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1296 Spitfire, best head gasket - my Payen has failed!


DippedHeadlights
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1296cc small crank GE engine bored +40 and with slightly higher than standard compression and larger valves in the Toledo 218141 head. 

So a bit of a challenge for the head gasket - and at the weekend it failed between 3 and 4. 

It was one of the new type Payen AK520 black ones and had been in there for 4 years, no warning, just pop (the pop being serious pinking as the gasses jump to the wrong pot and then burn at the wrong time) no oil water mixing luckily.

I was only a couple of miles from home and benefit of not being alloy is now it's apart the head and block look perfect, no need for skimming. 

So planning on cleaning then reassemble. Are these black Payens still the best gaskets?

Any other suggestions for reducing risk of it failing again when it's back together? I've been assembling it dry and torquing to spec (45lbft) and retorquing after 100 miles.

Maybe a bit tighter ? However I think real challenge is just how close the bores are so most important is going to be the tolerances and the quality of gasket ?

Thanks 

D

 

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Very frustrating.

Payen have a strong reputation as you know. However, one or two respected Triumph parts suppliers are now offering other gaskets, which are suggested to be better quality than current Payen.

I recently bought a head gasket set from Canley Classics and it's not Payen. Haven't fitted it yet, so can't comment from personal experience but... Dave at Canley would not supply a product he didn't believe in.

I would suggest you call Canley, have a chat and get their advice on which gasket is best.

Nigel

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the narrows between pots is the most likely fail when the gasket becomes unsupported

have a look at you washers they often deform under the nut and you loose clamping

on refit  run a die down the studs to remove any crud, sand the block and head faces to clean metal

get HD washers if yours are brinelled  nuts are also special to  take the   42/46lbft torque 

dont use any slippy sealer only a smear at the rocker feed hole and the cam follower chest edge

Pete

 

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Thanks guys. The studs are out at the moment so I can block sand the block to a super smooth finish. I saw a tip to slightly countersink the stud holes as they can peen up a bit so will try that. (although the failure was not near a stud).  I hope it's not a quality problem with the gasket, my thought was they are different materials to back in the day (clearly not asbestos!) and so I wonder if the torque settings are still relevant with the materials that they use now. Maybe they do need to be tighter. I will give Dave at Canley a call and see what he is using.

Anyone else we know who is putting together Spitfire engines for racing who might have a view ?

D

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I had that type of failure several times on my Mk1 Vitesse, between different pairs of cylinders each time, before the engine rebuild. The machining probably helped but I think the thing that really made the difference was new studs and special nuts from Mini Spares. As Pete says, the washers under the normal nuts can squash and lose the clamping force.

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Interesting about nuts and washers. I reckon that is deffo worth me doing. I see Minispares have: 

Competition head (spring) washers, set of 10.
Original ST spring type washer especially required when using original 6-sided head nut.

and also this:

EN24 Nickel Chrome moly steel studs, Competition head stud kit (11 studs, nuts & washers.) 4 long and 7 short.
This special kit was developed to replace the increasingly inconsistent standard items. The studs are manufactured in selected hi-grade steel and produced to exacting specifications. These studs do not stretch, so they pull the head down, not the thread up, this vastly increases head gasket life, even on high compression engines. Special thick washers, countersunk on one side, help clamping capability and reduce thread bottoming of the nuts. Note that even replacing the head bolt with a stud, only torque that stud to the factory recommended spec (25 ft/lbs), the other studs can be torqued to 65ft/lbs with oil, 55ft/lbs with ARP lube.

Studs I guess are different. but what Mini nuts and washers worked on Triumph stuff ?

And I have just had a quick lookup of that ARP stuff, seems to makes everything smoother in assembly but doesn't mean you have to reduce torque like with oil.

Sounds a good idea ?

Thanks 

D

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Thanks guys. I see those flanged nuts in my future! 

For ref this is what the gasket looks like. The fail between the pots clearly happened first then I think the other damage to the gasket was caused by the severe pinking. 

I maybe should have checked the release torque when I undid the head bolts. They felt normal though, none felt loose but certainly not tight either. I did lightly Moly grease the studs when I put it together so a few taps with rubber hammer and head lifted easily.  

Re driving experience. Very strange, it happened suddenly. Going uphill (normal A road hill that doesn't need 3rd gear), had been driving for over an hour, normal speeds and temps, all very normal, suddenly a really loudbanging like a metal fan hitting a shroud. Take off load and noise stopped. Also couldn't reproduce it revving when stopped. All temp and pressures of oil and water normal. No smells or bubbling. Less than 5 miles from home so carried on.  Still drove OK, maybe 20% down on power, just the banging under load which was getting louder. Compression test confirmed.

I did wonder if the rings might be damaged by the pinking but no scoring on bores so I think I will maybe set the pistons half way and put some thin oil in there to see if it drains down overnight and if not will leave well alone. Will do something similar to head in case it has burnt the valves but initial look they seem fine as well. 

D

P1200054 (Large).JPG

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We had a virtually identical failure on my sons MkIV about a month ago. It has a flat block Mk3 engine which was built with a Payen gasket about 4 years ago.

Story here - starts at the bottom of the page

http://sideways-technologies.co.uk/forums/index.php?/topic/7107-chriss-mkiv-basket-case-restored-to-glory/page/9/#comments

Not exactly sure why it blew. Head and block both appeared perfect. I do completely agree about the comments re clamping force. Trouble is the 3/8” studs and, more especially the nuts are pretty much on the limit at the standard torque.  We use the excellent Minispares flanged nuts. I retorqued after 4 heat cycles and will do again after a 1000 miles or so. Possibly ARP studs etc would help (presuming they can withstand more torque/provide more clamp) but they ain’t cheap.

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The first time it happened to my Vitesse I was near Brighton. The only classic specialist I could find round there was an MG place, who tested the compression then declined to do any further work on this mysterious unfamiliar engine. So I drove it home on four (and two parts) cylinders. I wouldn't have liked to do that with a Spitfire, though.

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Minispares do a pack of 10 flanged head nuts for the Cooper which look to be what I need. Total £14.52 delivered. Order looks like this:

1

C-AHT287
HEAD NUT FLANGED TYPE SET (10)CHEAPER THAN SEPARATELY
£ 9.40   
(Taxable)
 

10

CAM4545
HEAD NUT FLANGED TYPE FOR CYLINDER HEAD
£ 0.00   
(Taxable)
 

1

PO9
POST - SMALL ORDERS (PRICE CHARGED AT DISPATCH)
£ 2.70   
(Taxable)
 

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