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seeing how you have the heads, and presumably the intake too, I'd port and polish the heads, and intake, maybe beef up the cam. Go to Summit Racing, or Jegs and look up LT-1 and you would have a hard time not finding any thing for it.
Dear OP, if your LT-1 has aluminum heads, those cannot be magnafluxed, only cast iron heads can be magnafluxed.
Checking for cracks in aluminum heads is a different process. All but one of the water/coolant ports is plugged, (air and water tight) a device is installed into the remaining unplugged water/coolant port, (air and water tight) and air is injected into the water jacket, the head is submerged into a vat of water, and the machinist will then check for air bubbles escaping from the head.
seeing how you have the heads, and presumably the intake too, I'd port and polish the heads, and intake, maybe beef up the cam. Go to Summit Racing, or Jegs and look up LT-1 and you would have a hard time not finding any thing for it.
We found several things in the Summit catalogue, but nothing that really does nayhting signficiant until you get to the $2500 range. That is also where we found all kinds of difference gasket materials.
Does portiing the heads make any significant difference with fuel injection?
The last time the gaskets were replaced was roughly ten years ago (give or take maybe three years, I do not remember really well, it was a long time ago). The car did overheat then and it has overheated from various causes since. When I got it back after havng a shop do the work, I could smell coolant all the time. I took it back and they said some hoses were loose. Still smelled coolant. Took it back and they "adjusted something" Then there were two more problems I no longer remember. One time they had it for three or four days fixing whatever the problem was. No charge, so it must have been a mistake. I was ticked because this was a highly recommended shop. Since that replacement,I had endless problems with it overheating. The dealership put in a different relay for the elecric fan, so the fan ran all the time. That was fine in California, but when I brought the car to cold places, it would freeze up. The relay was replaced with the OEM relay. At some point I replaced the radiator. Later it overheated due to a leak. I pulled over as soon as I noticed it, but it spiked to the top before I noticed it. That was a leak in a hose somewhere. Then it started overheaing when it was idling like at a fast food drive through. I had to watch the temperature and turn on the AC to get the electric fan to come on when it got hot (probably that stupid relay again). Recently it overheated from time to time for no apparent reason, I suspect that was due to the head gasket problem. The oil pressure also tended to drop to zero when starting from a stop. We put bars leak in and it stopped overheating and the oil pressure returned to normal. It was not using any coolant to speak of, but we recently found coolant in the oil and air bubbles in the radiator when it was running. Then we had a shop confirm the problem is a blown head gasket. (Funny thing is our current mechanic quoted $1800 for the replacement, the shop in California charged $3000 ten or so years ago).
I will not likely drive this car much again. (I do not drive it in snow or ice and I am planning to replace it with a G-8 GXP, or maybe and AWD Charger, soon). I will give it to my son when he graduates from High School next school year (2014). I may drive it on and off next summer and fall. I told him he can have it upon graduation if he keeps his grades up (hence, his motiviation to replace the head gaskets, and to keep his grade up). It has 110,000 miles on it and having spent most of its life in California, it is in really good shape, so it is worth fixing. I sure would like to know why two head gaskets in 110,000 miles. I do not often drive it hard. Rarely even come close to redline, and have had it over 120 only a few times. If my son keeps it beyond a few years, I suspect he will rebuild and tweak or replace the engine. (He found an LS3 for $3000 and was trying to figure out if we could put that in it now - NO). Among other things, this is a learning opportunity for him. He is planning to become certified as a mechanic and then go on to engineering school (or possibly reverse order of that).
There is definitely coolant in the oil, but not vice versa. That worries me because there is bars leak in the coolant. I hope the bars leak did not get into the oil and damage the engine. It will probably be OK. I had this happen one other time and drove that car for two years (40,000 miles) and had no problem (other than the bars leak gave way). I just changed the oil and filter four times. We will do the same thing here.
I was planning to have the heads magnafluxed and checked for warping and the valves and seats checked at a machine shop. That is what i have always done when I did any work on the heads or valves on any car. (I replaced burnt valves in two Jensen Healey's replaced the head on a Dodge Ram Van and completely rebuilt a Honda CVCC engine.) I do not really know what magnaflux is other than it will divulge any tiny cracks in the head. If the valves need grinding I will have a shop do it, if they need replacing, . . . I am not sure. I cannot remember what I did with the Jensens when I replaced the valves. I think I had a shop put them in. The last time I pulled heads from a car, the shop lost the heads, then they closed before they found replacement heads. They claimed mine were cracked, but agreed to replace them since they lost them. However once they closed I was SOL. This was the primary machine shop all of the mechanics in our area relied on. I think sometimes I just have absurdly bad luck. Those heads had roller lifters (not sure what that is exactly, but it is uncommon), so it was very hard and very expensive to find replacement heads. Then I had to have those heads rebuilt because I had no idea where they came from. That was very expensive. Finally I got sick of the van sitting in the driveway and I started earning a lot of money, so I just took it in to a shop and head the entire engine rebuilt. (They really screwed up that job. We had it back to them about six times before I gave up and donated the van to charity. By that time, we could afford a new van). This time I will be very very careful in selecting a machine shop and I will try to figure out some way to ensure they do not disappear with my heads.
I looked into a performance upgrade and a kit with new heads, cams, valves and a timing chip or something was $2500. I am not going to put that much into this.
I may use copper gaskets if I can verify they are better. They are not that much more expensive. We will definiitely replace the head bolts, thanks. I also came accross some suggestion to modify the Optispark thingy that I may explore further. That is not an upgrade as much as a fix to help keep moisture out.
thanks for the information and suggestions.
given what you just posted, it sounds like the heads are probably warped from the constant overheating, and it is also possible that the block is twisted, again due to the constant overheating.
as for head gaskets themselves, for the street i prefer good old felpro permatorque head gaskets. i have used them on a variety of engines with only one issue, and that was due to my own error. leave the copper and aluminum head gaskets to the racers who pull the heads after every race and need a reusable head gasket.
as to the stock head bolts, normally i would tell you to go ahead and reuse them if they are not torque to yield bolts the manufacturers like to use these days, but since you have had constant overheating issues, replace the head bolts with some from ARP.
Intersting, my son said he found five of the intake bolts that were only finger tight (i.e. he could losen them with his fingers). No collection of dirt in there though. How did they get loose? It seems unlikely they have been loose for more than ten years without causing a problem.
Should we replace the intake bolts as well?
We found a set with gaskets and head bolts for $250. That seems reasonable.
Thanks for the info on metal gaskets. I thught they were probably for greater durability. The reusability makes sense.
I will be very surprised if the heads are warped. The probelms with the car are all recent and the instance of overheating were mostly years in the past (until the recent issues which I think were casued y the head gasket failure, rather than the other way around.). I have had other cars massively overheat to the point where they purned off paint, but the heads were fine. This car did nto get that hot, because i usally caught it pretty quicky. It does have idiot lights after all. Anything can happen though.
Intersting, my son said he found five of the intake bolts that were only finger tight (i.e. he could losen them with his fingers). No collection of dirt in there though. How did they get loose? It seems unlikely they have been loose for more than ten years without causing a problem.
Should we replace the intake bolts as well?
you might want to check your torque wrench calibration before using it again. however intake bolts do loosen up over time, vibration, gasket shrinkage both conspire to loosen up intake bolts. i usually recommend re-torquing the intake bolts after a few heat cycles, and adding 5ft/lbs pf torque to the factory setting when you re-torque the intake.
The heads may not be warped, but they could be cracked. Also, aluminum heads can crack/warp much easier than iron, which you may have had experienced heating with before with no ill effects.
Location: We_tside PNW (Columbia Gorge) / CO / SA TX / Thailand
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alum heads, leaking, overheating, head gaskets... BTDT every few yrs with (33)VW Diesels...
1) Get heads checked for leaks (Pressure test for aluminum)
2) Have heads surfaced (Fly cut for Alum) ASK for reference and SEE the quality of work the shop does. MUST SEE a rainbow / surface refraction on SMOOTH aluminum resurface, if not; find another shop. (I use Aluminum Head Rebuilders - Portland Oregon - . of course...) Alum heads REALLY work (seal) best after CORRECT resurface.. NO discernible machining marks or they will LEAK, often will leak if re-installed w/o surfacing. Surfacing is CHEAP compared to removing again and THEN resurface / re-install.
3) I use laminated steel gaskets for turbo applications, and copper composition for non-turbo.
4) I only use new head bolts when I have 'Stretch Bolts'. Std bolts are usually ok. If I want a CHEAP good head bolt, I use Holo-chrome 188,000# Tensile Rolled threads. (~$2 ea (mcmaster-carr or Grainger or MSC machine tool supply.) vs $20 for 190,000# 'famous name brand'...)
5) Be sure to clean and grease bolt threads
6) Be sure to use a tap and CLEAN and blow out / water / dry the threads in block (EZ to crack a block if you thread a bolt into a hole with WATER) BTDT when about age 12...(farm kid... had MANY cars before age 16)
CHEAP performance and good practice for 16 yr old... Have him read / study and PRACTICE porting / gasket matching head and intake. (this will keep him busy for a week or so). (I have a saying... young boys need to have their HANDS busy... My kids were without TV or video games so had to keep busy and they each rebuilt their own VW diesels at age 16 ($100 cars they got at auctions). (I paid for their rebuilt heads ($250)... but I got their cars for free when they left home.). I rebuilt a few aluminum heads myself for VW diesels, actually not all that fun or fast (triple grind on valves and seats.) BUt good lesson for me and my kids, as they at least know how to do it, and why $250 is OK to spend (If you have a good paying job).
I certainly would not buy new manifold bolts, but you can if you want. With Alum heads, I would be using threadlocker. (and never-seize on exhaust bolts / studs.) Frequent temperature cycle causes Alum expansion / potential loosening of bolts / gaskets. (thus stretch bolts are usually used in applications with aluminum heads)
Intersting, my son said he found five of the intake bolts that were only finger tight
Which is why you replace the head bolts including the intake bolts with new. The old ones have lost temper and will stretch. I'd also suggest using new exhaust bolts and use a lot of nickel anti-seize on them.
If you have a laser light, run it across the heads from end to end and side to side every inch or so. If the light shows all the way across the heads, they're fine. If it doesn't, they will need to be machined. Since you have them off, how about a valve/seals job? Think the rings are still good? If not, skip the valve job. New valve job and bad or slightly bad rings will make it burn oil.
Location: We_tside PNW (Columbia Gorge) / CO / SA TX / Thailand
34,694 posts, read 58,012,579 times
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Quote:
Originally Posted by TrapperL
... Since you have them off, how about a valve/seals job? Think the rings are still good? If not, skip the valve job. New valve job and bad or slightly bad rings will make it burn oil.
VERY important... NEVER do the heads on a weak engine... this will force rings to leak, then more trouble (blow - by)
I certainly wouldn't worry at 100K... about rings or bearings (if not burning oil and good compression)
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