I'm going to replace the head gaskets on my 95 5.0L 302... I am considering buying the "upper end gasket kit" from O'Reilly's for $80, which includes... uh... "everything" for the upper end, but I don't want to redo taking off all this emissions sh** for anything. Not ever again. $@#)(!@ smog pump! Does the manufacturer really make a difference for head gaskets? Have any of you used a "cheap" head gasket and have it blow out? Should I go strictly w/ Ford's?

My (dry) compression values seem suspect - 135, 142, 145, 155, 150, 148, 170, 140. Seems like there must be a problem there somewhere. I've never seen or heard of a real-life person w/ a cracked block before, but I suppose it can happen. I figure I can find a big crack myself, but how does one find hairline cracks that are too small to see w/ the eye? Is it even important? How would I know? When I take off the heads, I don't want to pay a machine shop a couple hundred to check the heads for me (I live in Seattle where they LOVE to overcharge). any advice for what I can/should do while the heads are out of the car? I vaguely recall my dad having me perform a "leak down" test when I was a teenager on my '72 volvo, but it seems kinda silly in retrospect.

speaking of heads - should I simply lap the valves myself with some lapping compound, or should I take them to a machine shop and have them "triple angle" ground? Does it make that much of a difference? And, if they grind them, doesn't that require new valve stems? How can they grind them and keep the angles the same?

thanks in advance

 

The parts stores pretty much all sell the same stuff, if not in brand then in quality. It's mostly Chinese junk. I don't buy any part that impacts the longevity of my vehicles in any of them. I buy either online or at the Ford dealer if I need a quality part.

Something is definitely up with those compression numbers. You can easily miss even a large crack unless you clean the head VERY well which is tough to do well without a parts washer. Small cracks can be all but invisible to the naked eye even in excellent lighting and with a meticulously cleaned part. You need to have the block and heads magnafluxed if you're worried about cracks in them. You can do it yourself. All you need is a powerful electromagnet and magnaflux powder. I'm sure there's a youtube video on how to do it. There's a youtube video on how to do just about everything these days.

A leak down test is where you squirt a little oil in each cylinder and re-do the compression test. It helps you isolate whether a compression problem is related to the rings or not.

I don't know much about valves, but it sounds like you need to figure out where your compression less is coming from before you start talking about possible solutions.

 

What's the difference in price between a cheap gasket and the best available? I bet it's not going to break the bank, anyway. Generally when I get into stuff I don't do every day much less ever before, one thing that helps is not to cheap out. If there's a special tool required, borrow it or rent it. If there's some strange procedure that everybody recommends, find out why. Preparation is key in this kind of thing, read as much as you can and learn from others experience. Because while the labor isn't too bad, it's probably not too bad once. You DON'T want to tear in to everything again. And again. Searching the web forums can save a ton of rookie mistakes.

 

well, the cheap kit from OReilly's is $20 for both head gaskets. They also sell one from "Mr Gasket" made out of "the good stuff" that runs $80. I bet the Ford one is at least double, if not triple, that.

I forgot to mention the car has been sitting for about 3 weeks. I was testing the compression values not only dry, but also with a very, very cold engine. It doesn't surprise me the values are different, but 170 - 135 is a pretty big swing. I hope the values change when I try the "wet" test. i can't get the engine up to warm temp because the entire top end is torn off. (my bad).

 

This is excellent advice to keep in mind with every repair.

I'm not sure how much stock to put in compression test results on a cold engine. Everything I've ever read says to warm the engine up first but I'm not sure know how it affects the results if you don't.

 

I don't know much about compression testing as I have not done it myself nor know the best ways to check for large compression swings, but these guys are giving some good advice.

I will say for the head gaskets, when I put my AFR heads on my 302, I did a lot of reading that Ford Racing makes some great quality gaskets. I went on summit and bought them and they sure do seem like very good quality. I believe I spent around 50 dollars on the gaskets.

I definitely would spend a little more on gaskets in this case, because taking the heads off and cleaning the block/head is extremely tedious and you don't want to do it again. If you order online, the Ford Racing gaskets from summit should be a good brand to go with.

 

Seems to me, if the compression test had passed w/ flying colors cold, that would be OK since presumably the numbers get better as the pistons expand reaching normal operating temp. Maybe the numbers tighten up and get more consistent, even. Or not. Supposedly a compression test is just that, and doesn't measure or indicate the health of the oil/scraper rings either.

Cold numbers aren't so useful in this instance. If it's a higher mileage engine it's easier to make an educated guess anyway, was it an oil burner, did towing duty etc.