Honda GX160 Engine help needed.

[r896neo]

After a good going over of an engine i recently inherited, cleaning and replacing a few bits i have had to replace the exhaust valve as the old one was slightly warped.

But in my haste i threw out the old one as it was warped and completely covered in carbon build up. I then ordered a replacement but when it arrived i notcied the face of it is dished (concave). The old one appeared flat but could of course have appeared flat due to serious carbon build up but surely not to such an extent that it appeared flat? Or could it.

All parts suppliers seem to say sorry we only do the dished ones the flat ones aren't available anymore. So can anyone shed any light on this for me as i assume putting in a new dished one if the old one was indeed flat will screw the valve clearances/ Cubic capacity up big time to the point that the thing wouldn't even run.

 

[crank39]

Give this guy a call or an email, he frequents a popular karting forum 'UK Karting' and his user name is Brian P, he's your man for anything GX 160.

http://www.ukpollards.com/

http://www.karting.co.uk/Notice/

 

[Burnerman]

So long as the valve seat mates with the valve, I can't see an issue here...the valve clearance would need to be checked and adjusted as necessary when any new valve is installed.
A concave valve, versus a flat one, would have a miniscule effect on the compression ratio but you'd never notice that.
If the old valve was warped, maybe its been seized in its guide and has been dinged by the piston at some time?
John

 

[r896neo]

To be honest john i want to think the same as it would be easier to just try the dished one i have. I put it in and set the clearances but havn't tightened up the head yet in case i needed to take it off to change it and didn't want to compress the nice new gasket.

I suspect the build up on the face of the old one had made it contact the piston but there is no mark on the piston crown so i guess it was a very timely rebuild.

With such a small displacement i was thinking that the extra space caused by the dome might have a noticable effect but am happy to hear others with more experience opinions!

 

[merlin50]

if honda say its ok to fit then it is ok, they build the best engines in the world. i think you are making a fuss about nothing.

 

[r896neo]

if honda say its ok to fit then it is ok, they build the best engines in the world.

Honda didn't say anything about it hence my question do you think it would be alright as it's simply a replacement pattern part i got from an online parts retailer and he led me to believe that i needed a different type due to the age of the engine.

If the consensus is that it would make no noticable difference i think i'll just go ahead. Thanks for the opinions.

 

[merlin50]

if its not a genuine part i would not trust it try and get a honda part

 

[Burnerman]

In retrospect it would have been good if you could compare the two valves together for stem length and head diameter, but no worries.
So long as the valve head fits the seat, there's a little clearance in the guide and you can get a tappet clearance I'd go for it....after all, these engines aren't going to be entered in a grand prix!
John

 

[mointainwalker]

Manufacturers introduce |running changes' all the time. Since you say it is a "dished head" ( and not a 'domed head" ) you have a shade more clearance and no other worries and the change to the cubic capaCITY IS MINISCULE

If that was your only worry, forget it.