5.7 Hemi & LPG

Author
Discussion

Quinny

15,814 posts

265 months

Friday 24th October 2014
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AdeTuono said:
I thought Matt made a very considered, informative and useful post. Just my opinion... getmecoat
Well FWIW......I'm currently running 2 LPG jeeps.... The old WJ, 4.7 (140k miles) and my newer WK 5.7 hemi ..(90k miles)

Popular opinion seems to suggest that the 4.7 suffers valve recession, and therefore should run flash lube....whereas, the 5.7 is ok to run just LPG.....

Mine is the other way around, purely because that's how they were when I bought themsmile.... The 4.7 is still going strong, and has never had flashlube.....as for the Hemi, well I haven't had it long enough to learn much about it, but the flashlube is fitted so I may as well use it, but it's turned down to the minimum....

Maybe I should rip it out and fit it to the 4.7hehe

Oh my mate had a 4.7 HO, and that suffered valve recession, but still lasted to 200k before it finally cried enough....

Matt Harper

6,613 posts

200 months

Friday 24th October 2014
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vaughan watkins said:
I probably did think you were being some what a tosser on a public forum, making my car un-sellable here in the UK which is a very small market for such a car, so you basically de valued my car in one comment,
I somehow doubt that my opinion has that much influence on the UK used car market.

The OP asked about the 5.7l anyway, so why you even raised this is something of a mystery. I sincerely hope that you continue to enjoy your SRT-8 and experience no adverse events due to the conversion - though I still have some doubts that there are "lots" of 372ci equipped cars in the UK - much less LPG converted ones.
No hard feelings from me.

I did notice this on the website of a UK Landrover/Range Rover dealer, who seems to be less confident about LPG too….

"All Major Vehicle Manufacturers will exclude any damage to engines caused by the installation of LPG, including Valve Seat Recession and Burnt Valves under their new car warranty.

All Warranties sold with LPG Conversions do not cover Valve Seat Recession or Burnt valves. Check before buying.

All After Market Warranties specifically exclude Valve Seat Recession and burnt valves. Check before buying.


All LPG Importers and Suppliers will not pay for damage to engines caused by the fitting of their LPG Equipment.

Make Sure: if you do decide to have your car converted to LPG that you ask the installer to give you a written Guarantee that their LPG Conversion, together with any associated equipment including any Flashlube or other type of Valve Protection Systems used are suitable for your vehicle and will not cause Valve Seat Recession, Burnt out Valves or Engine Damage whilst running on LPG, and that they will Pay in Full for any repair costs associated with the above. If they won't do this consider the risks, as repairs will cost more than the conversion in the first place, and the system will need to be removed to prevent the same thing happening again."

Source www.amrautos.co.uk

Edited by Matt Harper on Friday 24th October 20:00

vaughan watkins

512 posts

210 months

Saturday 25th October 2014
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AdeTuono said:
I thought Matt made a very considered, informative and useful post. Just my opinion... getmecoat
Ade if Matt had given me an informative opinion I would have been fine it was the statement he made saying my car was virtually un-sellable, I'm sorry but I don't find that a helpful statement and in my view un nesscessary. And calling me stupid I don't feel is polite, I will not comment further on this issue as it is pointless.

vaughan watkins

512 posts

210 months

Saturday 25th October 2014
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I somehow doubt that my opinion has that much influence on the UK used car market.

Matt there are probably a max of 20 srt8 in the uK and most potential buyers would be on this forum so I do feel your comment would have some influence.

Matt Harper

6,613 posts

200 months

Sunday 26th October 2014
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vaughan watkins said:
Nicely put Matt thank you, oh an the guy that did my car HAS DONE LOTS OF 6.1's !
vaughan watkins said:
Matt there are probably a max of 20 srt8 in the uK
I'm all confused now.

vaughan watkins

512 posts

210 months

Monday 27th October 2014
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Matt Harper said:
I'm all confused now.
They were just quotes that you made Matt and I put my responses under them, anyway enough hijacking this post, sorry to the original poster for my comments aimed at Matt and hi jacking the thread.

AdeTuono

7,240 posts

226 months

Monday 27th October 2014
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You seem to want it both ways Vaughan. You say the guy has done LOTS of 6.1's, then state that there are a max of 20 in the country. Even if 100% of them have been converted, it's not LOTS, is it?

vaughan watkins

512 posts

210 months

Monday 27th October 2014
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AdeTuono said:
You seem to want it both ways Vaughan. You say the guy has done LOTS of 6.1's, then state that there are a max of 20 in the country. Even if 100% of them have been converted, it's not LOTS, is it?
The 6.1 engine is is in the Chrysler SRT8 300c's and SRT8 Jeeps which is what he has done a fair few of, 20 is relating to Dodge Challenger SRT8's that are actually in this country period and nothing to do with LPG conversions.
I mentioned only about 20 cars in the country as when I come to sell it will be a small market that would be interested in it and most of which would frequent these pages so he basically in one statement made my car the one Not to buy which I fell is a bit off to be honest without actual proof that my car would in fact be damaged from running on LPG, it put me in a panic at the time so I contacted the guy who fitted it who said he had contacted the manufacturers prior to fitting and they had no concerns, basically the manufacturers of the LPG kits have lists of engines that are ok to run on LPG and those that are not, some require a Flashlube system fitted to stop valve burn ect but the 6.1 is given the all clear, now im not sure on how many have actually been done on the 6.1 but even if it was only 20 he has never had one come back with a problem, I have done from memory about 20k or so miles with no issues, no loss of performance or any other kind of issue, I don't have a problem with someone giving advise or raising concerns as that's what these pages are all about, but I do feel his words were poorly chosen which is why I mentioned it in this post as at the time I felt really gutted when he made his statement and I didn't want anyone else to go through the worry that I went through when he said what he said in a previous post which was actually about LPG and a mustang.

Matt Harper said:
You're running a 6.1 SRT-8 on LPG? (There may be trouble ahead……..)
Whys that Matt ?? Their reported to be no issues with it ? No need for flash lube like Chevys, so what do you know that prinz don't ?

Above is matts first comment with my genuine concerned reply below,

His reply

vaughan watkins said:
Whys that Matt ?? Their reported to be no issues with it ? No need for flash lube like Chevys, so what do you know that prinz don't ?
The 372ci motor needs very, very consistent upper cylinder lubrication in order to avoid valve seat damage (valves themselves are less susceptible due to sodium cooling). Piston crowns and valve seats are what you are likely to damage. I would imagine your LPG converted SRT-8 is rendered virtually un-sellable to anyone who has any mechanical know-how with this engine (which has very little in common with it's 5.7l sibling).

And the whole point of me raising this was this comment in the above:
"I would imagine your LPG converted SRT-8 is rendered virtually un-sellable to anyone who has any mechanical know-how with this engine"

Sorry everyone but I don't think that's a nice comment to make on a public forum, maybe im just being Stupid as matt said.

vaughan watkins

512 posts

210 months

Monday 27th October 2014
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swerni said:
Vaughn, don't be so precious.
Matt voicing his opinion isn''t going to have any impact.

Somebody either wants an LPG challenger or they don't, nothing one person says ( well maybe the head of engineering at GM) is going to have the slightest impact.

Have you limited the market for it? Of course you have, a percentage of the people will never want LPG and another percentage will want the full size boot.

I'm going to buy an SRT8 and may or may not get LPG, dependant on usage not Matts view.
now if you had the SRT8 i'd certainly be interested smile
Swerni I assume you mean SRT 8 grand Cherokee ? My buddy has just bought one from Roy at the mustang workshop, it was his own car, it is mental quick ! Plus it's supercharged, brakes upgrade, exhaust ect ect awesome bit of kit, I have been wanting one for my wife as she so misses her 4.7 overland so much, they are getting very reasonable in price now, a lot of car for the money!

scrwright

Original Poster:

2,602 posts

189 months

Wednesday 19th November 2014
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What size LPG tank can you get in the wheel well on a WH Grand? Seen a couple with 80l ones, is that the biggest before you have to put in a raised floor?

Quinny

15,814 posts

265 months

Wednesday 19th November 2014
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scrwright said:
What size LPG tank can you get in the wheel well on a WH Grand? Seen a couple with 80l ones, is that the biggest before you have to put in a raised floor?
The spare wheel on a WH/WK isn't fitted in a wheel well in the boot, it hangs underneath the boot area on the outside.
On my Hemi I have a 77litre, but looking at it, I'm pretty sure I can get a bigger one in there..... It's something I'll be checking out when I upgrade my LPG systemsmile

scrwright

Original Poster:

2,602 posts

189 months

Wednesday 19th November 2014
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Have a 105l in my WG, would want the same in a hemi to hit the 300 mile range ideally. Need to have a look under a WH grand, you can ignore my question on jeepforum now smile