35 replies to this topic

[Minigman]

It was timed in accurately. The chap that did the work builds race engines so I've no reason to doubt him. It's been back in to him to be checked over. I'm just wondering if the Weber DCD is letting it down. Plumbed in the heated inlet, fitted electronic fuel pump and regulator set to 2.5. Taped up the front of the K&N to stop the icing issue. It goes ok but not as good as previously owned cars. Went small bore instead of the 1380 route this time as I remember my old 998 in the 80s with a stage one kit went like the clappers. I'm just not feeling it with this set up sadly. Might need a trip to Slarks for further investigation.

Edited by Minigman, 24 March 2017 - 05:27 PM.

[sonikk4]

Have you done a compression check to see if all is well?? Low mileage or not, worth a quick check.

[hhhh]

I can't see getting the benefit of a 12G295 with stock exhaust ports no matter how high you lift the valves because they're the major restriction.

[Minigman]

Compression checked out fine. I know the engine as it's out me old car and I drove with it for a year before fitting a 1380 and subsequently selling that car. Bought a mk1 with the money and then bought another 80s mini when I realised my mk1 was now too precious to drive about as a daily. I never learn!

[carbon]

Would have thought a decent fast road 998 with 266 cam would be good for 60-65 bhp? The max torque also seems to be well up the rpm range, would have expected peak before 4000.

 

Have you measured the actual valve lift? 266 is low on lift at lobe. For instance if you use A+ rockers with 266 in a 1275 it won't breathe properly at high rpm.

 

If you're getting carb icing problems with the Weber a change to SUs makes sense. A HS4 on a decent alloy manifold with water heating connected should do the business.

[b_sdaddy]

It was timed in accurately. The chap that did the work builds race engines so I've no reason to doubt him. It's been back in to him to be checked over. I'm just wondering if the Weber DCD is letting it down. Plumbed in the heated inlet, fitted electronic fuel pump and regulator set to 2.5. Taped up the front of the K&N to stop the icing issue. It goes ok but not as good as previously owned cars. Went small bore instead of the 1380 route this time as I remember my old 998 in the 80s with a stage one kit went like the clappers. I'm just not feeling it with this set up sadly. Might need a trip to Slarks for further investigation.

Minigman, agree! My 'Red Hot' with a Stage One, was great around the streets of London, back in the 90's.

 

Q. I have a std. 998 from '78 with 50k. It's been on a rolling road, just to get it tuned right & I was told it was a 'tired' engine & adding a Stage One, might have a knock-on affect to vunerable components. Asking for a second opinion, and by no way, undermining the credibility of the initial opinion, what do you think.? Save up a grand or two & get it re-built, or chance a Stage One..?

 

 

cheers

[hhhh]

Stage one it. Mine has 80K and I've been driving it hard for three years and it's taking it fine. These are pretty tough motors and you won't be making enough HP to do any significant damage unless it's really knackered already, assuming your oil pressure is reasonable and blow-by is low.

[tiger99]

The 998 in standard form is the toughest of the A series engines, almost unbreakable and with a long life given proper maintenance. If you want to boost it's performance, I would just say go for it! Other engines such as the 1098 are much more fragile and don't like high revs due to the longer stroke.

If you do manage to break it, they are really cheap to replace compared to a 1275. Lots of practical things in its favour. Have fun! (If it isn't fun, you need a new hobby...)

[whistler]

If you have the manifold heating pipes connected there should be no icing at all, even with a DCD. Do you have a cork-like 5mm gasket between the base of the carb and the manifold?

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Edited by whistler, 25 March 2017 - 04:39 PM.

[b_sdaddy]

Stage one it. Mine has 80K and I've been driving it hard for three years and it's taking it fine. These are pretty tough motors and you won't be making enough HP to do any significant damage unless it's really knackered already, assuming your oil pressure is reasonable and blow-by is low.

Oil pressure's fine.

 

what the hell is blow-by.?

[Spider]

 

what the hell is blow-by.?

 

 

Combustion Gases that are 'blowing-by' the rings.

[Minigman]

The heater hoses are now connected via the inlet manifold. Icing is better now so doesn't bog down at full throttle. Still only getting 49.4bhp at 5500rpm on the RR. Torque is 54 lb ft at 4400rpm. Maybe that's all I'm going too get. If the DCD is as good as an SU or twin SU then not much point in changing it.

[Minigman]

The heater hoses are now connected via the inlet manifold. Icing is better now so doesn't bog down at full throttle. Still only getting 49.4bhp at 5500rpm on the RR. Torque is 54 lb ft at 4400rpm. Maybe that's all I'm going to get. If the DCD is as good as an SU or twin SU then not much point in changing it.

Edited by Minigman, 25 March 2017 - 08:42 PM.

[Cooperman]

Are you sure the CR is 9.8:1? Who measured it and who skimmed the head to get the right chamber volumes?

A 998 with that sort of spec should give c.60 bhp at around 6000 rpm.

I guess it could be a mis-match of components with the carb being the chief suspect.

Is the distributor curve right for the engine spec?

If you fit a pair of HS2 carbs it will be a 998 Cooper spec plus, so the bhp should be over 55. The induction system is suspect here. There were no carb icing issues with twin HS2's and the manifold was not heated.

[Minigman]

Hi Cooperman. Done by a local engine builder who's been preparing race engines since the 60s, so I've no reason to doubt his abilities. He's built previous engines for me and they've been very good and performed well. Do you think it's possible the DCD Coujd be performing this badly?