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Discussion Starter · #1 ·
So this poor car has just been troubled (to put it nicely) for the last year. First it was ignition coil and distributor rotor & cap problems... This time, I expected more of the same when it stalled out on my wife. She was driving home and it died, she called me to come pick her up and the whole time she was waiting for me, was trying to start the car to see if it would work (still has that mentality of when the Main Relay was dying I guess...). I got there, had her try to start, knew instantly something was horribly wrong and it didn't sound like it was even trying to start, just sounded like the starter motor turning. So we got it towed home to the garage, I pulled off the valve cover and timing belt cover, and was able to pull out the timing belt (looks like it had melted or something, but broken regardless).



[url=http://imageshack.us/photo/my-images/594/camerazoom2012120216441.jpg/]


So I'm planning on replacing it this weekend. My thing is (naturally) - the valves. I have to assume that after trying to start the car so many times, there are at least a few bent ones (I will be amazed if there isn't). I have a number of questions with how I should proceed from here:

1 - I'm assuming I need to replace the timing belt before I can check for bent valves, correct?
2 - After I get the timing belt on, how do I set the timing properly on it? This whole part confuses me, as I had always assumed that if you have your marks lined up on the cam and crank then your timing is good, but this would make the timing light useless, so I assume I have to be missing something here...
3 - Preparing for the worst, if there are bent valves, what do I need to get done to fix it? Is it as easy as just getting new valves and throwing them in (I am leaning towards no, because that would make it less frustrating haha).. Assuming there is no or minimal aside from the valve, am I safe to get away with just replacing the valve itself?
4 - If there are bent valves, am I just better off finding a new engine (or a new head) than trying to fix this one? And if so, what kind of head should I be looking for/is easily compatible with my current engine? It's a 1990 Si (D16A6 I believe).

I'll probably have more questions as these questions get answered (that just seems to be the way things go), but I know that if I can't get them answered here, I'm not likely to ever get them answered anywhere haha...

Poor CRX, it's way overdue to catch a break and enjoy living! :cry:

It doesn't help that I'll be trying to do this in -20C weather either :x

Oh, and let this be a lesson to everyone else who buys a CRX from a guy who says he just replaced the timing belt within the last month or 2 - Don't take his word for it, check the timing belt for yourself. 26,000KMs later and it broke. I should've known better.
 

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You can check for bent valves by pulling the head first. If you're thinking compression test then obviously the timing belt will need to be replaced first.

The physical (cam) timing is easy, just set both the crank and the cam to TDC. The timing light is for ignition timing, which you'll set as one of the final steps by adjusting the distributor.

If valves are bent, the repair depends on the extent of the damage. If the only damage is to the valves, then they could be replaced. If there is damage to the valve seats, you'll need a valve job. Personally I would replace all valve seals and guides if any valves are coming out. Once the valves are replaced the valve lash will need to be reset. In your case I'm guessing that having a machine shop handle this work would be better.

I would not lean toward replacing the head except in the most extreme cases.
 

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Discussion Starter · #3 ·
I'm guessing it would be easier to replace the timing belt and do a compression test rather than pull the head and checking for bent valves right? I'm trying to figure out everything I need to do, and in what order, to try and minimize the amount of time I spend doing this, as I'll only be able to work in short spurts due to the cold (forecast calls for -17C all weekend) so hands will get cold real fast... I'm wondering though, if I'm not touching the distributor is the ignition timing going to go out of spec very much? I'll be doing the ignition timing regardless, since I want this car to run in top shape as best I can, but I'm just moreso curious about it.

Another question: If there are bent valves, will they be pretty straightforward and easy to spot when I pull the head off, or can it be one of those things where you can't see it unless you know what you're looking for?
 

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Yes when you replace the timing belt the distributor should be close to spec. I would do that and check the compression. You might have lucked out. Some do although Honda is an interference engine. If not the head has to come off. It will be obvious if a valve is bent, it will be stuck out. I don't think you will just be able to properly replace the valve without a machine shop. It has to be ground to match the seat, or at least lapped to match the head. Best is 3 angle grind. Taking the head apart is not hard IF YOU HAVE THE RIGHT TOOLS. Otherwise, it's a pain. As Jeff said, if you have the head off the valve seals should be replaced and guides checked. IMO the best thing to do is just take it to a machine shop and have it done properly. Save your frozen fingers for putting on the timing belt and if necessary taking off and on the head.
 

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Discussion Starter · #5 ·
Yeah, I like praying the valves are kosher the most hahaha

And at least I know a machine shop is obviously going to be needed otherwise now. Any ideas on a ballpark price for getting a valve job done?

Good news is that I may have found a heated garage I can use, provided I'm able to push it up a short but steep incline into a narrow opening on ice haha ... It's definitely worth a try though to get out of the cold!

Thanks for the help guys, I really appreciate it! At least now I've got a much better idea of what to expect :)b
 

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IIRC when I had a b18 head done about 3 years ago in Washington, it was about $300 soup to nuts. Thats not kreplach but not too bad either.
 

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Remember that the valve timing and ignition timing are two separate things. They're related, but not identical.

Ignition timing is when the engine management system thinks is the right time to light off the spark. You use the timing light to set this, and you change it by twisting the distributor while the engine is running so you can get it set just the way you want.

Valve timing is when the valves open and close. That is purely mechanical, and is determined solely by the orientation of the crank and the cam. So you would line up the crank to TDC#1 using the TDC mark on the crank pulley, and spin the cam until the valves for #1 are both closed and the marks on the cam pulley line up correctly (however that is on your engine; it can differ). Put the timing belt on at that point, and make sure the cam and crank haven't moved. Put the tensioner on the belt and tension it, and make sure the crank and cam are still at TDC#1. You don't change this timing, unless you have an adjustable cam pulley, and you don't need that with a stock motor.

Start with the assumption that at least some valves are smashed. You'll have to pull the head to figure out which ones really are, and it would probably be best to have all of the valves checked by someone who knows how to. (Straightness, length, etc.) I'd probably take the head to a good machine shop and let them deal with it. You'll also want to at least look at the piston crowns to see how damaged they may be. Maybe take pics to your shop when you take them the head.

In really, really, really bad cases it can be possible to bend a rod. But that generally doesn't happen unless a valve comes apart and the head gets wedged into the combustion chamber... Very very unlikely for just a snapped timing belt.

--DD
 

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It also depends on what RPM the engine was going on how much damage you will have.
I would say that with a very high likelihood you have bent valves (I personally have never seen a Honda engine of those years that didn't have at least bent valves after the timing belt gave out). Absolutely worst case could be that your head is cracked, but that is very unlikely. I had a few valve guides cracked after a timing belt went out on the freeway. So it's really a case by case thing, how much damage you will have.
For a head job I usually have paid about $150 plus whatever parts you need. Usually it came out to about $250. A lot of times they will give you the rest of a gasket set, all the ones they didn't use.
If I were you, I would get an oem head gasket and intake manifold gasket. I have had really bad experiences with cheap gaskets.

Depending how old the water pump, tensioner, etc are, think about replacing all that stuff since you have already everything apart. No sense in using the old parts and then do the work again in 9 months
 

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Discussion Starter · #9 ·
Thanks for the wealth of information guys! I can't tell you how much I appreciate it, it's helped to reduce my stress about this significantly. Towing it to a garage to start working on it tomorrow morning, hopefully everything goes well. I've found a machine shop to take care of the head if there are issues already, hoping I can get the belt on and everything in a few hours (I'll have some help, luckily).

I can honestly say that I wouldn't have owned my CRX for more than a year if it wasn't for this site. Much love!
 

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You don't need to replace the timing belt to see if the valves are bent.
Pull the plugs, bring piston 1 to to dead center. Use a compression check hose (you can get at a parts store) hooked up to a compressor to check for leaks. Let the compressor come up to pressure (40psi will do) and shut off. Attach hose to compressor and listen very carefully for air coming out the exhaust or intake manifold. if the valve are bent you will hear a fairly pronounced woosh.
A very slight hiss is normal as air leaks past the rings.
When done bring cylinder 2 to TDC and repeat, do for the rest.
You can also tell if they are bent by your valve clearances being loose as the bent valve will not return as far opening the rocker gap.
If all checks out ok and the crank turns without feeling like it is binding up you may be ok.
Replace the belt and you got lucky.
If not, off with it's head!
 

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Dylan921 said:
You don't need to replace the timing belt to see if the valves are bent.
Pull the plugs, bring piston 1 to to dead center. Use a compression check hose (you can get at a parts store) hooked up to a compressor to check for leaks.
If you're going to do this, you'll need to also move the cam half as far as the crank when going to the next cylinder.
 

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As his wife tried to start the car repeatedly the issue may be moot. However you are right when referencing an interference motor.
I appreciate the correction.
 

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Discussion Starter · #13 ·
So I just got my Christmas present from the CRX early. We changed out the timing belt, ran a compression test (I think the numbers may have been a bit low - I was turning the engine over while a cousin was checking the numbers, and he said they were all within 5psi of each other, but I think they were down in the 140psi range) and came to the conclusion that she's good to go. Drives smooth and works fine. My wife says it drives better than it used to, same with both my cousins who were helping us work on it. However I feel like it's lost a lot of low-end power (it feels like it makes the same amount of power at 3,500 RPMs as it used to at 2,000RPMs). My cousin said that it could just be that they had the timing advanced a bit on the old timing belt which would make it feel more peppy. I'm wondering if having the timing advanced a bit would also explain the ****ty mileage I was getting before (I think the last tank before the timing belt went I got like 24MPG!)...

Just wanting a second opinion on the compression test numbers... Is 140psi (+/-5psi) acceptable for an engine in good shape with about 206,000KMs? I just want it to have that low end power that it used to again haha
 

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Sounds like the cam timing is off. I know from experience that'll kill the bottom end performance :wink:
 

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Discussion Starter · #15 ·
One thing I was kind of thinking warbird... If he set the timing the way you're supposed to on a DX/HF on an Si, would that cause this (or something similar to it). I wasn't watching him when he set it, but I heard him earlier when an uncle asked him about how to set TDC based on the cam markings, and he said you just need to get the 2 lines even with the bottom of the valve cover (Which is for HF/DX engines, right? The Si needs the mark on the front a little lower and the one on the back a little higher IIRC)....
 

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Yeah, the Si is timed differently than the rest. I'd pull the belt covers and double check the timing. The time I messed it up I just had it off by one tooth on the belt...
 

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warbird said:
Yeah, the Si is timed differently than the rest. I'd pull the belt covers and double check the timing. The time I messed it up I just had it off by one tooth on the belt...
Agree with above. You are likely off a tooth on the timing belt.
 

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Discussion Starter · #18 ·
So what's the easiest way to correct the timing on it? Do I need to take off the the lower timing belt cover and remove the engine mount, or can I get away with just the upper timing belt cover and the valve cover?

Another thing I'm wondering if I need to do (or could cause such low end power loss), is ignition timing. I know he didn't do it when he put the new belt on - we didn't touch anything on the dizzy so assumed it should be fine. I'm wondering if maybe the ignition timing could also be off perhaps? At least it drives, just sucks having to keep it between 3000 - 4000 RPMs at all times because I have no power otherwise (not to mention worrying about causing damage by being off time)...

Thanks again guys!

Edit: After thinking about, I'm assuming I'll probably have to do the whole thing over again, since I'll need to get everything to TDC again, correct? Otherwise, I'll want to go back a tooth, not forward? Since the front side of the cam pulley would be higher for a DX/HF than it would for an Si..

Edit Part 2: When I said back a tooth, I was referring to clockwise... I think the timing belt might actually run counter clock-wise, in which case it would be forward, right? haha
 

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Yep, you'll have to pull the mount and covers, and go through the process again... I'd just concentrate on getting the marks lined up correctly for an Si and not worry about which direction to move things :wink:
If the ignition timing was correct before and the distributor wasn't moved it shouldn't need to be touched; but it wouldn't hurt to double check it after you put things back together.
 

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Discussion Starter · #20 ·
Damn, not the answer I was hoping for, but to get the low end power back totally worth the time haha... As soon as I can get back in that heated garage I'll give it a try and hope for the best. Thanks again for the help guys!
 
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