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David Vizard

Imp tuning by David Vizard - Vizard did a series in Cars & Car Conversions during 1972. Every month he had a new article ready.

Jan. '72 Imp tuning Part 1 CCC look-in on the Imp : engine profile No.1 Chrysler 875cc engine / David Vizard; photos: Dave Grey. - Cars & Car Conversions, 19??. - p.85,87
This is the first part of a new series in which David Vizard tells all there is to know about tuning the Chrysler Imp
Feb. '72 Imp tuning Part 2

CCC look-in on the Imp / David Vizard. - Cars & Car Conversions 1972, February, p.48-49
This month David Vizard continues the Imp-tweak Saga and explains why bigger is better

Mar. '72 Imp tuning Part 3

CCC Look-in on the Imp / David Vizard. - CCC 1972, March, p.66-67, 69
About camshafts

Apr. '72 Transmission CCC look-in on the Imp / by David Vizard. - Cars & Car Conversions 19??. - p.54-55,91
Gearbox and gearing ratios: specialising your Imp
May '72 Carburation Look-in on the Imp / by David Vizard. - Cars & Car Conversions 1973, February?, p.52-53,55
This month David Vizard concentrates on the induction and exhaust systems to use at various stages of tune
June '72 Cheaper ways to power CCC Look-in on the Imp / by David Vizard. - Cars and Car Conversions, 1972, June. - p.68-69,71
The object of this exercise is to see how cheaply we can increase the power of an 875 Imp engine.
July '72 Front suspension CCC Look-in on the Imp / by David Vizard. - Cars and Car Conversions, 1972, July. - p.48-49
From understeer to nearly neutral camber.
Aug. '72 How to Group 1

Look-in on the Imp / by David Vizard. - Cars & Car Conversions 1972, August, p.60-61
After considering all the ways in which the Imp engine can be modified to give more power, we now turn to the problem of achieving extra go whilst retaining Group I spec.

Sept. '72 More on Group 1

Look in on the Imp / David Vizard. - Cars & Car Conversions 1972, September, p.82-83
David Vizard continues the Group I build - carried out on Jon Vicker's rallying Imp Sport.

Oct. '72 Modifying and strengthening the suspension

Look in on the Imp / David Vizard. - Cars & Car Conversions 1972, October, p.86-87,89,91
Tuning the Imp. A suspense-packed saga by David Vizard on modding and strengthening the Hillman baby's suspension. After taking a couple of months off to talk about Group One Imp preparation, David Vizard now returns to less standard topics and tells how to beef up and modify the suspension.

Nov. '72 Cooling

Look in on the Imp / David Vizard. - Cars & Car Conversions 1972, November, p.64-65
Don't blow the eau or boil the oil; David Vizard talks about the cooling system and suggests various setups. Reprint: Impressions 1985, April

Dec. '72 Contd. Look-in on the Imp / by David Vizard. - Cars & Car Conversions 1972, ?, p.64-65
David Vizard continues the 'ain't no substitute for cubic inches' theme and looks at the Paul Emery way of increasing Imp capacity
Jan. '73 Brakes  

Chrysler Imp / David Vizard. - pp.15-30. - In: Performance tuning : road, race & rally / Cars and Car Conversions; Michael Hill. - Crydon: Link House, 1972. - p.96
CCC Year book 1971; CCC Special 1972

Small bore power / David Vizard. - Cars & Car Conversions 1972. - p.48-50
reprint in Impressions 3 (1983), no. 8/9 (Sept./Oct.)
David Vizard tested both a single and twin Dellorto 40 DHLA Carburetors on a 875 Sport engine with a special head and cam.

In one of his articles David Vizard shows Strombergs to produce more power than the Weber.

Fitting pancake filters to an Imp is not recommended because of the position of the exhaust and the chance of drawing hot air in. Pancake filters get overhot in traffic and cause over rich fuel mixture due to very low air pressure. David Vizard wrote that he found that the standard air box gives more power than pancake filters. What valve sizes to use.
Standard seems to be 1.4" inlets and 1 1/8 exhausts. I read an article by Dave Vizard and from his tests he said 1 5/16" inlets were better, the 1 1/8 exhausts were only 2% better than the standard sport exhausts.
This sounds nice as less mass = better performance.

Rolling road Imp tune / David Vizard. - Hot Car 1975, May

Imp cam craft / David Vizard. - Hot Car
Imp camshafts only give their best if fitted the correct way. David Vizard gives you the low-down on doing it right.

David Vizard finds DynoTest No. 2 on the Imp a lot harder going / David Vizard. - Hot Car 1975, May. - p.36-37
the Piper 1RG is suitable for the ordinary Imp
Our cam swop, then, is really a comparison between the Piper 1RG and the Imp Sport. Those of you whose cars were built before the chassis number Imps with a standard Imp camshaft will get 3-4 bhp more with the Piper cam. Fitting the Piper cam to earlier Imps is no problem, as it doesn't affect the oil seals, but fitting the Imp Sport does, so the swop to the Sport cam is much more involved.
I did quite a lengthy piece on fitting Imp cams only a few issues ago, but it did deal more specifically with fitting the cam while the engine was out. the runs was that the mixture end which seats up against the Solex analyser showed that the mixture casting.

Vizard, D.
Cheap Imp head mods. / David Vizard and Andy Chesman. - Hot Car 1975, June

Special Reece Fish manifolds also exist. They're not cheap either. How much benifit is derived from these, is not clear. Vizard says that compared to the SU manifold it is a lot better and does away with the hot spot.

Welcome to the amazing vizard's workshop : Roller distributor; Bore preparation. - Cars & Car Conversions p.54-55, 57
Roller distributor: about fitting a roller bearing in the top bearing, the one directly under the advance/ retard system
Bore preparation: bores should be honed to finish them, because:

  1. during the running-in period on a plain bored finish (no honing), as much as 15% of the ring life is gone
  2. the running-in period (without honing) can be substantially longer, before the rings reach their peak sealing performance
  3. once they have reached peak sealing performance, it is often inferior to that achieved on a honed bore.


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Version of: 16 Nov. 2013
File started: 29 Sep. 2013