APRIL 27 rH , 1907.

THEAUTOCAR B Journal publisbet > in tbe interests of tbe mecbanicall\7 propellet > roat > carriage.

EDITED BY H. WALTER STANER.

No. 6or. VoL. XVIII. SATURDAY, APRIL 27TH, 1907.

[PRICE 3D.

TlfE AUTOCAR.

(Published Weekly. )

Registered as a newspaper for transmission in the United Kingdom.

Entered a s second-class matter in the New York (N.Y. ) Post Offiee.

EDITORIAL OFFICE:

COVENTRY.

PUBLISHING OFFICES:

20, TUDOR STREET, LONDON, E.C. , ENGLAND.

CONTENTS. NOTES

PA.OE

· · 595-596

US EFUL HI NTS AN D TIPS : LEAKY TYRE VALV ES ( 1LLUSTRATED)­

C U R I 1-G HARSH AND SQUEAKY B RAKES-D R1v1NG Co01.1NG FANS-F RENC H CHALK SPR I N KLER . .

5 97

SOME D ETAILS OF TH E ENFIELD C ARS (ILJ.USTRATF.D)

ROYAL A UTOMOBILE C1 .ue COMPETITIONS GEAR C HANCING. Bv MARCUS \V . BounooN . . WITH C AR AND T E NT .. TII E 25 - 30 H. P . PILGRIM ( AR (ILL USTRATED) • . CONTI NENTAL N OTES A NO NEWS {lt!.USTHAT E D ) TH E .M OTOR C L U B (ILL USTR ATED ) THE N EXT O LY)t P JA SHOW A VI S IT TO TH E W'EYBRJOGE RAC I NG T RA C K • , (ORRES PON DENCF. . . TH E 40 H.P. S IX-CYLIN DE R H UR MID C A R (ILLUS T RATED) . . I:s T H E H OUSE OF CO)tMOSS TH E K EW 30 H.P. \VHITE GENE RATOR (I L LUSTRATED) TH E N EW R OAD TO B L ACKPOOL .• TH E 4 0-50 11. P. S I X CYLI NDER R OL LS - ROYCE • . O ccASJONAL Goss 1r. Bv O TH E A VTOCHAT " CLUB DO I NGS ( ILLUSTR ATED) FLASH ES R OAD MAK I NG A ND l\1AI NTEN A NCE THE EORSE-POWER OF THF. PETROL :\I OTOR , • SO)I E QUERIES A SD R EPLl ES

.. 5 98-60 1

601 . . 6o2-603 . . 604-605 . . 606-6 10 .. \J u-61 2

61 3 6 14 61 4 . . 6 15-61 9

620 620 621 621 622 622 623-624 . . 625 -626 . . 627-E28

629-631

632

" THE AUTOCAR" SUBSCRIPTION RATES: Briti5h liles, 161. Abroad (thin paper edition ), zzs. Sd. per annum.

/ I Notes. Exhaust Anal ys is. Owing to the Vapour Emission Tria ls , th e question of exh aust anal ysis h as been consid erably dis cussed of late . I t appears to us th a,t an i,w es tiga tion of this sort might be made even mme use fu l if th e subject 11" ere considered fr om t 11" 0 stan dp oi nts in stead of one only. The mot or enginee r is na tur a lly Ye ry much interested in obtaining th e most . nearly compl ete combusti on possible. In oth er 1ro rd s, he wants t o make the ve ry best us e of his fu e l. On th e othe r h and, the person on the pavement, wh o, by the way, affects t o love loaths om e animal sme lls and to hate the odour left in the wake of a motor car , is o nly interested in that which issu es from the sil ence r. Now the recent Vapour Emission Tria ls deal t intenti onally with th e one aspect alone; that is , with th e exha ust as it issued fr om th e sil encer and 1Yhi ch might o ffend th e del icate sensi -

biliti es of th ose wh o breath e fretid odours with indiffer ence, if not pl easure .

What is ,ranted is an analysis of the products of combu sti on t a ke n right up at the exhaust port and another at th e silence r. At the exhaust p ort the gases ar e still at extreme ly high t emperatures ; in fact , combustion is not a lw a ys completed. This is, c ne o f th e grea t sources of heat loss fr om an intern al combusti on e ng in e , and th ere is no doubt th at a good deal cou ld be !earned by th e car eful consid erati on of th e actual cond iti on of th e gases as th ey pass fr om th e engine, that is , th e moment th e engin e has released th em, and not late r at th e silence r. It sh ould be understood that we a re not advocating the abandonment of ana lys,is at th e si lencer, but that such ana lys-is shoold e supplemented by an investigati on at the e xh , st po rt. The nature of this investigation may be le f t o th e R.A.C. scienti ts , but p ectroscopy has its ssibilities- and its limitati ons. Cylinder Deposit. In the las t issue of l'he .Llf otor Cycle particulars a re gi,·en of a n interesting investigation. The deposit on th e pi ston and cylinde r head ,ms scrap ed from th e engine of a motor bicycl e which had been driven 800 mil es, and ana lysed. I t was found th a t practi ca ll y fifty pe r cent . of th e deposit consisted of roa d dust , whic h, as the ana ly st , Mr. Stacey J ones, pointed out , had undoubtedly been sucked into th e cy lind er through th e ca rburetter . ~ 011·, it is generally known th a t th e engines of motor bi cyc les a re much more subj ect to deposit th a n those of a rs. At th e same tim e, car engin es, p artic ul a rly tho se with high compress ion , ha , ·e to be clea ned out occasiona lly and th e deposit remo1·ed fro m the cy linde r h ez. ,J, Ya lve chambers, a nd piston top. It has been gene ra lly ass umed th a t th e rapirli ty with whi ·h th e deposit form s in motor bic ycle eng in es is due to th e fac t th a t a s th e rnst majority of t hese engines a re a ir cooled and run a t 1·ery hi gh engine speeds lu b ri catin g oil ha; to be used 1·ery fr ee ly-in fac t , to some extent th ey ma \· be sa id to be o il coo led-an l it has been quite natura l to ass ume th a t owing to th e p ro fus e use o f oil th e b lac k encrustation has been fo rmed.

It woul d a pp ear fr om th e a na ly sis that pl entiful lubrication is only pa rtly res ponsibl e fo r th e rap id fo rm a ti on of deposit, as ha lf of it is foun d t o be roa d dust. The carburetter of a motor bicyc le is ve ry much exposed. It is not only unprotectecl hy a bonnet , but it is much more in th e d ust and mud th a n the a \·erage ca r ca rburet te r. Jn other word s, th e air pipe of the cyc le carburette r is un q uestionably suck ing a large r p e rcentage of dirt th a n th e air pipe of a ca r carburette r. At th e same tim e it must not be forgotten th a t the bonnet of a ca r does not rea lly keep th e dust a 11·av from th e air inl et of a ca rburette r , for e \·en if a we ll -fi tting unde rshield be used in additi on to th e ordin a ry bonnet th e radia tor is open, and th e air sucked through it by th e fan is full of d ust, and th a t same air is inh a led by th e carburetter. Tn th e majority of cars no p rol"ision is made fo r keep in g th ~