Project Car / Motorbike thread. Let's see 'em.

latheboy

Likes Dirt
11178268_1399787950344598_5607379934278696676_n.jpg

1:1 reg, electric fuel pump, always 2 psi more fuel pressure than boost to stop the fuel bowls getting emptied.. drilled holes in tops of the Carby's before the butterflies to get boost reference above the slides. 3 pitot tubes in the link pipe before the plenum, 1 for the reg and 2 hooked up to the carby overflows to pressurize the fuel bowls.
Drilling holes in the carbys was a stress as they are hard to get and exy.
With these mods to the carbs they keep working as if N/A
That's all before the tuning starts. Retarded the ignition 5°, stock compression @10.8:1 and 10psi of boost.
Each carby has a different needle height, different mains jet and different pilot jet to get the afr correct.. that took me a while on the Dyno.
 
I have a mechanical question, not really related to a project (kinda feels like it should be sometimes).

My mechanic believes my petrol/LPG motor is experiencing valve recession. I know how to cure it, question is what if I don’t ? Will it just run shit or do I risk doing catastrophic damage to the motor ?
 

Dales Cannon

The Olden Dazed
Staff member
I have a mechanical question, not really related to a project (kinda feels like it should be sometimes).

My mechanic believes my petrol/LPG motor is experiencing valve recession. I know how to cure it, question is what if I don’t ? Will it just run shit or do I risk doing catastrophic damage to the motor ?
Clearances get tighter but can usually be adjusted. If not the valves will ultimately stay open and burn. If it is the seats pushing into the head that can cause the head to crack. If the seats are wearing then the valves will struggle to seal properly. Flow will probably have better info but that is as I understand it.

Can you get a replacement head? Falcon LPG engine?
 

link1896

Is not a gynaecologist but will look at your fork
Is this engine know for dropping valve seats?

It’s a bad bad day when you drop a valve seat in.


 

Dales Cannon

The Olden Dazed
Staff member
1FZ is a good simple Toyota 6. Expensive to rebuild from what I have heard though that could just be lack of popularity. A few guys I know with the 1FZ opted to reengine rather than rebuild.

Cannot really help but I would be chasing wreckers to see what a used engine is worth, potentially getting one that has had the bottom rung out of it at 300,000km and getting the head done and swapsie. Seems like $2k will get you a useable motor. Do the head on that one, then fix yours and plonk it on the replacement and sell that?

Or find a 1GZ-FE... for a couple of thousand more...
 

komdotkom

Likes Dirt
View attachment 391724
1:1 reg, electric fuel pump, always 2 psi more fuel pressure than boost to stop the fuel bowls getting emptied.. drilled holes in tops of the Carby's before the butterflies to get boost reference above the slides. 3 pitot tubes in the link pipe before the plenum, 1 for the reg and 2 hooked up to the carby overflows to pressurize the fuel bowls.
Drilling holes in the carbys was a stress as they are hard to get and exy.
With these mods to the carbs they keep working as if N/A
That's all before the tuning starts. Retarded the ignition 5°, stock compression @10.8:1 and 10psi of boost.
Each carby has a different needle height, different mains jet and different pilot jet to get the afr correct.. that took me a while on the Dyno.
Wow, what a mission great work. I always thought boost pressure against the slides would give you trouble, sticking throttle/ binding.
What did you use for a turbo, finding something decent that had a small enough hot side can have been easy.
 

link1896

Is not a gynaecologist but will look at your fork
Valve seat recession or valve recession or both?

Been 25 years since I’ve owned anything running on LPG, was 18 cents a litre when I last filled up.
 

latheboy

Likes Dirt
Turbo is a T28 off a Skyline.
T25 would also work, just deliver boost in a different range and work a little harder.
Little turbos don't work on bikes, you don't size a turbo for a bike off the CC's. Car engines say 3L and 7000rpm, my bike is 750cc and 12500rpm.
Volume of air delivered across the rev range is the key to sizing the turbo.
Current set up boost is 1psi at 4000rpm, 10psi at 7000rpm and holds that to 12500
 

Shredden

Knows his goats
I've got an 80 series with a 1FZ running gas.. from what I've heard the valve seat recession is a matter of time, though mine is fine for now.

I'm not sure what causes it. I heard it is because gas burns hotter than petrol, wonder if there's truth to that?
 

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Dales Cannon

The Olden Dazed
Staff member
I've got an 80 series with a 1FZ running gas.. from what I've heard the valve seat recession is a matter of time, though mine is fine for now.

I'm not sure what causes it. I heard it is because gas burns hotter than petrol, wonder if there's truth to that?
Yes. The best barra to turn into a monster is the factory LPG motor. Better valves and seats.
 
I've got an 80 series with a 1FZ running gas.. from what I've heard the valve seat recession is a matter of time, though mine is fine for now.

I'm not sure what causes it. I heard it is because gas burns hotter than petrol, wonder if there's truth to that?
flashlube was touted as the solution to the hotter, dryer issue with gas, I’m not considering it as I will junk the lpg and put a stroker kit in it with a turbo with boost wound to the moon:eek:
 
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