18 replies to this topic

[racingbob]

I thought i would share my engine spec, reason for doing so is you can get good power 

 

for fast road without spending a fortune and may give you some ideas

 

my engine has just been on dyno at Slark giving 80hp at 5800 and 80 torque at 4700

 

the engine is a 1275 mg metro engine

 

a very nice new stage 3 head, compression around 10.1

 

block was honed and new rings

 

crank grind to 10 new main bearings and big ends new thrusts

 

bottom end was all balanced

 

original mg metro cam and followers (i like the mg cam but havent tried others similar so maybe more power there ) )

 

dizzy is a lucas 64d modded curve by AC Dodd, and 40,000 volt coil bp7es plugs

 

new oil pump and water pump with 70 lb oil pressure hot

 

timing chain ( but only dots lined up on timing gear so maybe some more power here )

 

original rocker gear but new shaft, tappets set to 14 and 16 ex

 

standard clutch  but balanced with new diaphragm and turbo plate

 

valvoline VR1 20 50 changed at every 2000 miles 

 

gearbox had new bearings and diff rebuilt with moly pin and 3.44 dif

 

hif 44 modded to vizard spec  with med substack and ramair filter and mg metro manifold

 

maniflow stage 2 lcb and twin box (but larger mid and rear for quietness maybe loosing some power here )

 

 

am realy happy the way car performs its ideal for b roads where i use it 2 or 3 days a week

 

the engine was actually built 5 years ago now done 21000 miles and should last a bit 

 

 

but the head and modded carb only just fitted so had to go back to dyno

 

the head and modded dizzy certainly made a noticeable difference

 

have probably missed some things done but gives the main info

 

 

 

 

 

 

[Carlos W]

I reckon there'd be good gains from properly degreeing in the cam

[neal]

Nice interesting read Bob and quite rightly good gains if you're on a budget without sacrificing reliability.

 

I think Carlos has made a good point there.

[neal]

Has anyone done any amount of testing on this method of cam timing, if so what was the results and what kind of power losses?

[Cooperman]

That will make for a really nice road car. It will drive smoothly with good performance for an old car.
More accurate cam timing might gain a bit, but on the other hand it might be quite accurate as it is. I put a new duplex kit on a totally rebuilt 998 last week starting out with it dot-to-dot and it was within 1 degree of nominal.
The 3.44 FDR is ideal as it will rev well

Enjoy 😎

[racingbob]

That will make for a really nice road car. It will drive smoothly with good performance for an old car.
More accurate cam timing might gain a bit, but on the other hand it might be quite accurate as it is. I put a new duplex kit on a totally rebuilt 998 last week starting out with it dot-to-dot and it was within 1 degree of nominal.
The 3.44 FDR is ideal as it will rev well

Enjoy

yes i couldnt be much more pleased realy, obviously you always want that just bit more

 

i remember having a e type jag in 1977 and after a month wanted just a bit more go

[Cooperman]

With modern cars it is possible to re-programme the ECU to give more top end power and, often, more mid-range torque.

But with 50+ year old classic cars basic improvements can be made by, first of all, 'blueprinting' so that the engine is built to optimum tolerances with cam timing, ring gaps, running clearances, etc., all set to manufacturers design figures. Then, secondly, improvements in gas-flow, compression ratio, ignition advance curve accuracy, carburation flow and exhaust efficiency will all yield more overall without any significant loss of bottom end. That is really what you have with the cam you are running and the other sensible modifications and improvements.

Anything further will be a trade-of between bottom end torque and top end power, thus giving the need for a lower FDR to use the 'hotter' cam as it should be used and accepting higher revs at cruise and when using all available power (and if you ain't gonna use that power there is not a lot of point in paying to have it!). In turn you accept a shorter engine life due to the higher revs being used and the drop in fuel consumption.

The only other way to achieve more 'grunt' without too much loss of bottom end is to go to forced induction which, in turn, brings other issues like transmission strength and heat dissipation, but that's another issue from what you are doing.

[InnoCOOPER]

I have a similar spec and had it on the rolling road at Slarks last week.

 

I have a NOS 1275 Block, Kent 266 cam, Head was modified by Brett Simms (10.1 CR), Lightened Flywheel ( not severely) and a Aldon Yellow Distributer.

 

I dialed in the cam within 1 degree using offset key.  I am running a simplex setup with a IWIS Chain from Claver ST.

 

The engine has been rebuilt with new cam followers, oil pump, pushrods, timing chain etc etc as I thought if im doing it i might as well do it properly. The engine covered approx 1500km since the rebuild.

 

It was only pushing out 66.4hp at 5299rpm  with 71 IIbs/ft at 4173 rpm which was a little disappointing.

 

 I am running std twin 1.25 SU's in the std airbox and a cooper freelow manifiold with twin box RC 40 which isn't really maximising the engines potential.

 

It was running very rich and on taking the out the std minispares paper filters it was noticed how compressed they were and also how dense the inside of the filters were.  Running it without filters to try and see the gains it immediately gained approx 5hp. It was obviously running too lean but showed how the std air filters strangled the engine.

 

To get the best out the engine i have really got to go to twin 1.5" or a single HIF.  A LCB would help as well.

 

I have put some K&N Filters in the std airbox and that has made a difference.  It is running leaner now.

 

Attached is my results from the dyno.

 

 

i presume that the figure is at the wheels?

Attached Files

•  Spratley Rolling Road Results.pdf   212.81K   45 downloads

Edited by InnoCOOPER, 28 September 2016 - 08:31 PM.

[Cooperman]

That looks about right. With that spec around 85 to 88 bhp at the flywheel should be expected.
The only strange thing is that the 266 cam in a 1275 normally gives maximum bhp at around 5500 to 5800 rpm, so maybe there is a bit more to come by some further improvements to induction, exhaust and/or ignition systems.

[InnoCOOPER]

That looks about right. With that spec around 85 to 88 bhp at the flywheel should be expected.
The only strange thing is that the 266 cam in a 1275 normally gives maximum bhp at around 5500 to 5800 rpm, so maybe there is a bit more to come by some further improvements to induction, exhaust and/or ignition systems.

 I think so as well.  Better intake with larger carbs and better inlet manifold coupled with a LCB should help i think.  The car goes well but i fell it has more to offer.   When it was at Slarks on the Rolling Road it was runnning rich due to the filters restricting airflow.

 

Also it is running std minspares forged rockers which i think could be improved upon. 

Edited by InnoCOOPER, 28 September 2016 - 08:44 PM.

[Cooperman]

You could gain maybe 2 to 4 bhp above around 5000 rpm with 1.5:1 rockers, but at the cost of some lower down 'grunt'.
The other suggestions sound good, especially bigger carbs and, ideally, a Maniflow LCB and a Maniflow twin box 1.75"
exhaust system.

[Spider]

I reckon there'd be good gains from properly degreeing in the cam

 

Only if it's 'out'

 

 

Has anyone done any amount of testing on this method of cam timing, if so what was the results and what kind of power losses?

 

I have done a fair bit of testing in this regards. On one particular engine - fitted with one of them coff coff quality Kent Cams, it just simply wouldn't do or behave like it should have, we tried Cam Timings from 92 degrees right through to 120 degrees, in 2 degree increments, to see if we could 'dial out' the issues and 'dial in; what it should have been, but was just a waste of a couple of days.

 

None the less, depending on the engine spec, the characteristics of the engine can be 'varied'. I wouldn't classify any of them as 'losses' if the Cam timing is generally kept within the ~ 98 to 118 degree 'zone'.

 

Generally speaking, advancing the Cam Timing will improve the low RPM Torque and bring hotter Cams 'on the Cam' at lower revs. Likewise, Retarding Cam Timing, pushes the 'Power Band' higher up the RPM Range, but there are limits.

 

For how I personally like my Minis and Mokes to 'drive' in nearly all circumstances, I tend to fit and time the Cams with Advanced Timing.

Edited by Moke Spider, 28 September 2016 - 09:43 PM.

[neal]

It would be nice to see more engine/transmission specs on here, this would make a fantastic library for others to reference prior to spending their hard earnt cash.

[Spider]

It would be nice to see more engine/transmission specs on here, this would make a fantastic library for others to reference prior to spending their hard earnt cash.

 

I'll cautiously agree, though, having a 'box of parts' is one thing, but how they are put together is another matter again.

 

You can always brows through the WinSU Program for a guide

 

BUT, I'd suggest not fixating too much on that peak number, to get to that 'number' you need to 'drive' up to it and seriously, how often is that 'peak number' called on or used?

Edited by Moke Spider, 28 September 2016 - 09:57 PM.

[neal]

Nice info there Moke Spider, but what I meant in my earlier post was has any one done any testing to see how accurate the 'Dot to dot' timing method is and how far out has it been measured.