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Triumph TR6 - Shifting RPM

Took the TR out of storage this weekend. It started right up and is running great. Perfect weekend..sunny and high 70's

I have about 800 miles on my rebuilt engine and I have started shifting around 3000 RPM (yeah I know..living life on the wild side). I never really drove this car much before the rebuild so I was wondering where do you "seasoned" drivers run these engines in rev's? Where is the torque peak? Does it like to run in the higer rev's? I can't imagine taking it up to redline. It feels pretty "torquey" around 3000 RPM but as I said I haven't tried any higer yet.

Thanks

henry
HP Henry Patterson

It really depends on the specs of your rebuilt engine. Specifically how your camshaft has been profiled.
I personally use a street profile gp2 from Good Parts which has great torque in the low to mid range in rpms. It sound to me that yours is a street profile also...
http://www.goodparts.com/shop/index.php?categoryID=9

benji

Good point Benji. My engine is stock.
HP Henry Patterson

Henry, my 6 has many, many a mile on it and it handles routine shifts just above 4 grand, because I can't help myself. Once I get to 3rd I tone it down as to avoid a pink slip. I think the highest torque is around 3 thousand or a little more.
Mine is not driven every day and if it were to be my trusty mode of transport (could you imagine) I would change my habits.

party on,

Chris
c.a.e. emenhiser


Thanks Chris.

4 grand sounds like fun. I better get some more breakin miles before I do that. I was having fun going into a turn and downshifting bring the rev's up to 3 grand and coming out of the turn with the rev's still up there. I thought I was really screaming until I checked my speedometer and saw I was going 40 MPH. Probably feels faster since it's a small low to the ground convertible.

Henry

HP Henry Patterson

While it may vary somewhat with your rebuild depending on the nitty gritty details, a quick and dirty look at "stock" type engine models indicates that torque will peak in the 3500 - 4000 RPM range. If you have the early type engine with higher compression, but a milder cam it is closer to 3500, if you have the later type engine with lower compression but a little hotter cam, it is closer to 4000 RPM. The shapes of the curves are similar, just offset due to the compression and cam profile differences.
SteveP

Thanks Steve,

I guess I didn't give much info. My car is a 73. I replaced the cam with a new stock cam from BPNW. If I remember correctly I got the older cam (pre 73) that is supposed to be a little hotter compared to the later cams. That's all I know. As you probably guessed I didn't rebuild it performance. I just wanted to bring it back to a fresh stock engine. That's just the replacement stock cam that they sell.

Henry
HP Henry Patterson

Henry
Since you are still in the break-in period, I presume you have some ZDDP aditive of some sort in there?
Rick
Rick Crawford


You bet Rick!

The "cam guy" told me not to bother since he thought I'm well past cam break-in. But like you said earlier 'if it's available why not go for the extra protection' (something to that affect) I agree so I added some cam break-in additive, loaded with ZDDP, that I had left. Since I'm now out of that I'll pick up some EOS for the next oil change. I've kind of lost track when true engine break-in is acheived but I figure about 1000 miles ought to do it. Actually, I don't know what's left to break-in... my rings are obviously well seated and my cam is certainly broken in. Maybe the bearings? Probably ok now. Either way I'm starting to run it a little harder and having fun.

Thanks

Henry
HP Henry Patterson

There were three camshafts used by the factory on the production TR6s, the early PI cam, the early carb cam and the late cam which was used on both PI and carb versions. The hottest of the three was the early PI cam, the mildest is the early carb cam. Odds are that if got a stock cam that is a little hotter, it is the late cam. Not a bad cam at all and one I considered running myself.

That early PI cam has a good bit more duration which made it a bit on the "pipey" side for street use. However, it did not have a lot of lift. So it made more power, but not as much as the duration would hint at and to get there you had to spool the engine up to where the piston speeds are higher than I like to see in street car (a consequence of having an engine with an under square bore/stroke relationship). The early carb cam, it doesn't really help make a lot of power, but it does pull well from right off idle until it runs out of breath in the 4500 to 5000 RPM range. If your use is in stop and go city slog traffic, it works like a charm. Spinning the engine faster than that with an early carb cam puts you on the back and down side of the power curve so no need to flog it with that one.
SteveP

I don't really care where the torque curve is, it's just fun to run it up to redline every once in a while.

I know the feeling, Henry. A big part of the fun of old cars is they feel like they're going a lot faster than they really are. At least when you are used to modern suspension and drivetrains.

Must be getting kinda geezer-like. Or spoiled. 100 miles feels like 400 in the regular ride. More than 4 times the smiles per mile, though.
Tom


Rick Crawford.. I know you have a few more miles on your rebuild than mine and I was wondering if you have re-torqued the head. I read somewhere that it should be done. Anybody else who may know if and when it should be done... SteveP?

I probably should have started a new thread. We'll see!

Thanks

Henry
HP Henry Patterson

It was pretty standard fare for new British cars of the era to call out a 1000 mile service which retorqued the head along with an oil and filter change.
SteveP


Thanks Steve.

I have a couple hundred to go yet before I do the re torque. That's good. I didn't feel like doing it now anyway.
HP Henry Patterson

Henry
Another project this weekend. I put about 2000 miles on her last year and yes, it needs to be done. I already did an oil change at 500 miles.
Rick
Rick Crawford

This thread was discussed between 23/04/2007 and 25/04/2007

Triumph TR6 index

This thread is from the archive. The Live Triumph TR6 BBS is active now.