Engineering company suggestions for hard valves/seats

[Pinger]

So that's where I'm at. I have had very bad luck with easy outs in the past so I don't want to break one in the crank here. But maybe I'm into that level now. Really I need an engine...

Very bad luck.
I suspect you are about right re easy outs and at 'that level now'.
Two things I'd try before going in with the easy outs. One, try hammering on the end of what's left of the bolt to 'shock' the Loctite free. Two, try and find out what best dissolves Loctite. If nothing, then a good penetrant (not WD40) and let it soak. If there was a way of pressuring it in all the better (all I can think of is (assuming the bolt is in a 'blind' hole) drill your crank bolt right through, drill your M12 bolt right through, tap it for a a grease nipple , fit the bolt and squirt solvent/penetrant through the hole before fitting the grease nipple, then pressurise with a grease gun and hope the penetrant is forced between the big bolt's threads and the crank's. Use a tube and hammer (when pressurised) to further add shock. Maybe, just maybe, it might break its hold and allow an easy out to do the rest).

[desauld]

So that's where I'm at. I have had very bad luck with easy outs in the past so I don't want to break one in the crank here. But maybe I'm into that level now. Really I need an engine...

Very bad luck.
I suspect you are about right re easy outs and at 'that level now'.
Two things I'd try before going in with the easy outs. One, try hammering on the end of what's left of the bolt to 'shock' the Loctite free. Two, try and find out what best dissolves Loctite. If nothing, then a good penetrant (not WD40) and let it soak. If there was a way of pressuring it in all the better (all I can think of is (assuming the bolt is in a 'blind' hole) drill your crank bolt right through, drill your M12 bolt right through, tap it for a a grease nipple , fit the bolt and squirt solvent/penetrant through the hole before fitting the grease nipple, then pressurise with a grease gun and hope the penetrant is forced between the big bolt's threads and the crank's. Use a tube and hammer (when pressurised) to further add shock. Maybe, just maybe, it might break its hold and allow an easy out to do the rest).

Thanks for the support guys and some good suggestions there. The internet says, so how could it be wrong, that thread locker hates acetone and chloroform. I unfortunately am right out of the latter, bit have some acetone in the cavity in the crank now behind an M12 bolt to hopefully spread it under pressure around the M16 remains, if that makes sense. I will go back at it tomorrow with propane, a tig torch with way too much tungsten stickout and heat it up as much as I dare. Locktight says over 260 deg c will soften it, so let's see...

[LPGC]

Very bad luck with it snapping and attempts to get it out so far, wish you better luck on your next attempt.

[Gilbertd]

Not easy to get hold of but if you can find a LH thread tap and bolt, that might be better than an Easy out.

[desauld]

Not easy to get hold of but if you can find a LH thread tap and bolt, that might be better than an Easy out.

I'm actually thinking of mashing in a no 12 or 14 12 point spline bit. I have had some luck doing this in the past on exhaust and turbo studs.

[Pinger]

Thanks for the support guys and some good suggestions there. The internet says, so how could it be wrong, that thread locker hates acetone and chloroform. I unfortunately am right out of the latter, bit have some acetone in the cavity in the crank now behind an M12 bolt to hopefully spread it under pressure around the M16 remains, if that makes sense. I will go back at it tomorrow with propane, a tig torch with way too much tungsten stickout and heat it up as much as I dare. Locktight says over 260 deg c will soften it, so let's see...

Don't forget shocking it from the front. Hammering on it will push it away from the direction it was pulled when it was tightened.
Good info on the acetone - easily found in nail varnish remover I think.
Hang in there - you can win this one!

[desauld]

Thanks for the support guys and some good suggestions there. The internet says, so how could it be wrong, that thread locker hates acetone and chloroform. I unfortunately am right out of the latter, bit have some acetone in the cavity in the crank now behind an M12 bolt to hopefully spread it under pressure around the M16 remains, if that makes sense. I will go back at it tomorrow with propane, a tig torch with way too much tungsten stickout and heat it up as much as I dare. Locktight says over 260 deg c will soften it, so let's see...

Don't forget shocking it from the front. Hammering on it will push it away from the direction it was pulled when it was tightened.
Good info on the acetone - easily found in nail varnish remover I think.
Hang in there - you can win this one!

The fecker is out!

Left it soaking in acetone over night, then heated a M12 bolt up which I had threaded into it so it was red hot right up to the nose of the crank for 10 mins. Then mashed in the spline drive, tightened it a bit first, could feel it start to move, then backed it out. So back to the rest of the job.

I have one head off, and the other almost ready to come off. Not difficult, just plenty to do. Everything looks good. Apart from the general mess. I filled all the ports with thinners and there is very slight weeping past some intake valves, mainly the one with low compression. It's only very little to be fair and a lapping in would allow it to seal.

[desauld]

Some pics

[desauld]

Interestingly, the tappets are one piece, and don't have the top part which removes, no wonder I couldn't get it to split! So to adjust the clearance on this engine you have to remove the cams. That are also smaller than the other spares I picked up. Odd.

[Pinger]

The fecker is out!

Result! Well done that man!

Re one piece tappets - that makes for a very high maintenance engine. On a par with a motorcycle engine.
I think it was yourself that mentioned (it must have been on this thread even if not you) that solid tappets were a Jaguar preference. If Ford were behind it then coming from their background of pushrod V8s with hydraulic tappets, that's a hell of a jump re maintenance requirements.

[Brian_H]

Some Ford engines use the same arrangement for the tappets as that shown. The Duratec ones I think are where that started. The later Zetecs were shimmed. Though those all 4 pot engines obviously.

Well done on getting it out though, acetone a good thing to know.

[Gilbertd]

Re one piece tappets - that makes for a very high maintenance engine.

Or one where they don't expect you to do any maintenance, just throw it away when it starts to wear out.

Re Acetone, I read somewhere that a 50:50 mix of Acetone and ATF works better than Plus Gas on seized bolts and mentioned this to someone I know who had an engine that had one cylinder open to atmosphere for a number of years and the piston rings had rusted to the bore on one pot. He misheard me and missed the ATF so filled the pot with neat nail varnish remover. After soaking for two days, he was able to turn the engine over!

[Pinger]

Some Ford engines use the same arrangement for the tappets as that shown. The Duratec ones I think are where that started. The later Zetecs were shimmed. Though those all 4 pot engines obviously.

Not sure is there's a technical reason that stops a hyd tappet being used between a cam lobe and a valve on DOHC valve trains other than adding a lot of height but I can't think of an engine configured so.
Usually rocker arms are employed with the hyd tappet being a pivot point at their ends. But there are myriad factors an engineer considers when selecting valve train configurations. Ease of production assembly (of a built up head) being one where the head bolts must be accessible. Increasingly, overall height for reasons of pedestrian impact protection is a priority - the reason Mercedes moved their cam chains to the rear of the engine. There's a minimum cam chain sprocket diameter dictated by the drive one which in turn is determined by the crank diameter. Easily circumvented on a bike engine where no drives are required at that end of the engine. Not so much when you want to hang a big torsional vibration damper and myriad accessory drives on the nose of your crank.

Well done on getting it out though, acetone a good thing to know.

Yep, especially as in nail varnish remover it's easily obtained.

[Pinger]

]Or one where they don't expect you to do any maintenance, just throw it away when it starts to wear out.

In fairness to solid tappets, they tend not to need adjustment - if the valves are made of decent material that is....
Our 'built in obsolescence' these days seems to be electronics. £1700 for an ABS/ESP ECU has effectively written off my smart. An otherwise good and useful little car - infinitely better than taking a bus ride in these Covid times.

Re Acetone, I read somewhere that a 50:50 mix of Acetone and ATF works better than Plus Gas on seized bolts and mentioned this to someone I know who had an engine that had one cylinder open to atmosphere for a number of years and the piston rings had rusted to the bore on one pot. He misheard me and missed the ATF so filled the pot with neat nail varnish remover. After soaking for two days, he was able to turn the engine over!

I've heard some swear by ATF and diesel mixed. It is said that ATF has high detergency but I've not seen evidence - or need. Auto trans don't see dirt like an engine does and a good oil shouldn't be carbonising.

[mgrover]

ahh i had mine done by mike at autogas. still driving me up the wall with lean trims.

[desauld]

Just to update and finish off this thread. The range rover is back up and running. All valves and seats had some wear and pitting, so all where replaced, the seats with Lpg compatible ones, which arnt just harder, but are sintered with materials that lubricate, and stop the valve and seat micro welding and wearing when on gas. I could of saved a few valves, but while your in this deep why would you. I built her up with all new gasket's, chains, guides, water pump etc. Valve clearance has been set slightly looser than factory which can't not help. Figure around 4k in parts...



This was not an lpg issue specifically. But the issue was definitely accelerated by the dry nature of the gas. I would of had this same issue on petrol, but slightly further down the road. The non self adjusting nature of this engines tappets, the inbuilt issue with too tight valve clearance, especially on this supercharged engine, and questionable valve and seat hardness all make this series of AJ engines less suitable to conversion to gas than say an Audi turbo engine that's got hydraulic tappets, hard valve and seats etc.

But I would still convert this range rover to gas again. I would keep an eye on valve clearance and probably get some used heads modified ahead of time, then take a week off work and swap them over. It's not a difficult job, other than the issue I had with the crank bolt, there is just a lot of work in it.

[Pinger]

Just to update and finish off this thread. The range rover is back up and running. All valves and seats had some wear and pitting, so all where replaced, the seats with Lpg compatible ones, which arnt just harder, but are sintered with materials that lubricate, and stop the valve and seat micro welding and wearing when on gas. I could of saved a few valves, but while your in this deep why would you. I built her up with all new gasket's, chains, guides, water pump etc. Valve clearance has been set slightly looser than factory which can't not help. Figure around 4k in parts...

Thanks. I'd been wondering how you got on. Got there in the end.

This was not an lpg issue specifically. But the issue was definitely accelerated by the dry nature of the gas. I would of had this same issue on petrol, but slightly further down the road. The non self adjusting nature of this engines tappets, the inbuilt issue with too tight valve clearance, especially on this supercharged engine, and questionable valve and seat hardness all make this series of AJ engines less suitable to conversion to gas than say an Audi turbo engine that's got hydraulic tappets, hard valve and seats etc.

Seems that some engines are more susceptible to ill effects from LPG than others. I worried that my engine may have suffered the same but doing some other work on it permitted access to its pushrods - which can be rotated between my finger tips which is I'm told the sign that the clearance on the hyd tappet needs tightening so no recession.

But I would still convert this range rover to gas again. I would keep an eye on valve clearance and probably get some used heads modified ahead of time, then take a week off work and swap them over. It's not a difficult job, other than the issue I had with the crank bolt, there is just a lot of work in it.

You were unlucky with that bolt but it could have been worse. Your perseverance (across the board) paid off though.

[dhallworth]

Sorry to revive an old thread here…

I took my cam covers off on Friday night to sort an oil leak on mine and whilst it was off I started to check the valve clearances. They should be between 0.018 and 0.022mm. I couldn’t even get a 0.009mm feeler gauge in on cylinders 1 and 5.

I then noticed whilst I was checking the clearances when the flats on the cams on the OS bank were in the locking position the ones on the NS bank were a mile out so it looks like I’m continuing to strip it down.

I managed to get a brand new set of cylinder heads off eBay recently but am having a bit of a dilemma at the moment. My car has covered about 100k on LPG before starting to develop issues. I can’t figure out wether to remove the LPG seeing as I only do 4-5k a year, fit the heads as they are in the hope I get another 100k before having any issues, or send the new heads away to have the seats replaced.

Do you know roughly what it cost you to have your seats replaced?

Where did you source the valve seats from?

Did you have any issues setting the valve clearances before you reassembled?

Any hints, tips or pointers that you can share having already done the job?

Parts cost is going to be around £750 for a timing chain set (4 chains, 4 tensioners, and 4 guides) and around £500 for gaskets and seals. Have got the timing tools arriving at some point this week.

Thanks,
David.