Process of Elimination

[zeds4ever]

Mate suggest you sort your carbie's out first . Would liken it to having your shoe's on ass about & trying to run in them. Ok while your standing still if you get my drift. Then go from there.

 

                                                                                                Regards: Alan.

[luvemfast]

Carbies first.

But still read the plugs anyway as you may have a problem anyway.

[salty]

if the front carbie is the cause for the low compression, then #3 wouldnt be that high and carbies dont give compression.

if you can hook up a vac guage to the front carb with the engine running  that might give you an indication of the problem.

my guess is  head gasket as compression is low between 1 an 2 or broken rings on 1 an 2

[bullzed]

The reading doesn't matter.  It's the difference in the readings that matter.  If they all end up much closer in value, it indicates a ring failure in the cylinders that were already low.  If they all go up by about the same amount, it indicates a valve issue. 

 

Just give each cylinder a good squirt and give it a try.

 

Ahhh okay. It's a comparative measure, makes sense now, cheers

 

I've got a VRS set coming in today and I'll do a valve grind and see if we can get this thing running. I've also sourced an MQ manifold and single 2 barrel to see if it's the carbies playing up as well. But one thing at a time. Cheers for all your suggestions.

[luvemfast]

I've got a VRS set coming in today and I'll do a valve grind and see if we can get this thing running. I've also sourced an MQ manifold and single 2 barrel to see if it's the carbies playing up as well.

I'm a tad confused

If you're doing a valve grind, you're taking the head off? correct?

What are you trying to achieve from a valve grind? Its not going to magically fix this problem.

Have you pulled the plugs out to read them yet?

Maybe its time to get a mechanic to look at it if you can't diagnose the cause?

 

[Linton]

have to agree with the last post, very easy to check with out pulling the head,, before you take off the head do a compression test if the cyl is low then squirt some oil into the cyl through the plug hole about a teaspoon

and re-test

if the compression comes up it needs rings

if the compression stays the same then it is most likey valves

 

[zedrally]

Just a long shot, but as your still using points, it could be the condenser.

The Gemini problem I've experienced first hand and it was a head scratcher, very frustrating...very much like this.

 

Good luck..

[bullzed]

Yeah I'm going to do the wet and dry test first. If it's valves, I'll do a valve grind and this will also allow me to see if it's also a blown head gasket between cylinder 1 and 2. If it's the rings.. the car will be off the road for a while.

 

If it's none of these.. it'll be the carbies, which will be replaced by a single 2 barrel MQ setup until I can afford another setup.

 

Just a long shot, but as your still using points, it could be the condenser.

The Gemini problem I've experienced first hand and it was a head scratcher, very frustrating...very much like this.

 

Good luck..

 

The condensor has been replaced already. All new electricals on the engine at this time.

[salty]

with readings that low and that different, more than 10% between the highest and lowest cylinders, I would expect some major work will need to be done

:'(

[bullzed]

with readings that low and that different, more than 10% between the highest and lowest cylinders, I would expect some major work will need to be done

:'(

 

Turns out it's the rings

 

Time to build that race motor then! 

[datozed]

Think it may be ignition timing , take out number one plug, poke something down the hole, roll the crank backwards and forwards to locate top dead centre .

When your sure it is on top dead centre check to see where the mark is on your harmonic balancer, I think it may be possible that your harmonic balancer has slipped . So if you are timing it with a light your timing will still be wrong have seen this twice before .

[silverz]

I take it the missfire is now cured after sorting the issue with the rear carby?

 

If it is that low on power, have you checked the harmonic balancer. Mine started to come apart causing it too slip hence the timing marks were in the wrong spot. A rebuilt harmonic balancer made all the difference. If this is the case try timing it by ear,  it will be rough but will give you some idea.

 

Maybe a long shot but worth considering.

 

Regards

Peter

[bullzed]

The car is still misfiring badly to the point that it hardly keeps itself going.  It's really hard to adjust the timing by ear as the cam makes the car sound rough all the time.

 

I don't think it's the harmonic balancer however there were many things that we've found to be wrong with the engine yet it still ran. Fuel blockage to rear carby, no vacuum to automatic advance/retard, timing was out, bad connection to the distributor, weak coil and unbalanced carbies... it still ran with all of that wrong on it... so the problem must be something internal.. probably burnt the valves in cylinders 1, 2 and 3 from the front carby running lean...

 

We can only try, but cheers for all your suggestions...