Compression Pressures, Vitesse 2L Mk2

[PatK]

Hi all, I'm starting work again on the Vitesse this winter and yesterday thought that I would check the cylinder compressions on Nr. 1 to 6. The engine does not seem to burn oil, but the exhaust fumes definitely smell of burnt oil and the plugs soot up easily. The test was done cold with the plugs out but I've just remembered that I did not open the throttle fully and I guess that this would make a difference?

These are the pressures, 1. 135 psi, 2. 140psi, 3. 140psi, 4. 135psi. 5140 psi. 6. 135psi.

Is this OK, the engine runs fine or perhaps the smell of oil in the exhaust is valve guide wear ?

Thanks everyone.  Patrick

[Iain T]

You need to test again with WOT but those numbers look nice and even. 

Are the plugs wet with oil or is it just running rich?

Iain

[johny]

A puff of smoke from exhaust when opening throttle after trailing down an incline would indicate valve guide oil.... Whats the mileage on engine and its rebuild status? Has it got a rocker oil feed?

[Pete Lewis]

just to check this doesnt have the dreaded external rocker oil feed fitted??  ( Ha Snap )

dont overfill the dashpots and is this on strombergs ,  had  feeling it had SUs

weaken off is the simpest move    rich running washes the bores too much that can make things oily 

Pete

 

[PatK]

1 hour ago, Iain T said:

You need to test again with WOT but those numbers look nice and even. 

Are the plugs wet with oil or is it just running rich?

Iain

Thanks Ian, no the plugs are not wet just get sooty quickly.I will do the test again and see how much it increases. I guess any reading around 150 psi is good?

[Pete Lewis]

yes thats some fair results on a cold engine   as all quite close  no wild variations ,

do check the breather in the rocker cover there should be a gauze held unde rsome cheap tinwork  take it out and wash in petrol 

you wont know if its blocked until you find it 

Pete

[PatK]

11 minutes ago, Pete Lewis said:

just to check this doesnt have the dreaded external rocker oil feed fitted??  ( Ha Snap )

dont overfill the dashpots and is this on strombergs ,  had  feeling it had SUs

weaken off is the simpest move    rich running washes the bores too much that can make things oily 

Pete

 

No Pete I have removed the dreaded fitting on your advice and also fitted Strombergs, I did notice that the oil level in the Strombergs seems to slowly go down, perhaps this is the problem?  I will weaken off the mixture and see if that makes a difference.

[Pete Lewis]

are the stroms top adjuster or jet underneath ??

Pete

[PatK]

18 minutes ago, johny said:

A puff of smoke from exhaust when opening throttle after trailing down an incline would indicate valve guide oil.... Whats the mileage on engine and its rebuild status? Has it got a rocker oil feed?

Hi Johny, sadly I don't know the true mileage, and yes it could be valve guide wear. The cylinder head looks like it was overhauled some time ago, having a non standard paint finish and I suspect it had been modded possibly with non standard camshaft and the fitment of over large SU carbs, which have now gone thankfully. If I get time this winter I will take the head off and overhaul it.

[PatK]

7 minutes ago, Pete Lewis said:

yes thats some fair results on a cold engine   as all quite close  no wild variations ,

do check the breather in the rocker cover there should be a gauze held unde rsome cheap tinwork  take it out and wash in petrol 

you wont know if its blocked until you find it 

Pete

Yes Pete I will do that although I did it not too long ago, but I will check again. As a matter of interest Pete, can you drop the sump with the engine in situ.?  I have a scissors lift and can get under it no problem.

[johny]

To answer that one, yes the sump can be removed for bearing and oil pump inspection and is well worth doing. However you need to undo the engine mounts to be able to jack it up quite a bit so the sump can drop down to clear the oil pump intake (remember this goes to almost the bottom of the sump) and can then be slid back over the rack and out. I did it without undoing the exhaust but the difficulty, especially if the car is up in the air, is where and with what to jack the engine - a hoist would probably be best but I jacked the engine and inserted wood blocks between mounting brackets and chassis to keep it securely raised...

[Pete Lewis]

yes the sump is a bit of a fiddle the oil pump gets in the way or easy removal 

you can faf around and it just drops off when you dont know why

on the vit6 it had a gauze  splash screen that got in the way in fact i undid the oil pump bolts through the gap and dropped the pump

it went back without the gauze who needs strainer anyway  Hmm  

yes lift the engine a fair  bit to allow clear air between rack and sump  just watch the hoses etc.

its a lot easier on the big saloon Ha!  

 

[PatK]

1 hour ago, johny said:

To answer that one, yes the sump can be removed for bearing and oil pump inspection and is well worth doing. However you need to undo the engine mounts to be able to jack it up quite a bit so the sump can drop down to clear the oil pump intake (remember this goes to almost the bottom of the sump) and can then be slid back over the rack and out. I did it without undoing the exhaust but the difficulty, especially if the car is up in the air, is where and with what to jack the engine - a hoist would probably be best but I jacked the engine and inserted wood blocks between mounting brackets and chassis to keep it securely raised...

Thanks Johny, thats good information, hopefully I may do that this winter, I assume that you can also access the crankshaft thrust washers here also, but I have yet to check the end float.

[PatK]

1 hour ago, Pete Lewis said:

yes the sump is a bit of a fiddle the oil pump gets in the way or easy removal 

you can faf around and it just drops off when you dont know why

on the vit6 it had a gauze  splash screen that got in the way in fact i undid the oil pump bolts through the gap and dropped the pump

it went back without the gauze who needs strainer anyway  Hmm  

yes lift the engine a fair  bit to allow clear air between rack and sump  just watch the hoses etc.

its a lot easier on the big saloon Ha!  

 

Thanks Pete, I'm quite good at faffing around and time wasting!

[johny]

Yes all accessible but front main bearing needs bridge piece removing so if others look ok probably best to leave alone. Difficult to get it to seal again without removing engine front plate. Other problem is maintaining cleanliness...

[Pete Lewis]

so why do you fancy getting oily then ??? is there a crank problem 

and something to order is  Canley do a THICK  sump gasket its worth getting one far better than the usual paper type 

Pete

Edited October 16 by Pete Lewis

[PatK]

Oily is my middle name Pete!  Actually thats why I was seeking information on the cylinder pressures because if the opinion was that they were all too low, then i thought that I would get the pistons out, re ring them and at the same time fit new big end and main bearings also plus a glaze bust. If my Jag Mk2 sells at auction tomorrow then I will have lots of room to work on the Vitesse and the money to do it with, but it probably won't sell as classic car prices have dropped off a cliff lately as we all wait for the budget, nobody wants to spend money.

[PatK]

4 hours ago, Pete Lewis said:

are the stroms top adjuster or jet underneath ??

Pete

They are jets underneath Pete

[johny]

Although your readings look pretty good you could also have done a wet test to compare how much difference a capful of oil in each bore makes. Obviously got to be the same instrument and then negates any error in it.... 

[daverclasper]

6 hours ago, PatK said:

Thanks Ian, no the plugs are not wet just get sooty quickly

Hi Pat. Maybe to bear this in mind?, that my Vitesse in slow running/idling, the plugs are quite sooty. general running, brownish. Cruising on Motorways at 2,500 rpm (overdrive and 3.27 diff), plugs are a pale grey. Other folk have noticed differences in plug colour, with different driving conditions. Maybe not typical, or how it should be?

[PatK]

Thanks Dave, that makes good sense, as after a couple of good runs this summer when it wasn't raining, I checked the plugs and they were light grey.

[PatK]

1 hour ago, johny said:

Although your readings look pretty good you could also have done a wet test to compare how much difference a capful of oil in each bore makes. Obviously got to be the same instrument and then negates any error in it.... 

Thanks Johny, I will do that later on when I start the complete overhaul of the car and engine, but only if the Jag sells.

[johny]

well if the oil makes no difference theres not much engine overhaul needed as both rings and valves good so its just a case of investigating possible worn valve guides?

[Pete Lewis]

and dont overfill  the dashpots 

i asked as top adjustables can leak out damper oil , bottom adjusters dont  have this problem

advise you dont use plugs with an R in the suffix 

and at 50 yr old whats the problem with a bit of oil burn , if you dont expect utopia

Pete

 

 

[PatK]

11 hours ago, Pete Lewis said:

and dont overfill  the dashpots 

i asked as top adjustables can leak out damper oil , bottom adjusters dont  have this problem

advise you dont use plugs with an R in the suffix 

and at 50 yr old whats the problem with a bit of oil burn , if you dont expect utopia

Pete

 

 

Ah Pete I wish I had a bottom adjuster, but at 83 years old its a bit too late!!