Need head gasket job advice
#1
Need head gasket job advice
OK, my 89 C4 350 needs a head gasket job. I have spoken with a parts guy (owner of a C4) and he said because of the tight quarters it is easier to unbolt the whole front assembly of the car (4 bolts) and slide the assembly out from the body under a raised car. Is this the way to go? I have looked on youtube about this, but have been unsuccessful. Because of the iron block and aluminum heads, I have been told it is common for head gaskets to fail on the Corvette, true? Best to install metal gaskets and overtorque by 7 lbs or so? What if compression tests indicate the left side (non air conditioner side) is the problem, but the right side shows strong compression, tempting to just do gasket on the left side. Very thankful for any advice.
#2
OK, my 89 C4 350 needs a head gasket job. I have spoken with a parts guy (owner of a C4) and he said because of the tight quarters it is easier to unbolt the whole front assembly of the car (4 bolts) and slide the assembly out from the body under a raised car. Is this the way to go? I have looked on youtube about this, but have been unsuccessful. Because of the iron block and aluminum heads, I have been told it is common for head gaskets to fail on the Corvette, true? Best to install metal gaskets and overtorque by 7 lbs or so? What if compression tests indicate the left side (non air conditioner side) is the problem, but the right side shows strong compression, tempting to just do gasket on the left side. Very thankful for any advice.
Last edited by Joe C; 11-19-2018 at 12:28 PM.
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Benny42 (11-17-2018)
#5
Drifting
I blew head gasket on my 89 last year. Driver side, number 7. Corvette shop wanted way to much to do it, so I did it myself. Used a field service manual and had no problems. Did not have to pull engine and did
both sides. Also had both heads milled flat so maybe I won’t have to do it again. I had a lot of choices on head gasket , but I decided to go with what Chevy recommended which was a .051 thickness. Compression calculation program shows I have compression just under 10 to 1 which is
perfect for me. Good luck
both sides. Also had both heads milled flat so maybe I won’t have to do it again. I had a lot of choices on head gasket , but I decided to go with what Chevy recommended which was a .051 thickness. Compression calculation program shows I have compression just under 10 to 1 which is
perfect for me. Good luck
#6
Melting Slicks
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Do them both.. Once you're down that far it is nothing to get the second gasket while you're there.
Agree with everyone above - Do it in the car. It's not a bad job. I did heads, cam and even bearings, rings and an oil pump without pulling the engine. It's not as scary as it looks.
Agree with everyone above - Do it in the car. It's not a bad job. I did heads, cam and even bearings, rings and an oil pump without pulling the engine. It's not as scary as it looks.
#7
Le Mans Master
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OK, my 89 C4 350 needs a head gasket job. I have spoken with a parts guy (owner of a C4) and he said because of the tight quarters it is easier to unbolt the whole front assembly of the car (4 bolts) and slide the assembly out from the body under a raised car. Is this the way to go? I have looked on youtube about this, but have been unsuccessful. Because of the iron block and aluminum heads, I have been told it is common for head gaskets to fail on the Corvette, true? Best to install metal gaskets and overtorque by 7 lbs or so? What if compression tests indicate the left side (non air conditioner side) is the problem, but the right side shows strong compression, tempting to just do gasket on the left side. Very thankful for any advice.
VEDDY INTORESTINK!
#8
Team Owner
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St. Jude '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-‘19-'20-'21-'22-'23-'24
While you're in there exerciser good judgement and replace those items with life limits. Water pump, belt tensioner and pulley. Maybe even the crank pulley if yours is showing signs of delamination. So many components are now accessible, why not get the job done once?
Good Luck
#9
Safety Car
You do have the FSM, don't you? Take pictures of your progress, keep bolts separated for each step of the disassembly, and mark your wires. After you remove the exhaust manifolds, stuff a rag into each exhaust pipe to keep from dropping a bolt or tool down the pipe. To minimize coolant getting into your cylinders, siphon coolant out of the engine by removing one bottom bolt from each head, then slide a small hose into the bolt hole, put your finger over the end of the tube and pull the tube out of the hole. Lower the end of the tube and coolant should flow from the tube. Do both sides.
#10
Le Mans Master
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Do them both.. Once you're down that far it is nothing to get the second gasket while you're there.
Agree with everyone above - Do it in the car. It's not a bad job. I did heads, cam and even bearings, rings and an oil pump without pulling the engine. It's not as scary as it looks.
Agree with everyone above - Do it in the car. It's not a bad job. I did heads, cam and even bearings, rings and an oil pump without pulling the engine. It's not as scary as it looks.
#11
Melting Slicks
#12
By FSM, do you mean the Shop Service Repair Manual? Field Service Manual?
Curious why your heads have been off twice, both blown gaskets? If so, how much time/mileage between each?
Thanks for the excellent input
Curious why your heads have been off twice, both blown gaskets? If so, how much time/mileage between each?
Thanks for the excellent input
#14
Safety Car
FSM . . . Factory Shop/Service Manual, by Helms Inc. Detroit MI (Not Haynes or Chilton's)
First . . . Complete rebuild @ 185,000 miles. (Note the unusual pistons, as opposed to Joe C's in post #2.)
Second . . . Cracked heads, casting #...624 (notorious for that).
#15
That would be the shop manual as printed by GM?
Should check if my casting is .....624? If they are...new heads from Summit?
I do not see what is unusual about the pistons....please fill me in,
Thanks
Should check if my casting is .....624? If they are...new heads from Summit?
I do not see what is unusual about the pistons....please fill me in,
Thanks
#16
Safety Car
SBC iron heads info:
Notice the valve reliefs. Joe has the original pistons, which must be installed with the valve reliefs toward the intake manifold. This means the wrist pin must be in the center of the piston, so the pistons on one side of the engine are upside down from the other side of the engine in relation to the rotation of the engine. (The "front" of the piston on one side is facing the "back" of the engine on the other side.)
My pistons have a notch that faces the front of the engine, because my pistons have the wrist pins slightly off-center in the piston. This requires four valve reliefs, because the pistons must all be oriented facing the same direction. This "off-center" of the wrist pin reduces the side loading of the piston during the power stroke to reduce piston skirt wear and slightly increases the power output of the engine because of the reduced friction. There is a slight change in the con rod angle, too.
Notice the valve reliefs. Joe has the original pistons, which must be installed with the valve reliefs toward the intake manifold. This means the wrist pin must be in the center of the piston, so the pistons on one side of the engine are upside down from the other side of the engine in relation to the rotation of the engine. (The "front" of the piston on one side is facing the "back" of the engine on the other side.)
My pistons have a notch that faces the front of the engine, because my pistons have the wrist pins slightly off-center in the piston. This requires four valve reliefs, because the pistons must all be oriented facing the same direction. This "off-center" of the wrist pin reduces the side loading of the piston during the power stroke to reduce piston skirt wear and slightly increases the power output of the engine because of the reduced friction. There is a slight change in the con rod angle, too.
#17
Melting Slicks
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If you can't find a FSM? A subscription to alldatadiy is cheap and a really good alternative.
I paid 26 bucks for a year, I think?
For a lot of jobs I like it better.. Like wiring for example. You can print out a diagram, drag it all over the car, write on it, get it filthy.. then just throw it away and print a new one next time.
I paid 26 bucks for a year, I think?
For a lot of jobs I like it better.. Like wiring for example. You can print out a diagram, drag it all over the car, write on it, get it filthy.. then just throw it away and print a new one next time.
#18
Thanks again.
#19
we seemed to have gotten side tracked with the OP checking for IRON head "624" castings. original post stated he has a 1989, aluminum head L98, and if original, would be casting no. 10088113.