Saturday 30 August 2014

Fingers Crossed - first start after fiddling

Hold your breath, turn they key.... starter spinning bravely but no life

Try again.... nope!

check electrical connections, yes there should be electricity, I can here the fuel pump going.

couple of good squirts on the throttle first to get some fuel in there..

couple of more tries then a cough and black smoke from the exhaust. Yep, there's definitely fuel in there and possibly a spark at vaguely the correct time.

Few more tries with no throttle to clear things.

One more try with a brief squirt then hold the throttle half open and its alive! for about 1 second, gave it a blip and it died before I could catch it.

Tried again, nothing nothing nothing. Fuel pump starting to sound a bit tired. Ahhh! Battery is going dead. Lambda gauge says "sensor not connected", never seen that before. Check volts on battery and it read 11.9 so definitely getting a bit tired. On with the trickle charger overnight and we'll have another go tomorrow

Sunday 17 August 2014

Vacuum leak, Dizzy Recurve and Fuel Pressure Regulator.

From previous post, Job 3 was to replace the carb gasket as it had a bit of a leak. I have had the carb off a couple of times to check and adjust float levels and the gasket must have got torn and damaged where it was half stuck to the carb.

Combined with the fact that I had a fuel pressure regulator to fit, I figured this would be easier if I removed the distributor. Now I know how to avoid disaster when refitting, I was a lot more confident about this. Made a few pen marks and whipped it off.

Carb came straight off, checked floats again just for piece of mind. 7/16 and 1" as per carb manual.


One carb removal, coming right up!


Label everything. Label the labels.


Ta-da!

The eagle eyed will of course now be staring at the top picture screaming out "his throttle return spring is going the wrong way, increasing the wear on the throttle pivot shaft!" Fear not, for just out of shot dangling on a bit of wire waiting for the paint to dry is a bracket made from some spare steel strip I had lying around.

With all that guff out the way, I fitted my fuel pressure regulator, an Aeromotive 13255. I thought long and hard about -6AN quick release fittings and braided fuel hose but when I priced it all up it was about £300 which I couldn't justify so I decided to stick with hose barbs and jubilee clips. 

With great pleasure I ripped out the temporary plastic elbow from where I tried to fit the previous fuel pressure regulator (the Edelbrock one that was terrible and leaked all over the place) and fit the new one, with a Moroso 65370 pressure gauge. A nice SMALL blob of Permatex 59214 high temp thread sealer on the fittings and all was well. 


I'm not 100% convinced about the lie of the braided clutch hose but that's as good as I could get it without major rework so that will do for now. Something to think about for the future.


Fitted and set to 5.5psi as per carb manual. With no regulator my Carter fuel pump gives about 7psi. According to the internet some people say the carb will take this and others say it will cause no end of problems. The manual says 5.5 and a fuel pressure regulator in the engine bay looks cool so there we go.

Now, carb back on with new gasket. Forward throttle return spring bracket. Not a patch on some of the fancy machined ones you can buy but hey it does the job and cost about 5 pence in paint.


Before I put the distributor back on I whipped to top off to see how my Accel advance kit was doing. The answer was, not very well! The bushings that slip on the weight pivot pins had fouled on the inside of the rotor arm and the weights were binding, the rotor wasn't snapping back on the springs. This means that my timing was probably completely messed up.

I ripped all that out and swapped the Accel kit for a much better made Moroso 72300. The bushings supplied didn't foul on the rotor (I don't know how I missed that when I assembled it with the Accel kit!) and the rotor moved very smoothly on the springs. I went for a combo of the lightest spring and the medium spring which should give total timing all in at somewhere around 2700-2800rpm. I don't yet know what the total mech advance is with this kit. The centre plate is the same shape as the stock one but the weights are a different shape.

With the Accel kit you may remember I had the Accel weights and the stock centreplate. The limit bushings in the kit are for the older points type distributor. The mechanical advance limit in the HEI dizzy is controlled by combinations of different shaped centre plates and weights. Or if your a ham fisted hick you can weld the slots up. The accel weights and stock centreplate limited the mechanical advance to around 15° which meant with 18° initial I was only getting about 32-33° total advance which is a bit short of optimum for a small block chevy. It should be said that I couldn't feel the difference when driving between 32° and 36° max advance but it would be throwing away a little bit on peak power.

The instructions that come with the Moroso kit say the centre plate and weights give a total of 23° mech advance but playing around with pen marks and manually rotating the rotor on the springs I'm not sure of this. I know the stock setup was 22°, my hyrbrid stock/Accel setup gave about 15° and the Moroso kit seems somewhere in the middle, probably 18 or 19°. We won't know until we get the car running again but hopefully it might just be perfect, allowing me to run 18° initial and hit the magic 35-36° total.



Exhaust Leak and other fettling

In the chase to get better part throttle running I had a smoke test done (where on the way I smacked the radiator, see previous post). The smoke test revealed a large exhaust leak so I got the car back to the garage and made a list of things to do.


  1. Remove exhausts at the header/collector slip join, clean up, apply LOTS of copper RTV and refit.
  2. Replace damaged lower hose. Actually this is handy because my coolant/water mix was a bit off 50:50 so drain and refill with correct mixture
  3. Replace carb to manifold gasket (leaking)
  4. Fit fuel pressure regulator


Job 1: Removing and refitting the exhausts is by far my most hated and despised job on the car. It beats anything, even brake/clutch bleeding. the potential for damage to the paintwork when heaving the exhaust around trying to get it off the slip joints makes me lose sleep. So - I decided to do this first and get it out the way. I removed the sidepipe/collectors as a whole. Cleaned up the ends with some sand paper, brake cleaner and rags to get back to clean metal. The leaks were obvious as there was soot everywhere.

Piled on absolutely masses of copper RTC and reassembled. Job done in about 3 hours. Things learned: fit the sidepipe as a whole with everything connected. Previously I just fit the collector, then fit the sidepipe sometime after. All the wiggling around when fitting the sidepipe would certainly have messed up the nice seal of the copper RTV on the headers/collector. This time I did things in a better order (I think).





Job 2: Coolant drain - I've done this many times now and it's not much of a challenge, just a pain. I pulled the lower hose off over a large bucket and just left it to drain for a bit. New hose, Samco Classic 38mm to 35mm reducing elbow. Trim to length, job done. 

Job 3: See next post.....

Saturday 9 August 2014

Close shave - almost a coolant disaster!

Had a very close shave the other day, the photo below is the bottom hose off the radiator. I missed a turning and decided to turn in the road rather than driving on to find a side road because the surface was fresh chippings. I got into a bit of a flap as there was an enormous queue of cars waiting for me and I thought I was in reverse. Nope! I lurched forward into the kerb and bashed the radiator bracket. Luckily I was about 200 yards from my destination (garage for a smoke/leak test). I could hear something rattling and scraping on the ground as I pulled into the garage.



I killed the motor quickly and hopped out and lunged straight under the car. Very athletic and impressive although I gave myself cramp in my left calf. The radiator bracket had been knocked off its mount on the drivers side. What I couldn't see at the time and only spotted when I got home (5 miles away) was the radiator bottom hose had been gouged and there was at best 1mm of silicone between happy motoring and total coolant loss!

I can't believe there wasn't more damage. The guy at the garage fished out a replacement bolt for the rad bracket, although we fitted it in the wrong hole (I had drilled a few when first fitting the rad before I was happy) so it was a bit wonky. I sorted it out when I got home and have now replaced the bottom hose. The whole rad/cradle bracket had been shoved back on the drivers side into the front chassis horns. The hose had the gouge in as above and the hose clamp was all mangled but I couldn't see this on my initial inspection at the garage. It was only later at home I realised how lucky I was.

The lesson learned: either find a good wide easy place to turn around, or if you absolutely have to turn round in the road then ignore all the disapproving and annoyed faces of the other drivers and think slowly! I drive the cobra so infrequently I really need to be careful that I don;t just bump up a kerb without thinking, but this whole episode might make me stop and think next time!