Jt
01-11-2007, 07:39 PM
I looked around the forums the other day and didn't really find any complete information on sealing an engine. I thought I would do a little write up on sealing an engine for all the new people that might not know what some of us are talking about when we say "seal the engine".
I hope this helps some.
It is a good idea when you get a new engine to inspect it good and seal it up to prevent any air leaks which can cause you head aches down the road with tuning and idle.
First off you want a nice clean work surface to work on. Don't want to introduce any foreign material into the engine.
Start by removing the pull start and the back plate. Inspect the inside of the block thoroughly for any burrs or fine metal fragments. Using nitro cleaner wash out the block if any is found. Using a clean cloth and nitro cleaner wipe the contact areas of the block and the back plate, where we will be applying the silicon sealer (Permatex Utra Copper is a good one). Use your finger and apply a thin coat to the back of the block where the back plate gets bolted on. Now you can mount your back plate being sure to align the crank pin on the back plate with the crank pin hole on the crankshaft. Using a bit of blue loctite on back plate screws and tighten in star or cross pattern. Then install pull start or rotostart assembly and snug those screws in the same pattern.
Next we move to the carb, remove the pinch bolt that holds the carb, then remove the carb. Using a very small screwdriver or pick apply a them amount of of the silicon sealer to the inside edge of the hole where the pinch bolt is installed. This gets done to both sides of the engine. Next apply a small amount of silicon sealer to the upper part of the carb neck. Install you pinch bolt in the engine and get the bolt started, install your carb and place it in the truck and get the carb lined up where it needs too be and will open and close fully without interference. Once lined up remove engine from truck and tighten down the carb pinch bolt and cover with the silicon sealer.
Now for the needles. Before we tackle them, hold the carb closed with one hand and tighten the HSN carefully until it stops counting the turns (be sure not to over tighten and damage the needle) write that number down that you counted. Repeat the same process for the LSN. When you reassemble the needles to the carb you will set them back to these numbers that you wrote down, these are the engine factory setting for break-in (new engine). Now remove the needles including the idle needle and inspect the needle housings for any foreign matter or o-rings that may may been cut on assembly. Using Associated's Green Slime put a small bead around each o-ring of the needles and re-install them back into the carb. Screw all the way down being careful not to over tighten and then back out the number of turns that you counted and wrote down for that needle, (putting them back where they were from the factory). Remember the idle needle gets set to about 1mm gap in the carb.
Lastly we will look at the fuel inlet, some use gasket material on both sides of the banjo fitting (fuel inlet nipple) others have a tapered fit. Remove the HSN housing from the carb and remove the banjo fitting. If there is a gasket remove it and apply a very small amount of silicon to both sides of the banjo fitting (to much can clog the fuel inlet). Reassemble the HSN housing and banjo fitting back to the carb being careful not to over tighten the HSN housing and making sure the nipple is facing the direction you want to be (usually facing rear for a stock savage).
Now you have sealed you nitro engine, allow the silicon to set and cure for 24 hours before you put fuel to the engine and and fire it up.
Doing the above should ensure that there isn't any air leaks in the engine.
Here are some other things to check if your engine isn't running right. If you have a fuel filter, be sure to check the o-ring seal in the filter assembly. Check your fuel lines for cracks, cuts, or pin holes also check your fuel tank for any cracks. Check your exhaust gaskets for cracks or splits and make sure that the exhaust stinger isn't plugged or the pressure nipple isn't plugged. Clean your air filter often enough, and that the air filter is secured to the carb neck firmly using a cable tie or a small hose clamp can aslo be used
That should do it, now go out there and BASH that savage.
I hope this helps some.
It is a good idea when you get a new engine to inspect it good and seal it up to prevent any air leaks which can cause you head aches down the road with tuning and idle.
First off you want a nice clean work surface to work on. Don't want to introduce any foreign material into the engine.
Start by removing the pull start and the back plate. Inspect the inside of the block thoroughly for any burrs or fine metal fragments. Using nitro cleaner wash out the block if any is found. Using a clean cloth and nitro cleaner wipe the contact areas of the block and the back plate, where we will be applying the silicon sealer (Permatex Utra Copper is a good one). Use your finger and apply a thin coat to the back of the block where the back plate gets bolted on. Now you can mount your back plate being sure to align the crank pin on the back plate with the crank pin hole on the crankshaft. Using a bit of blue loctite on back plate screws and tighten in star or cross pattern. Then install pull start or rotostart assembly and snug those screws in the same pattern.
Next we move to the carb, remove the pinch bolt that holds the carb, then remove the carb. Using a very small screwdriver or pick apply a them amount of of the silicon sealer to the inside edge of the hole where the pinch bolt is installed. This gets done to both sides of the engine. Next apply a small amount of silicon sealer to the upper part of the carb neck. Install you pinch bolt in the engine and get the bolt started, install your carb and place it in the truck and get the carb lined up where it needs too be and will open and close fully without interference. Once lined up remove engine from truck and tighten down the carb pinch bolt and cover with the silicon sealer.
Now for the needles. Before we tackle them, hold the carb closed with one hand and tighten the HSN carefully until it stops counting the turns (be sure not to over tighten and damage the needle) write that number down that you counted. Repeat the same process for the LSN. When you reassemble the needles to the carb you will set them back to these numbers that you wrote down, these are the engine factory setting for break-in (new engine). Now remove the needles including the idle needle and inspect the needle housings for any foreign matter or o-rings that may may been cut on assembly. Using Associated's Green Slime put a small bead around each o-ring of the needles and re-install them back into the carb. Screw all the way down being careful not to over tighten and then back out the number of turns that you counted and wrote down for that needle, (putting them back where they were from the factory). Remember the idle needle gets set to about 1mm gap in the carb.
Lastly we will look at the fuel inlet, some use gasket material on both sides of the banjo fitting (fuel inlet nipple) others have a tapered fit. Remove the HSN housing from the carb and remove the banjo fitting. If there is a gasket remove it and apply a very small amount of silicon to both sides of the banjo fitting (to much can clog the fuel inlet). Reassemble the HSN housing and banjo fitting back to the carb being careful not to over tighten the HSN housing and making sure the nipple is facing the direction you want to be (usually facing rear for a stock savage).
Now you have sealed you nitro engine, allow the silicon to set and cure for 24 hours before you put fuel to the engine and and fire it up.
Doing the above should ensure that there isn't any air leaks in the engine.
Here are some other things to check if your engine isn't running right. If you have a fuel filter, be sure to check the o-ring seal in the filter assembly. Check your fuel lines for cracks, cuts, or pin holes also check your fuel tank for any cracks. Check your exhaust gaskets for cracks or splits and make sure that the exhaust stinger isn't plugged or the pressure nipple isn't plugged. Clean your air filter often enough, and that the air filter is secured to the carb neck firmly using a cable tie or a small hose clamp can aslo be used
That should do it, now go out there and BASH that savage.