14 replies to this topic

[cal844]

Hiya folks,

My 998 went for an MOT

Standard A+998 fitted with HS4 and a 65DM4 dizzy

we have had to change the distributor as there was water(condensation) getting in(slight rust around the baseplate) due to a thread being stripped on the cap retaining screw


Also when I took up the rotational play in the shaft it wouldn't spring back(advance weight issue?)

We were thinking of getting a refurbishment on this dizzy ( a quote would be good, via PM)

Thanks again!

Cal

Edited by cal844, 26 February 2017 - 01:09 PM.

[petey81]

Hi contact Ac Dodd.

He did a perfect job on mine and re curved it.

[cal844]

Hi contact Ac Dodd.

He did a perfect job on mine and re curved it.

Wouldn't think it needs recurved, if you don't mind me asking, how much?

[petey81]

It would as the 998 never used the 65md4 so the curve is incorrect.


I will PM you.

[whistler]

65dm4 is a 1275 dizzy. Mine had a stripped thread on the cap too; I tapped a slightly bigger metric thread and used a machine head bolt through the cap. Worked fine ever since.

[cal844]

65dm4 is a 1275 dizzy. Mine had a stripped thread on the cap too; I tapped a slightly bigger metric thread and used a machine head bolt through the cap. Worked fine ever since.

It has two cap head machine srews fitted bit one doesn't tighten up, so will need to be repaired

[cal844]

It would as the 998 never used the 65md4 so the curve is incorrect.


I will PM you.

I am aware they are a 1275 dizzy.


Curve is good for this engine, the car pulls very well indeed and will sit at 70mph all day.

[KernowCooper]

Cal the 1275 distributor has more advance then the 998 engine and is usually a bit aggressive for the 998 engine as it goes up through the rev range, be interesting what weights yours has inside? been recurved already ?, whilst the engine may appear to run ok its not running at its optimum, and the main problem we see now is with the far east distributors which they say fits all A Series they don't! I'm waiting for the chap who buys one for a 1098 and the repair bills/ solicitors letters after

[cal844]

Cal the 1275 distributor has more advance then the 998 engine and is usually a bit aggressive for the 998 engine as it goes up through the rev range, be interesting what weights yours has inside? been recurved already ?, whilst the engine may appear to run ok its not running at its optimum, and the main problem we see now is with the far east distributors which they say fits all A Series they don't! I'm waiting for the chap who buys one for a 1098 and the repair bills/ solicitors letters after

We were thinking of stripping it and transferring the good parts(weights vac advance etc)to the one which is currently fitted

[1984mini25]

Cal the 1275 distributor has more advance then the 998 engine and is usually a bit aggressive for the 998 engine as it goes up through the rev range, be interesting what weights yours has inside? been recurved already ?, whilst the engine may appear to run ok its not running at its optimum...

 

That maybe so, But I've been running the same dizzy on a 998 for the last 11years with no issues, other than cheap ignition modules. Yes the curve is wrong, the vacuum advance has been blanked off and I've still got standard weights in mine. But there's no way I'd swap it for a points dizzy or one with a electronic conversation. The last time it was on the rollers it was only losing out a few bhp at the top end, but being an asthmatic standard 998 driven on the road it never gets revved that hard anyways.

[blacktulip]

I sent my 25d to h&h ignition and it came back brand new plus recurved to my new spec.

[tiger99]

The Distributor Doctor is the best place to go for such things.

[KernowCooper]

 

Cal the 1275 distributor has more advance then the 998 engine and is usually a bit aggressive for the 998 engine as it goes up through the rev range, be interesting what weights yours has inside? been recurved already ?, whilst the engine may appear to run ok its not running at its optimum...

 

That maybe so, But I've been running the same dizzy on a 998 for the last 11years with no issues, other than cheap ignition modules. Yes the curve is wrong, the vacuum advance has been blanked off and I've still got standard weights in mine. But there's no way I'd swap it for a points dizzy or one with a electronic conversation. The last time it was on the rollers it was only losing out a few bhp at the top end, but being an asthmatic standard 998 driven on the road it never gets revved that hard anyways.

 

But I've been running the same dizzy on a 998 for the last 11years with no issues

Other than not running at its optimum on bhp/torque through out the rev range, and the auto box is masking the issues of the wrong curve, if you ran it on the rollers through the rev range the correct curve would show a increase, Any distributor can be dialed in max power at 4000rpm, its whats going on every 100rpm through the range where benefits of the correct curve is found.

[Spider]

 

 

Cal the 1275 distributor has more advance then the 998 engine and is usually a bit aggressive for the 998 engine as it goes up through the rev range, be interesting what weights yours has inside? been recurved already ?, whilst the engine may appear to run ok its not running at its optimum...

 

That maybe so, But I've been running the same dizzy on a 998 for the last 11years with no issues, other than cheap ignition modules. Yes the curve is wrong, the vacuum advance has been blanked off and I've still got standard weights in mine. But there's no way I'd swap it for a points dizzy or one with a electronic conversation. The last time it was on the rollers it was only losing out a few bhp at the top end, but being an asthmatic standard 998 driven on the road it never gets revved that hard anyways.

 

But I've been running the same dizzy on a 998 for the last 11years with no issues

Other than not running at its optimum on bhp/torque through out the rev range, and the auto box is masking the issues of the wrong curve, if you ran it on the rollers through the rev range the correct curve would show a increase, Any distributor can be dialed in max power at 4000rpm, its whats going on every 100rpm through the range where benefits of the correct curve is found.

 

 

Not something I'd recommend and it could be or could have already done damage. Slightly over-advancing for extended period can have an effect of 'chipping' the piston crowns over time, in doing so, lowering the CR and so kinda saving itself. It's far enough off to be on the verge of this occurring, though depends on how it's been initially timed in.

 

The curves for comparison (these are in Distributor angles and RPMs - double them for Engine Numbers);-

 

 

So right on the usual cruising RPMs of 2000 - 3000 RPMs (1000 - 1500 on that chart), it's WAY off.  

 

Doesn't sound too sensible to me.

[1984mini25]

But my cruising revs because of the 2.9 diff work out at in 4th, 1500rpm at 30mph, 2000rpm at 40mph and 3000rpm at 60mph.