Aftermarket MS390/039 Engine Kit Review

[Poleman]

Boomer, I've done two of these 3-4 years ago for guys that use them every weekend doing tree work on the side. I used a Baileys kit which looked very good. Both are ported and are real sleepers.

 

[ssm1699]

Some of the these kits aren't chrome plated, but instead are Nikasil plated. That is what the Stihl products have on the cylinders and pistons, instead of chrome. I made sure to get a kit for my saw that was Nikasil plated and the entire thing has been running beautifully. I can't claim my saw to be a genuine Stihl anymore, because it doesn't have a stihl top end anymore. It is a FarmerTec top end only. I didn't do the entire engine because I wanted to know what I had in my engine and also wanted to know how to work on it. I am on the look out for another 1127 series PHO that needs a top end, because after I bought the parts and pulled my saw apart, the original top end really wasn't as bad as it looked through the exhaust port. So I may look to putting my original top end on a PHO that does need a new top end. I would install new rings on the piston and put it together. Maybe a set of crank bearings, as those aren't that expensive or hard to change.

 

[blsnelling]

Does anyone have long term durability opinions on the aftermarket parts. I hear both good and bad. I've heard the chrome finish has a tendency to flake is this true? I don't have any saws that need a top end yet. Just wondering if there more of play toy parts or will they hold up long term. Thanks

That's the biggest problem with AM parts. They're super inconsistent and apt to change at any time.

 

[Poleman]

Totally agree with Brad!!! I did another one earlier this year and order what I did previously and it was junk when I recieved it. Plating was in consistant and port bevels were bad.
The supplier replaced it no problem and said they had had issues with some and my order fell in that time frame. They sent out a new one that was great.
Like Brad said.....inconsistent......

 

[fearofpavement]

I've had relatively few issues with aftermarket parts I've purchased. I usually buy pretty comprehensive kits and then just replace the items that must be replaced. ie, I reuse as much of the oem stuff as feasible. Bearings on the 1127 series saw usually are ok to reuse unless it was straight gassed. On a typical refurb/rebuild, I install a new aftermarket cylinder, piston, rings, piston pin and seals. I sometimes replace the crank bearings, piston pin bearing and impulse hose. I rarely replace the fuel line but if I do, I try to use OEM. And then of course I fix any other part of the saw that needs attention. This series saw is pretty robust and a lot of them earn money for people every day.

 

[a. palmer jr.]

Considering that you have to remove the only bolts holding on the bottom pan, it will be interesting to see how they get around this for installing a "sealed" engine.

I usually seal the bottom pan using MotoSeal and let it sit overnight. The next day I remove the 4 bolts and it stays sealed up. Just put it in the saw and bolt it down again, never had a problem..

 

[a. palmer jr.]

I would like to see how this happens. The 4 bolts that hold that together will not fit on the block and tighten up without being on the saw. Unless they are going to install shorter bolts on it and you'll have to remove them before installing.

I always use 4 pieces of small pipe about an inch in length to make up the difference then take them out when I install the engine..

 

[fearofpavement]

I usually seal the bottom pan using MotoSeal and let it sit overnight. The next day I remove the 4 bolts and it stays sealed up. Just put it in the saw and bolt it down again, never had a problem..

I also assemble the engines outside of the saw and let them set at least a day. I then pressure test before I put the saw together. These aren't the easiest engines to seal and making sure it's right before all the installation saves time in the long run. (I usually have a couple built up engines ready to go in the next chassis)

 

[fearofpavement]

I always use 4 pieces of small pipe about an inch in length to make up the difference then take them out when I install the engine..

I use an assortment of bushings to make up the length difference. (essentially the same result as what a. palmer uses) I common area of leakage on these engines is around the bolt holes so I put a little Motoseal in them before the final assembly.

 

[a. palmer jr.]

I also assemble the engines outside of the saw and let them set at least a day. I then pressure test before I put the saw together. These aren't the easiest engines to seal and making sure it's right before all the installation saves time in the long run. (I usually have a couple built up engines ready to go in the next chassis)

I didn't have the stuff to test the pressure until recently. I will test them all in the future, it's fairly easy on these saws.

 

[Khntr85]

I use the dirko sealant, great stuff, but boy does it smell.... I bout 4-small bolts that I use to seal the engine, before its permanent installation....