Success today! Got her purring again!
The engine rebuilder said I had a cracked head, so I bought one that had been rebuilt and put it on. Followed the manual and put in a Cometic gasket and new copper seals on the fuel and oil banjo bolts. Today I wrapped up the job, put the bonnet back on and took her out for a spin. What a delight! I had forgotten how sweet she sounds! It will idle clear down to 350 RPM. SO smooth in the lower RPM’s, just a little guttural in the mid ranges. Sweet!
I work solo, so I installed a chain hoist to gently lower the head and to install the massive hood (bonnet).
I learned a few things.
Take out all but four head bolts to put the head on, then slip the others in and tighten them with a double nut.
Lower the fuel in the bowl 1/8" so it does not overflow or sit in the hisser. Use a 5/8" dowel to measure, not 1/2"
I still do not have the idle high enough. I thought the idle adjusting screws brought it up. They did just a little. Do I need to clean out that air circuit?
Again, just as happy as a kid with a new puppy. She is on the road again!
Update on Purrs like a Kitten.
I think I got her to purr like a kitten. Smooth at 600 RPM in gear. An occasional miss. Probably will update ignition and wires.
I found the “intermediate” specs for distributor advance in a Jaguar performance book. The static ignition timing (I assume not really running) is 5* BTDC for 3.8L dual SU, B head dark blue and 9:1 compression.
Glenn’s Tune Up Guide shows centrifugal advance starts at 225RPM. At 1100RPM, it should be 9* and at 2000RPM 13*. No wonder I could not get it right. I was timing at 5* at 600 RPM, like an American car, but the advance has already kicked in by then. The idle was way too high, and I could not figure why. I seated the butterflies properly, and put a good spring on the accel linkage. Now with the timing proper, it purrs.
Well, she purrs like a kitten, drools and wets like a puppy.
Beautiful car !! How fun to have it on the road and running well. Your Mark 9, 3.8 does have a spec of NO advance below 225 or 250 depending on comp ratio, but there won’t be much mech advance coming in at 225 rpm…which is well under idle of 500 spec for the Mk9. Mechanical advance can just barely start to come in at 200 to 400 but it is minimal, just a few degrees, reaching 7-10 at around 1000-1200rpm and 14-17 at 2500 to 2800. Then 9 deg of vac will come in if the original vac unit, (vac is often 11-13 of vac). Should be looking for 35-38 all in at 2800 to 3100 or so . If we take 17 mech and 13 vac you have 30…so static would be 5 to 8. Ta daaaa…and 5-7 is spec depending on engine, compression, distributor. Updating a distributor and vac unit could give slightly different data points…and static of up to 10 or 12. A lot depends on what compression ratio is…is compression near spec and even, are clearances set etc. Ultimately tho the running and listening/watching is the test…and a road test. If you put a little piece of wood across the cam cover can you set a full champagne flute there? If so…drink the champagne and congratulations. Start up quickly and without kick back? good. cruise in top at even speed with no miss: yippee, Lug in top gear up a hill with no ping or shudder? hurrah !! More champagne. Don’t let that chain touch the car !!!
Nick
Thanks, Nick! I had the timing chain too loose and it rattled at idle, now that is fixed as well.
The new head has perfectly set valve clearances. It solved my compression issues. The car is 9:1 compression ratio. I am using 91 octane gas, no ethanol.
My question, and I have looked for answers is: I have a timing light. I am using the crank timing marks. Do I set the timing at 9* BTDC at 1,100 like Glenn’s book WITH THE VACUUM OFF OR ON? I have all original equipment, and pulling the vacuum advance off makes a big difference. American cars you pull then plug the vac hose.
According to what I read from you, I am assuming off.
not quite sure what you mean/are looking for at 1100rpm…If your car is running great with the road tests I mentioned…great…as said sip champagne…and if so, You can check to see what the settings are so you can note them for future reference. The timing Spec for the Mark 9, 9-1 is 5 deg BTDC static…OK…good so you set it, not running at 5 deg BTDC. Then when running, if your timing marks are in some form of numbered degrees so you can see them, (if not you can make the marks with white nail polish) use the timing light to track your advance…run at 1000 rpm and see what it is…and at 2,000 and at 2500, 2800, 3000…(maybe 3200 as well) at which point all timing should be in.Glenns tells you (9-1 distributor) 40665A and if stock vac unit 5-12-8) that the mechanical will start to come in right away and give 9deg at 1100rpm and 13 deg at 2000rpm. I take this to mean that is the mechanical degrees of advance to be added to the 5 static…so you would see on your timing marks…14 at 1100 and 18 at 2000. When vac comes in it will increase to max of 12 more…and at whatever the max advance rpm is…will show 30 on your timing light. Under load it could be a little more as 34 -35 is about right at about 2800, …but again…the running seat of your pants road test tune is the final adjustment. (I have seen posts in the forum about 25 deg of mechanical advance…I don’t know where that number comes from?)
anyway,…using your timing light will just show you what your mechanical and vac are doing, and when …and what your all in timing is…: some like to tune using a vacuum gauge …I have not done that…maybe they will chime in. Also happy to have others comment on the above for verification.
Nick
PS…some time ago John Littler posted this: I set most carburetted XK engines at 10 degrees BTDC with a further
mechanical advance of 22-24 degrees. This brings the total advance to 32-34 degrees around 3000 RPM. It was also noted that the Jaguar Factory settings of the day were based on fuel of the day in England…80 some odd octane. I have a rebuilt distributor, re curved and a new re curved vac unit on my 8-1, 3.4 and I set the initial static at 11 D BTDC…seems perfect in start ups and road tests.
So in terms of physical engine smoothness (vibration) that’s possible (flute of champagne on cam covers?)
My engine idles well at 600 rpm in that there are no misses, it is stable and doesn’t threaten to stall or die, and accelerates briskly from said idle. But on this Series 1 4.2 E-type there is plenty of noticeable vibration at idle speed, which can be felt through the steering wheel. I have new uprated engine mounts from SNG (installed two years ago.)
Even at 800 there is still considerable shake, I don’t think it really eases until rpms exceed 1200 or so. I’m at about 8° BTDC when timing was set statically, vacuum disconnected, at about ~500 rpm. Originally around 12°, but after I retuned the carburetors I was getting some pinging on the open road in summertime temps. So I backed off a bit until there was only a hint of knock going up a hill in 4th at ~25 mph.
OMG! WOW! There is NOTHING like cruising a big Jag on historic Rte. 66 in a cool fall evening! She LOVES the back roads! I have invested many hours in making her run smoothly, with a head change, carburation work and timing tweaking, insulation and sound deadening. WHAT A JOY! She is quiet, responsive, agile, and those 4 disc brakes easily tame those 2 tons. The open cowl vent letting a little heat drift through the heater and floor vents…The purple aviator dash light…What an experience! No wonder a person could get hooked on these wonderful relics!
I do not think so. How would a person tune a running car, except by timing light and tach which measures engine RPM? Also I believe Glenn’s Tune Up guide of degrees of mechanical advancement to be actual, not added to the 5* static. When the vacuum advance is added, more advance is added.
I did as the book advised. Last night I ran regular American 87 octane fuel and had no pinging at WOT, low RPM. It starts immediately hot or cold and does not run on after shutdown. The exhaust is clean and the plugs a very light powdery tan. The engine seems to have good torque. My air/fuel mixture ratio is from 12.5 to 14.7. After MUCH tinkering, I think I have it right now.
Thanks for everyone’s input.
Today I am headed for Brits in the Ozarks, an all-English show in Fayetteville AR, USA. Gonna drive the back roads to Springdale and meet up with British Iron Touring Club of NWA and take two tours with them. It will be fun, now that she is running so well.
Between lags in this conversation I drove her from Joplin to Bentonville, distance of 62 miles. My daughter lives there. I will be showing the car in it’s mostly unaltered state. Seats are old, but original, cracked leather. Wood and chrome are excellent.
Good to meet you and your wife, John. Love the Jag E-type.
For us, it was proving weekend. I only had 200 miles on the new head.
We must’ve put on 400 miles. The British Iron Touring Group took tours Thursday of 160 miles and Friday of 80-90. Admittedly the big Jag was not as nimble on the Ozark twisties as the MG’s and XK140, but with some effort stayed with them. The highways getting to and from the show I ran for an 80 minutes each way at 70-75 MPH. Although it hummed along fine I thought the RPM a little higher than it needed to be, at 3-3.5K
No problems, except a sticky float valve due to a tiny speck of crud, fixed in 15 minutes.
Oh, and we got 1st place in our class, Early Jaguar Saloons. There were 158 cars registered
Castrol donated cases of 20-50W oil, of which all the English car owners were grateful.
