Hi folks,

I'm rebuilding the engine in my '91 Prelude 2.0si. Got the head back from the machine shop and bolted it on. Put cam sprockets on, but no timing belt. I made sure all pistons were down at least 1 inch in the cylinders.

I rotated each cam indivicually and adjusted the valves. One valve got "hung up" and wouldn't return to its seat. I thought the machinest had made a mistake.

I got ready to pull the head, but after I pulled the cams, I noticed that the valve had fully retracted into its seat.

Just to be safe, I pulled the head and brought it back to the machinest, to have him check everything. When I told him how I adjusted the valves, he scolded me, saying that the engine must have the timing belt installeed and be perfectly timed. Otherwise, the intake valves will hit the exhuast valves, or vice-versa.

I didn't have the cams installed in the head when I brought it back to him, so i couldn't test his theory. Still, I don't think he's right. The valves probably open not much more than a third of an inch, with stock cams.

Is he right? Can the valves in the same cylinder "kiss" each other if they are both fully open?

Thanks in advance.

--Craig Stangohr
Aiken, SC

yes. from what i know the valves never both open at the same time. one or the other is open. the timing belt keeps them from both opening up. once the intake valves open the air comes in then the valve closes, air compressed , gas is ignited etc im sure you know the process. then the exhaust valves open and expell that and then start all over again.

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The simple answer, like Julio already said....... hell yes they can hit each other. Whenever you rotate the engine as an assembly make sure you have the timing belt on and properly "timed".

I have to say though you were thinking when you took the head back to the shop to have them take a look. Most people wouldn't bother.

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there is usually some slight overlap in which intake and exhaust are both open. there's more degrees of overlap in NA motors (the boost would cause the mixture to blow through the chamber if both were open for a long duration).

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"Racing is a matter of spirit not strength."

Hey guys,
Thanks for the answer. I have been a mechanic for 35 years, so I am quite familiar with overlpa, lift, duration, etc., but I've worked on mostly v-8 and v-6 motors.

I figured the lift on my Prelude cams would be about .350"--or a little more than one-third of an inch. Possibly not even that much. I didn't think that even valves open on both sides of the same combustion chamber, that they would hit.

Well, the sign of a good mechanic is one who admits that he is learning about cars every day, and I certainly will attest to that!

Thanks, again.

Craig Stangohr
Aiken, SC

^^

35 years!! I guess that means you're older than me. I'm 33 and one of the elders around here (go figure). Well it's great you stopped by and I hope you check back and keep our site in your favorites. The staff and I are really trying to diversify the forum and to get some more people with you're type of knowledge and expirenece in here would be a great benefit, especially Domestic knowledge!!

Good luck with the engine rebuild and keep us posted.......

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Thanks for the warm welcome. Yean, I'm 51!

If I had known I would live to be this old, I would have taken better care of myself :-)

Other than the head, the rebuild is going great. Just FYI, the engine has 235k miles on it, and it looks like it has had no more than 3 oil changes. I have never seen an engine so sludged up in my life.

The kicker--cylinders are perfectly round, as are the pistons--no wear at all. No wear on the cam or valve guides. Main and rod bearings look like they have maybe 20K miles on them. I never have seen anything like it.

Damn good engines!

Regards,

Craig Stangohr
Aiken, SC

High mile Honda engines are always fun to see. My brother's Civic had 230k when we rebuilt it and when we tore it down you could still see the cross hatchings in the cylinder walls and all the bearings looked good. They built them to last, that's for sure.

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2000 S2000 Hardtop

nine.five.four.

Get your Tuner-Junction stickers today: http://tuner-junction.com/TJForum/showthread.php?t=4377

My acura has 323k on it. I wonder what it looks like on the inside?? THese engines were made to last man. I beat my teg daily and it comes back for more. Welcome to the board and hope you stick around more. Those old lude were horses. Btw, how did you find our site??

The overlap is very slight and usually its when one is on its way to close the other opens and thats your overlap. Never enough to cause them to hit as if the timing belt were not on. But yes there is some overlap i should have said that in the first post but im sure you understood what i was trying to get at.

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Hi folks,

I just found your site by luck, I guess. Just "Googled" in Honda Preludes, and I think yours was the first site to show up.

I will for sure stick around. I was given this '91 Prelude and I plan on keeping it forever.

Honda parts from the dealer are expensive, though top quality, for sure.

My sunroof leaks water. Dealer wants about $100 for the gasket. Are there any good sources for top-quality aftermarket Honda parts?

Thanks again.

Craig Stangohr
Aiken, SC.
1991 GMC Syclone
12.71@106.42 @18 lbs

I dont know any off the top of my head but there abundant. Im sure somebody knows a few off the top of their head.



JOHN google works!!!!!!!!!!!!

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Majestic Honda - The Internet's #1 Honda Automotive Parts Store

I believe the seal for my sunroof was something like $57 when i rebuilt it. Shipping is kindof expensive there, but if you need a bunch of stuff, you'll still save a ton compared to dealer prices. As far as aftermarket.. your options are pretty plentiful.

I got news for ya......I'll put money on the fact that it's not your sunroof seal which is causing the sunroof to leak, it's your drain tubes. Hondas have 4 drain tubes (sometimes two depending on the model). They are notorious for clogging and when they do the sunrrof pan fills up with water and it eventually spills into the car.

There's little one-way valves at the end of the drain tubes that always clog....

Numbers 10,4,6 in this photo of a 1990 Prelude sunroof.
Click For original image


If you can locate those valves clean them, if you can't try warm water with solvent and slowly pour it into the sunroof frame. Either way you need to un-clog those valves.

The seal may also be creating a slight issue but these sunroofs are designed to have no seal!! I have literally left my sunroof slightly open in a rain storm and not had any water in the car!! If the drains are working correctly they will drain the sunroof sub frame very efficiently.

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we always just clear them out with a blow gun with shop air, just cant go full bore, or else you blow the tubes off then you have a not so fun problem to fix

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Wow, that's invaluable information. You probably just saved me $100.00.

I'll check those tubes in the morning. Thanks, again!

All the best,

Craig Stangohr
Aiken, SC