If you've stumbled across this thread it's likely you are researching burnt or bent valves.

I have created a couple of posts in this thread that may help you isolate which set of valves may be your issue including pictures to help you visualize. The posts are #7 and #8, click here to be taken right to it, or read your way down to them, whichever suits your fancy.

The quote below was my original post of which after a bit of digging, I realized that #1 couldn't be in overlap as #2 was and why I could hear but not feel air coming from #2 but definitely felt the air coming from #1.

I've since edited this post to help direct future searchers to the relevant information and helpful tips I learned from this adventure, all contained in post #7 and #8 of this thread.

Cheers.

 

Well, head swap to be done probably next weekend.

As can be seen with the following 3 photos. I've got a exhaust valve leak in #3 which also explains why it smelled so gassy like when I pulled the valve cover off. And the pictures show the exhaust valve opening on one and closing on two as three becomes tdc to fire. Fits exactly what I was hearing, mostly from 1, a little from 2, nothing from 4 and felt air movement from 1.





Ordered the Ishino leak head gasket, Ishino intake gasket, Ishino exhaust gasket, a throttle body mount gasket and two axle nuts for under a 100 bucks before tax at autopartsway.ca

Free shipping means it should be here for next weekend. Should give me enough time to prep my old B7 head to go on her car.

Explains the reduction in power as well as the smoking after almost every stop and the sudden increase in oil consumption when before there was almost no consumption. The exhaust gasses burnt the valve seals on 3 allowing oil into the chamber more than usual.

Gotta love old cars. Cheers.

 

makes me want to work on my head.

 

look at the bright side- block looks very healthy.

 

Seems that way.

I got to try and get some pics of the piston tops. I couldn't see any valve reliefs through the spark plug hole.

I'm hoping it's a pm3 piston d15b block or there might be valve clearance issues with the B7 head.

Lots of carbon on the piston tops so I will try and scrape the excess off if I can find the valve reliefs to feel confident in pulling the head.

If not a used b7 motor for 350 will do the trick for awhile.

(Edited title to be helpful for future searchers of burnt/bent valves). Anyway I go, I will eventually have the pics of the head to show whether the valve(s) are bent or burnt.

Also of note for those who don't see it but the pics I posted above are backwards to our engines, #1 is on the left in the pic, while #1 is on the right when we face our motor from the front of the car. It still shows the proper firing order of 1-3-4-2.

Here is the animated version I stole the frames from to post above:

 

I'm in luck, the d15b carburetor block and head my wife has has the pm3 pistons. All is will for the B7 head swap.




After I pull the head and get pics of the problem valve(s), I will break down the animated gif into all the frames and post it up.

Then I will use it to list where air can escape for each cylinder set to TDC so as to aid in future diagnostics of blowing air into the cylinder for burnt or bent valves.

 

Acronyms:
ATDC - After Top Dead Center - After the piston reaches it's highest point.
TDC - Top Dead Center - The highest point the piston reaches in it's cycle.
BTDC - Before Top Dead Center - Before the piston reaches it's highest point.

Firing Order - The order in which the cylinder fire as the engine runs. Our 4 cylinder motors fire in this order 1-3-4-2.

With the illustrations in the post below you will be able to see the air flow characteristics that you should see present if you have a burnt or bent valve. Remember our cylinder numbers run from right to left. Going from left to right, like reading a book, we have #4, 3#, #2 leaving #1 on the right as seen in the pictures below.

Cylinder #1
With Cylinder #1 at TDC, we can see that #2 has the exhaust open, #4 is in overlap mode with both the exhaust and intake open but only slightly at this point. #3 has the intake open. So if you have Cylinder #1 at TDC and put air in, if you hear and feel air coming from other cylinders, you can decipher which set of valves is bent or burnt as follows:

If the air is felt from cylinder #3 you have an issue with the intake valves of cylinder #1. If air is felt from cylinder #2 then the issue lies within the exhaust valves of cylinder #1. In both cases you may hear some air in cylinder #4 but probably won't be felt like it is with the other cylinders being #4 is in overlap mode and the valves are only slightly open in comparison. Air will flow the path of least resistance.

Cylinder #3
With Cylinder #3 at TDC, we can see that #1 has the exhaust open, #2 is in overlap mode with both the exhaust and intake open but only slightly at this point. #4 has the intake open. So if you have Cylinder #3 at TDC and put air in, if you hear and feel air coming from other cylinders, you can decipher which set of valves is bent or burnt as follows:

If the air is felt from cylinder #4 you have an issue with the intake valves of cylinder #3. If air is felt from cylinder #1 then the issue lies within the exhaust valves of cylinder #3. In both cases you may hear some air in cylinder #2 but probably won't be felt like it is with the other cylinders being #2 is in overlap mode and the valves are only slightly open in comparison. Air will flow the path of least resistance.

Cylinder #4
With Cylinder #4 at TDC, we can see that #3 has the exhaust open, #1 is in overlap mode with both the exhaust and intake open but only slightly at this point. #2 has the intake open. So if you have Cylinder #4 at TDC and put air in, if you hear and feel air coming from other cylinders, you can decipher which set of valves is bent or burnt as follows:

If the air is felt from cylinder #2 you have an issue with the intake valves of cylinder #4 . If air is felt from cylinder #3 then the issue lies within the exhaust valves of cylinder #4. In both cases you may hear some air in cylinder #1 but probably won't be felt like it is with the other cylinders being #1 is in overlap mode and the valves are only slightly open in comparison. Air will flow the path of least resistance.

Cylinder #2
With Cylinder #2 at TDC, we can see that #4 has the exhaust open, #3 is in overlap mode with both the exhaust and intake open but only slightly at this point. #1 has the intake open. So if you have Cylinder #2 at TDC and put air in, if you hear and feel air coming from other cylinders, you can decipher which set of valves is bent or burnt as follows:

If the air is felt from cylinder #1 you have an issue with the intake valves of cylinder #2. If air is felt from cylinder #4 then the issue lies within the exhaust valves of cylinder #2. In both cases you may hear some air in cylinder #3 but probably won't be felt like it is with the other cylinders being #3 is in overlap mode and the valves are only slightly open in comparison. Air will flow the path of least resistance.

Now I recommend not pushing more than 15 PSI into a cylinder as I found anything above that tends to push the piston down and negates the quick and dirty air pressure test of the valves.

Also, when the air is felt in adjacent cylinders, i.e. air is put into #1 at TDC and you feel it come out #2, it could be an exhaust valve problem in #1 but it could also be a blown head gasket between the two cylinders. The way to confirm is to put the adjacent (in this case #2) to TDC and repeat the test. If the air only comes out #1 then you can be pretty sure its the head gasket. Either way, valve(s) or head gasket, the head has to be pulled off and you figured it out with just pumping 15 PSI into a couple of cylinders.

Cheers.

 

I have flipped the pics to align with how we see our engine when working on it in the car.

The next four pictures show TDC of cylinder #1,#3,#4 and #2 in ordering of the firing order. You can see all the valves open for each cylinder being TDC.





The next three photos show just BTDC, TDC then just ATDC so you can see the valve variance if you are just a little off of TDC. These photos are just Cylinder #1:

BTDC

TDC

ATDC

 

Interesting animation. for sharing this stuff.


What is a Ishino leak head gasket? When I did a head gasket swap on my d16y7 Speedfactory sold a Honda gasket with out the Honda label. Same thing?

 

no. the leak gaskets are thicker than OE, commonly used on d15 engines with previous head issues. tomcat- time to convert to fuel injection. i'd venture a guess that hard to regulate carbs had a role in the damaging of that valve.

 

It already is mate. When whomever transplanted the carb version d15b into the car they kept the car's intake and blocked off the head oil pump thingy.

If the head isn't toast, I was thinking it might be fun to hunt down the dual carb intake and get some weber carbs for it and see just what kind of fun I could get into.

But really I have other projects I want to do more. May just store the head until I'm old and grey for all I know.

 

Yeah nothing for you to worry about. The D16's already had mls gaskets. the Ishino leak gasket is a thicker mls as the non vtec D15's typically had a thick graphite gasket to maintain a certain quench. But the graphites are weaker and tend to blow sooner and easier.

I found using the thinner D16Y8 mls gasket actually forced me to retard my ignition timing being the quench is below .030" and I ping on the high rpm even with a degree retarded. I'm at 17° btdc for my ignition timing and still just barely detonate when I'm really getting on it.

I'll be using the leak gasket on my mini-me so my quench should be right around .035" with the head gasket and still be mls.

 

Interesting information. Thanks. I went with the speedfactory gasket on a d15b2/z6 head as well. Car isn't running yet but hope it works out.

 

When I took the head off, I did not see any visibly burnt valves but I was pretty sure I did my test properly when doing the homemade leak down test on cylinder #3.

So tonight I undid the rocker arms and popped the springs off the two exhaust valves on #3 and I found significant glazing with roughness to the valve seating area both on the seat and the valve.

Also, one of the valve dropped with no effort even with the seal in place so it told me the seal was shot and explains the excess oil going down that caused the glazing that was preventing the seal from happening.

I also verified the oil lobe on the cam shaft so it is indeed the carb version of the D15B head.

Here are the pics of the #3 exhaust valves and seats:







The pictures don't display the rough texture as well as can be seen with the naked eye but you might be able to tell a little bit of it from the pics.

I think I could probably clean up the valves, relap them and they would be good to go. Will also have to replace all the valve seals of course, so the head just might be salvageable after all. Will have to check the cam shaft play to see if it's still within spec but hmmm.

 

minus the tons of carbon everywhere, it looks ok to me.

 

The valve seat looks good, just a good clean up and relap. I got a decent relap kit from eBay with two different grit compounds that I used on my type3 with great results. If you want the info lmk.

Good luck!