Engine rebuild, but still same problem - HELP!
Discussion
Hi All,
I've owned and worked on Rover V8's for 22 years, but confused over my present problem.
My 1971 Range Rover with rebuilt 1976 SDI [some of it] lump, which I fitted 15 years ago has caused problems, running rough under load [missing four] changed dizzy and all electrics, still the same, tried another, same.
Fitted three pairs of carbs, still the same.
Complete rebuild of top and front end, still the same.
Test results showed very high HC, put down to induction leak, nothing found.
So the only part which was not changed, the inlet manifold, has now been changed [on removal the old one was distorted, so assumed this was the problem, open inlet gasket to main block, sucking sump pressure into 3 & 5 ports.
So thought this would solve the problem.
Well all back together, not been able to do a full road test yet, but I think I still have the same problem!!
Ticks over ok, but under load, runs very lumpy, only appears to be running on four, same as before.
Looks very nice, all clean and polished, but will not get me to work!
Will finish the bits and final tune up and try a road run, but don't look to good.
So the last two days of new inlet manifold, rebuild carbs [again] and distributor [again] may have been a waste of time.
One question, which I'm confused about and no one has been able to answer.
This was observed and still has the same affect after the complete rebuild and new parts of front and top end, including the flame traps and hoses and three sets of rebuild carbs.
On tick over, when I remove the L/H rocker breather, flame trap, from the carb the engine runs slower, yet if you remove the R/H the engine speed up??
The pressures should be the same, as should be from main block! confused.
I've owned and worked on Rover V8's for 22 years, but confused over my present problem.
My 1971 Range Rover with rebuilt 1976 SDI [some of it] lump, which I fitted 15 years ago has caused problems, running rough under load [missing four] changed dizzy and all electrics, still the same, tried another, same.
Fitted three pairs of carbs, still the same.
Complete rebuild of top and front end, still the same.
Test results showed very high HC, put down to induction leak, nothing found.
So the only part which was not changed, the inlet manifold, has now been changed [on removal the old one was distorted, so assumed this was the problem, open inlet gasket to main block, sucking sump pressure into 3 & 5 ports.
So thought this would solve the problem.
Well all back together, not been able to do a full road test yet, but I think I still have the same problem!!
Ticks over ok, but under load, runs very lumpy, only appears to be running on four, same as before.
Looks very nice, all clean and polished, but will not get me to work!
Will finish the bits and final tune up and try a road run, but don't look to good.
So the last two days of new inlet manifold, rebuild carbs [again] and distributor [again] may have been a waste of time.
One question, which I'm confused about and no one has been able to answer.
This was observed and still has the same affect after the complete rebuild and new parts of front and top end, including the flame traps and hoses and three sets of rebuild carbs.
On tick over, when I remove the L/H rocker breather, flame trap, from the carb the engine runs slower, yet if you remove the R/H the engine speed up??
The pressures should be the same, as should be from main block! confused.
I had a problem like this on the 101.Changed all the electrics,but it still wouldnt run properly under load and it was guttless.Turned out to be s**t from the tank coming up and clogging one of the carbs causing it to run on four cylinders.When it was off load it ran ok.We put this down to gravity letting the crap float back down the fuel line,and when under load forcing it back up.It was a bastard to find,but when we did, it ran properly with no further problems.
Well it's now a bit better, but still have the same problem, VERY lumpy under load.
Found various minor problems, and those you don't expect, but always get!!
Now found a problem with Dizzy dwell angle, sets up ok with Vac off, rev engine still ok, put on vac and rev, dwell 20% out.
Loose play in adjuster, reset dwell and rev up 20% out the other way.
Play in top plate of dizzy, not allowing plate to reset.
Rebuilt dizzy again! and will refit tomorrow, but don't look good.
May have to try the electo [1985] sytem which has been in the work shop for the last ten years.
Or get another points dizzy?
Found various minor problems, and those you don't expect, but always get!!
Now found a problem with Dizzy dwell angle, sets up ok with Vac off, rev engine still ok, put on vac and rev, dwell 20% out.
Loose play in adjuster, reset dwell and rev up 20% out the other way.
Play in top plate of dizzy, not allowing plate to reset.
Rebuilt dizzy again! and will refit tomorrow, but don't look good.
May have to try the electo [1985] sytem which has been in the work shop for the last ten years.
Or get another points dizzy?
Not been able to find the details.
what coil should be used on the Constant Energy Unit?
Can I use my new Standard 12v coil?
Is a ballast resistor required?
Dizzy is 35DM8 2585 42600A
the CEU details are AB12
48035A
3285
It is fitted with a very old coil at present, so would like to change.
I note that some Dizzy's were designed for certain carbs/manifolds and engine set ups, vehicles etc.
So if it helps, some details of my set up, let me know if I need to make any changes.
Engine main block;
1976 SD1 3528cc
11A50459
9.35:1
All other items [front and top end are new, including later heads etc.
Fitted in a 1971 RR with 86 4 door body.
4 speed B box.
87 Austrian wiring loom [don't ask!]
New 3.9 cam etc.
Inlet manifold and electronic set up from 25D/B EFI Auto 3.5 RR.
SU carbs with BAK needles.
Need any other details?
Urgent help required.
Pete.
what coil should be used on the Constant Energy Unit?
Can I use my new Standard 12v coil?
Is a ballast resistor required?
Dizzy is 35DM8 2585 42600A
the CEU details are AB12
48035A
3285
It is fitted with a very old coil at present, so would like to change.
I note that some Dizzy's were designed for certain carbs/manifolds and engine set ups, vehicles etc.
So if it helps, some details of my set up, let me know if I need to make any changes.
Engine main block;
1976 SD1 3528cc
11A50459
9.35:1
All other items [front and top end are new, including later heads etc.
Fitted in a 1971 RR with 86 4 door body.
4 speed B box.
87 Austrian wiring loom [don't ask!]
New 3.9 cam etc.
Inlet manifold and electronic set up from 25D/B EFI Auto 3.5 RR.
SU carbs with BAK needles.
Need any other details?
Urgent help required.
Pete.
I may be silly and on medication but still confused.
Can anyone explain why the electronic dizzy vac advance has two vac hose connections?
these appear to be either side of the diafram, so work against each other!
One hose from the throat of the L/H carb, the other from the balance port on the carb post.
Is this done to balance the vac advance unit?
If this is the case, which hose should connect to which connection on the vac unit, as I'm sure this could make a difference to the pressures if the hoses are the wrong way round.
Pete.
Can anyone explain why the electronic dizzy vac advance has two vac hose connections?
these appear to be either side of the diafram, so work against each other!
One hose from the throat of the L/H carb, the other from the balance port on the carb post.
Is this done to balance the vac advance unit?
If this is the case, which hose should connect to which connection on the vac unit, as I'm sure this could make a difference to the pressures if the hoses are the wrong way round.
Pete.
Greenman272 said:
Now even more confused, as that different to what others have told me!
Are you saying, remove hoses from the vac unit, so that it does not work?
Yes that's what I'm saying. The only reason for having the vac advance is to reduce fuel consumption and running temperature off load; the engine will run fine without the vac advance connected up and it lets you remove an unknown factor while you solve this running problem. Are you saying, remove hoses from the vac unit, so that it does not work?
Bluespanner, some more details will help.
As you will I've just done a complete rebuild and still have the same problem.
But have found many problems during the build.
Please give all details of your setup and ages.
Fisrt option, can you try another dizzy?
How old is the cam?
When were the lifters last changed?
Where in the country ae you?
Pete.
As you will I've just done a complete rebuild and still have the same problem.
But have found many problems during the build.
Please give all details of your setup and ages.
Fisrt option, can you try another dizzy?
How old is the cam?
When were the lifters last changed?
Where in the country ae you?
Pete.
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