Engine running on

[Guest Chris Draper]

After many weeks of labours, I've finally got my V8 back in service.

 

It's a new 4.6 block with a Piper 272 cam, weber 500 carb, my old 3.5 heads & the remainder of the old ancillaries.

 

Having eventually solved the problem of inlet manifold leaks, it goes pretty well (OK it pulls like a train...) except that it runs on for up to 10 seconds after switching off the ignition, often finishing with a blast back through the carb.

 

Ignition is timed at approx 6 degrees BTDC (& I've checked that the crank pulley timing mark is accurate), idle is set at about 800, CO is about 3% & HC is approx 280. Engine temp runs between 1/2 & 3/4 on the guage (mostly at 1/2). Also, all the ignition bits are new or nearly new including Mallory magnetic dizzy & sports coil, Magnecor plug leads, plugs...

 

Any ideas what I could look at?

[andrewt]

Chris

Is that with vacuum connected or disconnected? It makes a big difference depending on cam etc?

[Guest Chris Draper]

That's with the vacuum connected - guess you'd need that to get the correct ignition timing at higher revs?

 

Took it out for a longer run today (about 60 miles) - the engine ran at half temp for almost the whole trip & didn't run on at all at the couple of stops made during that period. Towards the end of the run, temp rose gradually, finishing up at 3/4 & started running on pretty much as soon as the engine temp began to rise. Kind of indicates a temperature issue maybe?

 

Not really sure why the temp rose like that, although I've been gradually bleeding more air out of the cooling system, so it may be down to air locks. Must say that I'm tempted to drill a couple of holes in the thermostat to ensure some water flow at all times.

[andrewt]

The SD1 timing figures usually listed are without vacuum, then once the vacuum is connected you get more advance at idle. i can't recall off hand what the figures are but it is around 4-6 deg without vacuum. I use the Haynes figures as is and this gives me a max advance of 34deg total with vacuum as well, this is what is recommended for the Real Steel cam i use. i have a manual SD1 dizzy, the advance curve is different to the auto dizzy's!

 

What plugs are you using? On a std engine some factors list Champion 11's for Range Rovers. This is too hot a plug for a Tr7V8 & could contribute to your running on problem, especially when the engine heats up too much. I use 9's just now, but i have also tried 7's. The 9's are better if you spend a lot of time sitting idling in traffic or whatever. The 7's if you spend more time running hard. e.g track days or welsh or scottish back roads....grin.

 

Do you have the circulation line from the top of the manifold blanked off? This causes the issue you describe as air gradually accumulates in the inlet manifold. This is easy in the SU manifold as the vline is apparent on the carb bridge. Return it to the expansion bottle on the wing. i don't know about the weber/offy set ups but on the Vitesse inlet i am using i have used an outlet that is meant to go to the heater under the throttle, then instead of returning it to the other line beside it i take it over to the expansion bottle. This also circulates all the time the engine is running. The second line i just block.

Hope that helps.

Andy.

[Guest pilbaratr7]

Hi Andrew,

I have a few questions about your EFI set up.

on the Vitesse inlet i am using i have used an outlet that is meant to go to the heater under the throttle, then instead of returning it to the other line beside it i take it over to the expansion bottle. This also circulates all the time the engine is running. The second line i just block.

I have the Range Rover 3.9 plenum and manifold which heater hose inlets/outlets do I block and which do I circulate?

Do you have any problems with water locks in the top radiator hose. Looking at mine the top hose is above the coolant expansion tank level.

Looking at your thermostat and top hose it runs around the dissy. I have the one that runs over the top of the dissy near the LH rocker cover.

Any other tips would be great.

 

Thanks

Glen.

[andrewt]

Hi Glen

I used the SD1 stat outlet on the Vitesse manifold, then a slightly shortened SD1 top hose on an early Tr7 style radiator (with a huge core & larger pipe inlets on it coutesy of Serck) This should help minimise the lock in the top hose, though a bleed vent on it would be a good idea.

To clarify something first, the cabin heater is obvious, but the heater i was referring to above is the throttle body heater that is to prevent icing in the inlet.

The heater hoses i refer to are the 1/4" or so bore line that stands vertically beside the temperature senders on the inlet manifold & the return line into the cabin heater line returning into the top of the pump. I take a hose from the one adjacent to the sender , run it through the throttle body heater then return it to the expansion bottle. i block the return near the water pump. The cabin heater is connected as normal.

 

Hope that is clear, as it works for me.

Cheers

Andy

[Guest pilbaratr7]

Thanks Andy, thats a great help.

What type of fan are running?

Do you have any recent photo's of your car and engine bay?

 

Regards

Glen.

[andrewt]

I'm running two Austin Princess fans set up to push air through the rad. One of them also pulls air through the oil cooler. I got Serck to add a thermoswitch to the rad whilst doing all the other mods and i use an 78 deg (i think it is) switch so that as soon a i pull up at lights or whatever the fans kick in. They are quite noisy (old design) but are very effective. If you open the door when stopped & the fans are on, the hot air blows up past you from under the floor quite satisfyingly. I will mail a couple of recentish pics. The car is not finished in them but i think the water plumbing was done.

Cheers

Andy