1950-1966 [Subscribe to Daily Digest] |
Bob,
To give proper advice about what you should consider doing to your engine, we would have to know your intentions for the car. Is it a fun toy to be driven on occasion, or are you counting on it to get you to work in the morning 5 days a week, and then use it for a 5000 mile vacation ride?
Since I don’t know, I will assume that your Saab is for fun, so take my opinions with that in mind. Also, keep in mind that while I have had a few strokers apart, I never had a V-4 apart. Therefore, my opinions are general in nature.
First, I think you should do as much assessment as possible before you remove the engine. Have you done the compression test yet? Have you done it both wet and dry? That will give you a good idea of condition. I don’t know what the compression should be on the V-4, but it shouldn’t be hard to find out. In general, a good engine will have no more than 10% difference between the highest and the lowest, and my guess is that a good V-4 will be in the neighborhood of 130 to 160 psi.
If doing the compression test wet causes a big jump, like 20 or 30 psi, then the loss is likely rings. If the wet test jumps up, but the compression is still low, it may be both. If the wet test doesn’t cause a big jump the rings are tight. A valve job can be done later without removing the engine, so you would not necessarily have to think about that while the engine is out. However, if you need a valve job and the engine is coming out anyway, then moving on to a full rebuild is not a bad idea.
You already know you have an oil pressure problem, so that isn’t something you have to consider to assess the condition. What about leaks? What about noises? If you have good compression and no odd noises, I would be inclined to find and fix the oil pressure problem rather than heading straight into a full rebuild.
While you have the pan off, you can inspect a sample rod bearing and main bearing, or you can inspect them all. At the same time, you get to inspect your crank. Assuming the crank is good, I tend to think it would be a good idea to replace the rod bearings. Doing so is routine maintenance on some larger engines like the older Cummins that were supposed to have new rod bearings every 100,000 miles and new mains every 300,000 miles. On many engines you can replace the main bearings without pulling the crank, or for that matter, without pulling the engine.
You will have to ask someone smarter than I to know if the rod bolts are reusable on the V-4. I expect they are, but I don’t know it for sure. It is likely that they should be measured for stretch to know if they are okay.
You should probably replace the rear main seal of the engine and consider doing the front main seal of the transmission.
As for whether you can do this or a full rebuild yourself, I’ll agree with the advice that has already been given, but will add that if you needed to ask the question you will be looking a steep learning curve along the way. Of course you have to start somewhere if you have any intent to learn.
I faced a similar problem as you with my MG BGT when it lost oil pressure. I could have just replaced the oil pump, but I did plan to put some serious miles on the car so I opted for the full rebuild.
On the other hand, I used to have an old Toyota Corona that broke a piston on a cross-country trip one day. I pulled head, and found one piston had broken at the oil ring. The rest of the piston was still attached to the rod, so I threw the piston crown in the glove box, pulled the push tubes out of that cylinder, and bolted it back together with all the original gaskets. I got another 10,000 reliable miles out of it that way before it broke another piston. There was certainly more than 10% difference between the highest and lowest compression, so things don’t have to be perfect to be reliable.
You need to decide what to do based in part on your intended use.
Cheap Charley
posted by 205.188.117...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
