2.4L Top End Rebuild in the UK

Silver911SC · Post by **Silver911SC** » Sat Oct 23, 2021 7:37 pm

Hi all

I was interested in peoples views on current costs to rebuild a 2.4L engine. Currently interested in knowing for an engine that is running and driving, no obvious taps or knocks but is burning a lot of oil.

I know this is a bit of a ‘how long is a piece of string’, but assuming only rebuilding it to factory spec and pistons and barrels don’t need replacing.

I’m seeing a lot of fixed pricing £4-5k rebuild offers from some smaller specialists, and closer to £7-8k for some of the slightly bigger names. These seem reasonable, but a lot of forums, certainly in the US are stating $20k rebuilds as a minimum. Seems like a big difference.

Really interested in peoples experience and thoughts of the U.K. market for top end rebuilds.

Thanks for reading

Gary71 · Post by **Gary71** » Sat Oct 23, 2021 8:22 pm

Not sure about commercial costs, but I wouldn’t advocate a ‘top end’ rebuild alone unless you have knowledge of the bottom end being done already.

I rebuilt my 2.4 using original barrels and pistons with a hone and new rings.

I debated opening the cases when I was at that stage but so glad I did as some of the bearings were through to brass with no symptoms.

neilbardsley · Post by **neilbardsley** » Sat Oct 23, 2021 8:39 pm

Can't you spend £30 have your oil analysed for bearing material and message crank end play? If nothing is amiss then why not do the top end only? Given that many cars do under 3k a year I'm suspect we over worried. You might get away with just new rings?

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Gary71 · Post by **Gary71** » Sat Oct 23, 2021 8:46 pm

This was my bill from 2016. All DIY other than the machining. Just shy of £5k including £1k of shiny exhaust.

Food for thought maybe.

911hillclimber · Post by **911hillclimber** » Sat Oct 23, 2021 9:19 pm

I've done 3 rebuilds now, and just starting my 4th.
Go and do what Gary did 5 years ago and you will get the figure by just doing all the parts needed.
To help, buy the Dempsey rebuild book and the book lists all you want.
Do notskimp.
Do the rebuild from the bare crank out and replace everything that can wear, maybe stopping at the oil pump IF the pressure is good, about 60 psi at 3 k revs.

Some U.K. specialists dorebuildkits that comprise of the bits you need and leave the oil pump, Pistons and barrels out.
Do not buy anything until you have it apart and measured the crank and check the chain Drive gears for play.

Change the valve guides!

Your rebuild must include the induction system parts.

Dempsey book is a good start. I'm assuming the engines are new to you, sorry if I assume incorrectly.

Sam · Post by **Sam** » Sat Oct 23, 2021 9:36 pm

It’s the ‘while you’re in there’ bits that will push it up towards £10k.

Replace a few bits of tired tinware, new oil lines here and there, replace rusted exhaust bits, grind the cams, oh look, the clutch is getting low etc.

The way it’ll get to £15k is if you decide to replate and paint everything so it looks like new when you open the lid.

Silver911SC · Post by **Silver911SC** » Sat Oct 23, 2021 10:05 pm

Thanks everyone. Really interesting response and all pretty aligned with each other.

Sounds like the garages charging £4-5k covers the labour and some of the basic parts, but add another £5k for ‘whilst you’re in there parts’…and £10k is about right. As Sam said, going over that would be in order to add mods and/or a more concourse finish.

P.S I have the Dempsey book and Bentley books which are superb.

911hillclimber · Post by **911hillclimber** » Sat Oct 23, 2021 11:15 pm

Just remembered!
Special tools for the cams and don't forget the engine stand Yoke.

MikeB · Post by **MikeB** » Sun Oct 24, 2021 9:29 am

Can I advocate the "If it ain't broke leave it alone" approach?

What is the history of your engine, has it had any major work done on it in the past, what mileage is on the engine? If it has never been opened than OK you should have a look inside, but if there was work done previously to the bottom end it will probably be OK.

Get a compression and leak down test done and that will indicate if there are piston ring issues. As has been mentioned, if your oil pressure is OK, then the chances are your bearings are fine. From my experience bore wear is rare in the Nikosil barrels. I think the most likely cause of your oil consumption is valve guides and their seals and as such a top end rebuild may suffice. As has been mentioned, once you split the case then the costs will double or treble.

Silver911SC · Post by **Silver911SC** » Sun Oct 24, 2021 10:40 am

Mike, those are all really good points. Currently trying to get more of the cars history; the car had been parked up for the last 30 years and lot of originality has survived, but the engine was apparently used in another car - that’s what we are trying to find out it’s story in the other car, and any rebuild history. For now I’ve attached a a couple of photos of the engine; to me the oil return tubes look clean enough that some work must have been done on it. But as I said it’s burning oil.

MikeB · Post by **MikeB** » Sun Oct 24, 2021 11:03 am

Looks like your right side has oil leaking onto the heat exchanger, so that is probably losing oil and giving you the burning smell. The left side looks perfect and from the shine on the oil tubes, I'd say those may have been changed. What is your exhaust outlet like, is the black sooty and oily? If not then your oil problem might just be the leak on the right. Look at the top of the engine and the thermostat at the bulkhead end, see if there is any oil sitting on the top of the engine in that area. If that is dry then it could be the lower valve cover, or the rocker shafts.

Sam · Post by **Sam** » Sun Oct 24, 2021 11:51 am

It’s got hydraulic chain tensioners so someone has definitely been in there since 1984.

hot66 · Post by **hot66** » Sun Oct 24, 2021 12:40 pm

And ideally get that sump plate rotated 90deg anti clockwise ( see pics on this link) … it’s an oil pick up thing

https://www.mechatronik.de/en/verkauf/v ... che-911-t/

Silver911SC · Post by **Silver911SC** » Sun Oct 24, 2021 1:23 pm

Thanks all for the comments, they’re really appreciated. Good observations as well.

The car was imported in 1981 and it was incorrectly given a 1981 plate that meant it needed an MOT/SORN up to now, and the DVLA show it hasn’t had an MOT since 1992 that matches what was said about the car. Looking at some of the older photos of it sat up in the UK there is an interesting wide body project next to it and a classic Porsche poster on the wall; so I wonder if that enthusiast possibly rebuilt it and used it in that other car is something. It does look clean underneath which makes me think someone has bothered to open it up and do work on it, with not many miles since.

Thanks again for the comments.

RobFrost · Post by **RobFrost** » Wed Oct 27, 2021 4:22 am

I was eyeing a rebuild for my 2.2T because it's a 50 year old car and was spewing out blue burnt oil smoke like an old battle tank on manoeuvres.

There was a regular knocking sound, lots of vibration and backfires and it was rough and reluctant to idle.

Mike B said to let it run for a while and it's likely to clear up. I did what he said and after a (good long) amount of running, the smoke slowly subsided and cleared up altogether.

I welded up a hole in one of the exhaust downpipes and the knocking noise went away. Chris68 helped me balance the carbs, I cleaned up the jets and, gave it a full tank of new petrol and overhauled the throttle linkage and soon the engine was running like a Swiss watch. It will happily idle smoothly at 500 revs now, pulls like a train even from low down and loves to rev too.

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