So I have an 88 bronco with the 5.0. The engine was rebuilt something like 50,000-60,000 miles ago. I've done a compression test and the number 8 cylinder had no compression. I added oil and tried again and still no compression. So I fabbed up a homemade leak down tester after some help from a few guys here in this forum. I ran the test and came to the conclusion that the problem had something to do with the exhaust valve on that cylinder. I opened the valve cover today(finally, been putting it off for a month) and after cranking the engine I'm little disappointed because the rocker arms moved fine andso did the pushrods. I'm not tremendously experienced with engine work so I'm kind of stumped. As of right now I have the covers off and I'm trying to think of how to find out the problem with out being forced to pull the head. Any and all help would be appreciated. If you have had problems with the eighth cylinder I would also like to know how you dealt with the problem. Thanks

Mike

88 302 with 4" superlift
Also workin on an 86 F-250 and I'm thinking of stealing the 460 and scrapin the truck to install it in the Bronco
:7

 

If your cylinder is infact leaking down, then it could be:
1) Worn valve guides - Does the truck puff white smoke at startup?
2) Burned piston - You'll never see this without removing the head
3) Broken rings - What condition are your plugs in? May have to disassemble to check ring condition, as well as bore wall.
4) Mushroomed valve/seat - Again, you'll need to remove the head and check the condition of the valve and seat. 302 valves rotate, so you may notice the truck running perfect, then all of a sudden it may develop a miss, then back to perfect.
All your check has done so far, is to make sure all mechanical parts are moving freely.

 

So thanks for the reply so basically everything leads me to removing the head. If I have to do that, my next question is does it make seense to pull both heads to have them inspected? The other thing is I was wondering if there is anything in particular that I should watch out for as I start to remove everything to get to the head.

 

As I been getting into the truck I've found two problems I am wondering about, the first is my upper intake manifold is broken and I was wondering if anyone has ideas about what to do about it (repair, or used, or new).The second is the throttle body and intake had build up in all the ports. I wanted to know if that is a sign of another problem or something I should look in to as far as the engine. Well hope someone can help cause I could use it.;-)

 

Hey so my problem turns out to be a broken exhaust valve. The reason I'm posting again is I was hoping someone out there may have some advise as far as how much work I should have done to the heads. I have never used a machine shop personally so I was wondering what I should ask and what to look for as far as a response. So I would appreciate any advice. The other question is how can I clean the engine now and the engine compartment? I'd like to get everything shiny again before I put it all back together.