6 replies to this topic

[jime17]

Hi all.

1990 998cc bog standard.

Just got my new engine running. Transferred manifold, carb, distributor, alternator, fuel pump and starter motor from my 998 auto.

I set the timing to 8 btdc static and cranked with the king lead off to get the oil pressure up.

I cranked some more because I forgot to connect the -ve to the points. Once I did that it started easily.

I need some advice on getting it running properly now. Its idling fast and a bit unevenly..

I've not touched the carb settings from when it was on the auto and I'm guessing I might need to fiddle with throttle linkage as well.

What process do you folks follow when setting up a 'new' engine?

Cheers.

[Its a min]

You've not said which carb but assuming it's an SU carb, the following should help. Just use the index on the left to select carb.

 

http://sucarb.co.uk/technical/

[Retroman]

Just found the thread...did you get sorted ?

[jime17]

Yes partly. I'm trying to sort out an annoying misfire now. It idles ok but with a noticeable 'blip' every 4 or 5 sec.

The timing is at 10 degrees with the vac disconnected and plugged.

The plugs are less than 100 miles old.

I guess the dizzy cap and leads are next to try.

One question though..I've not touched the hs4 jet setting since the carb was on the other engine and it was running quite lean according to the mot print out in October. (About 1.5% CO) I never changed it as it ran ok and I knew I was swapping engine.

I transplanted the whole manifold and carb as one to the new engine so expected it to remain lean but if anything I'd say it seems a bit rich now. The plugs are a bit on the sooty side which can't help the misfire..... could the new engine have different properties I.e different c.r or maybe the old one had an air leak between head and manifold that made it lean on that and now rich on the new one?

Admittedly I've not taken it on a good run yet.

Sorry for the waffling. I'm just thinking out loud and any input would be much appreciated...

[Retroman]

Ok Could be a few things

 

Which plugs are you using ? and did you gap them ?

 

Should be BP5ES NGK's gapped at 0.025"

 

Have a look at what needle and is it a HS4 ?  1 1/2 inch carb ?

 

I suspect it may be the needle as the auto would be different, would explain why it was lean before and the plugs are sutty now

 

The jet and needle may also be worn [assuming its a swinging needle]

 

You can try setting the idle fast at say 1000 revs and using the lifting pin lift the carb piston,

 

If it dies its lean, if revs rise and keep rising its rich 

 

You can then adjust the mixture nut up to lean it out....[assuming rich]

 

aiming for a small rise in revs and then settling back down 

 

But if the jet and needle are worn the mixture may well then be lean higher up the revs

 

Colourtune or exhaust gas anayliser needed really

[cal844]

I use BP6ES plugs with resistor leads on all my A+ engines

Edited by cal844, 16 December 2018 - 12:25 PM.

[jime17]

They are 6es but I can't remember if the leads are surpressed or not. I've got an old set of champions I can swap in.

Yes it's a hs4 with wax stat. It has no lifting pin which makes it awkward... AAC needle if memory serves. I couldn't see any noticeable wear on the needle when I checked a month or two back.

I reset all the valve clearances to 0.3mm yesterday but no change. Still the blip at idle . I've also re sealed the downoipe to exhaust union.

Wondering if the fuel might be dirty.

I drained the tank as I split the rubber section near the bulkhead when removing the old engine and poured a few litres back in to get it running.

Maybe it stirred up all the crud in the bottom of the tank.

Its got a 59d dizzy with power spark points conversion. I'm pretty sure that's ok.

The coil is a col201 which is 12v and I bypassed the ballast wire years ago.

It pulls well though. The missing doesn't seem to affect it.

Edited by jime17, 16 December 2018 - 03:36 PM.