LRP zr .28 spec 4

[Hyper Al]

Got the chance of one of the above to replace my Hyper .30 turbo.

are they any good and better than my hyper ?

[locky]

Will it be new or used? What is it going in? The LRP carbs can be a pain sometimes, but the Hyper carb fits. The spec3 should rev higher due to more ports with better torque throughout range. No guarantees it will be better as down to tuning etc and quantifying better will be subjective. Manufacturers performance numbers are not always reliable. Getting spares for spec3 will probably be hard, much easier with Hyper 30.

[Hyper Al]

It’s going in a hyper 7. Apparently it’s only been fitted to run the motor in. 
I’ve been getting a lot of oil from my hyper 30 and it’s all over the cooling fins and around the glow plug. 

So I’ve just been working on the hyper .30 and found the oil is coming up around the little pin on the glow plug top 😲

Going to get a new plug and try that.

I’m having a lot of trouble tuning it , it ticks over for about 10 seconds and then stops so I wonder if it’s down to the plug.

 

[Stormbringer]

trying a new plug wont hurt and may improve things 

[Hyper Al]

Hopefully yes. It’s very annoying.

[locky]

Check cooling head is fully tightened down, a turbo plug has no gasket whereas a standard plug does. Never heard of a plug leaking through its 'pin'. A 21 engine is best in a buggy as the torque, low down in a decent 28 and 30 just spins the wheels and likely blow tyres of their rims and wear drive train, but everyone wants more power, controllable power is best. 28 and above in truggies and trucks where there is more mass to shift. I've tried it and go back to 21, but whatever puts a smile on your boat race.

[locky]

If carb at stock settings then its probably too rich causing it to stall, so lean the hsn 1/2 turn and lsn 1/4 turn. If pinch is very tight when turning over from cold then preheating a new engine helps reduce stress on conrod and prevent pull start failure.

[locky]

Take a look inside the piston and sleeve after removing the cooling head as the condition will indicate how much it has been used. Check that there are the correct shims between the cooling head and burn room. Buying used can be a lottery.

[mickturnip]

The lrp 28 is a far better engine then the hyper 30 .top end will be faster then 30 and the power will be a vast improvement 

[Hyper Al]

Well I‘ve just fitted another glow plug and it’s stopped the leak. 
set the carb to …HSN 2.5 turns out and LSN flush and idle screw at 1mm.

started it up and brought it up to temp.

Tickover is very erratic and high.

To get tickover ok I have to reduce idle gap very small and it’s still up and down. 😡

[Hyper Al]

As an after thought it may have a air leak.

[locky]

Get some high gasket sealant. Remove carb, clean carb and neck then apply sealant, refit and tighten. Remove backplate, clean mating surfaces, apply sealant, refit. Leave 24hrs before starting/turning over engine. Is the Hyper 30 a used engine which you've never ran before? Check fuel line where they connect as splits can occur at ends. Check fuel tank lid makes a good seal. Check exhaust gasket isnt split where exhaust manifold attaches to engine. What the glow plug a turbo type or stnadard with washer? If it is anew engine a breaking in then the idle maybe erratic for a few tanks.

[Hyper Al]

I sealed the back plate yesterday, warmed up and still the same. So I’ve just applied some sealant to carb. Going to try it again later. I doubt it’s the carb because it’s new.

yes it’s a turbo plug and it’s a used engine.

[Hyper Al]

Well, just been out and it’s ticking over sort of ok but after a full throttle run the engine just stops 😡😡 and is normal ?

[locky]

Very dificult to diagnose on a forum as tuning is more about how engine sounds and feels during acceleration. It could be idle and lsn need adjusting. The piston/sleeve could also be worn out. Usual guide is to adjust hsn for top speed, then lsn for initial acceleration while adjusting idle to maintain idle speed so that it stays running. There is also a two stage idle where aftrer high speed run it stays high for a short period and then drops to lower idle rpm. The lsn usually needs leaning and idle adjusting to prvent two stage idle.  Best way to check piston/sleeve pinch is to remove them and then see/feel how easily the piston gets to TDC or beyond.

[Hyper Al]

I must admit when turning flywheel by hand the piston does go up fairly easily.