TPI injectors shorter than stock.
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Joined: Jul 2020
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
TPI injectors shorter than stock.
19lb Bosch 5.0/305 TPI Fuel Injectors. The Bosch Design 3 fuel injectors are .125 inch (3mm) shorter than the stock TPI fuel injectors and don’t fit using a factory fuel rail. Same applies to 22 and 25lb injectors.
I have bought the new Bosch injectors, can anyone refer me to who can supply injector lower seats/adapters to fix the height problem.
I have bought the new Bosch injectors, can anyone refer me to who can supply injector lower seats/adapters to fix the height problem.
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From: Florida
Car: 1991 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3:42 Auburn
Re: TPI injectors shorter than stock.
19lb Bosch 5.0/305 TPI Fuel Injectors. The Bosch Design 3 fuel injectors are .125 inch (3mm) shorter than the stock TPI fuel injectors and don’t fit using a factory fuel rail. Same applies to 22 and 25lb injectors.
I have bought the new Bosch injectors, can anyone refer me to who can supply injector lower seats/adapters to fix the height problem.
I have bought the new Bosch injectors, can anyone refer me to who can supply injector lower seats/adapters to fix the height problem.
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
Likes: 0
From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
I no longer have the factory head to compare. The top and bottom o-rings will just seat in their respective bores when the injector is carefully centred (not using the rail clips) but when it is fully seated at the bottom the top o-ring is just out of the rail (by about half the width of the o-ring). I suspect that engine vibration and heat exchange over time would cause the injector to drop fully into the lower bore, with leakage around the top.The factory injectors are Bosch design 1, and fit perfectly when clipped at the rail.
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
Yes, SouthBay also have manufactured adapters but these are only sold with the injectors, not separately.
Joined: Sep 2000
Posts: 2,508
Likes: 197
From: Moorpark, CA
Car: '91 GTA, '92 T/A Convertible
Engine: GTA: 350 w/Vortec heads, T/A: 305
Transmission: Pro-built 700R4
Axle/Gears: GTA: 3.27, T/A: 2.73
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
Agree, SouthBay have been great in the past but the initial request to buy adapters separately was unsuccessful. I will contact them again to see if they can assist.
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Re: TPI injectors shorter than stock.
so the reason why we do not sell the adapters separately is because you cannot just put them onto the bottom of the injector....if you do you'll have a vacuum leak because they will be loose. When we apply them they are on permanently.
The bosch 1's fit because you are using the clips.
You can always double up on the orings....
One will go on the bottom of the injector above the little plastic piece and one will go above that into the little groove. If you opt for the double orings....when you install them do not push them all the way into the intake.
The oring that is in the groove needs to be visible on the outside of the intake otherwise you will be defeating the purpose.
Which intake do you have anyway?
We only use the adapters for stock intakes and rails. You may not need the adapter. Let me know
The bosch 1's fit because you are using the clips.
You can always double up on the orings....
One will go on the bottom of the injector above the little plastic piece and one will go above that into the little groove. If you opt for the double orings....when you install them do not push them all the way into the intake.
The oring that is in the groove needs to be visible on the outside of the intake otherwise you will be defeating the purpose.
Which intake do you have anyway?
We only use the adapters for stock intakes and rails. You may not need the adapter. Let me know
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
I have a GM TPI lower intake manifold stamped 14081005 (Camaro 1985), installed new a few years ago.
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
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Re: TPI injectors shorter than stock.
The fuel rail is stock but the intake manifold is GM aftermarket, and has quite a deep bevelled opening at the top of the injector bore. The injector is more than half way down the length of the lower bore before it fully passes the bevelled edge and completely seals.
I no longer have the factory head to compare. The top and bottom o-rings will just seat in their respective bores when the injector is carefully centred (not using the rail clips) but when it is fully seated at the bottom the top o-ring is just out of the rail (by about half the width of the o-ring). I suspect that engine vibration and heat exchange over time would cause the injector to drop fully into the lower bore, with leakage around the top.The factory injectors are Bosch design 1, and fit perfectly when clipped at the rail.
I no longer have the factory head to compare. The top and bottom o-rings will just seat in their respective bores when the injector is carefully centred (not using the rail clips) but when it is fully seated at the bottom the top o-ring is just out of the rail (by about half the width of the o-ring). I suspect that engine vibration and heat exchange over time would cause the injector to drop fully into the lower bore, with leakage around the top.The factory injectors are Bosch design 1, and fit perfectly when clipped at the rail.
just double up the o-rings if you don’t have the press on adapters.
Re: TPI injectors shorter than stock.
again...the adapters are not just press on. They need to be on the injectors permanently. They cannot be loose and you should not be able to move them at all otherwise there will be a vacuum leak.
Where are you located?
Send them in to us and we'll be more than happy to apply the adapters for you....no charge for the adapters.
Where are you located?
Send them in to us and we'll be more than happy to apply the adapters for you....no charge for the adapters.
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
I’ve been told that placing a additional o-ring in the injector groove above the lower ring was standard practice for years before adapters were available.
I want the best fix. Is this with the double o-ring or the adapter?
I want the best fix. Is this with the double o-ring or the adapter?
Joined: Sep 2000
Posts: 2,508
Likes: 197
From: Moorpark, CA
Car: '91 GTA, '92 T/A Convertible
Engine: GTA: 350 w/Vortec heads, T/A: 305
Transmission: Pro-built 700R4
Axle/Gears: GTA: 3.27, T/A: 2.73
Re: TPI injectors shorter than stock.
Dude, send them to Southbay and let them do it right. Yes, the double O-ring will work, but SB is going out of their way to help you out.
Re: TPI injectors shorter than stock.
That is correct like i said we'll be more than happy to apply them to your injectors for you. Just let us know
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
again...the adapters are not just press on. They need to be on the injectors permanently. They cannot be loose and you should not be able to move them at all otherwise there will be a vacuum leak.
Where are you located?
Send them in to us and we'll be more than happy to apply the adapters for you....no charge for the adapters.
Where are you located?
Send them in to us and we'll be more than happy to apply the adapters for you....no charge for the adapters.
That’s a great offer to help me out.
I am in Australia and will pay the insured shipping both ways.
Confirming these are Bosch 274cc/min EV6 injectors to be fitted to a 1985 305 Camaro TPI with stock rails and intake.
If this is OK, what is the expected turn around time from when you receive the injectors to shipping back?
Thanks Tim
Re: TPI injectors shorter than stock.
Thought you were local.
Well As long as you have a stock intake and rail you will not have a problem with fitment. We can get them back out to you same day...depending on what time we receive them....or the next day
Well As long as you have a stock intake and rail you will not have a problem with fitment. We can get them back out to you same day...depending on what time we receive them....or the next day
Thread Starter
Junior Member
Joined: Jul 2020
Posts: 37
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From: Australia
Car: Corvette 1958
Engine: GM LB9 TPI 1985
Transmission: TH700R4
Re: TPI injectors shorter than stock.
I will ship these tomorrow, expect in 8-10 days. If you want me to address these to a specific receiver, please let me know.
The shipment will include email and return details etc.
Thank you for assisting, as you would imagine this level of technical help and service just isn’t available Down Under.
The shipment will include email and return details etc.
Thank you for assisting, as you would imagine this level of technical help and service just isn’t available Down Under.
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