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MG TD TF 1500 - Rods

With virtually all new parts in the lower engine(billet crank, bearings, forged pistons and rings, cam shaft and roller lifters) I am felling uneasy about staying with the old rods. They magniflux fine and my machinist says they are in good shape. Manley Ford recommends using the existing.

They will celebrate their 66 birthday on June 1, 2016.

So I need the collective wisdom of the BBS to talk me into using the old rods or recommend a good new set of rods. I don't race the car but I do spend a lot of time on trips cruising at 70-75 mph.
Mort 50 TD

Saenz rods are great - I have them in one of my engines where cost was no object: newer, better materials, better QC, better design, better everything. If you already have a forged crank, forged pistons, supercharger and a roller cam, then new rods will provide a greater level of security.

For a stock engine I would not hesitate to use the original rods - when was the last time you heard of an XPAG rod letting go, because of some weakness in the rod? Bolts, yes, rods, no. But for a modified engine like yours, I would definitely go with the new rods.

Tom Lange
MGT Repair
t lange

Second the Saenz rods...with MGB big ends to go with your new billet crank (also sized for MGB big ends).

It's only money 🤔
Gene Gillam

Mort,
You can always sell the old rods to recoup some of the money,,
Steve
Steve Wincze

You can also have the original rods shot peened (not sand blasted). Most aircraft engines have this done to relieve any stresses in the connecting rod. Check with an A&P mechanic at a local airport. Either they can do the work or recommend a company who can. I have had this done to the rods in my 82 year old MG PA engine. They are now as good as new. This assumes there were no previous cracks or distortion, which was checked before and after the shot peening by a professional magnafluxing company. Cost for all four was well less than one new rod.
Lew3

Got my rods from Crower Rods out of California, Pistons from Venolia. both are great, not an owener of the co, just good products.
TRM Maine

Having invested in all those new bits a new set of rods would complete the package. If you decide to use the old rods, there are things to check and things you can do to improve them.

Check the lengths match. I once assembled an engine and found two pistons protruded 20 thou' and one was short of the deck by about 10 thou'. The rods varied in length by about 30 thou' due to some sort of abuse in a previous life!

Check the big end and gudgeon are parallel. Nearly all rods I check need straightening! I don't think they bend in service but some people tighten gudgeon bolts wrongly. If the rod is held in a vice or the rod is on the crank, tightening the gudgeon bolt will be twisting the rod. They must be tightened with the gudgeon held firmly by a bolt through its centre which is held in a vice (or similar).

Although less likely to be out of order, you should check the big end tunnel is correct size (and round).

I have only ever found one rod which was cracked. However, to help prevent future cracking I always grind and polish the sides where cracks could start. This is standard procedure in race engines. I have attached a photo of a polished rod. Ignore the white marks. They were to show someone where metal can be removed to balance rods.

Bob Schapel

R L Schapel

This thread was discussed between 24/02/2016 and 25/02/2016

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