Stag Looking at a Stag-Radiator/Timing Chain Questions

[Ted19428]

I am a previous TR6 owner and I located a Stag I am interested in possibly purchasing. I inspected it once already and I am planning on giving it a very thorough examination this weekend.

I have read all the "buyer's guides" available on the internet and the two main problems are the radiator and the timing chains. How can a relative neophyte like myself determine whether there are any major problems with either of these components on this particulary Stag?

I am planning on letting the car run for at least 20 minutes to get an idea of engine temperature. However, it is not exactly hot in Philly this time of year, so that may not be of much help. Anything I should look for physically on the radiator that would indicate cooling problems.

As far as the timing chains are concerned, where the heck are they located, what do they look like, and how can I tell they are in good/bad/indifferent shape?

Many, many thanks!

TED

 

[startech47]

Re: Looking at a Stag-Radiator/Timing Chain Questi

Another area to watch out for is the head gaskets. The combination of iron block, aluminum heads, and early antifreeze resulted in a lot of failed head gaskets. The fix required prying the heads far enough up the head studs to allow the cutting of the studs between the head and block, brazing the deck surface of the block and draw filing it where it was eroded, heli-arcing (welding) the deck surface of the head/s and having the deck surface milled back down, a valve job done, and re-assembly. I made a lot of money off of these jobs.

To check the timing chain remove the valve cover. Turn the end in its normal direction of rotation watching a rocker arm for movement. Reverse rotate the engine until the rocker arm starts moving. The number of degrees the crankshaft has to move until the rocker arm starts moving will tell you how much slack is in the timing chain. There should not be much slack if the chain is good.

Look for signs of corrosion green stains on the radiator. You could also pressure test the system up to the pressure indicated on the radiator cap with a Stant radiator testor or equivalent.

Good luck.

 

[Ted19428]

Re: Looking at a Stag-Radiator/Timing Chain Questi

Startech,

Many thanks for your explanation.

Cheers,

TED

 

[piman]

Re: Looking at a Stag-Radiator/Timing Chain Questi

Hello all,

Aston Martin came up with a clever and relatively non destructive way of solving the problem of removing a stuck aluminium head, which essentially was a deep hole saw wich was used to machine a small clearnce between the head and the studs. I would guess that the bulk of the material would have been removed from the stud.

Alec

 

[Alan_Myers]

Re: Looking at a Stag-Radiator/Timing Chain Questi

Hi Ted,

Roger Williams discusses the Stag motor, its shortcomings and some solutions at some length in his "How to Improve Triumph TR2/3/4/4A" book (and perhaps other books in the series) because more than one Stag motor has found it's way into a TR4, plus he's a Stag owner and quite familiar with the problems and the fixes.

I don't own a Stag or claim *any* expertise, but the timing chains apparantly should be changed pretty frequently. Also, failing to change the oil on a very strict schedule will lead to rapid timing chain wear, apparantly. Perhaps there are some upgrades of the timing chains possible, I know some other TR models used a single row chain and changing to a duplex chain makes them much more durable. But, I don't personally know if this is a problem or even a possible solution on the Stag.

Stag cooling issues seem mostly related to the radiator being too low in relation to the engine, so air gets trapped in the system, especially effecting cooling at the rear of the heads, eventually leading to general or localized overheating and possibly warped heads. Williams recommends installing a coolant header tank and some other methods to be certain the system has no air trapped and is well filled.

A factory specified Cadillac additive for certain of their engines with aluminum heads on a cast iron block is, believe it or not, Bar's Stop Leak. It's use is standard and spelled out right in some of the factory service manuals and bulletins! I don't know if Bar's would work in the Stag, but might be worth a try! I've been using it in a friend's Pontiac with good results (and no problems!). It was the only way we could get coolant to stop weeping gradually into the crankcase in her Grand Am, a common overheating-related problem with this particular all-aluminum 4-cyl. engine.

Best of luck with the Stag!