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1500 engine performance mods

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tktrain Avatar
tktrain Tom Kohlmeyer
Evansville, IN, USA   USA
Oh well, I decided to go the conventional route for now. I just bought a Weber DCOE side draft and intake for the 1500. I'll build some compression and put in bigger valves and fast road cam with an aluminum flywheel, maybe roller rockers. The car already has headers.

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cokerart Avatar
cokerart Bob Coker
Atlanta, Georgia, USA   USA
1973 Triumph GT6 MkIII "Spit-6 Or Dr. Frankenstein"
I really don't know the difference between them, though I recall that Triumph had specific part numbers for complete boxes. Presumably the GT6 box is somehow sturdier.
-Bob

afer2261 Arnoldo Fernandez
Long Beach, USA   USA
Hey guys!

Reverse gear does not work. Won't engage? All other gears work good.

If you were me, how would you start the process of diagnosing the reverse issue?



Edited 1 time(s). Last edit at 2010-12-16 03:18 PM by afer2261.

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britsnspits Avatar
britsnspits Michael Stoliker
Bethlehem, PA, USA   USA
1976 Triumph Spitfire 1500 "The Phoenix"
1978 Triumph Spitfire 1500 "Lucky"
You might want to start by creating a new thread at the top level with an appropriate title instead of burying it at the bottom of a long thread about engine performance mods. Second I'd give a little better description of the problem, like you can't get the shifter to go into reverse, or you can get the shifter to go into the reverse position, but the car doesn't move when the clutch is released, etc.

Other info that might be helpful: Noises heard...whether this is a recent development...did you just buy the car and found it this way?

frank2 Avatar
frank2 frank roosa
NY, USA   USA
In reply to a post by 90632D I'll say I find your question far to vague to answer with specific recommendations. Do you want an engine producing 150 hp or one that idles? Does it matter if it's got torque to pull away from street lights nicely, or do you want racing power that only comes on at 5,000 rpm? Etc.

That said, there are some things I've done tried experienced and can comment on with regards to warming over a 1500. As well things I've seen others do.

Balance it. The whole reciprocating mass it very poorly balanced. Get it balanced and it will last longer and produce a bit more power (it's not wasted tossing around unbalanced parts). This is a good idea even for a street engine, as it will zip up past 4-5000 rpm in use.

Lighten it. From the flywheel to the excessive mass of the crank. The less mass you have to spin up the faster the engine will spin it up. The difference is appreciable. I've never had any trouble with idling or pulling away from stops because of lack of rotating mass.

Squish it. Higher compression means more power. True, you need to burn a higher octane gas. So you decide if you want to spend the money on the fuel. It's worth it to me, but not to all.

Shrink it. Turn the crank to fit the smaller diameter 1300 rods. Vizard, Kipping and others have done studies on this, as well run it. Reduces friction, reduces drag, reduces wear. All good things.

Stroke it. When you turn the crank down do it asymetrically and you can stroke the engine out to about 1700cc, as I recall. Kipping has done this. As I recall, the GT6 pistons work well with this modification.

Cam it. Fit the right one to your application. There is no one best cam. What cam has made me happiest of all the ones I've played with so far? The Isky ZM-66 I've got in one engine. That cam comes on nice! But there is no gentle idling either.

Port it. Generally not worthwhile, though it is the first thing most folks try wit ha grinder. The ports themselves aren't bad in stock form. Port matching generally gains one nothing. If you're building a real screamer, there is a good bit of meat in the heads for overall enlarging the ports quite appreciably. I sliced up a 1500 head just to see how meaty it is.

Bowl it. Now in the bowls, there's flow work that can make gains. Some very odd lumps and bumps and sharp edges that screw up flow. Work there instead of on the ports. But do it right, or you'll make things worse.

Valve it. As in a good valve job. 3 angle at least.

Rocker it. People love roller rockers. One of my engines came to me with them on it. Overkill for anything but the most extreme racing engine. But fun and not terribly expensive. Better, plug your stock rockers and redrill, giving more lift.

Zinc it. Ah, the terror of oils and EPA specs. It is a real problem, particularly with sharp ramped cams. So run good oil, like Gibbs, or even consider fabricating a roller lifter setup. It can be done. The more extreme your cam, the more you need to consider it.

Suck it. As in getting the air in. The Euro stock setup with a pair of HS4 SU carburetors is darn hard to beat for power, performance and economy. As in almost impossible. It will do it all with the right needles. Figuring out the needles can be an interesting experience. Folk love to genuflect to the side draft webber. Nifty, but expensive, and rarely setup right. But they look really cool. A dual set of DCOE will work better than the single, at the extreme. The single has problems with gasoline droplet seperation to the #1 and #4 cylinders. The ZS can be made to work well, but not as well as the SU. Interesting setup with a single 1-3/4" SU on certain ZS manifolds can yield very good results, as per John Kipping and a few others. I've built one, never run it. Fuel injection is also possible, as are motorcycle carburetors. Megasquirt has quite a following.

Blow it. The US spec 1500 exhaust manifold is terrible. Anything is an improvement, even a pacesetter header (which is a terrible header). Stahl is fantastic. Watch your collector shape more than pipe length, and quit worrying about equal lengths. Read some of Vizards studies on that. Don't neglect the rest of the system. The stock exhaust (sans cat) flows quite well for a stock or mild engine. Don't get lost in the mistaken thinking that noisy is stronger. Many do.

Spark it. The emissions distributor curve is lousy. Run an earlier distributor. Run a programable distributor (the 123 is pretty cheap), megajolt it.

Scrape it. Is your engine going to be screaming around the tracks at 6000 rpm and above quite regularly? A crankshaft scraper is possibly worthwhile. Oil ropes up remarkably. This sucks power from the wheels and doesn't help lubrication.

Undersize it. That stock alternator is big. So is the GM Delco many folk like to run. So is the stock 1500 crankshaft pulley. Go smaller. Less mass to spin, less mass to drag around.

Underdrive it. This works best with a screaming engine, not a street driven engine. But, no need to waste the power spining a water pump faster than it needs to go.

Disconnect it. No reason to spin things that don't need to be spun. From the air pump for emissions to the alternator. A clutch from an a/c compressor can make disconnecting things easy. But, almost no one does this, so it's pretty doubtful that it would really gain you much.

Lubricate it. Read the competition manual. Read Kas's first book. Then address the lubrication problems correctly. If you still go out and by an external oil line for the rockers you didn't read it correctly.

Cool it. More power is more heat. You'll need to deal with it.

MG it. As in bearings.

Pin it. Pin the thrust bearing. Consider the full circle unit from someone on the web (forgot who). The thrust bearing is a weak link. Treat it with care.

Clutch it. As in don't overclutch it. The American mindset is for massive clamping forces from the pressure plate. Those forces go right to the thrust bearing, wearing it out. Don't run a heavier pressure plate than is absolutely necessary. And almost always, the stock one is perfectly adequate to the job. Play with the disc instead.

Pan it. If you throw the car around on the track, you'll find yourself out of oil eventually. So widen the pan, install flappers, etc. All to keep the oil available to the pump, and therefore the engine.

Accept and understand it. When it's all said and done, you've got a punny little hunk of iron from England, built decades ago with then ancient thinking. After spending thousands of dollars to modify your Spitfire to an undriveable power house, you still don't have the power a stock Miata has. And the Miata idles and has air conditioning. So accept it. Accept the Spitfire for what it is.

Is there more that can be done? Sure there is. Carrillo rods, Honda pistons, custom heads, blowers, etc. As always, speed costs money, how fast can you afford to go?
How many miles per gallon do you get after those mods, 10? haha

yellowbookroad Avatar
yellowbookroad Gareth T
Somewhere in, Estonia   EST
1970 Triumph 2.5 PI MkII "Permanently NICKED Nickname"
You will find everything you want to know here
In reply to a post by oldag98 Come on fellas, Mike can't be the only one to reply...??? What have you done to upgrade your 1500's?

Just buy the book.



I routinely do these kind of upgrades in France,- in fact I have TWO to do this month, both to be sorted and delivered out on the road, and one being made out of entirely BRAND NEW parts for a chap in Paris called Sylvain.

The secret is really in a GOOD head, and of course faultless assembly.

I have spent several hundred hours researching how to make the head breath properly (via a flow bench), designed my own valves, designed my own camshafts, and got a 25% increase in breathing over any other work ever done before.
This means it's possible to get 100bhp/L out of a road engine (though not neccessarily a 1500 due to the longer stroke), so forget all those weird ideas from Kipping.

I was also the first to do an uprated close ratio gearbox for the Spitfire.
The car which used it won a major sportscar racing championship in the UK outright, and 25 years later is still running.
Kipping used to sell my transmissions for nearly a decade long run of uprated overdrive gearboxes, although this is scarcely known.

Everything you wanted to know here



Edited 3 time(s). Last edit at 2011-08-08 03:40 AM by yellowbookroad.

James5892 Avatar
James5892 Bruce Stribbell
Lake Orion, MI, USA   USA
Any of you guys have an opinion on roller rockers.

Getting prepared to send the engine out, I heard this motor requires min 3 mods.
1. Line bored crank
2. 3 oil holes at .25 need to be slightly enlarged
3. the cam has no bearings, need to be turned down and bearings set.

So I consider them the minimum up grades,
a. electronic distributor upgrade
b. Considering down draft Weber set up
c. Engine shop considers porting and polishing good idea

The engine mods I am considering are strictly from a smooth running low maintenance / reliability standpoint.

Roller Rockers, Opinions ??

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carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
If you're going to port and polish, you might as well get the larger valves. I've never tried roller rockers, so no opinion.



'S all for now
Vic

clshore Carter Shore
Beverly Hills, FL, USA   USA
IMHO roller rockers on a Spitfire are 'automotive jewelry' (i.e. Bling)

Pro:
-You get a bit less friction because the tip rolls instead of sliding.
-You get lower side force between the valvestem and the valve guide.
-reduces wear on the valve tips, allows you to run stiffer valvesprings, IF you need to.
-can run higher rocker ratio.

Con:
-Roller rockers, even aluminum ones, tend to have a bit more rotational inertia, since the heavy bits (roller, axle, support structure)
are at the very end, thus *lowering* the RPM where float can occur.
-Higher rocker ratio makes the rotational inertia issue above even worse.
-Based on real world experience of racers and hot rodders, roller tips have RELIABILITY issues, whether roller bearings or solid.

Let's examaine carefully how much sliding friction we are talking about:
Valve tip is 0.3125", but does not come into play.
The radius on the rocker tip is approx. 1/2", yielding an effective diameter of 1", circumference of 3.14"
The rocker rotates approx. 20 degrees max, so that means the tip slides a linear distance of: 20/360 * 3.14 = 0.174"
That's sliding distance to open, takes same distance to close, for a total of 0.348" per cycle.
A cycle takes two engine revolutions, so average sliding distance per revolution is back to 0.174"
At 8,000 RPM, 133.3 revs/second, that gives 23 inches/second.

Not much friction, even multiplied by 8.

OTOH, if bling is what you seek, go for it, nothing wrong with that, just be realistic about the reasons.

So, you can decide if it's worth it.

Carter



Edited 2 time(s). Last edit at 2013-01-21 09:05 AM by clshore.

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clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 863312 by James5892 ...
Getting prepared to send the engine out, I heard this motor requires min 3 mods.
1. Line bored crank
2. 3 oil holes at .25 need to be slightly enlarged
3. the cam has no bearings, need to be turned down and bearings set.

So I consider them the minimum up grades,
a. electronic distributor upgrade
b. Considering down draft Weber set up
c. Engine shop considers porting and polishing good idea

The engine mods I am considering are strictly from a smooth running low maintenance / reliability standpoint.
...

-For a 3 main crank, align boring is almost never needed on a street car. Check first, before spending the money.
-The center main oil feed needs enlargement, do the other 2 if you feel like it.
-Nothing needs turning down. DO NOT try to turn down a camshaft. The bearings fit into the current journals in the block, then you fit a small journal cam.

-Electronic distributor is a great upgrade over stock.
-I'm not a fan of the downdraft Weber, but it's worked for some folks. Dual SU's are the way to go. HS2 for a torque motor, HS4 if you do the internal work to support reliable high RPM operation.
-Porting/polishing is great if done right. The few folks that do it right are not cheap. Otherwise, you can just smooth out the rough bits in the passages. Don't attempt to remove any significant material, you will most likely make it flow worse. Kastner's books and Competition manual offer some proven advice.

You want reliability? While it's apart, pin the rear thrust washer (let the flames begin!).

90632D Avatar
90632D Fox Trapper
Various, USA   USA
Someone up above in the thread already mentioned that roller rockers were overkill for anything but the most extreme racing engines. Luckily, they are relatively cheap, so you gain nothing but it doesn't cost you much.

Learn about the crankshaft and the oil galley's to understand what could or should be drilled and plugged with regards to oil flow. Has to do with the split flow for the #2 and #3 cylinders. All of which isn't particularly necessary for a street engine anyhow. Not a bad idea mind you, but not crucual either.

Lots of fretting over a camshaft running without bearings. Yet motorcycles run camshafts directly in the aluminum heads, screaming them at much higher rpms, without much incidence. If you're going all radical, a set of replaceable bearings is nice. Use the earlier smaller journal camshaft and install bearings. Otherwise, run the stock sizes without bearings and make sure there is oil in the crankcase.

Electronic distributor. What do you mean? The late ones came with a GM HEI ignition already, which is darn good. What are you thinking of installing?

Downdraft Weber, why? What are you hoping to gain by running what is fundamentally a ho-hum smogged carburetor?

Porting and polishing is an interesting art. Done well it can gain nice things. Done poorly and you lose power. Most of the time it is done poorly. Especially when done without experiance and guidance to a specific engine.

clshore Carter Shore
Beverly Hills, FL, USA   USA
Running a steel journal in aluminum = OK
Running a steel journal in cast iron case = not OK.

The 'best' stock cam has small journals.

I took the 'Electronic Distributor' to mean elimination of mechanica advance.

90632D Avatar
90632D Fox Trapper
Various, USA   USA
In reply to # 863575 by clshore Running a steel journal in aluminum = OK
Running a steel journal in cast iron case = not OK.

OK, why do you say that? What am I not catching or thinking of?

I'm not arguing that a replaceable bearing isn't better, just that the stock non-bearing does in fact work.

carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
I don't see roller rockers as cheap either.
http://www.avrclassics.co.uk/_-Titan-Full-Roller-Rocker-Set-15-For-1275-Engines-_/product/?pid=48052

Of course these are midget rocker sets, but the triumph ones are just as much.



'S all for now
Vic

AJ6mod6 Avatar
AJ6mod6 Gareth T
Disabled Account, Antarctica   ATA
1989 Jaguar XJ40 "Animal2"
In reply to # 863575 by clshore Running a steel journal in aluminum = OK
Running a steel journal in cast iron case = not OK.

Camshafts don't have steel journals they are almost invariably made of CAST IRON.

In the case of the cams, they get chilled on casting so are VERY hard, then finish ground.
In the case of the journals they are NOT chilled so they are as soft as butter, but in classic DOHC & 16V engines have been finely polished with a small (low velocity) journal then run in nice soft alloy.

The Triumph engine is completely anti-mechanical by having soft cast iron running in soft cast iron with large diameter high velocity bearings.
It works OK most of the time but it's known for severe seizure on occasions wrecking everything.
It's why I routinely nitride them, it prevents this happening.

Here's one for you to think about...TASTY!


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