big end shennanigans

Moderators: Aceman, ecosselynx

chrismpw142
Posts: 8
Joined: Tue Oct 08, 2019 5:01 pm

big end shennanigans

Postby chrismpw142 » Tue Oct 08, 2019 5:10 pm

Hello all - new member here from North Wilts, with my 3rd "Jag" but my first classic "Jag" a Daimler V8 2.5 from 1966. I've run classics for 30 years - including 2 MGs (Midget and BGT), a Scimitar, a Rover p6. Generally I do all the work myself apart from major / heavy jobs.

I've had this car as long as it takes for oil to trickle from the tappet chest back into the sump. Overall its in great condition and drives beautifully HOWEVER......

On my prolonged journey home - longer than the quick test drive before buying - I've heard a subtle sound which is muttering the words "big ends" into my psyche. That and the oil pressure dropping to 20psi when hot, sometimes momentarily dipping lower on tickover. Dammit!

So my questions - is this the type of engine where the big end is an immediate issue where I could lose a con rod through the side of the engine, or is it something where I can enjoy the car for a bit before its taken off road?

Is it the kind of job that can be done on these engines just by dropping the sump off in situ?

Can anybody recommend a jaguar specialist or engineering specialist in the North Wilts / Gloucestershire / Oxfordshire area who would be worth speaking to?

Obviously I've just emptied my account on this rather lovely motor, and ain't got a lot to spend now!!

All the best

Chris

User avatar
J44EAG

Moderator
Posts: 5744
Joined: Sat Oct 20, 2007 9:57 pm
Location: Warlingham Surrey/Faversham Kent

Re: big end shennanigans

Postby J44EAG » Tue Oct 08, 2019 5:26 pm

Running an engine with low oil pressure will lead to progressively worsening repair costs and needless self inflicted damage. Oil and pressure are required to provide and engine with liquid protection. With reduced protection, major damage can and will result. Turning a blind eye to the issue could permanently terminate your engine. The more damage that is done to your engine, then the more it will cost to fix. Wear accelerates...it never improves.

Diagnose, understand and fix issues in this order. Then you can`t go far wrong.

Others here may be able to advise you of a local engine re-conditioner. Why not join a local JEC Region and take advice from local members who will probably know who to contact in their area.

Mike K
X350 Co-ordinator

2004 XJR

User avatar
JerryL770

Member
Posts: 75
Joined: Sun Jan 22, 2017 6:36 pm

Re: big end shennanigans

Postby JerryL770 » Tue Oct 08, 2019 8:12 pm

The XK engine is incredibly rugged and will run a long time with low oil pressure as long as you don't thrash it. I agree with Mike that sorting it sooner rather than later is best but just now, I think it is OK to run it for a while, depending . . .

20psi ?? At what engine speed? Is that the maximum you get? Does the pressure disappear completely at tickover? Is it better cold? How old is the oil? Long or short term treatment depends on the answers.

Without further knowledge, the first thing I would do would be change the oil and filter. I think the recommended oil for this engine is Castrol XL 20W-50. However, in your position I would use Castrol GTX. I think this would hold pressure better and will not burn as fast.

Good luck, I like the Mk 2s as well.

Jerry
JerryL
1970 E-Type S2 FHC. Dark Blue with Red interior. MX5 seats
Ariel Leader returned to the road since 1974 - now passed to someone more enthusiastic :)
Various R/C flying models

chrismpw142
Posts: 8
Joined: Tue Oct 08, 2019 5:01 pm

Re: big end shennanigans

Postby chrismpw142 » Tue Oct 08, 2019 10:44 pm

Thanks chaps, for your consideration and advice.

It's not an XK engine though, it's Turner's V8 2.5

On startup I get 40psi, this drops to 20psi when hot and idling (should be 30 by the book), and has dipped below to about 15psi when idling after a short steep climb. When hot and given the beans it gets to around 30psi, or 25ish while bumbling along at 40mph.

The oil is 300 miles old. However the type of oil in it is unknown. Not an ideal scenario I admit.

My head says have the engine rebuilt. However, the wallet says hang on a minute, and the heart wants to enjoy the car for a bit first, while the wallet recovers from its shock.

I am wondering if bearing replacement is possible with engine in situ and the sump off. This is a job I would be happy doing myself. I currently lack the means of hoiking the engine out in its entirety.

User avatar
piman

Member
Posts: 917
Joined: Mon Oct 29, 2007 7:32 pm
Location: Oswestry

Re: big end shennanigans

Postby piman » Wed Oct 09, 2019 9:58 am

Hello Chris,

The oil pressure gauge on MK 2s have a poor reputation for accuracy, so that is worth checking with a second gauge (mechanical), and as you don't know the grade of oil you have, it's worth a change to ensure the right oil. Is the engine mechanically quiet as worn engines tend not to be, especially when revved?

I would imagine that it is possible to do in situ, although I would expect that the front sub frame will need removing?
My only concern is that you will find that the crank is worn so a full strip down will be required? If the bearings are worn (showing copper) you might get away with replacing them even if the crank is worn but this will be a relatively short term repair. But at low mileage driving could be a year or two?

Alec
Mk 2 3.8 (long term restoration), MK1 Triumph 2.5 P.I.,2.5 X Type Estate, 564 Hymer Motorhome

chrismpw142
Posts: 8
Joined: Tue Oct 08, 2019 5:01 pm

Re: big end shennanigans

Postby chrismpw142 » Wed Oct 09, 2019 9:39 pm

The rest of the engine seems fine and she runs sweetly. My current thinking is to drop the sump and change the bearing shells in situ (so long as the crank isn't scored). I have some questions then for which I would gratefully receive opinions:

1. Has anybody done this?
2. Can anybody recommend or caution this route?
3. Can anybody suggest suppliers? (I'm aware of SNG Barratt and David Manners)
4. Would the shells be a standard size, or would I have to measure the specific diameter of the crankshaft (and hope its circular - how much non- circular is OK?).

I suffered an enormous amount of buyer remorse this morning and was quite grumpy. I've never suffered such remorse buying a car before. It was raining too. I'd spent all of my budget on the car, by far and away the most I've ever spent on a vehicle and have little scope to have her on the road. I was very annoyed with myself. And then I looked at her in the garage, smiling sweetly to me, those graceful lines and that pretty face and all was forgiven.

User avatar
piman

Member
Posts: 917
Joined: Mon Oct 29, 2007 7:32 pm
Location: Oswestry

Re: big end shennanigans

Postby piman » Thu Oct 10, 2019 9:35 am

Hello Chris,

It's a positive sign if the engine sounds good and runs well.

the shells will be marked with an undersize if they are, e.g. 010 or similar (10 thou under) no number like that is standard size, there is no need to actually measure the journal. Scoring is less of a problem than actual journal wear, you can polish the journalls with strips of very fine wet and dry (1500 grit r so) and light oil or WD40 as a lubricant if you feel it's necessary. As the shells have a groove in the middle, that part of the journal will not wear and it will be obvious if there is wear, as it can usually be seen and certainly felt.
Other sources of spares are engine reconditioners and engine spares suppliers e.g. :-https://www.fwthornton.co.uk/

I've no experience of the Daimler V8 engine but I would not expect it to differ practically from other engines I've worked on.

Alec
Mk 2 3.8 (long term restoration), MK1 Triumph 2.5 P.I.,2.5 X Type Estate, 564 Hymer Motorhome

User avatar
bobtills212

Member
Posts: 4
Joined: Thu Oct 10, 2019 9:35 am

Re: big end shennanigans

Postby bobtills212 » Thu Oct 10, 2019 9:44 am

Don't be disheartened!

I recently bought a 1968 model and despite looking over it the best I could when I got it home I found plenty of rust I had missed, which wasn't cheap to put right. It means that I have effectively paid over the odds for the car, but it's still my pride & joy. He gets admiring looks everywhere he goes and lots of people I've never met want to talk about him.

I also have a problem with the engine (more expense, I guess, but he's here to stay now so I'll just get on with it) - when the engine is cold there is a slight knock. I think, based on the speed of the knock that it is top end but I can't be 100% sure. When thoroughly warmed up - a journey of 30 miles or more - the knock disappears. There is a small amount of oil smoke coming out of the rocker cover breathers, but I believe this is normal.

The engine had a full rebuild 20,000 miles ago and oil pressure is Ok, about 35psi at 60 mph dropping to close to zero at tickover. It doesn't make any difference to the pressure if the engine is hot or cold. I haven't done an oil change yet but my 20W50 oil arrived yesterday.

Does anyone have any ideas about my knock?

Sorry for elbowing my way into your thread :oops:

chrismpw142
Posts: 8
Joined: Tue Oct 08, 2019 5:01 pm

Re: big end shennanigans

Postby chrismpw142 » Thu Oct 10, 2019 11:34 am

Thanks Alec that's encouraging.

I'm beginning to think I'm not as experienced as I thought at this game. Having yesterday taken out the heater box to renew the seals, unseize the flaps, flush and repaint, I put it all back together this morning. Then for the first time si central I've had her tried a cold start, to circulate and top up the water.

It wouldn't.

Oh blimey what have I bought? It won't even start in a reasonably chilled morning. The engine span and span (healthy starter and battery at least). Finally decided to rest her - probably flooded. Could smell fuel.

That's when I checked the engine bay and realised I'd had to take the dizzy cap off to remove the heater box. I'm such a monumental clown!

Fired first time with the aid of a spark!

User avatar
piman

Member
Posts: 917
Joined: Mon Oct 29, 2007 7:32 pm
Location: Oswestry

Re: big end shennanigans

Postby piman » Thu Oct 10, 2019 5:45 pm

Hello Chris,

your not the first to do something similar, we all have done things like that.

Alec
Mk 2 3.8 (long term restoration), MK1 Triumph 2.5 P.I.,2.5 X Type Estate, 564 Hymer Motorhome

340jag
Posts: 139
Joined: Sat Apr 22, 2017 7:35 pm

Re: big end shennanigans

Postby 340jag » Sat Oct 12, 2019 6:52 am

I find it very hard to justify spending £5000-7000 on a engine rebuild , when you can go and pick up a good 3.4 4.2 XJ6 engine for around £500-700 , you can keep the old engine , if it has a matching number to the car , to sale with the car .
That's what I did , it's more or less a bolt on job , made it look like a 340 engine , with HS8 carbs
On saying that , the way things are going , we all may need to drop electric motors in , if the Greens get there way :D

https://www.youtube.com/watch?v=TAoSCrBWgMo
Attachments
20180609_044018.jpg

chrismpw142
Posts: 8
Joined: Tue Oct 08, 2019 5:01 pm

Re: big end shennanigans

Postby chrismpw142 » Sat Oct 12, 2019 10:23 pm

Don't be disheartened!

I recently bought a 1968 model and despite looking over it the best I could when I got it home I found plenty of rust I had missed, which wasn't cheap to put right. It means that I have effectively paid over the odds for the car, but it's still my pride & joy. He gets admiring looks everywhere he goes and lots of people I've never met want to talk about him.

I also have a problem with the engine (more expense, I guess, but he's here to stay now so I'll just get on with it) - when the engine is cold there is a slight knock. I think, based on the speed of the knock that it is top end but I can't be 100% sure. When thoroughly warmed up - a journey of 30 miles or more - the knock disappears. There is a small amount of oil smoke coming out of the rocker cover breathers, but I believe this is normal.

The engine had a full rebuild 20,000 miles ago and oil pressure is Ok, about 35psi at 60 mph dropping to close to zero at tickover. It doesn't make any difference to the pressure if the engine is hot or cold. I haven't done an oil change yet but my 20W50 oil arrived yesterday.

Does anyone have any ideas about my knock?

Sorry for elbowing my way into your thread :oops:
Could your knock be piston slap? A piston rocking in its bore at the end of its stroke, but as if heats up and expands making less of a slap. Harmless so I hear (though annoying).

davidr

Moderator
Posts: 1913
Joined: Thu Sep 08, 2005 8:31 pm
Location: Salisbury, Wilts

Re: big end shennanigans

Postby davidr » Sun Oct 13, 2019 12:46 pm

This thread started to go of topic with an interesting debate about electrification of our classic cars so I have moved the last 2 posts to a new thread in the "General Comment and Chat" section of Club Comment so that conversation can flourish without hi-jacking this thread.
Best wishes
David Randall (Moderator)
XJS FORUM COORDINATOR
1996 XJS Celebration Conv. (shown on the JEC stand at NEC Nov 2015)
2001 XKR Convertible

Previously enjoyed!
1989 XJ-S V12 Coupe. 2006 XJ TDVi Sovereign. 1995 XJ6 3.2. 2013 XF 2.2d. 2009 X Type 2.0d Sovereign estate

User avatar
bobtills212

Member
Posts: 4
Joined: Thu Oct 10, 2019 9:35 am

Re: big end shennanigans

Postby bobtills212 » Mon Oct 14, 2019 8:26 am

Hello David.

Where is this section? I can't find it! :oops:

davidr

Moderator
Posts: 1913
Joined: Thu Sep 08, 2005 8:31 pm
Location: Salisbury, Wilts

Re: big end shennanigans

Postby davidr » Mon Oct 14, 2019 10:48 am

Hello David.

Where is this section? I can't find it! :oops:
Hi - try the link below

viewforum.php?f=10

Best wishes
David
XJS FORUM COORDINATOR
1996 XJS Celebration Conv. (shown on the JEC stand at NEC Nov 2015)
2001 XKR Convertible

Previously enjoyed!
1989 XJ-S V12 Coupe. 2006 XJ TDVi Sovereign. 1995 XJ6 3.2. 2013 XF 2.2d. 2009 X Type 2.0d Sovereign estate


Who is online

Users browsing this forum: No registered users and 1 guest