246
Rear shock absorbers for MGBV8s
Gordon Hesketh-Jones (Harvest Gold 1904) from Cornwall has just clocked 200,000 miles in his MGBGTV8 so clearly uses his V8 a great deal. This note sets out his research into rear shockers on his V8 and his findings which will prove interesting for V8 enthusiasts. (Feb 02)

The lever arm shock absorbers fitted to the rear of the MGBGTV8 were never incredibly efficient even when new and did not have a particularly long life. I feel they were a poor design from the beginning. You can buy replacements from places like MGB Hive for around £11.50 on an exchange basis plus the cost of return carriage, but you have to remember that these are not "remanufactured or new" units, but are simply old units, possibly 25 years old, which have been given new seals, topped up with oil and given a lick of paint. A dealer told me that he used to buy in these "repaired" units for £4.50 plus VAT, so with a typical labour charge-out rate of around £16.00 an hour, you can see how much time on average was devoted to "servicing and repairing" the shock absorbers! It seems quite rare for an MGBV8 on standard rear shock absorbers, doing an average annual mileage, to go through two consecutive MOTs without at least one shock absorber failure. So I feel considering replacement with telescopic units makes economic sense and gives a better ride as well.

In the early 1990s I was covering 20,000 miles or more a year in my V8 so had more than one failure of the old lever arm units every year. I quickly changed to Spax oil filled telescopic units which suited the five-leaf springs and lasted 150,000 miles without a problem, but one snag with these older Spax designs was that they were a bit long for the V8 so their mounting brackets extended down well below the springs which reduced ground clearance.

Nowadays Spax, Koni and Bilstein all make gas-filled telescopic units which are even more efficient. All three are basically of the same length and fitting involves taking off the existing lower mounting plates, swapping them from side to side and inverting them so that the mounting flange points down rather than up to allow for the longer length of the telescopic units. The Koni and Spax units are priced at around £100 for the pair including the fitting kit but the Bilstein units cost around £156 as they are a more complex design. Both the Koni and Spax units are adjustable, but the Spax are far easier to adjust as there is a 28 position adjustment screw at the base of the unit which can be easily reached, whereas I find adjusting the Koni involves removing the unit from the car. The Bilstein is not adjustable, basically because its design is said to have been pre-set to match each individual type of car. In all cases you have to specify when ordering that you require the shock absorbers for use on an MGBV8, due to the different length caused by the depth of our five-leaf rear springs.

Having covered some 200,000 miles in my MGBGTV8 over the last 15 years, here are my comments on the ride comfort provided by the different makes of rear shock absorbers when fitted to my V8, bearing in mind I have fitted the full Ron Hopkinson handling kit and front coil-over-Bilstein suspension.

Standard lever arm - I would give them full marks for comfort, but only 2 out of 10 for overall performance due to their relatively poor reliability and need for early replacement.

Konis - I find they are totally unsuited to the characteristics of our five-leaf rear springs even when set on their softest setting and they gave a teeth-chattering ride even on smooth motorways. I discarded them after less than 1,000 miles of use. Marks out of 10 - nil!

Bilstein - In theory these should give a good ride as they match the Bilsteins on the front of my V8, but the ride is choppy and harsh. Marks out of 10 I feel would be 4.

Spax - As I had such excellent results from an earlier set of oil-filled Spax telescopics, I now plan to fit the gas-filled variety and will report further when I have had them in service for a while.

We await Gordon's report on his gas-filled Spax units and the comments of other members on their experiences with shock absorbers on the MGBV8. (Editor: Gordon subsequently reported his in service experience with the Spax units - see the second footnote below).

Footnote from Roger Parker. Gordon's experience is long and extremely useful. However where he is about to tread I have already trodden so my comments may be useful. My own experience followed a similar path to that of Gordon with the performance of the lever arms not being dissimilar. I went to a Spax oil-filled conversion a couple of decades ago and found these gave superb service and performance. These only became subject to a change when corrosion on the upper sleeve cover then exposed the piston to the weather. I naturally changed these for another pair of Spax, but these were the new gas-filled Spax which had replaced the previous spec.

Expecting similar performance, I was a little surprised to find that immediately after fitting these I believed I had replaced the dampers with a solid steel bar, such was the solidity of the rear! Even winding to the minimum setting I found the ride at best poor and the handling only very good on smooth roads. Bumps in bends would see the rear bouncing out of line without the need for power inputs. The disappointment did not improve with time and miles covered and by 10,000 miles use I replaced them with Konis which have shown a much improved standard of control and ride.

I would therefore want to confirm that the gas-filled Spax of the late 1980s have been consistently softened in their ride compared with the product offered in 2002, otherwise I fear that Gordon's experience with previous Konis will be the same as with the gas-filled Spax.

Editor: The question of telescopic shock absorbers as suitable replacements for the original lever arms was raised at the first Don Hayter Talk put on by the V8 Register at Sandford-on-Thames on Saturday 23rd February 2002. The talk on the concept, development and production of the MGBGTV8 by Don Hayter was a magical afternoon with many insights into the issues and concerns that faced the team designing and developing the V8 powered MGBGT. Geoff Allen, the V8 Historian from the start of the V8 Register in 1978 and a member of the Rectifications Department at the MG Factory for over 27 years, provided his recollections of the V8 during Don's talk. The question and answer session that followed was fascinating.

A twenty three page transcript of Don's talk, Geoff's recollections and the question and answer session that followed, with photos, has been produced by Victor Smith. Copies of the transcript in Word and PDF formats are available on a CD for £7.50 (reduced price of £5.00 to members of the V8 Register). All cheques payable to "V8 Register - MG Car Club" please, mailed with your order to Victor Smith - click the "contacts" button for details of the mailing address.

Follow up report from Gordon Hesketh-Jones (May 02)
Having now completed a 2,000 mile trip to John o' Groats for the le Jog event and also a 6,000 mile trip to Sicily for another rally, I can report that the Spax gas filled shock absorbers, set to the softest setting (28) give excellent results in terms of ride and handling. Assuming that they will last as long as the oil-filled versions, I would mark them 10 out of 10. Does anyone want a slightly used set of Bilsteins!

Copyright reserved by the V8 Register of the MG Car Club, PO Box 251, Abingdon-on-Thames, Oxfordshire OX14 1FF