Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
The engine pings with load or when less than quality gas is burned. It looks like the rear plug is getting hotter but is burning well but the front has carbon deposits and an oil like substance down on the bottom towards the electrode.
Can anyone accurately read these plugs and tell me what you believe the situation is? No real work has been done to the engine except cam chain tension shoes, cam bearings, and a set of stock cams at 70K
Old Blue has been good to me because I have treated it well.
You really need proper lighting and magnification to read healthy plugs, but looking at your pic, my bet is that the front plug indicates oil leaking into the combustion chamber and severe detonation (chunk of ground electrode missing and melted metal deposits on the bend of the ground strap), the rear shows some detonation (look at the ball-shaped specks on the ground electrode and the porcelain) and the ground straps on both plugs indicate improper (too much) timing, especially the rear.
The articles above will teach you how to read the plugs and what to look for to diagnose.
Based on the plugs, I'd say your top end is likely ready for a major refurbishment (new pistons/rings, head work including new valve seals/guides, possibly a bore) Next step is to do a compression test and also a leak down test to really see what is going on.
Based on the plugs, I'd say your top end is likely ready for a major refurbishment (new pistons/rings, head work including new valve seals/guides, possibly a bore) Next step is to do a compression test and also a leak down test to really see what is going on.
A friend sold me his original 88 heads, cylinders, pistons, for $100 a couple of months ago. He upgraded at 10K. Will need to replace rings, do a cylinder hone, and clean off carbon. Going to wait until winter. I'm thinking if I baby it, it will make it OK.
I would not be to hasty on the rebuild, if it runs good do a compression test, if that is good, run some sea foam through itvto get rid of any carbon build up, that is what is probably causing the pinging.
Carbon build up raises the compression, and hot spots that cause detonation.
I would be curious what the cyclender looks like you can pick up a bore scope on eBay for twenty bucks.
Is it using any oil or burning it?
If you are running synthetic it will not show. Is it dumping any oil out the breather? That is a sign you have a lot of blow by or oil pump not scavaging.
Get rid of the carbon, if the compression is good these motors are good for 150k+
Last edited by Harleycruiser; 07-03-2015 at 06:05 PM.
I would not be to hasty on the rebuild, if it runs good do a compression test, if that is good, run some sea foam through itvto get rid of any carbon build up, that is what is probably causing the pinging.
Carbon build up raises the compression, and hot spots that cause detonation.
I would be curious what the cyclender looks like you can pick up a bore scope on eBay for twenty bucks.
Is it using any oil or burning it?
If you are running synthetic it will not show. Is it dumping any oil out the breather? That is a sign you have a lot of blow by or oil pump not scavaging.
Get rid of the carbon, if the compression is good these motors are good for 150k+
Is the breather to atmosphere or back to motor behind Air cleaner, if so relocate to atmosphere. If anything else, looks like possible valve guides.....for oil. Do comp test an leak down before you tear it apart.
07-01-2015, 08:55 PM
TC88 with 125K lot of pinging plugs look odd
