V8 distributor vacuum pipe

[allan]

Hi all,

 

My TR7 V8 engine is from a 1970's Range Rover and as I have not owned it for very long, I am just getting to know what's what. Yesterday, when checking around the distributor, I noticed a pipe missing from the "lower L/H" outlet of the vacuum.

The "upper" pipe is in place and connected. If I fit a pipe to the lower outlet, does anyone know where it connects to?

Also, the performance of the engine is very good but it seems to "level out" at about 3,000 revs....is this normal or could missing pipe be causing this?

 

Thanks, Alan.

[andrewt]

The second vacuum pipe is not normally used, or at least has never been on any of the engines i have run. Also the Range Rover engines from the 70's were very low compression (to run on jungle fuel) so would be all bottom end power. An SD1 or later RR bottom end (or pistons anyway)and slightly wilder cam would transform it. Also try to find a distributor from a manual SD1 as this is the best of the factory advance curves.

 

Andy

[Cinnobar]

Mine runs a Defender engine, they're 8.13:1 CR and very soft cammed.

Before the complete rebuild I had the heads skimmed by 1mm (40thou) which makes the CR 9:1 and it crispened the throttle response but not by a massive amount. Running K & Ns & the normal tubular TR7 V8 conversion manifolds makes the mixture very weak & on SUs you need either BAC or BAF (from memory) needles. I suspect its the weakness thats stopping it reving or fuel starvation.

Does it still have a points distributor? It could be ignition issues as the early dizzy was mediocre.

Mine in original form on K & Ns would rev through to 5,400 and gave 136BHP at the wheels & 170 at the flywheel. It also had better torque than a lot of diesels 219Lb/ft peak but 119 at 1100RPM!

 

Jim

[allan]

Thanks chaps.

 

Andrew, is the vacuum pipe port that is left un-connected blocked off, or left "as is"?

 

Jim, I'm not totally sure what I've got! Yes, the dizzy still has points which are adjusted from the side externally. The power output is pretty good but it does flatten out at the 3,000 RPM mark. The carb's are Stromberg which I'm told are not very good and I have been advised to change to SU's (other than the very expensive alternatives) I think the Stromberg's must  also be the originals.

 

Regards, Alan.

[andrewt]

Allan

The vacuum port is left as is, also i would definitely recommend the SU's as a definite advantage over the strombergs. Cold start is better for one as the choke works on both carbs on the SU's instead of on one for the strombergs. Properly set up SU's are far better than 4 barrel carbs that are not set up properly and in my experience also give better MPG. This is not to say that getting a 4 barrel set up properly is not the way to go but if the engine is otherwise standard & is limited by heads & cam, then I see no point in spending big money on expensive carbs.

A late version electronic ignition is also a good idea, though personally i have a lumenition fitted as i got fed up with the early style opus ignitions giving out.

Depending on the age of the engine it may well have very old style heads as well in which case the SD1 heads are a big advantage. Basically the engine went through continous improvement so the later the parts you get the better. Hardcastle's books are very informative on all aspects of this, i can recommend them.

 

Andy