LPG for a VH?
Hi all. Can anyone tell me if they have put LPG in their VH and if so, did it make a difference to the running of the car and did it overcome any of the problems associated with the Varijet carby. Did they change the carby completely?. We are considering putting LPG in ours but would like some opinions first.thanks
Banned
If you are going to go dual fuel, the varijet is going to be retained. Whatever problems you have on petrol with it will be retained as well......not that Im aware there are inherent problems with it. LPG operation should not be affected by any problems with the varijet.
If you go lpg only, then the varijet would be removed and an lpg carby(mixer) fitted in its place. Going lpg only has decided advantages in a car of this age, an important one being that you can legally deactivate all adr27a emission controls on the engine and have the engine setup best for lpg rather than so it will work on petrol as well(timing + spark gap). The system is also far more simple and reliable running lpg only.
A simple setup for the vh would be an impco 225 mixer + convertor + tank. This is a very basic conversion and would be hard for even the most incompetent fitter to stuff up and is a tried and true setup. All this stuff could be setup new for ~ $1200 8 years ago.....but given the lpg rebate, Im sure installers would want double for the same setup.
Its a 24+ year old vehicle......do you intend to keep it for another 10 years?.....if so then the conversion may be worth the time and effort.
LPG in VH - Is it worthwhile
Many thanks for the detailed reply. I do intend to keep it so i will phone our local LPG installer and see if he can do the conversion you mention, what converter would you advise? Also, do they have to change the manifold or any other major alterations, sorry but i am new to all this gas businees. We inherited this VH from a family member who had it from new and it is in lovely condition and we do not want to stuff it up as it will hopefully be passed on to our kids so any more detailed info on what is required for the LPG conversion would be great. At least i pretend to know what i am talking about when i go to get a quote lol.. I really dont mind it being gas only but can you tell me if it has any adverse affects on the motor by not being able to run petrol thru it now and again? thank you.
Last edited by farkamhall; 15-12-2007 at 03:13 PM.
Banned
I ran/run the model J convertor on warm 202s with no problems, but believe its near maximum capacity. Certainly if you have a high revving highly modified motor the next model up, model L, may be considered.
Running lpg will cause valve seat recession etc. This will happen regardless of whether you run it on petrol once a week etc. How long this takes depends on how much open road/ spirited driving you do. The motor may happily go another 200 000km without any problems or if a lot of high speed driving it could be sooner. ( I havent had any valve problems in 15 years with lpg on 3 202s, however, most of our use is suburban. Either way, wouldnt do anything until the problem shows up. A reconditioned cylinder head for your motor is relatively cheap. I wouldnt bother with upper cylinder lubricants ....its just cheaper to get the cylinder head reconditioned with mods for lpg(if it ever needs it) than feed it flashlube forever.
If you run lpg only, you can request to have the distributor advance adjusted to suit lpg. Sometimes the installer will just disconnect the vac advance, but to do the job properly vac and mechanical advance is restricted from petrol settings. This is to allow an initial timing setting in the 12-15 deg range.
LPG for a VH?
Thank you so much for that info. Gas only sounds the way we will be going. we only have the basic 3.3 blue motor with no mods and mainly suburban and a little freeway driving so i suppose the model j converter should do. what do you think? could you please explain a little more about " to do the job properly vac and mechanical advance is restricted from petrol settings. This is to allow an initial timing setting in the 12-15 deg range" and also, what is flashlube. Thanks
Banned
Distributor advance: your car has two mechanisms.....vacuum and centrifugal.
Hope Im not getting too basic here, there is probably a website that tells it better, but will take only a minute or so for me to type here :
The spark plug should fire just before the piston gets to the top of the compression stroke, rather than right at the top. This is because the mixture takes time to burn, and we dont want the full force of the burn to be happening too late in the power stroke.
As the motor goes faster, the burn speed doesnt increase at the same rate so the spark has to be set off earlier to account for the piston moving faster towards the power stroke. The amount of spark advance with rpm is controlled by the centrifugal advance mechanism. It will be limited to a set amount that is probably reached at ~3500rpm or so on your motor.
The speed at which the fuel burns is also determined by the dynamic compression of the motor and absolute fuel intake. At wide open throttle the dynamic compression ratio is much higher and the fuel will burn faster once ignited, so less advance is required. At cruise and relatively small throttle and low dynamic compression, the spark needs to occur earlier. When full throttle is used vacuum pressure falls away and on part throttle vacuum is high......so the advance to the distributor can be controlled for these conditions by changes in vacuum.
Lpg is slower to burn than petrol at low temperatures/ dynamic compression so more advanced timing of the spark is needed at low rpm. As temps increase the burn speed actually increases (at a higher rate than petrol does) so the amount of both centrifugal and vacuum advance needs to be restricted from those of petrol. If the spark goes off too early, the explosion is basically trying to move the piston in the opposite direction to its travel....not a good thing!
Flashlube is an upper cylinder lubricant that is meant to mimmick the properties of lead in petrol that lubricate the valve inserts etc. Cars that werent designed to be run on unleaded have harder valve inserts etc.....yeh forgot......if youve been running your vh on unleaded petrol, then its not getting to be an different on lpg either(in terms of upper cylinder lubricant)
LPG for a VH?
PHEWE!!! thats telling me . Many thanks once again you are a godsend to an idiot like me. if i can be a pest once again. if we go for full gas only, which we will do, what do i tell the installer to set the advance to? also, before we got started thinking on gas only , as you wisely suggested, our local installer quoted $2400.00 for a dual fuel conversion. Do you think the gas only conversion should be more expensive or less?
Banned
Generally for this type of conversion there isnt much difference in price, as really all the same hardware is needed. Your present fuel gauge should be also be still used rather than a tacky add on device.....it just means they have to order the correct sender for the tank.Originally Posted by farkamhall
If your installer knows his stuff, he shouldnt need to be told by you how to set it up, however, you can use what you know as a starting point to see if they do know what they are doing, or perhaps are looking to take shortcuts.
The optimum advance for the distributor should be done on a dynometer, which all good gas fitters should have. If you dont have the distributer modified, then as mentioned b4, they can set it up to get max power with the vac advance disconnected.....and this wont cause any problems with the car pinging at any other situation, however, it wont be optimum for cruise and idle etc. They may want just leave it on the petrol setting as the results will be okay and cant cause any damage.
In reality, it doesnt make a huge amount of difference.....but its worth getting right for the small cost involved.
In short if standard dizzy left there with vac advance still connected, then timing should be set to ~ 8deg btdc at idle.
vac advance disconnected.....timing set to ~10-12deg btdc
modified dizzy for lpg....timing set to 12-18deg btdc
Commsirac, you are a legend. Thank you ever so much for all your time and effort, it has really been a great help and very much appreciated. I will post here once i get the quote and let you know how it all went. I just posted some pics on My Ride section if you would care to take a look. have a really nice xmas mate and thank you once again.
just a question to follow up on this. i spoke to an impco rep re the gas conversion for our VH and he was suggesting the 300A mixer with a model E convertor. Anyone got any thoughts on this as the general opinion seems to go for 225 mixer and model j convertor. just wanted to know the differnce or if anyone has used the 300A\Model E setup.thanks
Banned
Did the rep give a reason as to why recommending the 300A. Its much more mixer than you need, the 3.8L comm v6 fact system uses the 225 and it will rev harder than your vh 3.3L motor. (are the 225 mixers hard to get hold of atm?) An impco 125 mixer is really all you need for a 3.3L vh, the 225 is just allowing you a little "breathing" space.
Id of thought it would be harder to get the mixtures right on a smaller engine for cruise, idle and max power with the 300A and make cold starting a little more difficult.
hi commsirac. the rep didnt say. i only phoned him because when i phoned the lpg installer he wanted to fit a 300A , reckoned it was easier to maintain. I am going to go for the 225 anyway but the installer said he would get back to me with availability so i presume he may be having probs getting one. just wanted to know what you guys thought and as always, very helpful.thank you
Banned
A good site to visit: WPS:LPG, it has handy links for impco catalogues as well as Tom Jennings detailed account of how he set up his 63 Rambler 232ci on a 125 Mixer etc.
According to the catalogue the 330A comes along in four variants.....put the installer on his toes and ask which one he has in mind!
thanks mate will do.gonna take a look at that link now.
The 300a will bolt to the top of the varajet easily with a adaptor.
Fitting a 225 in there would be a lot harder.
Dont forget there are model and flow variants of the 300a.
The 1and 20 is the way to go.
The 225 will be more than enough for a 3.3 but its all about the fit.
It is much harder to source adaptors and parts for the 225 for what you want to do.
The 300a is just MUCH easier to fit in this application.
225's are more suited to EFI applications where you can fit them in the intake hose.
300a's at the best for carby applications or dual fuel carby applications as the amount of different configurations in fitting them is amazing.
Even for a straight gas set up the 300a is the way to go as there are two barrel throttle bodies available to mount them directly to the manifold.
Straight gas convesion will cost more do to the fact that there will de more money in the adaptors and throttle body plus much more time in setting the accel cable and throttle switch for the timing computer.
Correct me if I am wrong but does the VH not run a timing computer and a crank angle sensor ect??????
Last edited by blownba; 20-12-2007 at 11:31 PM.
thanks blownba, i do not want dual fuel only straight gas so this is getting a little confusing as i belive that quite a few people have used the 225. i dont have a clue about the timing computer and crank angle sensor etc so perhaps someone who knows could answer that.thanks mate
Banned
Blownba: Have 2 holden red motors running 225 mixers on straight gas on the standard red six manifold......doesnt seem to be any issue about having room to fit it, it sits lower than the carb it replaces......what do you mean about right angled connection?
VK was the sophisticated one, VH was just first with electronic ignition.
Its too late at night and I am too tired.
The VK had EST or electronic spark timing not the VH.
If you really are serious about straight gas and you want to do the job right get the dizzy regraphed to suit LPG.
Usally when I do straight gas conversions we include this in the price so we can maximise the benefits of the higher octane rating of LPG. So we regraph distributors to suit.
I used to do them myself but have since sold the distributor test bench because there is just not the call for it anymore and it was just gathering dust.
Any good ignition place will be able to do it with their eyes closed.
blownba,so are you saying that the impco225 would do the job or would it still have fitting probs?
Best he speaks to the guy that is gonna do the coversion and see what he can source or what he is happy to use.
300a with the Impco throttle body bolted to the bottom of it and than bolted to the manifold and a a31 aircleaner on top. They sit lower than a 225 ever would with the throttle bodies you need to suit them.
The body of a 225 is higher than a 300a.
I am not gonna argue with you commsirac you are the master. I shall kneel before you.
Please disregard all I have written previously in this thread.
Thank you.
????????????!!!!!!!!!!! time for bed me thinks
Banned
Blownba: I am very disappointed by your response ^, its not helping farkamhall at all
I have only brought up the following:
Blownba: Have 2 holden red motors running 225 mixers on straight gas on the standard red six manifold......doesnt seem to be any issue about having room to fit it, it sits lower than the carb it replaces......what do you mean about right angled connection?
as it doesnt seem to gel with the first hand experience I have with my vehicles. The purpose of such being that a dialogue would be available for farkamhall to get the best information possible on his options, not for purposes of oneupmanship on the forum
The opportunity was there for you to clarify/explain that there may be other issues or that they may be of concern and indeed I was disappointed that I was the only person that had replied to the thread. I too want to learn more and if what I have written is incorrect or no longer best practice, I want to know about it too.....Id still like to know what you mean about the right angled connection on the 225 restricting its installation.
Do you think my concerns of not being able to setup the mixtures on the 300A as well as for the 225 would be relevant (looking at the specs there isnt much difference in the 300A-1) , that would be good for farkamhall to know.
I have been impressed with your knowledge of all things relating to LPG operation and your business ethic and your passion that you report for doing your job well.......and certainly if I was looking to have a conversion done would have looked to your services.
Its not relevant to me if an installer remembers every nuance about every car manufactured in the last 30 years or not just that they do bother to get it right when the car is presented to them.
Last edited by commsirac; 21-12-2007 at 10:26 AM.
I appreciate your comments as always commsirac and i think you have put this in words a lot better than i could have done. I am very new to this as it is our first commodore and we are really loving it. We want to do things right the first time and not have to chop and change things around, which is why your own experience with the Impco 225 is something we have really been able to understand, the confusion was with Impco themselves and the LPG installer, and perhaps they have their own reasons for suggesting a 300A.
blownba, i do appreciate your comments and opinion as you seem to be well informed and experienced as an installer. Perhaps the lateness of night contributed to the some of the comments being muddled. Like commsirac, i would appreciate an explanation on the "right angle" comment and would welcome your coming back to answer both mine and commsiracs questions.
The information that i can understand as a "layperson" with no experience with this conversion would, i am sure, be very helpful for other forum members who are thinking of doing the same to their car.
Just as an afterthought, i too would have thought that more members would have been able to contribute to this post considering that a lot of LPG conversions have been carried out on members cars and they may have had some similar experiences\problems.
Last edited by farkamhall; 21-12-2007 at 08:13 AM.
Theres a mob in the US called Nashlift, I bought an Impco 425 gas carb for my 308 VK running straight LPG, was about 250 cheaper than any price I was quoted in Australia and that was even after $40 US for air freight.
try this site for all your LPG questions, Raso Enterprises Main Page
there's a bloke called Franz on those forums thats a guru when it comes to LPG.
google this "TIMING AND VACUUM ADVANCE 101 by John Hinkley"
its an excellent article on ignition timing and distributor curves.
I had muddled up a 225 with a 200.
I had edited it within the 10 mins after posted but the damage was done. If you look at that post know there is no mention of it now.
200 are a right angled in and out.
Your right it was a bloody LOOOOONG and very busy day and I have just opened up my own shop. I feel sometimes overwhelmed by comsirac and the rings he runs around me but thats my problem and it should not have messed with the thread and for that I am sorry.
I have always used 300a's on this type of application due to the ease of sourcing parts and fitment options and the performance gains over a 225. Even for a dual fuel the 300a bolts to the top of the carby and than a A31 air cleaner mounts to it and the added benifit of the 300a is that you can run a pull cable for dual fuel so when you are running on petrol you can lift the air valve up from in the cabin and this provides unrestricted air flow to the varajet which is suseptable to poor operation if it needs to lift a air valve of a gas mixer to run. But this is all dual fuel stuff.
For straight gas I would go the 300a as it will give much better flow rates purely due to the size of the hole in the centre of them allows clean air flow whereas the 225 needs to 'bend' the air flow and make it change direction to get it through it therefore less flow and also turbulant air flow because of all the diaphram mounts and sharp edges of the mixers design.
The 300 a has air entering the side and straight down through it with no restriction to it. Far better from a performance perspective.
I have always used 330a's on carby aussie sixes when I go straight gas. It really is so much easier. My XY 2V 250 ran one with a genuine Impco throttle body before I went 4 barrel and that made some pretty wicked HP gains, and mountains of torque down low, going from a well jetted holley 350 to straight gas and a 300a on its own. You will see what I mean when you do it yourself. Torque curves down low can be amazing when compared to petrol. This makes for a much nicer drive, and its half the price!!!!
You will be able to get some pretty decent ignition advance from experience and if its done right the performance gains and just overall better driveabiltiy make the straight gas option well worth it. But like I said be prepared to pay extra for the priveledge.
Posting Permissions
LinkBack URL
About LinkBacks
Reply With Quote