3.8 engine rebuild ........any mods whilst I am at it?

[andrewh]

I am just starting the rebuild of my 3.8 litre engine. I have to say its pretty good inside but have not crack tested anything yet. Looks like its been little used and well maintained in terms of the oil .
I am interested in whether you guys think I should include any upgrades to give it a bit more poke and make it leak free.hah!

I have standard carbs which have already been done, so I suppose its about head work, pistons, flywheel, rear crank seal but I am planning on keeping the standard manifolds. I realise that the exhaust is one of the biggest potential gains but not quite got my head around stainless tubular headers, unless I can be persuaded that it is a must. Easily put back to standard if I ever wish I suppose. Would appreciate any ideas/experience you guys have. thanks

[Heuer]

I would think seriously about messing about with the engine specification unless you hand it over to a trusted builder who can give it a bit more power. But you will lose the lovely steady tick-over and it will be replaced by a lumpy one. You may gain power at the top end (which you will rarely visit) but at the expense of low down torque. If you lighten the flywheel gear changes will be rough and the rope crank seal (done properly by leaving it in a jam jar full of oil for a fortnight) is perfectly acceptable but be wary of the lip seal conversions because there is no going back if they do not work (you have to modify the crank).

As regards the exhaust system it is quite simple to release more power by using the standard manifolds with 'straight through' silencers and resonators - it is the baffled silencers that cost you that 10%. Go big bore if you want more noise but 2" is the maximum for road use and they must be fitted with 1.75" venturis - see ClassicFabs or Eccosse Motorsport - or stick to 1.75". You can get another 6% if you tinker with the inlet manifold by losing the drum filter and fitting a ITG Maxogen one in its place. Easily reversible and only costs ?60 but you also need to change the SU needles to UE. Lots of articles on these and other mods in our 'Upgrades' Forum. The other thing is to look at reducing weight so consider SBS40 battery (half the weight, lasts forever - mine is 14 years old and still going strong), plexi headlight covers, Cambridge Motor Sport ally radiator and header, Borrani wheels, lightweight starter motor etc etc

Making small changes to the standard specification can be a game of consequences where you solve one problem and create another which needs another solution which creates ................

Best things you can do to the E-Type if you really want to use it are:

1. Mangoletsi cable throttle
2. EDIS/Megajolt ignition
3. Borrani 5" or 5.5" wheels with Michelin XVS 185 tyres
4. MX5 seats
5. Zeus callipers

Things not to do to an E-Type if you want to use it:

1. Koni shock absorbers
2. Solid mount steering rack
3. 'Upgraded' poly bushes - stick to rubber or softest poly you can find
4. Smaller steering wheel
5. Wide wheels and 205 or 225 section tyres (specifically Pirelli P4000's)

[andrewh]

thanks David for the comments and advice. I am only interested in engine mods to get the best out of the car. The rest is staying true to original , but clearly there is an opportunity within an engine to "improve" with modern internals. It really does seem that Jaguar probably got it about right in terms of tractability and reliability so maybe from what you say I should stick with the original . I had been considering the change to a lip seal but I think you have put me off. I don't know of many classics that don't drip a little oil, as they say about Aston Martins, if its not leaking oil on the floor then it hasn't got any in.

I think I will get the head flowed a little and work on the ignition as you suggest. I can check the posts as you say in the upgrade section.

As a matter of interested, what did Jaguar do to the test cars to obtain the 150 mph figures? It has often been referred to the engines being hand built but ?

[Heuer]

The engine used in 9600 HP to get the magic 150mph was described as 'experimental' by Jaguar. Don't think anybody truly knows (the engine was removed immediately after the test) but I guess it was gas flowed, D-Type camshafts, polished internals and a higher compression ratio. The over-riders, mirrors and badge bar were also removed to improve air flow. Not that difficult to modify the engine to achieve that speed nowadays. My car has been clocked on the Millbrook bowl at 151mph and it was still pulling so it could have got to 160mph+ but we decided not to push our luck as we attained what we set out to do. It has a VSE02 engine with different spec cams to maximise torque. Give VSE a call and get a quote or try Rob Beere. The car is very quick and lots of fun to drive but probably too fast for UK roads.

[andrewh]

Sounds fun but expensive. I am not too fussed with a reallybhotmengine and build my own engines anyway sondontnwant to pay for anything other than machining. I derive a sense of satisfaction from driving the thing after I have done the work. Rob beers is. Very hot engine but pretty expensive for a jag aren't they?

[38E]

I am interested in whether you guys think I should include any upgrades to give it a bit more poke and make it leak free.hah!

I think a worthwhile upgrade to a 3.8 would be to add the inlet valve seals and another would be a proper balance job. The 3.8 is already smooth but a balance will ensure it stays that way.

I rebuilt my own engine about 15 years ago but more recently added the valve seals and a new set of cast iron rings. The crankshaft seals I used were the original stock Jaguar seals and they don't leak.

I made a couple of mistakes the first time. One was using a chrome ring set which never bedded in properly and another was having bronze liners installed in the valve guides. I had the guides replaced with newer silicon bronze type. (The new guides are required anyway for the inlet seals.) My bores and crank are still STD and have negligible wear and the pistons are original. My oil stays much cleaner now and consumption is way better.

[andrewh]

Thank you Clive. That is really useful. I will talk with the guy who is going to machine it for me . When you said valve seats do you mean for lead free fuel or bigger valves ?

[christopher storey]

Clive was referring to Seals on the inlet valve guides, not seats

[38E]

Thank you Clive. That is really useful. I will talk with the guy who is going to machine it for me . When you said valve seats do you mean for lead free fuel or bigger valves ?

Hi Andrew,

No, the original seat material Jaguar used is fine for unleaded gas. And you don't want to change the seats unless you really have to. For instance in the case that they have been cut too deeply in the past which would present problems for achieving a shim size in the required range.

For the inlet valve seals, you'd need to have the guides changed because the old type are lacking a circlip groove to hold the seal. Then you'd need the later shorter type collets, valve retainers and spring seats. All these provide clearance for the seal.

Here you go:-

(Ha! The photo title doesn't show for some reason, so the new hardware is on the left, if that's not obvious.)