Double valve springs??

[bashford1]

Prepping for doing the head gasket or finding it’s a cracked head. Removed rocker cover to repaint or just polish the whole thing and looking at valve springs they appear to be double springs. Is that normal for a uk 1974 interceptor

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[slotcarone]

Not sure about the springs but the engine is clean as new inside!

[thomaslk]

Hi Bashford,
what you see are no real double springs. The inner part is not a conventional spring but a spiral made from flat steel - the so called damper. I had the same setup in my 1974 US Interceptor with matching numbers engine which was most probably never opened. Valve stem seals were extremely brittle and partly already broken. I would suggest to replace the seals. It is not much additional work if the heads are already off.
Good luck with your engine. I guess it will be just the head gasket.

rgds
Thomas

[johnw]

Did you do a compression test yet? Sorry it I missed that. Will help massively to know which cylinders are good.

[thomaslk]

I left the heads in place as compression was fine. Just replaced the stem seals because of high oil consumption.
Was fully cured by the stem seals. Interestingly my valve springs were painted in red.
rgds
Thomas

[thomaslk]

... and here is the pic
Thomas

[bashford1]

Hi john,
Sorry for they delay in replying to your question “did I do the compression test”. I have now when you asked I had only done a pathetic attempt. Didn’t realise how difficult it would be on these cars upside down with wheels removed and hardly any room on number 8 cylinder. Originally I only had 2 compression testers (see pictures below) one push on and one screw in of the old tyre pressure gauge type. Due to their size and design I couldn’t achieve a successful result, not on this car anyway.

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So………. I bought a new set to do the job which I used this weekend.

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The wet test results after adding a couple of squirts of oil weren’t much different so the problems do not appear to be with the pistons:
Cylinder compression dry test:
Cylinder 1 = 30 psi
Cylinder 3 = 80 psi
Cylinder 5= 110 psi
Cylinder 7 = 110 psi

Cylinder 2 = 127 psi
Cylinder 4 = 50 psi
Cylinder 6 = 55 psi
Cylinder 8 = 32 psi.

I only appear to be running properly on 7 cylinders as No 1 appears to be misfiring.
I can’t remember if I Have said but when I bought the car there appeared to be lots of gas bubbles in the cooling water. The oil is fine. So I am assuming a blown head gasket or cracked cylinder head.
Thanks to a discussion with Steve Payne I should get some reconditioned heads soon with hardened seats (the car has done 144,000 so the old case hardening done on these heads has probably worn away) that I can swap out.

[johnw]

It sounds to me like your head gaskets are cooked at a minimum. Perhaps it overheated badly in the past and finished off the gaskets. Who knows. OK so you can test the old heads with them upside down and petrol poured in to see if there are leaks past the valves on the low comp cylinders. Also keep the old gaskets for now they should have signs of leaks on the faulty cylinders if the valves are good.

I would be very tempted to clean the outside of the block now while the heads are on ready for paint. It is so easy to detail and paint the engine just as you have done the rocker covers once all is in bits.

It is very enjoyable and rewarding this job! I hope you get time to take it slow, enjoy and bond with the car!

[bashford1]

I’m cheating on the heads someone is reconditioning a pair of cast iron heads for me to fit with Steve Payne. I think painting will have to come later I’m a little impatient to get her going reliably at the moment.
Otherwise it’s good to be back under a Jensen. My poor 1986 Porsche 945 is sitting outside a bit unloved but it was great doing some classic road rallying in the 944. I hope the Jensen can cope with that

[johnw]

I realize you are not using the old heads. My point was to inspect the old heads and old head gasket to confirm the cause of low compression. You might have a broken piston ring etc.

[Grant]

The trouble is with the old cast iron heads is that you won't normally see the crack untill you have spent the money and had the seats cut, then that reveals the crack..do away with them and replace with new complete Alloy Heads, they come with various compression ratio options, they have new stainless valves, bolt them on a go Mr Bashford My Ole Fruit, they run cooler so you can run higher compression aswell, I know they have been a bit scarce recently due too all the problems with Covid etc, but they will be back instock soon and it's a much better option than messing around with these old cast iron heads that are invariably cracked

[thomaslk]

Yepp - these heads were really a steal some years ago. I remember i paid less than 1000€ per pair but now exchange rate and prices are substantially worse. (Un)fortunately the 440source stealth heads ended up in my son‘s Challenger instead of my Jensen but the „father and son stroker project“ was really a great experience and fun.
Rgds
Thomas

[Grant]

Yepp - these heads were really a steal some years ago. I remember i paid less than 1000€ per pair but now exchange rate and prices are substantially worse. (Un)fortunately the 440source stealth heads ended up in my son‘s Challenger instead of my Jensen but the „father and son stroker project“ was really a great experience and fun.
Rgds
Thomas

Hi Thomas ..They're still worth every penny in my opinion Thomas..but they are hard to find at the moment..that'll pass though

[Grant]

Looks like they are back in stock at the moment >>> http://store.440source.com/Stealth-Alum ... 00%2D1055/