When to rebuild an engine…
Question:
Dear Kevin
I need your advice. I am about to overhaul my motor. When I reach 50 MPH I get the oil pressure signal and the siren goes on and the red light flashes on the dashboard. My mechanic advised to have the crank grinded. I am taking the crankshaft for grinding as it is currently making a knocking noise. Please advise what other things will need to be replaced after the crank is done in order for the engine to last me longer, and to do a proper job. I will prefer to do this myself. I am not a professional mechanic but would like to learn more.
Hoping to hear from you soon.
2. Once the engine is removed and stripped down, measure the cylinder bores and pistons for wear. If within factory specs you can get away with honing the cylinders and replacing piston rings. More often than not, you will have to bore the cylinders which will require new pistons and rings.
3. You seem to have a handle on the crankshaft, but I would check into a replacement crankshaft, sometimes they can be cheaper than getting your crankshaft refinished. With the crank out, check the main bearing webs for cracks and wear. If you spun one of the bearings in it’s seat, you will have to have the block align bored/honed. This will re-establish the center-line of the crankshaft and assure no future wear issues.
4. Depending on the mileage on the engine, you should also consider getting the cylinder head/s refinished. At minimum it should be checked for cracks/warpage and new valve seals installed. Any competent machine shop can check for cracks and warpage as well as change the valve seals.
5. When re-assembling the engine, here is a typical list of required new parts you should purchase. Full gasket set, oil pump, water pump, timing belt or chain, timing belt or chain tensioner, oxygen sensor, air filter, oil filter, and fresh oil.
Now that you know what is involved, take a look at your local salvage yard for a low mileage engine and compare pricing. It may be worth your time to find a 30,000 mile engine from a wreck instead of rebuilding your engine. They will often come with a short-term warranty 1 – 2 years 10 – 30K Miles.
Good Luck,
Kevin
Posted: 23rd September 2008 | Author: Kevin Schappell | Category: Engine
Changing Rear Main Seal
Question:
I have a 5.7L (350 cid) V8 in a 1982 corvette. I believe it is an L83.
What does it take to replace the rear main seal? I have heard it minght be
possible to do so without removing the transmission. Any advice?
Thanks,
David
Answer:
I believe the rear main seal is a two piece design, so yes, it’s possible to change without pulling the transmission. You will have to remove the oil pan and the rear main cap. You can then remove the old seal and replace it. The seal is a rope style seal and you will have to use a small piece of string or wire to pull the new seal into place.
Kevin
Posted: 28th August 2006 | Author: Kevin Schappell | Category: Engine
Valve Seals 2000 Toyota Camry
Question:
Just purchased (July) 2000 Toyota Camry from Toyota dealer. The 3 mo.
warranty doesn’t cover valve seals. Car has 130,000 miles, runs well, very happy with it otherwise. When it starts there is some smoke, doesn’t do it once car has run a minute even with start stops for errands. Smoke is white to perhaps slightly blue.
Doesn’t appear to be using oil and no drips under car. I won’t put enough
mileage on the car to get to 200,000 by the time I retire in 5 years and
buy a new car but I do want to take care of it.
AAA said 1,500 to replace seals. Toyota dealer said 1,100 to replace
seals. The used car dealership consultant said there is no big problem and
not to worry about it that I’d be spending money needlessly as long as there
is no big oil consumption going on I’m okay. He said he’s sure no oil will
have to be added between changes.
What is your opinion? Should I have repair done or just watch how much oil
it uses?
Thanks!
Miranda
Answer:
I would keep checking the oil level, and live with it. You may wear out your spark plugs a little sooner, but not a real big deal. Besides the annoying smoke at cold startup, you are not doing any real damage to your car. You may want to look at your owners manual and change your oil to the highest viscosity recommend. So if your car manual says the range is 5W-30 to 10W-30 I would make sure the next time you get an oil change they put in 10W-30. The higher the number, the lower the viscosity (thicker oil) Running a thicker oil in the engine will allow less oil to seep down past the valve seals. I would stay away from oil treatments which advertise to reduce oil consumption, they never seem to do any good, and sometimes do bad things to your engine.
Kevin
Posted: 28th August 2006 | Author: Kevin Schappell | Category: Engine, Oil & Lubrication
Celebrity 2.5L Engine Won’t Start
Question:
I have a problem. – 86 Celebrity 2.5L
Car will crank but not start. While swapping battery and connecting
positive cable first I heard a popping sound by the right firewall. I
finished hooking up the battery and tried to start the car:
1. Car would crank but won’t start
2. Checked for spark wth timing light – no start
3. tried to pull codes (with paper clip) old fashion type – light would not
flash
4. radio fuse blew, all others ok
5. Could it be the computer? If not what could it be?
6. Is there a way out can check the computer – or just buy one from a junk
yard”
Answer:
It could be the computer, or a fusible link in the wiring harness. A fusible link is basically an inline fuse, that is not replacable. You would have to find the link in the harnas and replace it. Sometimes there are fuses/relays in the engine compartment also, but that is more common on foreign cars. To really diagnose the issue, you need a multi-meter, and a good repair manual with wiring schematics. You need to see if the computer is getting power, and test some of the outputs to see if it’s working.
You can buy computers out of a junkyard, and this may be an easy way to diagnose your problem without spending too much time or money. (depending on the cost of the computer) I would think you should be able to get the computer from a junkyard for less than $150. Check out www.car-part.com to search junkyard inventories.
Kevin
Posted: 20th August 2006 | Author: Kevin Schappell | Category: Electrical, Engine
5.7L SBC Interference Engine?
Kevin,
Question:
First off, you have a great blog. Very informative and useful.
I own a 1982 Corvette with a 5.7L(350 cu) V8. Is this an interference
Engine?
My timing chain broke, and I’m wondering if there will be valve or cylinder
damage.
Thank you very much,
David
Answer:
From my knowledge the stock 350 is not an interference engine, so you should be ok. If you were at very high rpms or have an aftermarket cam shaft, then all bets are off. A higher lift cam could cause the valves to hit the pistons. Also if you have a set of high compression pistons in the car, same outcome.
The good news is that it’s fairly easy to change the timing chain on the SBC and you should be able to do it in a day and fire it up to see if there was any damage. This will save you the hassle of taking the intake and heads off to inspect for valve/piston damage.
Good Luck,
Kevin
Update…
Kevin,
Thanks for your answer to my last question. I have another question.
My car is a 1982 corvette with a 5.7L V8. My car started with a timing
problem. It would idle, but stall when I tried to drive it. I replaced
the fuel filters and retimed the distributor. Everything was fine for 2
days, but suddenly it refuesed to start. It won’t even turnover. It just
cranks.
I have replaced the ignition coil and module in the distributor. The car
is getting plenty of fuel. Also, the spark looks “weak.” It just has a
small orange spark. I have been told that a HEI should have a good strong
spark.
The only idea i have left is the timing chain, but to change that I am
supposed to remove the oil pain, steering linkage, water pump, etc.
Do you have any ideas what might be my problem?
David
———————————————-
Take the distributor cap off, and crank the engine… see if the rotor is spinning, if it’s not then the timing chain is the problem. More than likely the chain skipped a tooth, and when you readjusted the timing, it ran for a little bit until it skipped again.
If the rotor is turning, then I would recheck the timing. The engine won’t fire, but you can still spin it over with the started and get a reading. If it’s off again, I would still suspect the timing chain, it just has not fully snapped. If the timing is ok, then I would check spark again, check the power wire to the coil for loose connections. If nothing shows up with those checks, then it’s time to check vacuum leaks, fuel issues (fuel pump, float level, or sensors) I can’t remember if the 82 had a carb or had that goofy crossfire fuel injection !
Good Luck,
Kevin
———————————————-
Kevin,
I haven’t seen you post this on your blog, but I thought I’d let you know what I found out. The timing chain did slip.
And the 1982 corvette had the crossfire fuel injection. However, MY 1982 ‘vette has a holley 4 barrel and an edelbrock intake manifold. I bought the car as a project car, and I”m having a lot of fun.
You’re blog is awesome and you do great work. Keep it up!
David
Posted: 20th August 2006 | Author: Kevin Schappell | Category: Engine
