Honda GXV390 rod and head torque values

[landcruiser]

I've rebuilding a Honda GXV390 (13hp, vert crankshaft) and need to know the rod torque and head torque values. Does anyone have a book on these engines that you could look this up in? Also curious as to the rod to crank pin clearance. Thanks for any help.

[Restrorob]

You got your PM.....

[landcruiser]

Hey Restorob, I didn't get a PM from you. I don't know what happened but can you post the message here instead? Thanks for your help, it is very appreciated.

[Restrorob]

OK, Specs. as follows;


Rod torque, 8.7-11.5 Ft-lb
Head torque, 23.1-27.5 Ft-lb
Rod to crank pin clearance, Oil clearance is 0.0016-0.0026 " with service limit of 0.005", Crankpin standard is 1.4167" with a service limit of 1.415"
Nominal bore, Standard is 3.228" with a service limit of 3.235".

Good luck

[landcruiser]

Thanks restorob. Are you positive on that nominal bore value? This mower was bought new by the fellow I'm working on it for and has never been into. Upon dissassembly, I measured the bore at 3.465-3.466 from best to worst in the cylinder. The piston seems very tight in the cylinder as well. I hope the numbers you gave me are for a different engine - maybe a GXV340 has this smaller bore?

[Restrorob]

Yeah, I did give you 340 specs. , Because the 340 and 390 use the same with the exception of the bore which I forgot about. Somebody walked off with my 390 manual. I spent a hour and a half this morning down-loading web based files that stated 390 service manual only to find the freekin things were owners manuals so I gave up....

[newz7151]

Yeah, I did give you 340 specs. , Because the 340 and 390 use the same with the exception of the bore which I forgot about. Somebody walked off with my 390 manual. I spent a hour and a half this morning down-loading web based files that stated 390 service manual only to find the freekin things were owners manuals so I gave up....

Well, seems our copy of the service manuals expired without anybody sending us an update disk, so I'll just have to type instead of posting a PDF capture.

Bore & Stroke is 3.46 x 2.52 "

[landcruiser]

Sorry for you spending all that time just for me. I truly appreciate it. I bet my bore value is dead on since it only varies .001" over the entire cylinder. I have a 3 stone hone that I am honing it with but I am deathly scared of doing it too much. The stone have a spring tension adjustment and I have the spring tension as light as it will go as to not ream the cylinder out. All I want to do is put a good cross hatch in it for the rings to "bite". I've seen this done before at the machine shop so I did it the same: Put a light coat of transmission fluid in the cylinder for lubrication then run the hone up and down gently while twisting it with a conventional drill. Question is, how much? I did it a couple of times for about 30-45 seconds, then cleaned it out with a cloth. The cross hatch still doesn't look smooth and consistent and I measured the cylinder and can't tell that I changed the bore at all. I guess I need to hone it more, I just don't want to "bore" the cylinder any with the hone. Any comments or suggestions?

[landcruiser]

Thanks newz7151. My bore is dead on then. Will you read my last comments on honing the cylinder and make comments/suggestions? Thanks so much for your help.

[Restrorob]

Honda cylinders are some of the hardest I've seen so I don't believe you will get into in too quickly. I use what they call a dingle berry hone, Have sizes to fit nearly any cylinder and doesn't take but a couple ups and downs to get the perfect cross hatch. Also I do mine in my parts washer with mineral spirits and a air drill,You may find using WD-40 may get you a quicker hatch.

[landcruiser]

It must be VERY hard. It seems like I should have a good hatch even though I've hit it very little but I bet since I have the spring pressure so low on my hone combined with the hard Honda cylinder, I don't have a good cross hatch yet. Again, I'm using auto trans fluid as a lubricant but sure this doesn't matter... Thanks so much for your help. Also, do you think I should install a new piston even though my bore measure dead on standard and my piston skirts don't look worn? I've been told never to use an old piston, while other say it doesn't matter if the old one isn't worn. What's your opinion?

[Restrorob]

I don't understand why your not getting my PM's :hammerhead:
I sent this to you 5 mins. after the specs. ; If the piston looks good with no skirt wear or scratches I re-use them, Why replace a perfectly good part if you don't need to.