Venom/ Python injector defective

[Mike]

Some months ago, I posted a thread re. a less than year old defective fuel injector (the plastic cap over the pintle fell off into the cylinder) that required my removing the head and replacing the valves in the problem cylinder. The injector was a Venom/Python 36# (orange) in a TWM set up. After months of aggravation, here is the full story.

Easter Sunday: I started the car up for a car show and heard a rattle. Come to find out, the cap was missing from the injector and had gone into the cylinder. I informed Python customer service shortly thereafter, and spent weeks trying to come up with an 'easy' solution. Finally bit the bullet, and scheduled (another 4 weeks) the engine builder to pull the head. With 30+ years of experience, he (Matt Johnson's, St. Louis) said he'd never seen anything like it. Turned out the plastic conical cap had split into a 'U' shaped piece and become jammed with one leg of the U in the intake port and one leg in the exhaust (hence not blowing out the exhaust). Both valves (Ferrea stainless) had to be replaced.
See attached pics.
Aug 1: emailed photos of head/pintle cap to Python.
Aug 15 and $1600.00 + later, finally got it back together, at which time I again contacted Python to inform them of the result. Python then requested I send the defective injector to them for inspection, which I did. They received it 8/22.
October 23: After several emails and calls, I was told the injector was up to spec. and no deficiencies were found. They had (and have) no idea why the cap fell off. They now had to decide what, if anything, they could do for me.
Nov. 12: After 4 months and with CEO's approval, Python decided to reimburse me $500.00. It is clear that their warranty stipulates 'replacement' of the injector in case of failure, so anything over the cost of one injector depends on their evaluation of the situation and their "reputation", in this case not quite a third of the cost of repair.

Considering this was the second Venom injector problem within a year (the first one split and leaked at the seam midway down the barrel), I have switched to Bosch disc type injectors (no plastic cap).

Perhaps this rather expensive and time consuming lesson will be helpful to those of you with DFI. Inspect the plastic caps on your injectors veerrryyy carefully, or better yet, buy injectors withOUT pintle caps.

Happy turkey day.

[Leonard]

Mike,

Thanks for the heads up. I am running an Accel DFI system on my car. I will be checking the injectors this weekend. I am sure my injectors are not Venom/Python but will check the ends just to be on the safe side.


Leonard

[Big-Foot]

This is a really odd thing...

Typically the holes that the injectors seat in are just big enough for the tip of the cap to fit into - not near big enough to have the cap fall into the intake port..
For those that have never seen what these caps look like - I found this picture that might help - The caps are the dark orange covers on the bottoms of these injectors;



Glad to hear that you have the problem taken care of..

[Jim c]

Mike

Randy has a point about the cap, it should not pass
It lives in a 14mm counter bore with a 10.2 to 10.5 mm hole for the pintle to pass through.
The brim on the cap should sit in the bottom of the counter bore.
Is that the case with your manifold.

You are better of with the bosch anyway.
The Venom spray pattern droplete size is to large in all the ones I have seen.

Jim

[Mike]

Hi, guys. The injector port on the TWM throttle bodies (Weber like) does not have a lip. It's a straight-through bore that fits snugly (with silicon grease) around the O-ring. The spray goes almost directly to the back of the intake valve. There is no 'lip' to stop the cap...unfortunately. Having said that, nobody has been able to come up with a how or why it happened. The bottom line is it DID happen, to the tune of $1600+ and some 4 months. Can you spell "P. O'ed"? )
Mike

[Jac Mac]

Mike, Funny things happen in intake ports due to wave reversion, vibration ,rapid temperature changes etc.Might happen in one engine & not in another. While your problem may be due to a faulty part , the design of the injector boss where the 'cap' is unsupported and free to fall away is also flawed as Jim & Randy have pointed out. Is it possible to install an alloy sleeve or insert that can be fitted to the boss to prevent this happening again.

Jac Mac

[Mike]

Hi, Jac Mac. I guess I could try something like that, but it would take a lot of 'pretty technical savvy' to do and lots of opportunity to screw something up. I'll just stick with Bosch disc type injectors that don't have those damn caps (I understand some people even pop them off before installing them). Seems Venom's QC isn't foolproof. )