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Second Motor, looking to rebuild it

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Will_Ringrose

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So, I have picked up a second Motor, its in really ruff shape, looks like its been outside in the weather for years... i am going to fully strip it down and rebuild it. now the question is how to get more power out of it :devilgrin:

Its a block for a late 73 GT6. I don't care about having any emissions stuff on it. I am just looking to get this little guy putting along nicely.

Someone before said that there was way to get about 150 HP out of the inline six. what parts would I need to get this done?
Any advice on what to stay away from? And anything i should be worried about using it as a daily driver?

Tanks a lot
Will
 
Before building the motor, make sure your car will handle the added horsepower. That's a lot of added strain to the drive train and everything attached to it.

Be ready to spend a few thousand dollars or more. Machine work will be in excess of a thousand with balancing everything, boring, shaving(keep CR under 10.1 to keep using pump gas, lightening.... New pistons, all new bearings, distributor recurving, carburetion, header and probably exhaust, oil pump, push rods, cam, new flywheel or stock one lightened, rocker shaft and rockers rebuilt or replaced, valves, springs, and the list goes on. If you can't do it yourself, you will also have to pay a builder.

There are several suppliers of performance parts. Richard Good at www.goodparts.com carries a number of parts for the 6 cylinders.

Your mileage will drop a bit.

Take your time and research what you want to do. Make up a game plan, there's a lot involved. Be ready for setbacks...I had a summer of them which left my TR6 undrivable most of the time.
If this will be your only car, wait until you have a daily driver before you start tearing into things, unless you don't mind walking. There is a lot of problem solving when you modify that much.

You will probably find that you'll need to modify the suspension so handling will be on par with performance.

If you do it and haven't lost your sanity and spent every penny in site, you WILL have a ball driving once it's completed.
 
This will be an expensive goal. Supercharging will help, but that number will only come with a lot of dollars. And will most likely be at the flywheel, not at the rear wheels, without help in the breathing department.

Take a look at my site and what I did to my engine and the actual dyno results.

Am I disappointed? No way, I'm very happy, as my car runs great and has a ton of power, yet is very good in the city traffic. It's just that the 150HP PI mystique was probably one more of creative advertising on Triumph's part than reality.

If I were to do my again, I would do everything that I did, except the triple carbs and I would have gone with the supercharger. Then I would have been at 150 or close at the rear wheels.
 
I also spent a lot on my engine and although happy with it if the goal would have been to get the most HP for the dollar I would have also went with a SC.

Also, the GT6 engine should have 3/8" less stroke. So a different crank is probably in your future.
 
As stated above, the down side for you on ultimate power production is that you are down 500cc from the bigger 6 that made the claimed flywheel 150hp. Displacement does matter. The upside is that the 2.0 will rev easier and higher if you want it to. It would be interesting to know if the Moss supercharger would fit under the GT6 bonnet. :computer:

The other thing to remember is that the the GT6 is MUCH lighter than the TR250/6 so it doesn't really need that extra torque. The stock trans and diff on the GT6 are supposed weakspots as well. Reportedly barely being able to handle the stock power of the 2.0 I6. I do know of a few GT6 racers that will disagree with that with one warning. Don't jack rabbit start or dump the clutch and you'll be fine. Roll on the power from a stop gradually and once underway you can add power rapidly with less shock to the system.

Otherwise, there is no real secret to making power. Maximize the efficiency of air/fuel in and out. Naturally aspirated equals cam/compression/air flow (intake & exhaust). It's always a balancing act for power and reliability though. Keep youg goals realistic for your desired use and you should be okay with it.
 
And from a reliability point of view I can tell you this from recent experience.
I had a highly modified TR6 engine that by all descriptions was a reliable engine....for 20k miles. Then the combination of modifications took their toll.
Although the engine started on first crank, and ran like the devil until the day I tore it down..it was a timebomb. Tough little engines that will run reliably for thousands of miles despite having potentially destructive flaws in the modification designs or combinations thereof.
Don't get too carried away; racer's are risk takers by nature and don't generally expect the same longevity from their highly modified engines as the average enthusiast might.
You might be better off with a different engine altogether, if you want to push the envelope.
Just my 2 cents.. sporting a whole new attitude.
 
swift6 said:
It would be interesting to know if the Moss supercharger would fit under the GT6 bonnet.
Click to expand...

Bennett French used to offer a supercharger he claimed would fit a GT6...
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Tough little engines that will run reliably for thousands of miles despite having potentially destructive flaws in the modification designs or combination's thereof.[/QUOTE]

Ken, there is a fine line on any engine project between being safe and pushing it just a little to far. I chose to stay safe with stock rockers, milder cam and moderate compression. But I went with full balancing, cam bearing and line boring of the block, custom made thrust washers and aluminum flywheel with every part that I could add made for longevity and reliability (ARP studs and bolts, silicone v/c gasket, front engine bar, updated new alternator and wiring and on and on. I may have 15 less HP than others, but I'll probably never live to see it torn down again.
 
I think TR6BILL thought he had done everything right the second time around. He had some pretty well respected folks advising him. I guess you never know for sure once you start deviating from stock.
Perfection can sometimes be elusive under the best of circumstances.
 
OK OK so after reading though the post here maybe 150HP is a goal a little out of my reach... But as far as making it a reliable motor with better than stock power? I still wanna keep it sane. I am not looking to be a power house on this car (maybe with the GT6 MK2 I found and am working on saving from a clasping shipping container) but this car I wanna be able to take on road trips with my girl friend cross country. So something with a little more pep, it maybe pulling a very small tear drop camper trailer. Something like this maybe. This project will be while off still. I am just getting some ideas and a general understanding of what I have gotten myself into.

thank so much for the info thus far.
 
Will,

I have looked into trailers for my TR6. I have the smaller one which is an old Coleman brand. And a photo with a Teardrop. The factory recommended towing cap for the TR6 is 2,000 lbs. They do recommend trailer brakes over 700 or 800 if I remember.

I felt the Teardrop was too wide and clumsy for the TR6. Also at around $5,000 a little too much money, actually a lot too much money.

I decided to paint the Coleman and put new lights on it and use that. With the money saved I can pay for a lot of motel rooms which will be more comfortable and have other amenities to make the trip more enjoyable.

It will also be much easier to make a suitable hitch for the lighter trailer.
 
Tom,

Thank you the photos. i was not aware how big they really were, or how high the hitch would be on them.

But I am an old Eagle Scout, I think just having more than a tarp to lay on and a lean too is high living.
 
Will,

My wife and I used to do a lot of camping. We kept all our equipment in that little Colman trailer. A 10x10 Eureka tent, 12x12 Eureka screen tent, sleeping bags, air mattress, stove, lanterns and all the other things we liked to have, even a couple folding chairs. And it pulls very easy. What more would you need.

At least a dozen years ago we drove our Saturn with that trailer behind and toured the Ozarks. Stayed at Montauk State Park in MO that trip and did some Trout fishing. We got 35mpg with the trailer and our gear. And had much nicer accommodations than the Teardrop would have provided.
 
trailers2.JPG
 
Just got through having a 72 gt6 engine rebuilt.
-Lose the domed pistons and go with the earlier flat tops (counterintuitive I know, But gives better flame travel)
-Get the bigger exhaust valves with inserts
-have cam bearings installed
-balance reciprocating assembly
-get head milled
-roller rockers are nice,but expensive.

Jim
 
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