Fox engine rebuild

[WIMPUS]

Hi, 

I've been planning an engine rebuild on my Spit 1500 engine with 324.000kms/201.000miles.

 

Its using a fair bit of oil..

Last year changed the head etc.

It needs a re-bore, crank re-grind etc.

 

Soo.. 

 

Been thinking of fitting an MK3 profile cam.

What are the positive and negative things fitting it? 

Seems County pistons are not bad.

And bearing wise I wanted Glyco, but seems I cant find them.

So probably County to.

 

[thescrapman]

All positives, no real negatives, so fit a Mk3 profile cam.

Mike Banks did it on his 1500, works really well. 

He did have bearing issues though with the crank.

[sparky_spit]

Colin is correct.  It makes a really nice torquey engine, with good power right through the revs, and with no downsides that I can think of. I never got to the stage of fine tuning the ignition map and carb needles before I had crank bearing issues (unrelated) so it could have been even better.  Hopefully the rebuilt version will be, once I get time to finish the rebuild.

[sparky_spit]

Hi Wim - a couple of things I have remembered, the cam was supplied by Canleys and was a Mk3 grind on a large journal original. It was 25, 65, 65, 25 with 110 max lift. I fitted it 2 to 3 degrees (crank) advanced to favour increased torque rather than outright top-end power.

Carbs were HS4 with AAQ needles and yellow springs to start off with.

The ignition map was a compromise between a Mk3 FD Spitfire and a 1500 FM Spitfire using an Aldon Amethyst unit.

As said above, all this was just a happy compromise for running in the engine, but it never made to the rolling road to set it up properly (nor the 2019 10CR) as I had crank bearing issues after about 800 miles or so. Its now sitting on an engine stand waiting to be put together again after some remedial work on the crank and me finding some correct sized shells.

Motobuild Racing here in the UK can supply King tri-metal main and big-end bearing shells. They use them in their MG Midget 1500 racing engines. The price is pretty competitive too.  They can be contacted via motobuildracing75@yahoo.co.uk

Edited July 1, 2021 by sparky_spit

[WIMPUS]

18 hours ago, sparky_spit said:

Hi Wim - a couple of things I have remembered, the cam was supplied by Canleys and was a Mk3 grind on a large journal original. It was 25, 65, 65, 25 with 110 max lift. I fitted it 2 to 3 degrees (crank) advanced to favour increased torque rather than outright top-end power.

Carbs were HS4 with AAQ needles and yellow springs to start off with.

The ignition map was a compromise between a Mk3 FD Spitfire and a 1500 FM Spitfire using an Aldon Amethyst unit.

As said above, all this was just a happy compromise for running in the engine, but it never made to the rolling road to set it up properly (nor the 2019 10CR) as I had crank bearing issues after about 800 miles or so. Its now sitting on an engine stand waiting to be put together again after some remedial work on the crank and me finding some correct sized shells.

Motobuild Racing here in the UK can supply King tri-metal main and big-end bearing shells. They use them in their MG Midget 1500 racing engines. The price is pretty competitive too.  They can be contacted via motobuildracing75@yahoo.co.uk

Thanks for the info Mike ! 

I have found a german place that sells the King tri-metal ones.

I usually bought them at James Paddock.

Seems my carbs will not need much tweeking to.

Im already on AAQ & yellow springs 😄

 

[WIMPUS]

Also.. another question.

Can the engine be removed and installed with the bonnet on and gearbox remaining in the car ? 

I expect the gearbox lining up will be harder.. (would remove tunnel and prop, so can turn the output shaft to line up with the engine).

 

We do have something big to lift the engine... 🙃

Linde forklift from 1985.

[RobPearce]

Hmm.... I don't think I'd try that. You might just get away with releasing the bonnet stay and tilting it an extra 20-30 degrees over centre, if the under-rider boxes allow that. Even then, I think it'll get in your way and it's probably easier - certainly safer - the remove the bonnet first.

[Dannyb]

I have done that. No problem. I did take the bonnet strut off so I could lift the bonnet higher and tied it to the roof of garage. 

I found I needed to have the front wheels on blocks so I could slide the engine hoist under the car. 

Without the gearbox there's plenty of room. And was surprised how easy it was to mate it back onto the gearbox. 

Danny

Ps... I did it on my own. 

[sparky_spit]

When I did the last quick-and-dirty engine swap singlehanded, 3 days before the last 10CR I left as much still on the car as I could. The engine came out using a chain block attached to a beam in my garage, with the bonnet still on and the gearbox still in the car. The radiator was moved forward and the gearbox bell housing supported on 2 wooden blocks placed between the chassis each side and the webs on the bellhousing. A bit of wiggling with a jack underneath and the engine came out forward and up.  The spare engine went back in very quickly afterwards. Lining up the input shaft was okay, just enough room to do it using a threaded stud in the topmost bellhousing hole and turning the crank pully slightly to get the splines engaged, and more wiggling on the supporting jack.  I do have hydraulic bonnet struts which makes the bonnet open much further and almost upright, but as Danny says, you could rig something up to replicate this. Its doable if you are in a hurry, but taking the bonnet off is safer if you have help at hand.

Edited July 2, 2021 by sparky_spit