• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR6 Shortening TR6 Stroke.....

G

Guest

Guest
Guest
Offline
Just curious, is there any way to shorten the stroke on the TR6 block? Seems shaving the block and the head and using shorter connecting rods might allow for a shorter stroke, and thus higher rmps. Or is there just not enough meat in the block to pull this one off?


Bill
 
OP
G

Guest

Guest
Guest
Offline
Bill, jooi - why'd you want to do this? It seems like a pretty complicated option compared to fitting a steel crank, or using a GT6 bottom end mated to a TR6 head (7k easy that way but less bottom end oomph).
 
OP
D

Deleted member 451

Guest
Guest
Offline
To shorten the stroke you must replace the crank shaft and lenghten the connecting rods. The stroke is determined by the crank.
 

martx-5

Yoda
Country flag
Offline
Correct. If you shorten the stroke, you lower the displacement. Displacement is equal to the bore area (pi*r^2) times the stroke times the number of cylinders.
 

bunzil

Jedi Trainee
Country flag
Offline
I have to hand it to TR6BILL, his threads tend to be among the most interesting ones here. Seriously, his are always a good read.
 

Bob Claffie

Jedi Knight
Country flag
Offline
Depends on how much of a decrease you would be looking for. A machine shop could grind the crankshaft offset. Old time racer trick looking for the unfair advantage (depending on which side of the crank was ground). Bob
 

YankeeTR

Luke Skywalker
Offline
A TR6 should be good for maybe 6500 RPM? Why would you need more rev's? More HP? To get more high RPM HP would require extensive head mods, higher compression, a radical cam, headers, stronger rods, a steeper rear gear to get the car rolling, etc.

I guess you could do it...but a new crank would be about $3K...you might get it done for another $5K....

Rotsa Ruck....!!!
 

swift6

Yoda
Offline
There are race prepped 2.5litres spinning to 8000rpm though it takes much more work to get there than YankeeTR mentions. Loads of specialized parts and machining. When all is said and done your looking at $20k-$25k just for the engine for that type of RPM. Even then, it has a limited lifespan. A GT6 crank already has the shorter stroke, but as has been mentioned already, you'll lose displacement for the increase in RPM. TR6's are heavy enough to need that torque from the long stroke and the extra displacement.
 

piman

Darth Vader
Offline
Hello Bill,

it's not only the GT6 that had a 2 litre engine, The Triumph 2000 sedan also used a 2,000 cc or a 2,500 cc engine depending on which you chose. 2,000 engines are, in your language, 'a dime a dozen' over here. Sourcing and shipping a 2,000 crank and connecting rods would be cheaper than having yours machined, and will fit straight into your block.

One Triumph specialist over here (www.chriswitor.co.uk) prefers the 2,000 as it is livelier and smoother.

Alec
 

YankeeTR

Luke Skywalker
Offline
[ QUOTE ]
There are race prepped 2.5litres spinning to 8000rpm though it takes much more work to get there than YankeeTR mentions. Loads of specialized parts and machining. When all is said and done your looking at $20k-$25k just for the engine for that type of RPM. Even then, it has a limited lifespan. A GT6 crank already has the shorter stroke, but as has been mentioned already, you'll lose displacement for the increase in RPM. TR6's are heavy enough to need that torque from the long stroke and the extra displacement.

[/ QUOTE ]

Well said...
 
Similar threads
Thread starter Title Forum Replies Date
TomMull Shortening a throttle cable Q&D with stuff in the shop. Restoration & Tools 5
KVH TR4/4A Shortening the Steel Wrapped Heater Control Cables Triumph 2
JimTR4 TR4/4A Shortening the gear stick Triumph 2
regularman Shortening the list of things yet to be done. Spridgets 14
vping MGB Shortening a MGB shift lever MG 51
G Shortening my Chrome-Moly push rods Triumph 12
R TR6 Crazy Ignition Failure in TR6 engine… Triumph 7
mctriumph For Sale 69 Tr6 Triumph Classifieds 0
B TR6 TR6 block decking Triumph 2
A TR6 How many fuel filters-TR6 Triumph 20
Got_All_4 General Tech TR6 Transmission Troubles Pops Out of 3rd gear Triumph 2
J TR6 Repadding TR6 frame Triumph 0
S Wanted Need an HVDA conversion kit for 73 TR6 Triumph Classifieds 3
M TR6 Sorting out new TR6 Triumph 10
tr6nitjulius For Sale TR6 Clutch Master Cylinder $40 Triumph Classifieds 0
S TR6 '72 TR6 distributor issues Triumph 3
R TR6 Limit Mechanical Advance on TR6 distributor? Triumph 8
RonC General TR TR3 Shifter on TR6 Triumph 8
B TR6 TR6 convertible top frame Triumph 0
K TR2/3/3A The TR6 gearbox Ist gear.... Triumph 1
tr6nitjulius For Sale TR6 tail light assemby & Resurfaced/New Ring Gear Flywheel Triumph Classifieds 0
tr6nitjulius TR6 TRIUMPH TR6 Triumph 7
S TR6 New tr6 purchase Triumph 31
Jim_Stevens TR6 Barn find of TR6 and many TR3 parts Triumph 9
nichola TR6 Hot spot on cylinder head - 1973 TR6 Triumph 2
R TR6 Heater control bezels TR6 Triumph 2
L For Sale 1974 Tr6 for sale Triumph Classifieds 0
tr6nitjulius TR6 TR6 Parts Visualization Triumph 0
Got_All_4 For Sale 1969 TR6 Driver Seat Triumph Classifieds 0
R TR6 TR6 Choke Cable Triumph 11
Got_All_4 For Sale TR6 TR250 TR4 parts for sale Triumph Classifieds 2
B For Sale TR6 Carburetors Triumph Classifieds 0
R TR6 TR6 Triumph 6
Chrisc9 TR6 TR6 brake light Triumph 6
glemon TR5/TR250 Answering My Own Question Rear Tube Shock Conversion Numbers TR4a-TR6 Triumph 0
tr6nitjulius General TR TRIUMPH TR6 the possibilities! Triumph 12
SherpaPilot TR6 Unidentified fitting on TR6 Engine Triumph 3
Got_All_4 TR6 Need 1969 TR6 Expert Got Questions Triumph 17
tr6nitjulius General TR 6/24/23 TRIUMPH TR6 (5) TR8 (2) Spitfire (1 RHD of 2) TR3A (1) Triumph 0
AngliaGT ANOTHER TR6,& an MGB Spotted 0
A For Sale 1974 TR6 Triumph Classifieds 1
Got_All_4 TR6 Triumph TR6 PDWA Brake Question Triumph 1
EWD For Sale ‘74 TR6 original wheel trim rings Triumph Classifieds 3
EWD For Sale ‘74 TR6 original radio Triumph Classifieds 0
EWD For Sale ‘74 TR6 original starter Triumph Classifieds 0
EWD For Sale ‘74 TR6 original steering wheel Triumph Classifieds 0
JPSmit TR6 at lunch today Spotted 0
E Wanted looking for a tr6 bell housing Triumph Classifieds 12
jfarris For Sale TR6 Yellow Fan - new Triumph Classifieds 0
L Wanted right front turn signal 1975 TR6 Triumph Classifieds 2

Similar threads

Top