My engine has just let go !

[lotusguy]

nevpugh308 said: A mechanic at the place where my wife works has just had a look at the pics. He says that his mate had something identical with his X flow a few years back, and that it was down to the carbs being out of tune with each other, causing the valves to overheat and eventually melt. He says, looking at the colour of the valves, that this looks to be the case here. This doesn't cheer me up much, the fact that I could have avoided this (theorectially) and that it's my fault

Serious comment : if anyone knows of a tuned X flow (1600/1700) engine for sale in the Midlands area (or thereabouts) could you drop me a line ?

robp ... followed that link, couldn't see anything about it on the site, is this insider knowledge ?

Hi,

My condolences on your trouble, it isn't pretty and won't be cheap. I concur with your mechanic friend about carburettor imbalance being the cause of the problem. I saw similar damage to a carb'd Esprit which had the same issue. It also looks as if bits of debris came off the valve and allowed the piston to bounce them around the cylinder as well.

I would assume that the damage is restricted to the valvetrain, piston and cylinder and that your block was spared. Good Luck...Jim '85TE

[grahambell]

nevpugh308 said: Quick question :

Assuming my engine MIGHT be salvagable, could I just replace 1 piston or would I have to replace all 4 ?

Also, anyone know how much crack testing a block might cost ?

Hi Nev.

Ouch! Had a piston melt on a tuned X-flow in the past and just replaced the one piston. In my case I think - like Paul's Mini - it was down to having a too soft grade of plug and the plug in the offending cylinder was well knackered. Rebuilt engine with harder plugs - no more problems.

Might be worth picking a few tuners' brains to see what grade plug they recommend for similar spec engine.

Looks from your pics like you might be able to get away with cleaning up the head (valve seats might need refacing or inserts adding) though the crack in the bore if there is one could be a problem. Might be able to get away with getting it sleeved depending how bad it is.

Best bet for quotes for crack testing might be a look through Yellow Pages for Non-destructive testing.

[nevpugh308]

Thanks all for thoughts and feedback (and sympathy ... I need it .... I've just looked up how much a full race head is from Burton ... ulp !)

Graham : I think, to be honest, the head is scrap. Where the inlet valve used to mate the hole is maybe 3 to 4mm bigger in radius !! Plus there's extensive "impact" damage in what used to be the flat surface of the combustion chamber, basically BIG chunks taken out (to 3-4mm depth)

[kevinday]

I'll always remember one of the mechanics tuning a Lotus at the garage I worked at in the early 80's, it had twin twin-choke carbs and he used four plastic tubes connected to liquid barometers, when the levels were all the same the carbs were balanced. Throw in idle and other adjustments and it was not as easy as it sounds.

[grahambell]

nevpugh308 said: Thanks all for thoughts and feedback (and sympathy ... I need it .... I've just looked up how much a full race head is from Burton ... ulp !)

Graham : I think, to be honest, the head is scrap. Where the inlet valve used to mate the hole is maybe 3 to 4mm bigger in radius !! Plus there's extensive "impact" damage in what used to be the flat surface of the combustion chamber, basically BIG chunks taken out (to 3-4mm depth)

I think you're right Nev, the head is scrap! Burtons have never been cheap (but they do seem to be good). You'll get a more reasonable deal from Vulcan. Alternatively, have you checked the ads in Motoring News as you used to find companies in there that used to break old rally cars. One such is/was Ian Harwood in Cheshire which specialised in Escorts. Used to be on 0151 339 2801. Worth a call?

[gbgaffer]

Hi Nev

Sorry to hear the news.

You might try here www.racecar.co.uk/cgi/forums/YaBB.cgi?board=misc_parts&action=messageindex&start=0

All sorts of race engines etc.

Cheers

Graham

edited to add this may be what you are looking for!

www.racecar.co.uk/cgi/forums/YaBB.cgi?board=misc_parts&action=display&num=1043274204

>> Edited by gbgaffer on Tuesday 28th January 14:20

[richardincov]

I have a 1600cc X-Flow up for grabs at the moment. Only at a mild state of tune, (RR figures from Aldon and Emerald at 96bhp) but good condition and would be ideal for a base engine to aid your rebuild. Get in touch if your interested.

[nevpugh308]

gbgaffer - thanks for that link, I'll check through all the ads. The specific engine you pointed out isn't a 711M block sadly, so that's no good.

richardincov - depending on how I go, I'll bear that in mind and I'll get in touch. from your name, do I take it you're in Coventry ?

[gbgaffer]

No problems Nev!

You could also try here http://racemagic.com/index.html as there is a full race x flow on there but maybe a bit pricey at £3,500

Good Luck

Graham

[Mr2Mike]

Wow, that's not a pretty sight. Certainly the inlet valve has let go at some stage, although finding out what caused it is going to be tricky. Have the valve stems been waisted behind the head? I've seen an engine in the exact same state after the owner decided that he'd make his own race valves by turning down the standard ones to thin down the stem.

[nevpugh308]

Got the westie engine out on Saturday morning. There's a lot of mayo and debris in the pan (remember the piston was holed)

Something I noticed on the head ..... looking sideways on, one (of the remaining 3) valves sits slightly higher than the surface of the head (the combusion chambers on the head aren't really recessed). The other two are sitting slightly lower then the surface of the head. The car was/is fitted with one of those fuelcat things and the previous owner always ran the car on unleaded (though it wasn't an unleaded head). I wonder if the valves were badly recessing, and that's what caused the no.4 inlet valve to give up the ghost .... ?

There's probably about 2 or 3mm difference in height between the one that's standing proud, and the couple that are recessed.

[trackdemon]

Nev, how about wedging this into your little beastie: www.findit.co.uk/cars/tvr/519906.htm

Would make for an 'interesting' drive...

[nevpugh308]

Hehe ... might upset the balance a little bit mind

No, I'm sticking with X flow I've decided, and I'm going to have a go at building it myself. All I need now is a block .....

[Mr2Mike]

Valve seat recession wouldn't have caused that. At worst you'd have got a burnt valve, but it wouldn't have lunched itself in that kind of style.

Out of interest you are running air filters on your westie aren't you (I've seen quite a few without on throttle bodies)? If not it might have sucked something nasty in.

[nevpugh308]

Fair nuff.

Yes, I am running filters (K&Ns). Mind you, I might have to replace one of them, as there's a 100 million tiny fragments of metal on the inside of the filter, where the exploding engine threw its guts up, back through the carb.