8 replies to this topic

[AsR@F]

hii friends..

know i use GT 1275 but.. not all the original part GT1275.i mix A+ & Aseries. only the block gt 1275

this year i upgrade my engine.only 7500 rpm can go full throltell. i can't exept this perfomance.i expect can get 8000 rpm. this i list part i use.

Head 1300 metro A+ (skim head)
rocker 1:3 ratio
block GT1275(skim Block)
+0.040 piston
metro A+ crank shaft
Kent cam 286 SP.M
duplex timing gear
3:44 gearbox ratio
standart flywheell 1.3
carburator HF6 use ramp pipe

all this part i use know in my car.

from what i use know,how bhp for this engine?

i hope all my freinds can give idea & suggestion.

thank you.

[NunoGT]

Are you going to use it for racing?
That cam doesn´t has its use in the 2000-7000 rpm range?! Around these figures at least.

[Jammy]

To get to those sort of limits I would look at getting a centre main strap, fitting double valve springs, and having your crank worked, I think I would also look at uprating the rocker assembley.

[AsR@F]

Are you going to use it for racing?
That cam doesn´t has its use in the 2000-7000 rpm range?! Around these figures at least.

some time i use for racing just for fun.my car can going to 7500 rpm full throtel, my father car use the same cam MD286ssp but can get 8000-8000rpm full throtell.

what the probblem know?

because some time i want to challange my father car.

any idea to impove?

[Guess-Works.com]

You wont get near 8k without, a Center mainstrap, a better cam (nearer 290-300 degree duration) and probably high cr... what sort of pistons/rods are you using ?

Or...

Putting a short stroke crank in.

Please remeber this is a 1950's pushrod design engine, not you modern Vtec/VVC Overhead cam unit.....

Race engines which do the 8000 upwards rpm, cost 10's of thousands to build

[AsR@F]

You wont get near 8k without, a Center mainstrap, a better cam (nearer 290-300 degree duration) and probably high cr... what sort of pistons/rods are you using ?

i use original rods GT1275 & +0.040 piston

a Center mainstrap, a better cam (nearer 290-300 degree duration) and probably high cr...

what u means?can u axplaine detail to me.

thank you.

[The Matt]

A centre main strap is a method of strengthening the central main bearing journal on the crankshaft for higher revving engines. Basically you machine the cap flat and fit one of these:

strap

The CR is the compression ratio. You can achieve a higher CR by having metal skimmed off the head or by fitting different pistons.


A 286 cam like yours denotes the duration of the camshaft (how long the valves are in their open phase for) something like a 296 may be more suited for a higher revving engine, but you may lose some of the driveability at lower revs.
It might not be as easy to drive in traffic or at slower speeds. :wink:

Edited by mini mad me, 18 November 2005 - 03:15 PM.

[Guess-Works.com]

As standard A series engines have a cast center main bearing cap... the more you increas power and rpm, the more strain is placed on this cap, to the point that the crank will basically break it in two, thus endeth engine... .

To circumvent this, performance engines should have the maincap machined flat and a Steel bar is then used to provide additional support to the cap. In standard form the original two bolts holes are used, but in realy high spec engines then this is replaced with a whole new cap which utilises 4 bolts.

The duration of the cam is the time at which the valve is open, a 286 has a 280(ish) degree opening.

CR - Compression ratio... shoudl be looking at least 10:1 if not higher

Pistons, why type , ie are the cheap sh*te pistons or high performance ones..


The other thing is, if you run at 8k rpm... what sort of life do you want out of your engine... how often do you want to be rebuilding it.. ???

[AsR@F]

tHANK YOU for your information.

at malaysia got dyno test but it is very expensive for 1 time test.

from what i use know,how bhp for this engine?