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TR2/3/3A shaved heads

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Could I use a stock head and still get the High RPM or would I need to use the shaved head. I would want this thing to idle at maybe 9 or 10 max. Having to run at a high idle makes driving on the street kinda unsettling
 
Higher compression actually smooths the idle, as it tends to purge the old gases from the cylinder better, so less exhaust recirculation. The cam grind will have the biggest affect on your idle....but it is a catch 22...

Your trick parts can still wind faster than stock, but won't have much more horsepower unless you have a longer duration cam profile. So, for a good idle you lose top end power. To gain the top end, the idle will suffer. There is an exception, though. Roller lifter cams can open the valves faster, so you can increase top end without killing the idle. That's one of the reasons modern cars are making so much power, yet they still idle smoothly. I wonder if anyone has tried a roller cam in the TR's?
 
Not to worry. Turning that kind of rpm with a stock crank, no matter how well prepared, isn't going to last long. I believe it was Ken Gillanders (although I can't find the quote at the moment) that said "There is only one word for someone who consistently exceeds 6500 rpm with a stock crank. BANG!"
 
There was a crank with the boxes of parts I bought, but the guy said I think it is shot. The guy I got the stuff from was more of a driver than a mechanic. He had a very nice home and a very clean garage with pictures and gas pumps, and racing shirts…. The parts were from his mechanic/buddy who has been speeding 30 to 40K on engines and not winning, so maybe there was some truth to his fast talking. Maybe I got luck; it has been a while. The crank looks stock. I did not see any brand names. What should I look for?
 
TR3driver said:
Not to worry. Turning that kind of rpm with a stock crank, no matter how well prepared, isn't going to last long. I believe it was Ken Gillanders (although I can't find the quote at the moment) that said "There is only one word for someone who consistently exceeds 6500 rpm with a stock crank. BANG!"
Click to expand...

I used to turn 7k with cast cranks, but they have to be prepped properly. If an unprepped stock crank can spin 5.5k, I would have no worries visiting 7k with a fully prepped crank. Start with a stock forging with standard journals and give it a full x-ray check for internal flaws, and die penatrant for external flaws. You will likely have to toss several before you find one that passes without flaws. Then the key is in the generous fillets on the journals and de-burring to remove stress risers. Finish with balancing and full shot peening. That takes a metal prep shop that specializes in aviation mil-spec shot peening. This is a far cry from shot peening offered at "speed shops". Mil spec uses 8 nozzles in a rotating cabinet...very controlled. The result is a fatigue resistant work of art!

Of course, if you want serious RPM, there's always an internally balanced crank machined from a billet of 4340 carbon steel, ion nitrided and ready to spin. Steve, your cool rods and pistons are just crying for a comparable trick crank to compliment them!

Sorry, getting carried away....thinking of days when my projects all envolved racing instead of restoration.
 
CJD said:
I used to turn 7k with cast cranks,
Click to expand...
On a 3 main TR3 motor?

And how many tens of thousands of miles did that last?
 
Get adjustable rods. There may be different thicknesses of head gaskets too.
 
If you simply want to know if the crank is fatigued or cracked there is a simple test, which I have no doubt the guy who sold you the parts knows.

Using a piece of wire or something similar suspend the crank in the air. tap lightly with a hammer or wrench on a non-vulnerable part. If the tone is like a bell ringing the crank is ok, if there is a dull thud it is cracked.
This will at least tell you if there is something obviously wrong.
The bearings may also have been turned down to the point that the crank is unusable, so measuring them would be the next step.
 
I will take the crank into a shop and see. My old back is not what use to be and those things are right at my limit or maybe past.
 
sp53 said:
I will take the crank into a shop and see. My old back is not what use to be and those things are right at my limit or maybe past.
Click to expand...

Steve, if it checks out good, I can give you details on proper performance prep for the crank. The area inside the rear bearing is the weak spot on the TR3 crank.

Just remember that the TR3, even with all these trick parts, is still not going to be a fast car. Like, maybe the difference between 12 second and 9 second 0-60mph times. Even our huge Escalade will do it in 6 sec. So it's not worth spending a lot on performance unless you are interested in vintage racing.
 
CJD said:
I've never seen a cast TR3 crank, have you?
Click to expand...
No, the stock TR3 crank is forged rather than cast. But lots of folks don't know the difference.

My point is simply that you are not talking about a TR3 crankshaft and motor. Probably not even a 3 main. Since they aren't the same, it is irresponsible to suggest that a stock TR3 crank, can realistically be turned at 7K rpm, no matter how well prepared.
 
Irresponsible...? Randall, I'm not going down that road with you again. I do know what I am writing about.
 
So, let's be clear about this, you have never spun a TR3 motor to 7 grand in your life. Some other motor you built will turn that fast (probably a small block Chevy, even kids in my high school were doing that), but you won't even admit how many main bearings it had.

You're right, we've been through this before. You didn't know what you were talking about then (tempering is not the same as hardening) and started calling me names and misquoting me when I disagreed with you, gave sources and so on. This time maybe you do know something, but whatever that is has nothing to do with a TR3 motor and/or crankshaft.
 
Here is a TR4 engine spinning to 7k pretty regularly:

Driver is 82yo and backs off after getting up to 3rd place (after the silver TR6) to save the car for later on.

Lots of people claim to spin to 7k, my observation is most rarely spin to 6500rpm and very, very few are spinning to 7k. The bottom end isn't the problem with spinning that high, it's the valvetrain.

Same car with a younger friend of the driver behind the wheel. Passing lots of newer cars ;)

 
Fly by, short shifting around 6700rpm here:
[video=youtube;pNNHZigBqVQ]https://www.youtube.com/watch?t=13&v=pNNHZigBqVQ[/video]

For sound reference, that's a 1.8L Alfa behind it

Also, the top TR4 racers spun to 6700ish in the 1960s. They had to replace the rods every 3 races and the cranks every 5-8 races.
 
Very cool, Bob!

I spent the first 10 minutes trying to figure out how he got an auto box in the car. Of course finally realized he was working the overdrive. Impressive for 82!

I notice the peak power band seemed to be best in the 5 to 6.5k rpm. That makes me rethink the breathing on these engines. Apparently much better than I thought it was. Makes me want to put the TR2 on hold and go build up Marv's spare motor...

...Hey Steve....if you ever wanna get rid of those trick parts!?!
 
CJD said:
Very cool, Bob!

I spent the first 10 minutes trying to figure out how he got an auto box in the car. Of course finally realized he was working the overdrive. Impressive for 82!

I notice the peak power band seemed to be best in the 5 to 6.5k rpm. That makes me rethink the breathing on these engines. Apparently much better than I thought it was. Makes me want to put the TR2 on hold and go build up Marv's spare motor...

...Hey Steve....if you ever wanna get rid of those trick parts!?!
Click to expand...

The port entrances are very large. The limiting factor is the zero included valve angle which kills how big of an intake valve will fit. To make up for it, you have to keep lifting the valve further and further and making the valve lift area off the seat as fat as the valvetrain can stand.

The engine can make a lot more peak power and rev higher, but it's a road race engine. It's about maximizing area between the two peaks (well, that's every engine be it drag racing to land speed, but road racing seems to reward shaving maybe more off the top than some other types).

It takes a lot of cylinder head R&D by a very competent person. Not going to do with with the typical faces in the cottage industry or following 50yo prep manuals. Lots of other things going on too. You'll be easy $2500+ in the head alone!

Trick is subjective...

Take a look at this rotating assembly for BMC A-Series engines.
https://bwrperformance.com/a-series-all.html

Nothing stopping anyone from doing that for a 4 pot TR engine and it will likely be closer to $10k for a rotating assembly if you wanted to go that route due to things being a little larger.
 
That's the billet machined crank we need...internal counterweights and all. Lightened forged pistons, lengthened rods, and even a 4 bolt cap on the center main. Truly beautiful!

So I think what you are saying is Steve's deeply shaved head is done to unshroud the valves?
 
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