Rebuilding heads....a ?

[DHMag]

in the next few days, im gonna be tearing down the motor for a head overhaul. i already have the upper gasket set and plan on replacing all valve stem seals, cam seals, having the valves and seats ground. since im gonna have the top half of the motor open, is there anything else i should replace ? injector seals, o-rings...anything that might be prone to fail ?

 

[sdpatt]

Dale, you may want to talk to MikeD before having the valve seats ground. That creates a tight situation at the cam lobe-to-shim interface that necessitates very thin shims. Mike had to go to bike shops to get the 2.000mm range shims that were necessary. You will certainly need a supply of thinner-than-normal shims when the valve gaps are reset.

 

[DHMag]

sdpatt:
Dale, you may want to talk to MikeD before having the valve seats ground. That creates a tight situation at the cam lobe-to-shim interface that necessitates very thin shims. Mike had to go to bike shops to get the 2.000mm range shims that were necessary. You will certainly need a supply of thinner-than-normal shims when the valve gaps are reset.

i plan on redoing the shims as well. though, i hadnt thought about the valve gap changing when the valves are ground. thanks for the input Scott !

 

[AREA 91]

When I "rebuilt" my heads, I just lapped the valves & seats by hand. This left a clean cut, and only changed my valve shim clearance a thousandth or so. Just my 2 cents. wink

 

[shojuan]

witsimpala:
When I "rebuilt" my heads, I just lapped the valves & seats by hand. This left a clean cut, and only changed my valve shim clearance a thousandth or so. Just my 2 cents. wink

I was actually thinking just the other day, why get new valve seats and/or regrind the seats unless there's an actual problem in that area with the heads? Lapping the valves by hand is the final step in a valve job anyways, I think it's a good idea what you did. If that area looks likes it can make the 300,000 mile marathon then why not just leave it at that like you did?

I would just check the valve stem to guide clearance and replace the guides if necessary and no matter what I would install new valve stem seals.

Just my $.02!! I've never had a valve job done in my life. The only time I've ever seen the backside of a head up close was when I pulled the blown head of my truck and installed a rebuilt one.

 

[DHMag]

the reason im rebuilding my heads is because at high RPMs, im blowing something out of the exhaust (other than exhaust). i can only see it at nite when theres another car behind me. cruising at 70 MPH in 4th...drop to 3rd and hammer it, smoke plumes out the back, at 80 MPH, shift to 4th and the smoke is heavy and constant. i literally left a Stang GT in the dust the other nite. i believe im blowing oil past the valve seals. so i bought a upper gasket set (RCM Automotive - Russ McCoy) and plan on tearing it down...as soon as i get my truck to pass inspection..*onto the rangerpowersports forum i go..*

Dale

 

[billyshoe]

piston rings absolutely. bearings aswell. it would be pointless to sink the time & money into headwork & bolt then back on a used-up block.

 

[Bizzy]

It could be oil blow-by...but what color is that "something out of the exhaust (other than exhaust)" ? Try it during daylight hours and have someone watch behind, or have a friend follow you. Color is important.

White - Coolant
Black - Oil
Blue - Fuel

It may be blow-by, or something else (?).....

 

[yamahaSHO]

Bizzy:
It could be oil blow-by...but what color is that "something out of the exhaust (other than exhaust)" ? Try it during daylight hours and have someone watch behind, or have a friend follow you. Color is important.

White - Coolant
Black - Oil
Blue - Fuel

It may be blow-by, or something else (?).....

Actually,
Blue - burning oil
Black - rich mixture


Blow-by is when the combustions process "blows by" the piston rings down into the block.

Sounds to me he is either burning oil or a rich mixture. Hard to tell without him describing the color.

<small>[ August 25, 2003, 10:02 AM: Message edited by: yamahaSHO ]</small>

 

[jasonty]

Just some insight, you need new piston rings. My car does the same thing. When I hit about 5000 RPM's, I see a nice black cloud in my rearview mirror. On hot days, I can hear one of my pistons knocking inside the cylinder as I start out. I'm almost positive this is caused by lack of lubrication. My car had a nasty oil leak when I was in Germany, and the person who was driving my car while I was gone for 2 years didn't check the oil level as often as they should've. Your problem is not in the valves, but rather the rings.

 

[yamahaSHO]

jasonty:
Just some insight, you need new piston rings. My car does the same thing. When I hit about 5000 RPM's, I see a nice black cloud in my rearview mirror. On hot days, I can hear one of my pistons knocking inside the cylinder as I start out. I'm almost positive this is caused by lack of lubrication. My car had a nasty oil leak when I was in Germany, and the person who was driving my car while I was gone for 2 years didn't check the oil level as often as they should've. Your problem is not in the valves, but rather the rings.

AGAIN.... If it is black smoke, you are running rich. Blue smoke would indicate that you are burning oil.

 

[DHMag]

if i knew what color the smoke was, i would have never posted about rebuilding heads. im not a rocket scientist but i do know what to look for when a certain color of smoke appears. ive tried it during daylight hours and cant see it at all. its only when i have background illumniation. im aware it could be blow by and this head work is not gonna cure it but itll be a piece of mind, knowing my valve stem seals et al are new, not 130K/12 yrs old. i do have a an oil leak at the cam seals, i also have a mysterious water leak. yes, i could be running rich since i have a 155 lph pump installed and maybe my HEGOs arent operating as they should, but highly unlikely. ive ran codes, 111 across the board. bearings, as in rod bearings ? never known them to cause an exhaust to carry oil out the pipes, but they were changed 6 months/7K miles ago. another observation, it only does it when the secondaries are opened. last nite, while merging onto the highway in 2nd at about 50 MPH, i romped the throttle, checked the mirror, and there was the smoke.

 

[yamahaSHO]

DHMag:
. yes, i could be running rich since i have a 155 lph pump installed

This will not cause you to run rich.

 

[Mr Anonymous]

I think what Jason is trying to say is that your heads may be perfectly fine and that you need to do some more diagnosis before assuming that rebuilding your heads will fix anything.

If you can't figure out what is burning in your abnormal exhaust, I recommend first going to a shop with emissions testing equipment to find out just what the composition of your exhaust is, including an A/F ratio test.

If the smoke you're seeing is due to an overly rich mixture, you're most likely going to be looking at an engine management problem such as a sensor not doing it's job, or at something as simple as bad spark plugs. As Jason mentioned, the fuel pump flow rate does not effect mixture.

If oil is getting into the combustion chamber, you're right that the valve stem seals may be the culprit, but your pistons/rings/bore would be equally as suspect. The increased crankcase pressure due to combustion gasses 'blowing by' the piston rings can result in additional oil entering the intake tract via the PCV system. This is where a compression test (and even a leak-down test) is going to be of great help in identifying the source of the problem. If your problem is due to piston/ring/bore wear, you're essentially looking at an engine rebuild. If your problem is indeed the valve stem seals, they can be replaced with the heads still on the car (albeit a bit challenging).

Again, you're going to be far better served by doing more effective diagnosis before jumping in and just rebuilding the heads. This is not to sound mean, but by the sound of some of the things you've said in your posts, I get the impression that you may not fully understand just how engines work. If that's the case, just do some research on the internet, etc. -- there's a world of information out there. It's not 'rocket science' by any means, and a better understanding will go a long way in helping you properly maintain your engine. I applaud you for being willing to jump in and tackle something like rebuilding your heads, but if the heads aren't the problem that could be a lot of time, effort, and money wasted. That's what everyone has been trying to say. First identify the problem, then you can plan your approach to fix it.

Think of it this way: If you were sick and went to the doctor, would you want him to perform some tests to determine what was wrong, or just send you home with a prescription and the hope that it would make you better?

<small>[ August 26, 2003, 01:28 PM: Message edited by: SHOooo ]</small>

 

[DHMag]

SHOooo:
I get the impression that you may not fully understand just how engines work.

and i get the impression you wasted a lot of time typing that post out.

 

[AutoSHO]

DHMag:

SHOooo:
I get the impression that you may not fully understand just how engines work.

and i get the impression you wasted a lot of time typing that post out.

Well, I was thinking about posting, but since you're going to be a complete D I C K, nevermind. You ought learn that we're not trying to tell you you're stupid (although I now consider doing so) we're trying to help you not spend money to be disappointed. Grow Up.

 

[DHMag]

ok, ill be a dick again, and reask my initial question. while i have my heads off, what should i replace/maintain that is otherwise inaccessible ? i am not asking for help on what my problem is, im asking for maintainance ideas.

AutoSHO - if i want your opinion of me, ill ask for it

 

[yamahaSHO]

DHMag:

SHOooo:
I get the impression that you may not fully understand just how engines work.

and i get the impression you wasted a lot of time typing that post out.

I thought he did a good job on that post. If you don't care what we have to say, just buy a Helms manual and learn from that.

 

[billyshoe]

well, you'll need special tools to deal with the head or you will f/u it. it would be much more benificial if you pulled the pistons, cleaned the grooves, a light hone & new rings.

 

[billyshoe]

Open the hood. on the battery side disconnect the DIS, unfasten the end of the intake & remove it, take a peek in side the plenum and you will see the oil puddled up that gives you a big "puff" when you floor it. actually the rear plenum feeds a big splash of oil when braking. this is some of the oil that the engine is burning. the rest is going out the tailpipe at all times. you just don't see it. Don't tell me you don't smell it. this problem is cured by ring replacment.