1982 RR V8 3.5 not starting after rebuild

[R0vers]

Evening all, im new on here, so,please be gentle..

After a day of carrying out pre-start checks the engine doesn't seem to want to growl..
Engine is a 1982 rRc carb'd
ive gone around in circles checking things, so here is my summary:

engine turns over well with starter
coil has +12v live feed
coil output is good - brand new
all plugs have sparks via new leads
New spark plugs
no1 cylinder aligns with tdc (have checked that it's not 180)
fuel pump works and is new - when fuel hoses taken off, ful spurts out at a rate of knots!
fuel is getting to both Stromberg C175 carbs(rebuilt)

Ive had a brief couple of "bang" (beautiful post rebuild exhaust smell) but that's it.

since then ive re-checked everything once again.
TDC set correctly on the compression stroke of no:1 cylinder (I used a rubber glove cable tied on a tube from a compression gauge) when balloon inflates, I know I'm on the way up, and then aligned tdc on the crankshaft.

Ive replaced the ignition amplifier on the side of the dizzy 35DLM8 with a new Lucas one - White lead (+to coil )and white/black(- to coil)

Ive been going back and forth on this an its doing my head in!!

Any help would be gratefully appreciated

[ChrisJC]

I would double check you are not 180degrees out. I do this by removing the 'even' rocker cover and turning the engine until both valves on no. 6 cylinder are both just open a crack.
Then I check that the distributor is pointing at no. 1.

Check it is pointing at the middle of no. 1 post, as it might be pointing 1/2 way between no. 1 and no. 8, or no. 1 and no. 2.

Chris.

[DEVONMAN]

Cheeky comment I know but it has been known for some guys to get the piston layout wrong.

No 1 is at the front left when looking forwards from the drivers seat in a front engine car.

[ChrisJC]

Cheeky comment I know but it has been known for some guys to get the piston layout wrong.

No 1 is at the front left when looking forwards from the drivers seat in a front engine car.

I've done it myself!

Chris.

[DaveEFI]

The SD1 manual gives a fool proof way of inserting the dizzy from scratch so it also catches the oil pump drive easily. If you've not got that I'll copy it here.

And this is the standard plug lead layout. It does sound like you've got something pretty basic wrong - and we've all done that, I'd bet.

[R0vers]

I would double check you are not 180degrees out. I do this by removing the 'even' rocker cover and turning the engine until both valves on no. 6 cylinder are both just open a crack.
Then I check that the distributor is pointing at no. 1.

Check it is pointing at the middle of no. 1 post, as it might be pointing 1/2 way between no. 1 and no. 8, or no. 1 and no. 2.

Chris.

Thanks Chris. Just checked this as you suggested, but still nothing. As that valves open and close in sync, do you mean that small window when the are both 'open'?

Thanks for your suggestions

[R0vers]

Cheeky comment I know but it has been known for some guys to get the piston layout wrong.

No 1 is at the front left when looking forwards from the drivers seat in a front engine car.

Hi Devonman, yes had got no1 in the right location...It's all very frustrating.

[DEVONMAN]

Stale fuel?? Floats stuck shut?? Camshaft not timed correctly??

[R0vers]

Stale fuel?? Floats stuck shut?? Camshaft not timed correctly??

Hmmm fuel is ok, carbs rebuilt and stripped down again and re checked. Camshaft I thought was spot on when I installed it(but that was over a year ago when I was rebuilding her) so I may have to strip the front down and recheck the timing chain,unless there is an easier way to do it?

though if I've got tdc on the compression stroke with both valves shut on no1, (and aligned with the marks on the crank pulley) would this cause my symptoms?

[DaveEFI]

Do you have a timing light? Easiest way to be sure the spark is happening in the right place without dismantling anything. It should work OK when cranking, but you might need an assistant to do this.

Worth using some white paint etc on the timing marks to make then easily seen.

[ChrisJC]

Thanks Chris. Just checked this as you suggested, but still nothing. As that valves open and close in sync, do you mean that small window when the are both 'open'?

Yes. that's right.

Is No. 1 at TDC when the two valves on No. 6 are just open? That would confirm that the camshaft timing is somewhere near right.

Can you swap the carbs with a known good pair from somewhere?

Chris.

[ChrisJC]

It also occurs to me to do a compression test. I had an engine that wouldn't start because I hadn't lapped the valves in. After enough cranking it slowly gave signs of life, and eventually did start. I had 3 starters though and kept swapping them as they got too hot.

Once running, it was perfect and gave a long and reliable service!

Chris.

[DaveEFI]

I flooded my old BMW E39 by starting it from cold then stopping it. Cranking over on full throttle to clean out the excess fuel didn't work - even with the injectors unplugged. And new plugs. Pouring some oil down the bores did, though. Which I found by Googling.

[R0vers]

Thanks Chris. Just checked this as you suggested, but still nothing. As that valves open and close in sync, do you mean that small window when the are both 'open'?

Yes. that's right.

Is No. 1 at TDC when the two valves on No. 6 are just open? That would confirm that the camshaft timing is somewhere near right.

Can you swap the carbs with a known good pair from somewhere?

Chris.

No1 wasn't at tdc when valves of No6 were just open. Do you think it's then a possibility that I haven't aligned the camshaft properly.....although I'm confused about how this could happen...

[ChrisJC]

Hmm, that's interesting. How far from TDC is No. 1 (or No. 6 for that matter, it is the same as No. 1) when the valves on no. 6 are 'on the rock', i.e. both equally open?
I don't know that it has to be perfectly at TDC, but in the ballpark is a must.

If it's 1/2 way down the bore, then that is your problem.

I think a compression test will read very low if the valve timing is miles out too.

Chris.