-
Hi Guest!
If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
There are some perks with a member upgrade!**Upgrade Now**
(PS: Subscribers don't see this gawd-aweful banner
Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
PI installation?
- Thread starter jd72tr6
- Start date
Share this page
G
Guest
Guest
Guest
Offline
I saw one recently where they just looped it back to the pump.
What sort of PI system are you going to install jooi? Original Lucas mechanical, or aftermarket?
What sort of PI system are you going to install jooi? Original Lucas mechanical, or aftermarket?
G
Guest
Guest
Guest
Offline
No - the inlet using a Y.
You have all the pieces, right?
You have all the pieces, right?
angelfj1
Yoda
Offline
At one time I considered converting the 250 to a 5. I had the thrill of a lifetime when back in the 80's I drove Charles Runyan's TR-5. There is nothing like 50 percent more power. I was considering an original Lucas setup. I started researching what this project would entail and decided it wasn't worthwhile. If you have a US spec TR-6 engine, almost everything but the block, pistons and crankshaft are incorrect. The PI requires a different cylinder head, intake and exhaust manifold, camshaft, and distributor. Then add fuel metering unit, injectors, lines, high pressure electric fuel pump, modified fuel tank and lines and other bits and bobs. Major deal and done correctly I'd say $5K + in parts alone. Then, if it doesn't run, what do you do? I haven't met any mechanics on this side of the pond who are familiar with the system .These Lucas systems were not known for reliability. If you want PI, you have other options. There are modern aftermarket systems for these engines, including a throttle-body setup, where you would retain both carbs.
NickMorgan
Jedi Knight
Offline
You are at a real disadvantage, being on the wrong side of the Atlantic. You have to consider the octane rating of your fuel too. You could consider contacting Revington TR who produce a modern system that may be easier. Here we just need to find a 2.5PI saloon and take all the parts off that, but of course all our TR5s and 6s are fuel injected anyway!!
swift6
Yoda
Offline
[ QUOTE ]
You are at a real disadvantage, being on the wrong side of the Atlantic. You have to consider the octane rating of your fuel too. You could consider contacting Revington TR who produce a modern system that may be easier. Here we just need to find a 2.5PI saloon and take all the parts off that, but of course all our TR5s and 6s are fuel injected anyway!!
[/ QUOTE ]
We are at a disadvantage for mechaincs being familiar with the Lucas PI system as fitted to the TR6. Octane ratings are a non issue though. Our octane ratings are lower because they are arrived at through a different method of rating. There is no effective difference in use between your high octane fuels and our high octane fuels. Don't let the numbers fool you. /ubbthreads/images/graemlins/wink.gif
As far as reliability of the PI, I can only think of a few things that weren't reliable. Primarily the fuel pump(easy fix with newer pumps), after that it was the older rubber o-rings not agreeing with the newer fuel mixes(another easy fix) and then it was clogged injectors after many years of use. The cleaning and rebuilding of the injectors are where we in the US are really in trouble. The folks in the UK that do it only do so on an exchange basis, no outright sales.
Other than that, the biggest complaint that I remember was a very rough idle on the 150hp (early cars) due to the cam which was changed with the later 125hp cars. BTW, the later US TR6 heads ('72-'76) that used the long runner intake manifold have the same port spacing as the PI cars. Skim the head to match the PI's higher compression and that is one less headache. Though many many more do await you in the rest of the conversion. /ubbthreads/images/graemlins/tongue.gif
Revington makes some really nice kit for EFI but the exchange rate is murderous. Can build systems other ways for much less money, though not in one nice complete kit.
/ubbthreads/images/graemlins/cheers.gif
You are at a real disadvantage, being on the wrong side of the Atlantic. You have to consider the octane rating of your fuel too. You could consider contacting Revington TR who produce a modern system that may be easier. Here we just need to find a 2.5PI saloon and take all the parts off that, but of course all our TR5s and 6s are fuel injected anyway!!
[/ QUOTE ]
We are at a disadvantage for mechaincs being familiar with the Lucas PI system as fitted to the TR6. Octane ratings are a non issue though. Our octane ratings are lower because they are arrived at through a different method of rating. There is no effective difference in use between your high octane fuels and our high octane fuels. Don't let the numbers fool you. /ubbthreads/images/graemlins/wink.gif
As far as reliability of the PI, I can only think of a few things that weren't reliable. Primarily the fuel pump(easy fix with newer pumps), after that it was the older rubber o-rings not agreeing with the newer fuel mixes(another easy fix) and then it was clogged injectors after many years of use. The cleaning and rebuilding of the injectors are where we in the US are really in trouble. The folks in the UK that do it only do so on an exchange basis, no outright sales.
Other than that, the biggest complaint that I remember was a very rough idle on the 150hp (early cars) due to the cam which was changed with the later 125hp cars. BTW, the later US TR6 heads ('72-'76) that used the long runner intake manifold have the same port spacing as the PI cars. Skim the head to match the PI's higher compression and that is one less headache. Though many many more do await you in the rest of the conversion. /ubbthreads/images/graemlins/tongue.gif
Revington makes some really nice kit for EFI but the exchange rate is murderous. Can build systems other ways for much less money, though not in one nice complete kit.
/ubbthreads/images/graemlins/cheers.gif
NickMorgan
Jedi Knight
Offline
That's interesting. Our standard unleaded fuel is 95 RON and our super unleaded is 98. How does that equate to the USA octane rating?
Nick, here is an excerpt from a post by Dave Russell. As always, thanks again to Dave for his wealth of information.
Jeff
"There are two test methods, the Research Method which yields a Research Octane Number (RON) and a Motor Method which yields a Motor Octane Number (MON). The number posted on the gasoline pump is an average of those two numbers, (R+M)/2.
Today, gasoline octanes range for 85 to 94 (R+M)/2 with the typical grades being regular unleaded at 87, midgrade at 89, and premium at 91 to 94. Prior to the eighties, gasoline octane was often posted based solely on the Research Octane Number which allowed postings as high as 100 octane. Premium gasolines sold today often have a research octane number of 100 or higher but must post the (R+M)/2 value. For instance, a 93 octane premium will likely have a motor octane of 85 and a research octane of 101 (101 + 85)/2 = 93.
-------------------------------
USA uses the (R+M)/2 rating system. As it says, prior to the 1980's USA used the "research" rating. Today, many European countries & some others still use the research rating method. Bigger numbers for the same equivalent octane rating. AV gas uses yet another different rating system.
Approximate equivalent ratings:
USA = 87 -- Euro = 91 -- RON = 91 -- MON = 82.5 -- R+M/2 = 87
USA = 89 -- Euro = 95 -- RON = 95 -- MON = 83 ---- R+M/2 = 89
USA = 93 -- Euro = 98 -- RON = 98 -- MON = 88 ---- R+M/2 = 93
USA producers are allowed some variation between their posted pump octane ratings & the actuals. Each batch of fuel may be slightly different & you may find that one brands actual octane ratings variy a bit from day to day. The "must have gotten a bad batch syndrome". In the end, it's a matter of what you are most satisfied with. For most modern cars with adaptive timing controls, few folks will notice much difference between 87 & 93 octane. Older cars excepted, of course.
Additionally, there are seasonal variations in the volatility (how easily the fuel is vaporized) from region to region. This can lead to a more volatile winter blend causing vapor lock on an unusually hot day."
Jeff
"There are two test methods, the Research Method which yields a Research Octane Number (RON) and a Motor Method which yields a Motor Octane Number (MON). The number posted on the gasoline pump is an average of those two numbers, (R+M)/2.
Today, gasoline octanes range for 85 to 94 (R+M)/2 with the typical grades being regular unleaded at 87, midgrade at 89, and premium at 91 to 94. Prior to the eighties, gasoline octane was often posted based solely on the Research Octane Number which allowed postings as high as 100 octane. Premium gasolines sold today often have a research octane number of 100 or higher but must post the (R+M)/2 value. For instance, a 93 octane premium will likely have a motor octane of 85 and a research octane of 101 (101 + 85)/2 = 93.
-------------------------------
USA uses the (R+M)/2 rating system. As it says, prior to the 1980's USA used the "research" rating. Today, many European countries & some others still use the research rating method. Bigger numbers for the same equivalent octane rating. AV gas uses yet another different rating system.
Approximate equivalent ratings:
USA = 87 -- Euro = 91 -- RON = 91 -- MON = 82.5 -- R+M/2 = 87
USA = 89 -- Euro = 95 -- RON = 95 -- MON = 83 ---- R+M/2 = 89
USA = 93 -- Euro = 98 -- RON = 98 -- MON = 88 ---- R+M/2 = 93
USA producers are allowed some variation between their posted pump octane ratings & the actuals. Each batch of fuel may be slightly different & you may find that one brands actual octane ratings variy a bit from day to day. The "must have gotten a bad batch syndrome". In the end, it's a matter of what you are most satisfied with. For most modern cars with adaptive timing controls, few folks will notice much difference between 87 & 93 octane. Older cars excepted, of course.
Additionally, there are seasonal variations in the volatility (how easily the fuel is vaporized) from region to region. This can lead to a more volatile winter blend causing vapor lock on an unusually hot day."
swift6
Yoda
Offline
Additionally, high altitude (like Colorado) has lower ocatane to go with the lower density air. Usually in the range of 85-91, you can occasionally find 93 octane fuels up here. Our winter mix used to include MTBE as an additive to reduce pollution during the temperature inversion prone winters. Then they discovered that the MTBE was bad for ground water (what goes up must come down /ubbthreads/images/graemlins/wink.gif) so now we have a year round mix of ethanol (roughly 10 percent).
heliguy
Jedi Hopeful
Offline
Jim, back to your original question. The return line from the metering unit ( there is always flow through it ) is routed back to the tank via a fitting welded to the top of the tank. This is low pressure return fuel so the fitting could even be brazed on i suppose.
I am in the midst of converting my TR250 to a PI spec car. I have bought 2 complete sets with one spare set of throttle bodies and have spent less than a grand ( including shipping ) . Kinsler in Michigan I think, has the ability to rebuild metering units and injectors. I have stripped a couple of metering units and its not rocket science here guys, we are talking 1960's mechanical technology. The big problem is setting the units up to the car. You need lots of time, patience and access to a dynometer. If not, Kinsler or Prestige in the UK can do it for you. As far as injectors go there is only one 25 cent "O" ring inside of them that wears out. Pop off a small circlip, change the "O" ring and away you go. The Lucas system got a bad rep early on but most of the "bugs" have been fixed. I say go for the Lucas system!
I am in the midst of converting my TR250 to a PI spec car. I have bought 2 complete sets with one spare set of throttle bodies and have spent less than a grand ( including shipping ) . Kinsler in Michigan I think, has the ability to rebuild metering units and injectors. I have stripped a couple of metering units and its not rocket science here guys, we are talking 1960's mechanical technology. The big problem is setting the units up to the car. You need lots of time, patience and access to a dynometer. If not, Kinsler or Prestige in the UK can do it for you. As far as injectors go there is only one 25 cent "O" ring inside of them that wears out. Pop off a small circlip, change the "O" ring and away you go. The Lucas system got a bad rep early on but most of the "bugs" have been fixed. I say go for the Lucas system!
heliguy
Jedi Hopeful
Offline
https://lucasinjection.com is the gospel for PI stuff.
swift6
Yoda
Offline
Kinsler does appear to have a good bit of Lucas Mechanical Injection experience which doesn't have to be TR6 specific. Your right its not rocket science but if he has to rely on locals having knowledge of the system to help him out the resources will be pretty thin. Depending upon how close he is to Michagan.
/ubbthreads/images/graemlins/cheers.gif
/ubbthreads/images/graemlins/cheers.gif
mgb4tim
Jedi Trainee
Offline
[ QUOTE ]
https://lucasinjection.com is the gospel for PI stuff.
[/ QUOTE ]
Have any links like this for the TR7 FI?
https://lucasinjection.com is the gospel for PI stuff.
[/ QUOTE ]
Have any links like this for the TR7 FI?
Offline
[ QUOTE ]
Additionally, high altitude (like Colorado) has lower octane to go with the lower density air. Usually in the range of 85-91, you can occasionally find 93 octane fuels up here.
[/ QUOTE ]
Hi Shawn,
You are of course correct. to put numbers on it, since air density decreases about 3.4% for each 1,000 ft. elevation increase, compared to sea level, air density at 5,000 ft would be reduced by 17%. This corresponds to a static compression ratio reduction of from 9 to 1, to about 7.8 to 1.
D
Additionally, high altitude (like Colorado) has lower octane to go with the lower density air. Usually in the range of 85-91, you can occasionally find 93 octane fuels up here.
[/ QUOTE ]
Hi Shawn,
You are of course correct. to put numbers on it, since air density decreases about 3.4% for each 1,000 ft. elevation increase, compared to sea level, air density at 5,000 ft would be reduced by 17%. This corresponds to a static compression ratio reduction of from 9 to 1, to about 7.8 to 1.
D
swift6
Yoda
Offline
Yep, we pretty much figure a full point of compression loss at our altitude. Your math backs that up and then some. More volatile fuel helps some what. /ubbthreads/images/graemlins/grin.gif Puts bigger grins on our faces when we can drive to lower altitudes as well.
It also allows us to 'get away' with using pump gas on higher numeric static compression ratios. 10.5-11:1 CR's are possible (though not always recommended) with 91 octane fuels up here. Just be ready to add octane boosters when dropping to lower altitudes since 93 might not be enough when getting closer to sea level air density.
It also allows us to 'get away' with using pump gas on higher numeric static compression ratios. 10.5-11:1 CR's are possible (though not always recommended) with 91 octane fuels up here. Just be ready to add octane boosters when dropping to lower altitudes since 93 might not be enough when getting closer to sea level air density.
[ QUOTE ]
Kinsler does appear to have a good bit of Lucas Mechanical Injection experience which doesn't have to be TR6 specific. Your right its not rocket science but if he has to rely on locals having knowledge of the system to help him out the resources will be pretty thin. Depending upon how close he is to Michagan.
/ubbthreads/images/graemlins/cheers.gif
[/ QUOTE ]
Shawn, and Jim.
Kinsler is only about 6 miles from where I work, if I can help out in any way. Sometimes face to face is easier than email or telephone.
Jeff
Kinsler does appear to have a good bit of Lucas Mechanical Injection experience which doesn't have to be TR6 specific. Your right its not rocket science but if he has to rely on locals having knowledge of the system to help him out the resources will be pretty thin. Depending upon how close he is to Michagan.
/ubbthreads/images/graemlins/cheers.gif
[/ QUOTE ]
Shawn, and Jim.
Kinsler is only about 6 miles from where I work, if I can help out in any way. Sometimes face to face is easier than email or telephone.
Jeff
Thanx to everybody for their input, The guy who is selling the pi systems lives in new zeland,tells me they were removed because of rough idleing and replaced with carbs because they are more forgiveing. he says the rough idle was caused by loss of manifold pressure and the systems that were removed are fine. I'm still undecided what the heck I'm going to do! Nothing is easy with these cars.. Thanx again, Jim
heliguy
Jedi Hopeful
Offline
Jim, the rough idle on the earlier single balance pipe 150 HP cars was due to a pretty hairy cam. Later 125 HP cars with the dual balance pipe throttle bodies had a milder cam that gave the car a bit more manners in traffic. If you are going to go the PI route, might as well go for the 150 HP set up ( if possible ) and if you can get injectors that are repairable/rebuildable as compared to ones that are crimped together then you want to do that as well. There is ALOT more tinkering to be done with a PI car for sure, some of it beyond the back yard mechanic, so you just want to make sure you know what you are getting into.
Good luck!
Mitch
Good luck!
Mitch