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MG TD TF 1500 - XPAG pistons

Good day to all,
I have a question about new pistons. Bores not measured or sonic tested yet, but it is possible that I will need to move to .100" over. I have an early block with the banana water holes, and I have heard that there is a little more meat in the block for the .100" overbore. In any event, I will sonic test and get shop's advice. This car will not be run hard, but I have a 4.3:1 rear end and I don't want to get run over on the interstate.

I may have to buy new pistons and I was wondering if the Moss Aerolite sets are acceptable. Do you have other advice on pistons? This is a pretty standard rebuild. I will increase CR to about 8.6:1. Sorry, no billet crank or racing parts. My crank is a TF and has been magnafluxed. I have sourced original connecting rods and they have been magnafluxed.

What do you think about pistons?

Jim
TD17744
JV Smith TD17744

First you need to find out the current bore size. Though some (not all) blocks can be taken out to + 0.100 - +0.120 , many can not. It all depends on the casting thickness and amount of water jacket corrosion. In general I would not suggest it. If your block is truly needing to go that far toutnto clean it up I would prefer to resleeve the bores and save the block especially since you already plan to up the compression. Be aware that upping the compression will also increase detonation requiring you to use a higher premium grade fuel to prevent this. Your cooling system will also need to be in perfect order to keep temperatures down. With higher compression ratios , bring a bigger bang in the combustion chambers, making more horsepower. Horsepower creates more heat which leads to detonation hence the need for better cooling and proper ignition timing curves.

Bill Chasser
TD-4834
W A Chasser

last year I had my XPAG block bored to .100" over and installed the Aerolite pistons. I have about 1,500 - 2,000 miles on the rebuild motor and (knock on wood) so far, so good. At the same time I installed Len's roller lifters and CSI distributor. The car which is otherwise stock performs quite will.

Jud

J K Chapin

Judd,
I was thinking the same for mine. Len doesn't know it yet, but I am planning on adding the roller lifters too....well, I guess he knows now. Whether I go to .100" remains to be seen based on the sonic testing and machine shop discussions. My other alternative is to sleeve the block back down some. At this point, I think I will recondition my original distributor and see how I like that.

I mostly wanted to see what people thought about pistons.

Jim
JV Smith TD17744

Since in a perfect world pistons don't rub against anything, I kinda think rings may be more critical. A particular set of rings were recommended but I forget which ones they were. I'll check and let you know.

Here's one of the pistons I replaced.



J K Chapin

I have a distinct favorite for rings - DEVES. I have had bad experiencesd with other rings, including Hastings and the ones that come on modern "AE" pistons. ( Modern "AE" pistons have nothing at all to do with the venerable and respected compamny of that name. Like most current Lucas products, the trademarked name has been co-opted and applied to products and packaging, often made inexpensively in foreign countries other than the UK.)

I strongly recommend DEVES rings, especially for engines that have added increased HP and stress. When you call DEVES with a question you are transferred to the owner, who truly knows his onions.

Tom Lange
MGT Repair
t lange

Tom,
The AE pistons you refer to are the "Aerolite" sold by Moss?

If so, What "quality, standard" pistons do you recommend?

Thanks,
Jim
JV Smith TD17744

Jim - I buy NOS pistons on eBay whenever I can; unfortunately, I have no +.100" pistons now - I used a set last year in a TC racing engine.

For longevity and for high-stress use (like a supercharged engine) I get forged JE pistons, and have the crowns ceramic coated.

I'm sure Moss's Aerolite pistons are perfectly adequate for casual around-town driving.

Tom lange
MGT Repair
t lange

Tom,
Thanks for your input. As you know, I considered a supercharger, but even though I would love the fun of a supercharger, I have decided not to add one. The added stress on the engine and the need to add higher grade(and cost) internals is just not worth it to me.

Jim
JV Smith TD17744

This thread was discussed between 28/08/2021 and 29/08/2021

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