Help with hot (but reliable) engine
 

All,

I have a HSP 1/10 with the .18 vertex engine. I know its an ebay special but its been good to me. Meant to get me into the hobby and 6 years and many gallons later its still going strong. Truck is great, however, I cannot get the engine to reliably run below 250-270. I'm running Byron 25%/8% fuel/oil (was doing the same thing on 20%), #4 plug and i cannot make this thing any richer. Low speed needle seems to have good response. What am I doing wrong? Idle's great, starts right up. I'm pretty convinced this really isn't an issue since its been doing it all its life but just wanted to make sure I'm not getting lucky here. Blasting down the street i will see temps as high as 320 temporarily. Again, no issues yet, but I've always thought this wasn't right. Tried everything.

Thanks!

You've been running this engine for 6 years? My first thought would be loss of compression. But you say it's always ran this hot? When it comes to temp there are general guidelines, and then there are engines that don't go by them. As long as it looks good(plenty of smoke at full throttle) and sounds good, it's not too hot. What type of temp device are you using?

Thanks guys. Running for 6 years yes, but there were years where I just had the car stored. Don't want to give it too much credit. I have it torn down now for transmission replacement, wheel hub upgrades, etc. as I've neglected this thing for a very long time only focusing on engine performance. I'm monitoring the temp with one of those sensors that wraps a wire around the cooling fins of the engine and stays on the car. When tuning should i richen the LSN tune the HSN first and then tune the LSN? I've read a million articles on this but just wanted to make sure I'm doing this right. I know what the truck needs to sound and look like when tuned correctly but i want to make sure I maybe don't have a position where the LSN might be lean and the HSN is way rich to compensate. Could that cause the engine temps i'm seeing? I always have good smoke on full throttle but i feel like i could pretty much back the HSN all the way out and it would still run fine (and hot).

When replacing this thing Vertex .18 (i'm sure the time will come), are there any better options for an upgrade that would still share the same mounting points and shaft size? I'd like to go bigger but I've read that the shafts on the larger motors are longer and the engine mounts might not fit my chassis without modification. This is is the part of the hobby i was looking forward to. Modification.

The condition you are referring to can give you a false good idle, but it won't affect full throttle performance as the lsn is completely bypassed at full throttle. The general consensus is tune hsn first, and it's very important to get the engine fully up to temperature before tuning. I personally like to start from rich, lean hsn until it starts to cut out at full throttle then richen 1/8 turn. I do a few full throttle passes to make sure I've richened enough and I'm getting good smoke and top end. Then I do the pinch test to get the lsn into the ballpark, then test throttle response until it takes off with no hesitation(rich) or cutting out(lean). Then I lower the idle to a nice steady gallop.

My favorite engine to replace the vertex in hsp vehicles is the SH .18. Half the price of an os cv-r and (imo) 85% of it's power and reliability. Wide tuning window and if you get one pulled from a new redcat it'll drop right in.

Thanks for the feedback tcharger. Have you seen the HPI Nitro Star T3.0? Double the power of the Vertex and looks like it would drop right in. Not sure about reliability though. All the gears in the truck are metal so i'm sure it would handle the power. While the Vertex is cheap, its been very reliable.

I've never had any issues with the t3.0 engines I've used, more bottom end oriented than optimal for the rs4, but would work well in a 1/10 truck

The t3.0 does have additional mounting holes on the bottom to mount directly to matching hpi vehicles, and these can interfere with some motor mounts, particularly one-piece mounts. Something to keep in mind.

My HSP has the two pedestals. One on each side. It seemed like everything measured out. I was just a little concerned about shaft length. Seems a few MM shorter than the VX but very close. Are there parts available to extend these thing needed? The s3.0 seemed to long. Be nice to transfer over all my parts from the bell to the flywheel.

Too long can be cut down, too short is more of an issue.

One time I stuck a diff ball into the clutch nut to let it extend a bit while still tightening properly.