Had the compression tested on my car the other day because I felt a loss of power, slight loss, but I still felt it. One piston's conpression was low. My mechanic told me I need a valve job. No damage to the engine, but to get it back to par I need the valve job. How much should I expect to pay for a valve job on my 84 mondial Euro Cabrio. Please help, I want to make sure that I don't get bamboozled.
Silly question, but: Couldn't any competent machine shop do this? At least the machining? Does the quote include all new stainless valves/new seat/guides/etc? $5000 sounds cheap, as you are basically getting a $3500 major plus a valve job. So thats $1500 for the valves. Maybe thats right? Most of the machine shops now a days use cnc type equipment. The milling machine doesn't care what head its working on. It flattens the deck, drill out the guides, and typically does a 3 angle job...
well if the 5-7K figure is for a major service which includes the valve work, then it sounds right to me.
$6K plus DIY, $10-15K at a good shop. By the time the engine is out and the heads are pulled, the chances its just going to be a simple valve job will dissapear faster than you can say "new pistons?". Anyone whos been watching these cars over the last 20 years knows you aint ever going to fix one without multiplying the original estimate 3 or 4 times with a lot of while your in there's. There just isnt anyway to really know how far it goes have until its apart, and it WILL go farther, you can bet on it.
How bad was the compression? Rebuilding a motor thats works with some loss of compression seems silly. Very little return for your money. If it isn't burning enough oil to blind people and foul the plugs, just use it. It is a very old car after all. If you spend $15,000 to fix it, every other part of the car will still be a risk of going at any given time. My opinion, just drive it. Also, get a leakdown and a second opinion. And on top of that, run a bunch of techron through it. You are making a huge decision on very little info.
i had the heads redone on my 81 308 and required 4 new valves. bill was over 6k by a very reasonable guy. jon s
Sometimes. With 4V engines, generally yes. With 2V engines it depends on how corroded the studs are, which depends mostly on whether or not the coolant was changed regularly. The 2V studs often corrode to the point that it's a major effort involving heat, a head pulling plate, wedges, etc. that can't be done with the engine in the car. In a couple of cases it reportedly took making very deep hole saws from thin wall steel tubing with an ID the diameter of the stud & running the saw down the stud to machine out the corrosion. Theoreticly it can happen with a 4V engine, but I haven't actually heard of a case. You can search the archives for some head removal stories, & pix of a head pulling plate.
How was the compression test done? To determine if the cause of low compression is rings or valves, a small amount (3-4cc) of oil is squirted into the cylinder & the compression test re-run. If the compression increases dramaticly after the oil is added, then the problem is blow-by the rings. I did a test recently on a 2V 308. Compression on cylenders was about 130-145 & not too uniform. A couple squirts of oil in a cylinder that tested 130 & compression rose to 205!!!! Bad rings fer shure. If compression stays low when oil is injected, the problem is valves.
On it s one piston ir it seems 0 and on another it seems to be down to 80. Excuse my ignorance, but what is Techron.
There is nothing in a can thats going to bring it back from zero compression. You may want to have it bore scoped. Most airports have a mechanic with a decent one and thier labor is very inexpensive. Have someone scope it before you proceed. Zero compression is hard to achieve with a valve, especially with your description of a noticable rapid power loss. It sounds like the piston failed, which is why I suggest having it scoped, so the damage is physically eyeballed. If you have a failed piston, to put the motor back right you are going to put a ton of money into it. I have almost $8K wrapped up in the first cars engine in parts. The only machine work I had done was having the crank checked and polished. I dont have the heads done yet, so probably another $2K. I havnt charged myself anything either. If you paid a shop to do this level of work you will be in for over $15K. Right now your car is in one piece and runs. You may want to sit down and consider your options carefully before proceeding. Cars, including these, are just like aircraft. Its why you see so many airplanes for sale with run out engines. Because the cost to overhaul does not increase the machines value equally. You may find you would come out better to sell it as is and look for something fresher. I mean, there are so many out there who believe they are so much smarter, that they can fix one of these cheaper than everyone says and will overbid everyone to get thier hands on one cheap. I say let em have at it.
I'll attest to this. My car had scored cams/heads, checked the heads, tons of slop, pulled them off, oil wash on all the pistons, pulled them out, need to oversize.... Once you dig into these motors it adds up very quickly. I thought about dumping my car when this started, but I decided to go ahead and rebuild as I already had some money in it. In hind sight, I kind of wish I'd walked away from it and bought a new car. That said; I'm gonna end up with a fresh, fast 308; which is never a bad thing to have.....
A little late in the case of JScar, but the best time for these kind of tests is during PPI. After that running these tests on a good or even "fair" running motor just raises $$$$ anxiety feelings and reduces the ability to enjoy the car. As said in a previous post, enjoy the car for what it is. Also oil is very cheap. So unless your car turns into an embrassing mosquito abatement vehicle, add oil as required. Only when the car tells you with missfires, shorted plugs etc that it is really on its last legs, that you take action (engine teardown) that could possible include compression and leakdown tests. Martin
I agree. After all, what is an 84 mondial Euro Cabrio worth these days? It sounds like it could easily cost more to fix than you could ever sell it for. Still, if you decide to do a valve job, the last several that I've done included all new stainless valves, manganese bronze guides, titanium retainers, and a basic port job for around $3500 Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
