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Triumph 1500 to 1700 stroker?

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openfold Oli Penfold
Fareham, Hampshire, UK   GBR
i havent got the transmission yet, i can see the benefit of the wide ratio so ill look for one with wide ratio when the time comes. but i still like the idea of the 1700 or a stroked 1500 to something. i guess this combo would work pretty good. what about 3.63 gears? i live in a bit of a hilly area so i dont want it to struggle with hills, would the type 9 offset this at all?



Edited 3 time(s). Last edit at 2014-06-12 06:14 PM by openfold.

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grumpicus Steve Jackson
Leicester, Leicestershire, UK   GBR
The wide ratio Type 9 boxes were originally used on large, heavy Ford saloon cars (like the Granada in the UK), where a low first gear was required just to get the thing rolling. Most of the Type 9 boxes retrofitted to small sports cars tend to come from cars such as the UK Ford Sierra, which have ratios more in keeping with a medium weight saloon car with a 1.6 to 2 litre engine - neither close nor wide ratio. There are also close ratio sets available, but these are more expensive. Before parting with money, I'd do a lot more research on the Type 9 boxes currently available, and decide what you need - e.g. define the engine speed you want in top gear at 70mph, for example, and work from there. Don't get the wrong impression, I'm not saying that you should not fit the wide ratio box, it's just that you might find 1st gear extremely low, and would have to select second gear almost immediately.

If you were to fit a 3.27:1 axle, with a Type 9 gearbox, my initial guess is that in 5th gear, you would get something like 24mph per 1000 RPM with standard wheels & tyre sizes. An unmodified UK Spit 1500 with 3.63:1 axle gives around 18mph per 1000 RPM in 4th gear, and when overdrive is fitted around 22mph per 1000 RPM in overdrive 4th gear.



Edited 2 time(s). Last edit at 2014-06-13 03:59 AM by grumpicus.

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
A fascinating technical debate, but following on from Foxy's excellent explanation, if you want more torque AND more power, why not go down the route that Triumph took? The six cylinder engine.

The 2 litre for 98bhp in standard form, the 2.5 for 150 if you want it, while for the same reasons that Foxy gives, a 2 will rev safely to 7K or more, while the 2.5 isn't safe much beyond 6. Pshaw! you will say, I can get a 1300 to 8 all day, properly prepared, but for a whole tower of torque in fairly standard form, the 2.5 can't be beat.
JOhn

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openfold Oli Penfold
Fareham, Hampshire, UK   GBR
i like the idea of a 'Spit 6' but i want to keep the 4 cylinder for insurance reasons. plus i like the idea of having an awesome 1500 rather than a normal 6 cylinder. i was thinking the 3.63 gears because it seems like it will the best compromise. plus my UK spit probably already has it. as for the type 9 i was just going to get one off ebay as they are relatively bullet proof and then swap it out later for a performance one if i think i need it. The car is never going to see an autocross course, i just want to have fun in it and show up all the youths in their french hatchbacks that they have put a silly exhaust on (you may laugh, but in the UK its a big problem).

in a type 9 with a 0.82 ratio in 5th and 3.63 in the rear the engine will be running at 3092rpm at 70mph and with 3.27's its 2785rpm. so here there isnt a lot in it but it seems that using 3.27's would sacrifice low end torque. im probably never going to go much faster than that in it, unless the motorway is clear...you never know. might get triple digits grinning smiley at 5172rpm with 3.27's its 130mph and 5741rpm with 3.63's. in a spitfire this would be terrifying though haha



Edited 1 time(s). Last edit at 2014-06-13 10:59 AM by openfold.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1215355 by tapkaJohnD A fascinating technical debate, but following on from Foxy's excellent explanation, if you want more torque AND more power AND more weight, why not go down the route that Triumph took? The six cylinder engine.

The 2 litre for 98bhp in standard form, the 2.5 for 150 if you want it, while for the same reasons that Foxy gives, a 2 will rev safely to 7K or more, while the 2.5 isn't safe much beyond 6. Pshaw! you will say, I can get a 1300 to 8 all day, properly prepared, but for a whole tower of torque in fairly standard form, the 2.5 can't be beat.
JOhn

Nowdays, many automakers are choosing turbocharging as preferred solution over bumping up the displacement.

90632D Avatar
90632D Fox Trapper
Various, USA   USA
In reply to # 1215371 by clshore
In reply to # 1215355 by tapkaJohnD A fascinating technical debate, but following on from Foxy's excellent explanation, if you want more torque AND more power AND more weight, why not go down the route that Triumph took? The six cylinder engine.

The 2 litre for 98bhp in standard form, the 2.5 for 150 if you want it, while for the same reasons that Foxy gives, a 2 will rev safely to 7K or more, while the 2.5 isn't safe much beyond 6. Pshaw! you will say, I can get a 1300 to 8 all day, properly prepared, but for a whole tower of torque in fairly standard form, the 2.5 can't be beat.
JOhn

Nowdays, many automakers are choosing turbocharging as preferred solution over bumping up the displacement.

Yes, and when they're water cooled, almost all the coking problem goes away. Wife has had several turbo cars with hundreds of thousands of miles on them, and nary a turbo problem. Turbo's work very well.

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
I think I've linked from here to this post before, but it's relevant again:
http://sideways-technologies.co.uk/forums/index.php/topic/6500-supercharging-a-triumph-gt6/?hl=turbodging#entry86110

Post No.7

JOhn



Edited 1 time(s). Last edit at 2014-06-13 04:48 PM by tapkaJohnD.

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jdeatsch Avatar
jdeatsch Jim Deatsch
Penfield, Neu Yawk, USA   USA
1978 MG MGB "Orval Shiftright"
A VERY interesting discussion of the merits of 'no substitute for cubic inches'.

However, ahem, why not investigate a more modern 4 cylinder device with gearbox. There are plenty of Japanese engines that make a TON more hp and torque than the 'lorry' design. Not to mention that the 5 speed the engine will likely have attached.

Get thee to the breakers (as they say in the Olde Country).

Jim

openfold Oli Penfold
Fareham, Hampshire, UK   GBR
thanks for the input everyone but i wouldnt be able to put a japanese motor in my spitfire. i want it to be sort of a resto mod. forced induction i agree is good but its not what im looking for and its too expensive.

Here is my plan so far

Option one (1535cc):
bore 40 thou over/fit +40 thou pistons
H beam rods
-10 undersize crank (just because i already have it)
unleaded head conversion
head skim
oil pan baffle
oil cooler
4,2,1 exhaust
megasquirt controlled injection
ford type 9
3.63 gears
aluminium radiator
electric fans
newman PH1 cam
balance bottom end

OR

Option two: (stroker)
bore 40 thou over/fit std TR6 pistons
MK3 rods
offset grind crank
unleaded head conversion
head skim
deck block
oil pan baffle
oil cooler
4,2,1 exhaust
megasquirt controlled injection
ford type 9
3.63 gears
aluminium radiator
electric fans
newman PH1 cam
balance bottom end

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clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1215466 by openfold thanks for the input everyone but i wouldnt be able to put a japanese motor in my spitfire. i want it to be sort of a resto mod. forced induction i agree is good but its not what im looking for and its too expensive.

Here is my plan so far

Option one (1535cc):
bore 40 thou over/fit +40 thou pistons
H beam rods <-- see comments below
-10 undersize crank (just because i already have it)
unleaded head conversion
head skim
oil pan baffle
oil cooler
4,2,1 exhaust
megasquirt controlled injection
ford type 9
3.63 gears
aluminium radiator
electric fans
newman PH1 cam <-- look around
balance bottom end

OR

Option two: (stroker)
bore 40 thou over/fit std TR6 pistons
MK3 rods
offset grind crank
unleaded head conversion
head skim
deck block
oil pan baffle
oil cooler
4,2,1 exhaust
megasquirt controlled injection
ford type 9
3.63 gears
aluminium radiator
electric fans
newman PH1 cam <-- look around
balance bottom end

How much money are you willing to spend on 'H beam rods' (WEAKER than 'conventional' I beam rods for the same weight BTW, just cheaper to manufacture).
You will find them to be rather spendy.
The 'Spitfire' H beam rods are limited to 5/16" conrod bolts, because their parting line split is straight, not 'angled' like ours, so rods with proper 3/8" bolts are too wide to fit (about 3.10"winking smiley into the cylinder bore (about 2.90"winking smiley.
(but there's an easy bodge, read on).

The stock rods are plenty strong, just tombstone heavy.
If you are willing to put in a few hours of manual labor, you can lighten them by perhaps 50%
You need a bench grinder, some stone wheels, some craytex wheels, and a cheap scale to keep track of the weight.
IF you can also get a stationary belt grinder, it makes the job go much faster.

##############################

To fit the wide conrods with straight parting line and STRONG 3/8" bolts, you must grind two relief pockets into the bottom of each cylinder,
about 0.100 deep, 1/2 wide, and about 1-1/2" up from the bottom.
A milling machine with ball end mill is great for this, but a carbide burr on a hand grinder will do the trick, no precision is required.
This enables you to insert the rods *from the bottom*, far enough that the conrod pin end sticks up above the deck.
You can then insert the piston into the bore, align and insert the pin, and retainer clips, and then attach the ring compressor, and install the piston into each bore, sliding the assembly back down to install the bearings and attach conrod caps as in a 'normal' assembly.

Oh HORRORS some may say, the notches will introduce rapid piston wear, the rings won't seat, etc, etc.
BULL FEATHERS say I!
At the BOTTOM of the bore, gas pressure is minimum; combustion stroke has ended, exhaust stroke is starting.
The side loading from piston to bore is NIL, because at BDC, the conrod angle is nearly straight on.
The RINGS are at the top of the pistons and NEVER travel down far enough to touch the notches.

The Honda guys have been doing this for AGES, notching the bottom of the bores for crankshaft clearance when they stroke their motors.
AND IT WORKS.

Ahem.



Edited 1 time(s). Last edit at 2014-06-13 07:58 PM by clshore.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1215447 by jdeatsch A VERY interesting discussion of the merits of 'no substitute for cubic inches'.

However, ahem, why not investigate a more modern 4 cylinder device with gearbox. There are plenty of Japanese engines that make a TON more hp and torque than the 'lorry' design. Not to mention that the 5 speed the engine will likely have attached.

Get thee to the breakers (as they say in the Olde Country).

Jim

Actually, not so many RWD donors out there, not in USDM anyway:
Miata (of course)
RWD Corolla and variants - USDM never got the good stuff, but you can import 20V RWD w/5 speeds
Ford Duratec N/S from a Ranger.

All of these have some kind of physical fitment issues, mainly they are too tall too wide, too big.
There is about 25" of vertical clearance under the Spitfire hood, 27" if you use the GT6 hood.

Many folks are unwilling to alter the hood.

Then there is the frame, specifically clearance for the rack & pinion.
Yes, the rack can be moved, but the suspension geometry cannot be preserved.
Spitfire motor has rear sump, most others do not.
Yes, you can fab a custom pan and oil pickup.
Yes, you can move the cross-member (but NOT the rack & pinion).
Can you move the motor backwards in the frame?
Yes, along with everything else. But it can and has been done.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1215447 by jdeatsch A VERY interesting discussion of the merits of 'no substitute for cubic inches'.

However, ahem, why not investigate a more modern 4 cylinder device with gearbox. There are plenty of Japanese engines that make a TON more hp and torque than the 'lorry' design. Not to mention that the 5 speed the engine will likely have attached.

Get thee to the breakers (as they say in the Olde Country).

Jim

Actually, not so many RWD donors out there, not in USDM anyway:
Miata (of course)
RWD Corolla and variants - USDM never got the good stuff, but you can import 20V RWD w/5 speeds
Ford Duratec N/S from a Ranger.

All of these have some kind of physical fitment issues, mainly they are too tall too wide, too big.
There is about 25" of vertical clearance under the Spitfire hood, 27" if you use the GT6 hood.

Many folks are unwilling to alter the hood.

Then there is the frame, specifically clearance for the rack & pinion.
Yes, the rack can be moved, but the suspension geometry cannot be preserved.
Spitfire motor has rear sump, most others do not.
Yes, you can fab a custom pan and oil pickup.
Yes, you can move the cross-member (but NOT the rack & pinion).
Can you move the motor backwards in the frame?
Yes, along with everything else. But it can and has been done.

What are you trying to accomplish?
How much work are you willing to do?
Will the result still be a Spitfire?
(would you be happier just getting a Miata, and leaving the Spitfires for us Maniacs?)

tapkaJohnD Avatar
tapkaJohnD John Davies
Lancaster, Lancashire, UK   GBR
Oli,

Just thought to set out your lists in two columns, rather than one, to compare:
And it's rather difficult to do here!

But It reveals that you only intend to deck the block for your 1700 plan.
Surely both?

And,
4,2,1 exhaust for both. As your 1300 would need to be a 'screamer', high revving, a 4-1 would be a better plan to extract and obtain best power at high revs.

A newman PH1 camshaft for both. For two so different engines, with different aspiration characteristics, will the same cam be ideal? The Triumph head shrouds the valves rather well and hi-lift cams don't help much, so longer duration. At a lift of 352, and a duration of 246. I'd say that the PH1 isn't the best for a long stroke engine. I note that the Citroen Saxo 1.6, for which this cam is recommended, has a stroke of 82mm, which is long, so maybe you can ignore me, or else think the opposite - it's so much longer than the 76 of the 1300 that it's not suited for that!
JOhn

openfold Oli Penfold
Fareham, Hampshire, UK   GBR
yes sorry, i do plan to deck the block on both, i copied and pasted the list and added a few things and changed some. i just forgot the cam... :/ long night

ive been looking through this to compare all the camshafts i could get http://auskellian.com/paul/links_files/spitfire_cam_specs.htm

i was going for H beam rods because thats all i could find to replace the 1500 ones. ive read that stock they are good for about 100hp but id rather be safe (especially with engines that are known for putting a window in the block) while im here. does anyone have any opinions on the lightened flywheel from moss? http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=18070



Edited 1 time(s). Last edit at 2014-06-14 05:31 AM by openfold.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1215561 by openfold yes sorry, i do plan to deck the block on both, i copied and pasted the list and added a few things and changed some. i just forgot the cam... :/ long night

ive been looking through this to compare all the camshafts i could get http://auskellian.com/paul/links_files/spitfire_cam_specs.htm

i was going for H beam rods because thats all i could find to replace the 1500 ones. ive read that stock they are good for about 100hp but id rather be safe (especially with engines that are known for putting a window in the block) while im here. does anyone have any opinions on the lightened flywheel from moss? http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=18070

Well, stock rods used to be mandatory in SCCA Prod classes, and were good for 125+ HP @ 8500 RPM.

Rods mainly fail structurally in two ways:
1) Compression buckling, 'bent rods'.
2) Tension failure, 'separation'.

#1 is due to combustion gasses, most often from extreme pre-ignition, extreme super/turbo charging, Nitro or NO2.
#2 is usually due to extreme RPM, (which is independent of the HP generated) and/or fatigue failure of the rod bolts.

Neither of these really apply to a street driven Spitfire.

Remember that rod bolts are only stressed in tension, so during crank rotation approximately between 270 and 90 degrees.
Also, rods are far stronger in tension than compression.

The chief advantage of custom rods is lighter weight, particularly on the bigend.
That reduces the inertia loads on rod bearings, enabling safe(r) operation at higher RPM.
Also, many of them feature higher performance conrod bolts.
But, as I've said, Spitfire custom rods use smaller 5/16" (or 1/4"!!!) conrod bolts (and thus WEAKER than stock 3/8"winking smiley.
BTW, good luck finding a set of custom rods for the small journal. Plenty of big journal ones though.

Spitfire rod bearing failures account for the majority of issues.
If the driver ignores the obvious symptoms of a rod bearing failure and continues to drive, the bearing shell will actually melt,
and material will extrude out between the rod and crank. (Yes, I AM guilty of this, but managed a second place finish by continuing)
A rod will ventilate the block, 'throwing a rod', when a conrod bolt loosens or fails, allowing full or partial separation of the cap,
and the inevitable occurs.

BTW, the stock Spitfire conrod bolts are very good, but you can easily purchase higher performance ones, and far cheaper than a whole set of custom rods.

My point is, you have a good list, so maybe spend your time and money first on the things that actually make the most difference.
If you want bragging rights to say 'Oh yeah, I've got a set of H beam rods', it's your money.
But for same outlay and effort, I'd prefer to have a car that performs BETTER.



Edited 1 time(s). Last edit at 2014-06-14 08:33 AM by clshore.

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