Thank you for the numerous responses to my post regarding the question of whether or not I bent valves when I reinstalled the head. I have not touched the parts involved since that time, about a year ago, and therefore am uncertain how to even begin. Several people have already suggested what could be done. Thanks for that. However, I wanted to advise you of the following as it may affect your recommendation of what to do first.
Yesterday, I removed the two valve covers to see the relative position of the two camshafts. On the intake camshaft, what I think is called the camshaft tappet, (the part of the camshaft that depresses the valve?) is dead center on valve #2 (the second valve from the back of the engine). On the exhaust side, at the fourth valve from the back of the engine (valve 4?) the tappet is slightly below the center of the valve tappet.
I donāt recall which way the camshafts rotate so I am uncertain if the camshaft has already depressed #4, or is just about to depress it. My question is, should the two camshafts be in sync as far as the relative position of the valves? For example, if the tappet on the #2 intake valve is dead center on that valve, should #4 exhaust tappet be dead center on the #4 valve?
#1 will be at TDC (ābunny ears,ā where the setting tool is engaged, on both cams) and #5 will be taking on fuel/air, meaning the intake-side lobe of #5 will be close to opening 5ās intake valve.
Canāt help with cam timing specifics on this engine. I can offer a path to better understand the process.
Check a diagram for the two chains at the front of this engine. The engine runs in a CW manner. Does it follow that the cams also turn CW? Stare at the drawing or picture and conclude. Best way to learn, do. As opposed to listen to what others say. Not to demean that process by any means.
Most if not all six cylinder in line engines have the same firing order. Look it up. The ābestā thing again.
Check the four cycle principle of engines., I could name them, but will defer to your discovering or remembering them.
You may note that two cylinders will appear at TDC at the same time !!
You may not eth position of the valves on each at that time.
So, can you deduce if the valve positions are correct in respace the position of the respective piston???
AKA āthink it outāā¦
Now, if I can āthink outā ho to restore the WIFI to my was smart TV!!!
Lou,
You donāt mention the model year of the car in question and I seem to recall that you have more than one. What year is this about? Do you have the correct Jaguar Repair Operations Manual (ROM) if this is a Series I or Series II or the Series III Service Manual if this is a Series III?
These documents provide detailed instructions on cylinder head removal and replacement including the special tools required, like the camshaft timing tool. I am trying to understand what documents you followed when you removed and replaced your cylinder head if you did not know to use the camshaft timing tool when setting up the camshafts.
You really need that tool. You can get close by eye but every time Iāve tried and then stuck the tool on, it was several degrees off. Assuming you havenāt disconnected anything, rotate the engine until the notch in the cam behind the first bearing cap is facing up and centered between the two rails that the cam cover seals on. Both cams should have that notch facing up the sane way, but since the cams are angled the notches will point away from each other, kind of 1 and 11 oāclock if you are looking at it from the front. The tool balances on the side rails with the tab in the notch when itās at perfect TDC
I havenāt read this for accuracy but the picture shows the tool placement.
Paul: The car is a 1971 XJ6 with the standard straight six Jaguar engine and automatic transmissionā¦ As with most USA cars it has the Zenith Stromberg carburetors. Itās air conditioned. The car is āas builtā, with no modifications to the engine or associated parts. It has about 44,000 miles. Iāve owned it for 32 years.
I have thee manuals for the car; the Factory Manual, AutoBooks and Intereurope.
Frankly, I find the factory manual to be complete but confusing for a novice like me. As it should, it assumes the reader already has knowledge about how an engine functions. For most work, I depended on the Autobooks manual supplement by the other two.
I also have all the technical bulletins issued by Jaguar between 1971 to 1973; Lucas Fault Diagnosis and Part, and Lucas Confirmed Specifications and Service Parts. . I recently picked up a Damlier Workshop Manual, which is to totally different from the Jaguar Manual. Although it covers the same car and years. First of all, its written sideways. You must turn the book 90 degrees to read it. And itās filled with drawings. So I seem to have written stuff covered.
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The intent of valve timing is indeed to synchronize the valves with the piston movement, Lou - and the cams with each otherā¦
Your description of cam positions is pertinent, but too complicated to sort. As other have said; to synchronize everything (cam timing) you set the engine to TDC - then set the cams with the cam setting tool - then fit the head to the engine, and fit the chains. If you omitted either; your cam timing is dubious - like playing Lottoā¦
You do not state if the cam chains are fitted? The point is that the engine must be on the TDC for a meaningful assessment of cam positions. At which stage the cam tool can confirm correct cam positions - if you are on the correct TDC.
A āsafeā suggestion; disconnect the cam chains from their sprockets, unbolt the cams enough to avoid the cams opening the valves, turn the engine to TDC, reposition the cams to roughly correct setting with the cam setting tool.
Then bolt down the cams, again checking setting with the cam setting tool - and fit the chains. If this is successfully done; the cams are correctly set - and the engine can be turned safely. To check valve clearances or using a compression test - eventually detecting bent valvesā¦
Or simply remove the head and check the valves for bend, replace bent valves and refit head with the correct procedureā¦
