Re: P6 project: BW35 to LT77 manual box swap: the verdict

Re: P6 V8 project: Engine upgrade finished! :)

I hear you Dave,
Your right, had enough of engines for a while LOL, retuned the carbs & reset the timing, topped up the carb dashpots with oil, running really nice, took it for 10 mile drive, certainly got some power there to unleash once its run in for 500 miles....hate the blue puff of smoke...hate classic cars now, changing hobbies :wink:

One thing I noticed is when I accelerate from say 40 to 60mph, I can hear a metallic sound under load, almost sounds like its pinking, timing perhaps, its set to 6°BTDC, when I rev the car by hand when stationary, no noise, I guess it has to be under load. Also notice a vibration when accelerating from say 50mph upwards, one thing I did was to mark the location of the torque converter in relation to the flywheel before unbolting it, this I forgot & did not align the two up when refitting, would this create the vibration or inbalance or is my BW35 auto box on the way out? I do have the 5-spd manual to go in for my next project.

cheers damian
 
Re: P6 V8 project: Engine upgrade finished! :)

DamianZ28 said:
Also notice a vibration when accelerating from say 50mph upwards, one thing I did was to mark the location of the torque converter in relation to the flywheel before unbolting it, this I forgot & did not align the two up when refitting, would this create the vibration or inbalance or is my BW35 auto box on the way out?
Click to expand...

It's possible but unlikely that putting the converter back in a different position has caused the vibration, but the way to prove the point is to put it back in the position it was previously and see if the vibration disappears. Converter vibration will be relative to engine speed, not road speed, so if you were to hold it in SECOND past 50mph and the vibration was still the same then it's not the converter causing it, but I'd wait until it's all run-in before trying that one. In most cases it should also be there at the same rpm when revved up at a standstill.

It's even less likely to be something inside the box itself if it is a vibration. You can get judder when the box is on the way out though, which can be confused with vibration.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Harvey, come to think of it it does feel like a judder, maybe the box is saying good bye,

thanks for your advice, cheers damian
 
Re: P6 V8 project: Engine upgrade finished! :)

DamianZ28 wrote,...
One thing I noticed is when I accelerate from say 40 to 60mph, I can hear a metallic sound under load, almost sounds like its pinking, timing perhaps, its set to 6°BTDC
Click to expand...

What compression are you running Damian? As you surmised, definitely sounds like pinging, which will only occur under load and essentially only up until the point of peak torque. How much total mechanical advance are you running and at what rpm is it all in by? With the Mallory, you can adjust the curve so you can dial out the pinging.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Ron,

Thanks for the information but I'm I get a little confused when mechanical advance is thrown in, I wouldnt know what the curve is at said RPM, there are extra bits that came with the mallory to change the curve but I dont know how to do it :oops: I dont the have equipment to dial in, only a timing gun, hence my ability to adjust it to factory 6°BTDC, would setting it to say 8° or 10°BTDC make a difference? it that advancing or retarding ? I'm guessing the first .
With the SD1 heads it was fine, also had standard 3.5 cam, so with the 3.9 heads & 3.9 cam its made a difference which I knew it would, just a case of getting it set up right.
Is there much difference between the SD1 & 3.9 heads ?

Thanks a lot Damian
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian,

The 14 bolt 3.9 heads came factory fitted with waisted stem inlet valves, the same design as those fitted to the Rover Vitesse heads. If you had standard SD1 heads, then this will be the major difference. These valves allow for improved breathing and greater performance.

The 3.5 litre engine typically requires 36 of total mechanical advance. This is made up of the initial advance, in your case you have set it to 6 degrees BTDC, and another 30 degrees built into the distributor. Do you have a separate tachometer that you can connect and see whilst working under the bonnet? Mark out on a piece of tape all the timing marks from 0 degrees BTDC right through to say 40 degrees BTDC, then attach that exactly over the existing timing marks on the crankshaft pulley. With your timing light running, slowly increase the engine revs whilst watching the timing marks and the tacho. You will see the timing advance as the revs rise, and then at a certain rpm no further advance for increasing revs. This is the point of total mechanical advance, note both the rpm at which occurs and the number of degrees.

The kit that you have will include some springs, some stronger than others, which you can swap with those already fitted which will allow you to experiment with different rates of advance. The lowest rpm that you would want the full mechanical advance is likely to be no less than say 2800 rpm, with the highest rpm say 4500. The lower the rpm point at which full mechanical advance is achieved, without pinging, the better your engine will perform.

If you set your engine to say 8 degrees BTDC, then you have advanced it by another 2 degrees, so ideally now you would want another 28 degrees of mechanical advance built in. The advance weights inside the distributor will (should) have a number stamped into them which is the amount of degrees of advance built in. Most likely it will be between 14 and 16 degrees, which is half that shown at the crankshaft.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Ron,

Many thanks for the detailed reply! I think I get it, One thing I need to check is to make sure the actual pointer is set correctly when no#1 pistioon is at TDC, I know these can move.

So just that I'm correct my head, the early SD1 heads are better then the 3.96 heads ? or are the 3.9 heads better? I think mine were the early heads.

Sorry for so many questions, thanks again for your advise!

Cheers Damian
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian,

The 3.9 litre heads are better than the SD1 heads.

As for asking questions, not a problem, glad to help where I can.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Now I'm feeling quite of ashamed of mine. Thanks! :LOL: All kidding aside, it looks suberb. But as the engine had the newer rocker covers before (which I presume also have the intgerated oil splash pan, as on mine) did the original splash pans mounted on the rockershaft fit? I'm planning the same conversion and I just assumed they will fit.. The older rocker covers make for a much easier route for the leads and the breather pipes so I'm keen on it to fit properly!

Andries
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Andres,

No worries and thanks!

The rockers covers and splash plates are the originals off the old engine, the pic of the SD1 engine on the previous page is another spare I have, its not from my car.

All I have changed is the engine block for a reconditiond one, the rest of the parts are original apart from the 3.9 heads, Mallory electronic disty.

Cheers Damian
 
Re: P6 V8 project: Engine upgrade finished! :)

SydneyRoverP6B said:
The 14 bolt 3.9 heads came factory fitted with waisted stem inlet valves, the same design as those fitted to the Rover Vitesse heads

Ron.
Click to expand...

Hi Ron,
I think you might've got that wrong about the 14-bolt 3.9 cyl' heads? The Rover Vitesse cyl' heads had the valve stems waisted just behind the valve heads. Whereas the 3.9 cyl' heads had standard inlet valves (the same as a non-Vitesse SD1), but the exhaust valves had exhaust gas anti-reversion steps behind the valve head.

I beleive the 10-bolt 4.0/4.6-litre cyl' heads had the Vitesse type valves, but just on the inlets.

Sorry to be anal about this, but I know how you like to get these things correct :) Info source: The Rover V8 Engine by David Hardcastle.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Guys,

Pinking bl*ody pinking, ok before I loose the plot (from being to impatient) :oops:

I’ve double checked the timing pointer is in its correct position for TDC, which it is, so after various timing settings from 10,8,6,4,2°BTDC and even TDC, the engine still pinks under load.
Worst case is 6~10BTDC and at say 0~2°BTDC its not as half bad but still present, I’m a tad worried that I’ll damage the new engine.

So I’m thinking, is it because I’ve added the 3.9 cam and 3.9 heads? has this thrown it all out of spec and what can I do to fix it? Do I need the change the jets / needles on the carbs ?
Is a rolling road the answer to get it set correctly? Do I cover the car in petrol & throw a match at it in a fit of rage ? :evil:

Also have the Mallory electronic distributor, do I need to change the spring or weights is it ?

The old engine was running SD1 heads and standard camshaft which was new back in 2010 with no pinking, also had the mallory fitted.

Sorry to keep on but thanks for reading my techincal rant!

Damian (about to change to stamp collecting for new hobby)
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Lee,

I am as sure as I can be that waisted stem inlet valves were fitted to the 3.9 litre heads from circa 1989 onwards. I don't have the text that you quoted, although in the ones that I do have from David Hardcastle, he makes no mention of this.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian,

You don't want to be running your ignition ATDC, TDC is as retarded as you would ever want to go. Does your engine have 10.5 : 1 pistons?

You can do a simple check as to whether your needles are too lean for the changes that you have made by,....going for a drive, accelerate to bring on the pinging, then immediately pull the choke right out. What happens to the pinging? If it goes away then you have your answer, the needles need to be changed to richer ones. What needles are you currently running?

If your distributor is advancing too quickly, that will also initiate pinging.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Ron,

The replacement block is an SD1 unit so I guess it has the 9:35.1 compression, I've use composite head gagkets too, will this have lowered the compression ratio too much perhaps with the skimmed 3.9 heads?

When cold the pinging is bad, once warm its not as bad, I'll try the choke test, think I may have already done so but its worth checking, carbs have standard needles, there the later versions as my car is s 73 model.

If its none of this then I have internal mechanical failure ..... :shock:

Many thanks Damian
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian,

Running composite gaskets with 14 bolt heads will lower the compression ratio by at most 0.6. As your heads have been skimmed, the reduction would be less, the amount though being dependent upon how much was taken off. Are you running 98 octane fuel?

If the needles are the standard factory fitted items, then swap them out for a pair of BAK or the slightly richer BAF.

Be sure to also do the check with your distributor that I wrote about yesterday. If it is advancing too quickly, then you'll certainly get pinging.

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Ron,

Again thanks for your time & detailed replies not sure what octane fuel we have over here, its regular unleaded I used for the car.

I need to find the mallory box with all the 'extras' sods law that I cannot find it now...hopefully in my loft! Need to look and see what is in the distributor at the moment.

So if I got this correct, (example only) if I swap the spring for a slightly stronger version then this'll slow the advance and could stop the pinking?

Many thanks Damian
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian

Sparky pinks with regular unleaded (95) octane.

Pop into Tesco and get some momentum - see how that goes.

Richard
 
Re: P6 V8 project: Engine upgrade finished! :)

Hi Damian,

There are two advance springs within the distributor, typically one slightly stronger than the other. Don't change them yet until you know for sure if the rate of advance is the problem. As Richard advised, fill up with the right fuel first, then take one step at a time.

What type of oil are you using within the dashpots?

Ron.
 
Re: P6 V8 project: Engine upgrade finished! :)

Sorry to be anal about this, but I know how you like to get these things correct :) Info source: The Rover V8 Engine by David Hardcastle
Click to expand...

Agreed; the Vitesse heads were machined differently to the standard SD-1 heads ( tho' these share the same casting number ) and are a different casting to the later heads; the SD-1 Vitesse heads are something special...

GW
 
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