| Author |
Message |
    
Steve Roberts
| | Posted on Thursday, 26 April, 2001 - 09:53: |    |
I'am not happy with the air intake on the carburator. The big pipe going to the front of the engine bay dosen't seem to have much access to air. If it is removed and a small filter is placed over the SU carburators is it going to have any deterimental effect. Also has anyone ever fitted fuel injection on a 6.3 litre Rolls-Royce engine and what is the likely cost. I know the later model 6.75 litre motors had Bosch fuel injection. |
Martin Cutler
| | Posted on Thursday, 26 April, 2001 - 12:33: | |
Still air capacity is important, ie, the size of the "air box". Sound wise this also helps keep the induction noise down. May be more practical to look at the type of filter material. "UniFilter" up at Hornsby do custom filters. I have fitted them to my MG ZA Magnette and the MK VI Bentley. Improved flow, and they are washable. Both cars have retained the stock air cleaner housings. In the case of the MG, I was able to loose about 2 kg's of oil bath cleaner. |
Richard Treacy
| | Posted on Thursday, 26 April, 2001 - 18:12: | |
Advice: don't fool around with air filters. The SU carburettors are specifically tuned to the air filter arrangement, and the air intake of the T-Series car is perfectly adequate. Any changes, even to the filter type, will involve expensive and time consuming carburettor tuning (different needles and jets for a start) and produce negligible improvement. To prove this, simply remove the air filter duct at the carburettors and try to drive the car: it will be noisy, will cough and splutter, and will backfire like mad. Fuel injection is theoretically possible, but would be prohibitively expensive and again very time consuming to optimise.
These cars run wonderfully in original carburettor and air filter trim. I must say that our twin SU T-Series and R-Type (the Australian R-Type has an oil bath air cleaner) run far sweeter than my fuel injected Turbo R, and I run only genuine standard filters on all these cars. Be aware, I am an experimenter, not a purist, have tried many novel modifications, and have learned mostly the hard way. Please, don't risk melted pistons by fiddling around with the air intake systems. Crewe really knew what they were doing with SUs, especially those big bore early T-Series carburettors, so please leave well alone. |
Martin Cutler
| | Posted on Friday, 27 April, 2001 - 10:06: | |
Hi Richard,
Thanks for the info. When I got my MK VI, the "filter" consisted of some chicken wire wrapped around and around at the front of a large cylinder. The cylinder is about the length of the block, but 7/8ths of it is just empty space. The chicken wire was filthy dirty, but looks original. Would this be so?
Marty |
Richard Treacy
| | Posted on Friday, 27 April, 2001 - 19:24: | |
Hi, Martin
Your original filter would have been one of three types:
Bentley type (early Mk VI)
AC Air Cleaner (later Mk VI)
or
Oil bath cleaner
The Bentley and AC types were both as you describe: a hollow cylinder the length of the block (this is the very effective silencer) with a copper mesh filter at the end. The mesh should be washed out regularly and dipped in oil. Export models had the oil bath filter like mine. It consists of a long silencer mounted along the length of the rocker cover, fed by the oil bath filter mounted above the starter motor. The oil bath filter works extremely well, and needs cleaning and refilling every 6,000 miles.
The SU carburettor jets are all 0,100 inch, and the needles are determined by the filter, carburettor and engine bore:
3 1/2 bore motor, 1 1/2 inch carburettor: LB needles for Bentley air cleaner, SC for AC from chassis B2BH. SF for oil bath filter
3 1/2 bore motor, 1 3/4 inch carburettor: SJ for AC filter, SF for oil bath
3 5/8 bore: manual choke 1 3/4 SU: SP for AC filter
3 5/8 bore: automatic choke 1 3/4 SU (like mine): SH for AC filter, SF for oil bath.
I have since fitted SE needles (from memory; I can look it up later this year), which run slightly richer to match my high-lift long-duration/overlap camshaft ground by Waggots (I still have the original camshaft stored of course).
As you can see, the slightest change to the oil filter affects the needles used. I agree that the AC air filter is a bit naff, but care is needed in tuning the motor (ie choosing needles) if an alternative is fitted. The best solution if to retrofit a genuine oil bath filter arrangement from a Mk VI or R-Type with the correct carburettor needles, as the oil bath works very well and needs no service parts, just oil replacement from time to time. It is also very silent. With over 700,000 km on the R-Type, I can vouch for the oil bath.
If you are unlucky enough to have a Zenith type DBVC42 carburettor, the game is even worse, with a whole range of main and bypass jets needed for the different configurations. These jets even vary depending on the altitude at which the car is normally driven.
Thank your lucky stars you run those fabulous twin SUs.
Regards,
Richard |
BOB (62.7.120.93)
| | Posted on Monday, 13 May, 2002 - 02:32: | |
I am not over sure about this but, I assume you wish to get more power from your engine. I guess that a 6.3 produces about 230bhp @ 4500 rpm.and the 6.7 250bhp at 4500 rpm. The car is gear to 26.2 mph per 1000 rpm in top gear. Which is 117.9 mph top speed. I think RR intention is that the car has adequat power but not enough to damage itself. More power may cause the engine to wear quickly. VW Beetles were the same the max speed was the max cruising speed as well. I have never found either engine lacking in power. Its a lasy V8 that produces 37bhp per litre which is about the same as a moggie minor. Leave well alone the air intake will pass more than enough air for the engine.IT is actually very well designed it silences the air intake and also is a FLAME TRAP. Do waste your money buy petrol instead and enjoy the car. Car designer spent vast amount of time and money getting it right. So before the bloke down pub reckons he can get more out of it remember that. |
rhys norman (203.24.100.132)
| | Posted on Monday, 27 January, 2003 - 15:25: | |
Im looking for some information on my hydramatic transmission in shadow 1.
If any one knows the torque settings for adjusting the bands it would be much appriciated. |
David Gore (63.60.9.65)
| | Posted on Monday, 27 January, 2003 - 19:08: | |
Rhys,
Your transmission checks should be in the following sequence:
1. Check control linkages
2. Check main line oil pressure
3. Check band adjustment.
Two tests for the gearbox:
1. Road test vehicle and check gear change points against road speed and engine loading.
2. Fit a pressure gauge to the pressure tapping on the gearbox and record operating pressures [you also need a tachometer to record engine speed for this test].
Check results against factory specifications and use fault diagnosis guide to determine if a band adjustment is necessary. Both bands must be set when any adjustments are required and special tools are required especially the setting gauges for the front and rear bands. If you do not have access to these or equivalent gauges, DO NOT ATTEMPT TO ADJUST THE BANDS. Go to a transmission specialist who is experienced with GM Hydramatic transmissions and get the job done properly and avoid unexpected repair costs.
If you send me your email address at technical@nsw.rroc.org.au, I will forward you the relevant diagnostic information for the transmission. |
Richard Treacy (217.162.168.47)
| | Posted on Thursday, 30 January, 2003 - 01:09: | |
What type of transmission is it ? If it is a 4-speeder I can send you a detailed description by e-mail. The bands on these are set to a clearance, not a torque setting, and there is a specific procedure, including final fine tuning of the linkages and bands.
If it is a 3-speed (GM Turbo 400 Hydramatic), there are no adjustments to speak of, only the vacuum modulator on some cars. |
David Gore (63.34.228.13)
| | Posted on Thursday, 30 January, 2003 - 21:48: | |
Rhys,
Did you receive the two emails I sent - one direct and one to Claire?
Will send information when space available in your email file.
Regards David |
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