Low Compression on All Cylinders

[TarheelEB]

Driving the other day and engine cut off. Would not start up. Engine cranks but will not turn over.
Towed it to a shop and they are saying low compression on all 8 cylinders.
302, C4, 2Barrel Carb, Factory AC, PS, Disk brakes in front, drums in rear.
68 to 70 on the left side and 80 on the right according to the shop.
They are saying I need a new engine.
The 302 in my '77 is the original engine so I do not want to part with it.
I will be keeping the engine for a future rebuild.
Should I take it to another mechanic and have a second opinion or should I have this shop replace the engine?
I was also thinking about towing to the house and garaging it until I come up with the best solution. At this time I really don't have the time and tools to pull the engine myself.
This seems like a great opportunity to do an EFI conversion.
Any suggestions on a used engine to put in that would be good for this conversion?
Also, the shop says they have a "new" 302 that they can put in for $3600 total. The engine cost is $1900 and labor is $1700.
Would a mustang engine from 89-93 work if I wanted to do an EFI conversion?
Any help or advice would be greatly appreciated.

 

[Blue Bastard]

Seem a little pricy to me.....

 

[jw0747]

ask the shop how much to rebuild your engine? low compression is caused by worn piston rings and/or bad valves which can both be corrected provided the block and heads aren't ruined.

 

[Broncobowsher]

If compression is really that low it will be a bad oil burner. How bad is the oil consumption? I would be looking for different shop opinions. That is a lot of money for a basic 302 engine replacment.

 

[ENDLIFE]

Even if your compression was super low it would still start, but you would lack power. With a problem like that it's either fuel, or you lost spark somehow. I would get a second opinion.

 

[miikee73]

I don't believe that low compression would run one minute and not run the next. As stated above ,was this using a lot of oil? I'd get a second opinion on the comp test. They could be using a bad gauge and your reading is level ,just low. I would get it checked out more before you let them do a motor.

 

[Amac70]

sounds to me like you skipped a tooth on the timing chain or stripped it out if it was one of those plastic ones. possibly bending some valves and pushrods. this is a non noisey way of killing a motor they just sort of shut off and don't run anymore.

 

[jckkys]

Something must have happened quickly. simple engine wear would have progressed over time. The timing chain may have jumped one or more teeth. Have another mechanic look for that before you rebuild the engine. If the timing chain sprocket is nylon pieces of nylon will be in the oil pan so make sure they clean that out.

 

[broncnaz]

Compression tests should be done with the engine warm. If it wasnt then the numbers are not a true indicator of overall condition. I'd look a a few other things like igintion and fuel problems before hitting a engine replacement. If the engine was running decent before there is a reason its not now.
As was said I'd get some other qoutes on a engine install the one you have is a little high. A shop should be able to do the replacement in around 12 hours or less. I know I can do it in less than that. But still shops will charge a lot for labor so its not unexpected.

 

[Broncobowsher]

Good call on timing chain, I forgot about that. That will cause a sudden drop in compression without any other symptoms of a worn out engine. Quick and easy fix. Age is correct for it going. Bone stock engine will usually survive without taking out valvetrain, enough that I would try it without pulling heads.

I still say look for another shop, from there diagnosis and pricing they really don't want to work on it. Or if they are going to work on it they are going to be damn sure they make a good profit on the job. I garantee there price quote will be low as they will find several other little things that need to be replaced as they do the engine that were not expected. Suddenly you need a new distributor, and carburator, and belts, and alternator, and the hose they thought was good really isn't and you need that as well, we can't garantee that engine with a radiator in that shape so you need a new one of those as well, etc.

 

[u10072]

Lets say the engine is toast-- how much mechanical skill do you have or tools? Any of your friends skilled? Honestly best engine for the money is the 96-01 Explorer. If $3600 is in your budget --$1900 for the engine doesn't sound bad its the labor thats pretty stou. I know I would R&R an engine for that all day everyday especially in an EB. Are you are low on tools or skill-- go buy an engine for $500-$1000 at a wrecking yard, an engine stand and cherry picker off Craigslist for $200, $1000 worth of tools, and find a guy off CL to R&R it on a weekend for say $400 (or call a friend for $100 dinner/beer), and throw $1000 worth of fun stuff on it-- thats $3600 on the high end. You can sell the cherry picker and stand when you are done! Might seem dumb and a hassle but the $1000 worth of tools will pay off 50 fold, you get some sexy parts, and learn something!

 

[blubuckaroo]

Why not just rebuild the original motor? If you can't do it yourself, you can have it done by a good machine shop. The quality has a better chance of being better than a used or crate motor especially if you deal with the rebuilder in person. Also, if emission compliance is important to you, you won't need to adapt stuff like those odd '77 side ported thermactor heads.

 

[u10072]

The 77 motor had like 140 hp is the reason I wouldnt put a dime in that thing-- unless you live in California you shouldn't have an issue-- at least I wouldn't think so-- guessing you are in NC??

 

[73azbronco]

Ask the shop if it was a wet comp test or dry? That will tell you if it's heads or rings. But all of a sudden going dead? My bet is bad fuel pump, or ignition issue.

Either way, take it to a shop you trust, that one doesn't sound right saying low comp.

 

[patterdale]

I would run, not walk to another shop. Make sure the timimg is correct, that will tell you if the timing chain is off. The distributor drive shaft could have broken also. If it wasn't burning oil and smoking like a poorly timed diesel the rings/valves can't be that bad. It stopped running for a reason that is not compression related. I drove an old 69 300 CID for years in an f-250. It ran like a champ. My reply at the gas station to the pump jockey was, "fill the oil and check the gas". (yes it was in the days when self serve was a disgusting new idea). The guy I eventually sold the engine to said it had no compression and 2 piston skirts were totally gone. I would drive it @250 miles and have to add 2 qts of oil. The 76 Bronco I had years ago supposedly had the original engine in it. Someone lied. When my high school buddy's dad took the engine apart he found that the valves had hammered themselves into the heads because someone installed old ones without hardened seats. It ran like crap but it still ran. The bone stock engine is not an "interference" or close toleranced engine. The piston cannot hit the valves unless a spring/keeper breaks or a rod goes bad.

 

[broncosbybart]

My thoughts here on originality. A mustang EFI engine will bolt right up to your truck. It requires a different flywhee/flex plate for that engine. You can't re-use your original flywheel/flexplate off of the 77 engine. If your truck is all original and in nice shape, I could see wanting to stay with the original engine. If it is modified, no one will care about the originality of the engine. You will have quite a bit of cost involved with the EFI swap, if you are going to have someone else do it all. Hope that helps give you some direction.

 

[TarheelEB]

Update

I appreciate all of the responses.
I contacted the shop today and they are saying they have a new (reman) 302 engine that they can put in for total of $3700. I want to keep the old engine so they are charging a $200 core for me to keep it for a total of $3900 big ones.
I will be paying the tow fee they charged and the diagnostic fee and then I will be towing it to my house.
I will park it at the house and do my own compression test on each cylinder.
I need to figure out if I even need a new engine or not.

I looked into buying a 5.0 engine from a late eighties to early 90's mustang and purchasing the parts needed to do a fuel injection conversion from BCBroncos. With the carb it is difficult to start in the cold and last winter I had to spray starter fluid in the carb just to get it to started.
I found a used mustang engine for $800; guaranteed by the auto salvage place but I do not know how many miles are on it.

Anyway, the reason I was considering having the shop replace the engine was that it is my daily driver and now I do not have transportation.

Thanks everyone for your input.

I am located in Northern Virginia; does anyone know of a good place to take my Bronco so I can get a second opinion?

 

[73azbronco]

First, the place you are talking too, in my opinion is ripping you off if they try to charge YOU $200 to keep YOUR old engine. That is a fraud on so many levels.

Second, avoid an old mustang engine, they are no better than what you have, go for the explorer motor, roller block, mostly used synthetic oils ond I just opened an 80,000 mile one which appeared to have no wear. These can be found for $400-1,200 in running condition.

 

[needabronco]

A basic reman 302 from a parts house will run you around $600-1000, and in all honesty to swap an engine it could be done in an afternoon by a competent shop. Even if they leave in a few hundred for unexpected extras like belts, hoses... They are making a killing! Granted I don't know what the book rate is, but it's likely less than 12 hours and could be as little as 6. The last Toyota engine I did only paid 6.

I agree you should take it home and do some homework. I'd suggest you research rebuilding your mill and buy some basic tools and give it a go. If that's the route you think you will go I can suggest a few good books on rebuilding Ford small blocks that will pretty much walk you through the whole thing and give you great suggestions that are Ford specific.

A basic rebuild kit and other parts should run you $5-700, labor from a reputable machine shop for the heads and block will probably be about the same. So if you buy a basic Craftsman tool set from Sears for $400 you could very realistically rebuild your own engine for around $2 grand and you'll know every square inch of your engine and have the pride knowing you built it! Cherry pickers can be rented almost everywhere, and most Bronco guys will help you out for the nominal fee of pizza and beer.

Post up where you are and likely someone will chime in and be willing to help you out.

 

[jckkys]

The '77 302 suffered from a lag in the industry's adaptation to the EPA. Ford lowered the compression ratio to 8.0 to 1 and retarded the cam timing. A rebuild, by a competent machine shop should correct both issues as part of the basic service or you could simply make them understand it needs 9.0 to 1 compression and a torque type RV cam installed straight up. A roller timing chain is only a few bucks more and will last as long as the engine, avoiding what I believe is the current problem. It will then be the equal of the '70 302 Ford rated at 200 HP and look as original as it does now. After the 4 grand estimate I would get my truck out of that place.