Thread: Disco1 V8

I've spent a year chasing a misfire in a Rangie 3.9 v8. I did everything else with only minor improvement. Then fitted a Bosch ignition module on bee uteys instructions.
Problem solved straight away.

First question: Discovery workshop manual here: http://www.landroverresource.com/doc...hop_Manual.pdf

Gap 0.84-0.96mm

Second question: No gaskets are used there. Just some sealant. Section 19, starting on page 13.

Apply ’Hylomar’ sealant to intake manifold face

I recall another S African having no success getting the Bosch BIM024 module sent there. An alternative is the Chev HEI module (example) which performs a similar function. I haven't installed one yet but I have replaced a Chev module with a Bosch module with perfect results.

Bosch ignition module thread.

As for plug gap, anything around 0.8mm should run fine.

Hi guys, thanx for the info and links. Sort of at wits end here, so willing to try, look at anything. Will keep you guys posted.

Ballistic,
On the gasket question, a common mod amongst the Ginetta/TVR/kit car crew in the UK is to insert a 10mm "gasket" of nylon or bakelite between the intake manifold and ram housing, and also disconnect the hot water feed into the manifold. The idea is that the nylon creates a thermal barrier and reduces intake charge temps. The hot water feed is to prevent the fuel condensing in the intake runners in very cold conditions, not a problem most of us face, so its removal is not missed. The addition of the thermal barrier is by itself supposedly worth 6-10 horsepower. A further mod is to shorten the ram tubes. The thinking is that there is relatively little space between the tops of the tubes and the roof of the plenum. As revs rise the airflow in the plenum becomes unstable and the feed into the ram tubes is less than ideal. Supposedly they can be shortened by up to 20mm without too much impact on torque characteristics - although I'm sure that a sub 1,000kg kit car can survive with less low down torque than a Disco! I'm doing the nylon gasket mod on my D1 at the moment, and whilst I'm at it I'll knock some length out of the ram tubes also. Unfortunately I won't have a "before and after" comparison as I've also done a cam change.

"...On the gasket question, a common mod amongst the Ginetta/TVR/kit car crew in the UK is to insert a 10mm "gasket" of nylon or bakelite between the intake manifold and ram housing, and also disconnect the hot water feed into the manifold. The idea is that the nylon creates a thermal barrier and reduces intake charge temps. The hot water feed is to prevent the fuel condensing in the intake runners in very cold conditions, not a problem most of us face, so its removal is not missed. The addition of the thermal barrier is by itself supposedly worth 6-10 horsepower..."

This is interesting, I'd imagine any increase in power/effieciency could translate into more mpg if driven gently.... Seems a simple enough modification. - My Classic 3.9 needs all and any improvements for her insatiable thirst!
- BeeUtey's IGN has already sparked her up a bit. Worth every cent, - and change the rotor arm. The alternate one is wider at the sparkler end making it betterer for advancing timing beyond official specs. Dizzy housing and leads are worthwhile too, as the 'engine room' gets incredibly hot and shortens the life of anything rubbery...

So, removing the manifold heating is'nt a problem in sub-arctic Melbourne?

I've also read somewhere about adding a similar sized gasket to the ram-plenum housing to give the tubes more breathing space but I have'nt looked to see if it's practical. - have no idea if the added lift (again) would put it too close to the bonnet.
That would save hacking into 8 tin tubes, not applicable in my case as The Lady Sarah is never allowed over 3500 rpm

Cooler intake does give you more power. But on a petrol warmer intake gives you better mpg.

It's about reducing throttle losses.

Superquag,
At 42 degrees C, which now seems to be standard Melbourne summer temp, I'm not having ANY issues with fuel droplets coming out of suspension in my inlet tracts!