/Automotive-Lubricants-Motor-Oils/Lubriplate-No-105-Motor-Assembly-Grease.aspx

Peter
Peter Burgess Tuning

NAPA carries an excellent assembly lube that I use all of the time with excellent results. On the cylinders though, I use only 30W oil or ATF so that the rings seat in very quickly. If you use assembly lube there, the rings may never seat in. Too slippery. RAY
rjm RAY

This thread was discussed between 13/09/2014 and 26/09/2014

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