| Author | Message | ||
     Jeff Martin Frequent User Username: jeff_r_1 Post Number: 255 Registered: 07-2018 |
If one looks in the manual it clearly states that IO is 12 degrees from TDC and EC 6 degrees after TDC, but taking actual measurements, it's not even close. I was going to add some more timing marks to get a better idea when setting the ignition timing. Is RR talking about cam shaft degrees on the flywheel, but that still makes no sense to me. The cam shaft makes two revolutions per one revolution of the flywheel, so if one doubles up the space, it still does not get to my 12 degree mark. It has to be actually 12 degrees and 6 degrees, it has to add up to 360 on the flywheel, but it doesn't.      . | ||
| Bill Vatter Experienced User Username: bill_vatter Post Number: 139 Registered: 09-2004 |
There are different camshafts, different flywheels, and different books containing specifications. You really need all three to match if you want to make sense of it. The data you quote is for a Silver Wraith. The flywheel you show is for a Bentley. | ||
| Bill Vatter Experienced User Username: bill_vatter Post Number: 140 Registered: 09-2004 |
The data for a Bentley: inlet opens 3.5 deg. after TDC Inlet closes 43.5 deg. after BDC Exhaust opens 40.5 deg. before BDC Exhaust closes 1.5 deg. before TDC Data is for valve clearance set to 0.030 inch, the "flywheel marking clearance." | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 256 Registered: 07-2018 |
Thanks Bill, that makes sense now !  | ||
| NORMANGEESON Unregistered guest Posted From: 81.99.74.184 |
Jeff The dimensions that you are seeking for your flywheel are 3.5 degrees and 1.5 degrees. Unfortunately, you have made the classic error of using measurements from a manual for early flywheels. Even with the correct flywheel marking data you will need to know the part number of the camshaft that is fitted. Although some four camshaft part numbers are commonly listed, in fact, at least nine camshafts and two more variations were used across the six-cylinder post war range. The flywheel markings, except for TDC, will be of little use to you. If you have not fully modified the damper and also increased the slipping torque, as R-R did, any static settings will go out of the window once the engine has bedded in. The best you can do is set the timing at (IO) inlet opens @TDC, with No 1 inlet valve tappet set at 0.030 inch / 0.035 inch. With that setting the inlet valve will open 26.3 degrees BTDC and open for 304 degrees. You will find this opening is far longer than any Ferrari, Aston, Jaguar or American engines. For that reason of long valve opening duration, I would suggest you keep to the factory spec. Norman (Message approved by david_gore) | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 262 Registered: 07-2018 |
This thread is not about cam shaft timing, it's about ignition timing, and my confusion about the degree marks on the flywheel; and that has been solved, or at least it has satisfied me. Yes the distributor is effected from the movement of the damper, but not really since there is so little movement of the damper, it doesn't affect the ignition timing, even more so when the engine is idling at around 400 to 600 rpm, the damper is not even doing anything because the crank shaft isn't even flexing at that speed. If the damper springs are broken, the the ignition timing may very well be affected, but then the damper will have to be repaired and a timing light may even show the fluctuating spark because the damper is moving around to the point that's effecting the ignition timing. If the damper was in this state, I would think the car would not be drivable at highway speeds, and most likely the crank would have a catastrophic failure. At any rate the part number of my cam shaft is RE 19517, from this thread and all it's info on the subject. My question was not really answered on the last post, just to bring that up. http://au.rrforums.net/forum/messages/16999/41837.html?1627256905 | ||
| David Gore Moderator Username: david_gore Post Number: 3970 Registered: 04-2003 |
Jeff; Christopher Carnley has asked me to post the following contribution on his behalf:  . |
