1973 2.4T CIS Restomod

[MT]

This really was a bummer for Charles (and me really) - when he says a loose head stud, what I found was that the two outer head barrel nuts were loose - not quite finger tight, but not much more, so that was most likely the cause of the gasket popping. Charles had followed my advice and put the car in to a local Porsche specialist to get the valve clearances checked, and the head nuts re-torqued, when he had the oil and filter changed after the first 100 miles. Did they do them all, or forget the two at the back.........

As for the pistons/cylinders I think this is not a good recommendation for JE and their supplier, Kokoparts who I understand have washed their hands of the whole thing. True I did not remove the pistons from the barrels before fitting, and therefore I didn't check the ring gaps, but the advice at the time was that they had been professionally assembled and that it was unnecessary and more likely to do more damage (i.e., break a ring) dismantling them than just fitting them as they arrived, so all I did was a quick wipe with a minimum of new engine oil on the inside of the barrels and fitted them.

There were no broken or damaged rings when dismantled .... just a very large gap ( over 3mm difference in diameter if I recall correctly) between the cylinder and the piston when you put them together without any rings on the piston.

Looking at them as they came apart it is clear (not just to me, but to several pro's Charles has shown them to subsequently) that the pistons are way way too sloppy in the barrels, and that no piston ring is ever going to cope with that gap..... hence the evident blow-by. So it was either new (bigger dia.) pistons in these cylinders, smaller bore cylinders, or another set of both. Another call for Charles .....

Back to the tale ...

Mick

[Bruce M]

I'd be inclined to believe that JE made to pistons to the requested spec and AA either spec'd them incorrectly or made the cylinders incorrectly. Only a hunch though.

[shoestring7]

As Mick says; when my shiny new JE pistons arrived from Kokoparts they were already fitted with rings and installed in the AA barrels:



We didn't split them, partly because we made an assumption that they would be right, and partly because we didn't want to risk breaking a ring in doing so.

The first specialist I took the components to was Barry, who builds engines for a Sussex based Porsche specialist. After a quick inspection of the heads and bores, he fitted a piston into its barrels, rattled it about and announced "That's a bit crap". Even taking into account the different expansion rates he felt the fit should have been a lot tighter; the OE Mahle sets he normally works with would have been. However he clearly was a bit reluctant to take on the project - with a 2.4T case, worked heads, 'E' cams, PMOs and JE/AA P&Bs it was a bit too much of a mongrel for his tastes.

Next I travelled down to Russell Lewis of RSR Engineering near Hindhead. We had form already; Russell had re-built my 964 lump after its big-end failure, and had produced a quiet oil-tight unit that felt like it was producing more that its factory-claimed 250bhp.

After checking over the components Russell confirmed that in his opinion there were no signs of abuse, over-heating or major parts failures. He also commented that in his years of working with 911 motors he couldn't remember pistons so loose in their bores. So then he cracked open a very expensive looking set of bore-measurement instruments, grabbed three of the P&B sets and made the following notes:







The long and short of it is that the pistons and barrels were not correctly matched; combustion was finding its was past the rings, pressurising the case and causing the heavy oil consumption. Whether this was as a result of poor QA, incorrect Kokoparts specs, or some other factor is moot. I clearly needed another set of pistons and barrels and to fund another engine build - my third in 18 months BTW the response to my request to the supplier to examine my evidence and consider a refund amounted to GFYS.

The engine bits sat on my garage floor while I railed against the Porsche Gods, raised more funds and considered my options:



Clearly the objective was the same as it always had been; a reliable, useable and entertaining road engine to suit my S/T-lite hotrod, but above all this time I needed the confidence we wouldn't be tearing the thing down again in 18 months.

So I got on the phone to Nick and ordered one of his money-no-object twin plug screamers*:


C>
*No I didn't!

[sladey]

[yoda]

Good lesson for us all here!!!

[MT]

Good lesson for us all here!!!

More than one I think

[911hillclimber]

What a sad story.

If you had pulled the pistons out without the gauges and the experience you would still think/assume all is well and end up in the same place.

For the supplier to reject your claim is in many ways so much worse.
So, out of pocket and still no engine that is right...
Would drive me mad!

[shoestring7]

This pretty much brings me up to date.

After considering all the options (including chucking a match at the thing), I decided to go ahead with another engine build. I looked at various piston & cylinder alternatives; but during the summer I had a stroke of luck. One of Russell Lewis' wealthier customers bought in his competition 2.7RS engine for a refresh, including replacement of the p&cs. The old Mahle set were barely worn, and would be suitable for my engine. I negotiated a fair price with Russell for the build, and in November 2016 I gave him the green light.

Sourcing these critical replacement components for my engine from Russell, as well asking him to take on the rebuild had two big advantages; firstly I should have some come-back in case of any problems, and secondly I could be about as confident as I could be of ending up with a good reliable engine.

A couple of weeks later a SMS arrived with the shopping list. Just the usual then:


We decided to remove the conrods and replace the bearings, but as the car would only be used on the road the original studs would suffice. Just as well, recent price rises mean the RS studs are now £34 a piece

I was able to make use of some trade contacts (I paid about 60% of what my friendly local OPC quoted), and a few weeks later a small, expensive box of bits arrived from Belgium:

(The parts-getter has been earning its keep)

This afternoon I popped down to Bramshott and dropped the bits off. My engine was already on the stand waiting:


The parts laid out ready for assembly; the bearing surfaces on the 43 year old crank were prefect:


By this time the case had been machined to take the 90mm pistons, and I was also pleased so see that it had already been time-serted. Clearly someone had been in the engine before the Badger club!


The pistons are the high compression (~9.5:1 vs 8.5:1 as std in the 2.7RS*) version with the raised crown and the deeper valve cut-outs. I could see little wear on the bores, the cross-hatching was barely marked:


The heads still needed a final clean-up, but the valves had been done and could be re-used:


In a week I'll drop off the engine shroud and the heat exchangers - with luck there will be more progress to report!

C>

*I haven't been able to find a part number or price for these new, other than a reference to being on a 2007 Mahle 'Race' price list. Can anyone help?

[sladey]

Better luck this time and keep the pictures coming

[911hillclimber]

Gives you the feeling this one will be right.
Need a good write-up on the build, will be good to see a specialist build-up.

[shoestring7]

Graham, I don't think Russell Lewis is going to give too many hard won secrets away!

The original yellow shroud was looking a bit tired, so I decided to use some glass fibre paint to freshen it up:



Big mistake. It didn't go well: the paint reacted with some contaminates and didn't adhere:



So Russell will have to wait while a professional bails me out on that one.

I also discovered the fan strap has disappeared at some point in the engine's travels, but dear old Porsche can supply a new one (albeit with a 964 part number) so I ordered it from my friendly local OPC.

Meanwhile the engine build has progressed:





All looking good, the only unforeseen issue was with a short blind stud up by the breather that pulled out.

Hoping for more progress next week.

>C

[shoestring7]

I was wondering if I could fix the engine shroud or if it would need a new replacement, when I remembered that I'd previously found someone in Chichester who had done a very nice job repairing the car's old and battered rear bumper. This chap works in the boat building industry, so is skilled in repairing glass fibre. I arranged to take the shroud down for him to take a look.

We agreed that he'd try and strip the paint that had failed to adhere, repair the various holes and re-gel coat it in a matching yellow. All for a reasonable sum, so I left it with him.

Now I should perhaps mention that this chap has his problems; his mother (with whom he lives) isn't well, his wife left him, he doesn't see his kids and he appears to suffer from depression. This all came back to me over the next few weeks, when I found myself acting as part customer/part therapist, slowly trying to encourage him to leave his house and re-engage with his life.

Eventually he managed to find the will to go into his workshop, and a few days later I got a message to tell me it was ready. Even then he couldn't face me - I collected the shroud from his doorstep, and stuffed payment through the letterbox.

But he'd done a fabulous job, the paint was gone, almost all of the small faults had disappeared, and he'd managed to achieve a pretty decent shine on the 40 year old fibreglass:





On Saturday I dropped it into Russell Lewis'.

One oddity; of the new fan strap I'd paid OPC Portsmouth to deliver direct to RSR there was no sign. However, the old 'lost' one had re-materialised, so Russell was now only a few hours work from a finished engine!

>Charles

[shoestring7]

Exactly a year to the day since we pulled the engine out it was time for it to go back in. Russell Lewis delivered it to me last week, I've got a more substantial dolly this time (should it become again necessary to drag it half a mile down the road!) and it fitted perfectly:



Yesterday Mick turned up bloody early, and we prepped the engine and the car:




Dolly sitting on Mick's lift

It's always a little more difficult to do this on a floor, the angles don't help when the car's tail is in the air, but there were no major snags with the help of #1 son by 11am the engine was back in its rightful home.



No engine start yet: I needed the gaskets before fitting the drive shafts, and there's a slightly worrying loose wire in the distributor area. I think its left over from Jonny's attempt to sort out the Classic Retrofit CDI box, but once sorted we'll go for a start up.

C>

[shoestring7]

Well, life has got in the way!

By 'life' I mean a move to a new gaff 60 miles away, and a new job. Mysteriously one-bed double garages were in short supply when I was looking for a place, so while the new Shoestring Towers does have a garage, it's not big enough for an immobile 911 along with two bikes, a pile of furniture and other stuff that doesn't fit into the downsized new place.

So April and May were taken up with move, while the 911 languished an hour and a half away in Ascot. My first attempts on a start failed, the engine spun but showed no signs of wanting to start. A second attempt a couple of weeks later was similarly (and frustratingly) unsuccessful, and my amateur diagnostics suggested the spark box wasn't sparking.

I think getting the Green Flag guy along to look at a car that's not moved for 18 months would be abuse of privileges, so it looked as if I was going to have to arrange for the car to be transported to a specialist, with the inevitable big bill. A 'doh!' moment followed; and I called Russell Lewis, who lives only 10 minutes away from the car, and I arranged to meet him at the car's location one evening. On a bike, the 90 minutes drive was dismissed in just over an hour, so one evening last week I was watching Russell checking over the electrics with his multi-meter.

A bit of wire wiggling and plug re-inserting later, and the car looked much more interested in life. Another few seconds and there was the lovely welcome sound of that lovely rasping engine note, a good couple of tones lower that in its previous smaller-bore incarnation.
And blessed relief; no signs of heavy breathing or oil smoke!

One of the things Russell had spotted on the tear down was that the alloy plugs used to block the injector ports were slightly fouling the inlet manifolds, resulting in an air gap between manifold and heads. It hadn't been spotted until that point, it meant the the jetting that PMO had supplied with the new carbs was changed in an attempt to compensate. Before a meaningful running-in process can start I need to re-set the jets; Richard Parr has given me a base-line setting so I need to swop idle and possibly main jets, reattach some bits and present the car for an MOT.

Summer motoring awaits!

>C

[MT]

So what was the cause of the 'lack of spark' then Charles ...... do tell ....