black88z51

Does anyone have a good link or step by step instructions on how to replace head gaskets on an 88 L98 w/ Aluminum Heads. Any tips would be appreciated. Roughly how long will it take me? Thanks in advance.

bogus

www.helminc.com - they are the publishers of the Corvette Factory Service Manual.

As for time? Dedicate a weekend.

It not hard. Just a **** load of bolts.

black_89_vette

Rick? Someone is stealing your handle man. Except they don't buy parts and resell them only to buy them and resell them again....yet.

samsonb

I know these have bad gaskets in them from the factory. What head gaskets is everyone using on those L98's? Part number?

Where do you look for signs of a head gasket leak? My 89 has 87K miles, original head gaskets. Would the spark plugs give signs?

bogus

the plugs would be white and the coolant low.

samsonb

Ok, I'll look for white plugs. With this common head gasket leak, does it always leak into one of the cylinders? I figured this would tell me of any internal leaks by checking the spark plugs.

AdoptAVette

My 91 would blow thick white smoke when first cranked. After about 10 minutes once the cat warmed up you never say anymore smoke.

Another sign was hydrolock. Coolant would enter a cylinder overnight. I try to crank it the next day and the starter could not turn the motor over. If it gets to this state you can pull the plugs to see which one drips coolant.

Another sign is milky oil where the coolant can mix with the oil.

As far as how long it takes to do the job? It depends on your skill level. A lot of the guys here can do it pretty quickly. Me? I'm new and taking my time. I would give yourself at least two weekends. Just don't change the head gasket. Take your heads to a machine shop to check them for warpage and to at least replace the valve seals. Heck, you may want to do a complete valve job since they are out. Springs do tire over time.

hexane

I know I've used the factory equivalent, Felpro 1010 on my 89.

Pete K

I have always used the lesser expensive, felpro gasket. 7733 pt-2 is the part number.

87 rag

Removed, case of mistaken identity.

samsonb

I thought that smoke a start up was bad valve seals?

I'll do the plugs sometime in the near future, if there are any white plugs, I'll park it till I change the head gaskets.

bogus

puffs of white at startup can be attributed to moisture in the exhaust. If it lasts longer than a couple of minutes, then you have a problem brewing.

The failure is always with #8, at the 7-o'clock position.

There are some theorys... the best one I remember is some kinda galvanic interaction between the intake/head and the block.

black88z51

In my case the car began to stumble (acceleration wasn’t smooth anymore) then overheated and red warning came on. I pulled over turned it off for a while, checked the rad and noticed I lost coolant. In addition after I had it towed home I had to back it up into the garage and I could see white smoke blowing out of tail pipes. Before I start this job I'd like to read up on the proper procedure. I got a Haynes repair manual but it is not in detail. Does anyone have any copies or pics of better instructions or any tips? Also, is it true that I have to remove the distributor?

90Indy

Also, is it true that I have to remove the distributor?[/QUOTE]

You will not only have to pull the distributor but also the intake manifold and the exhaust manifolds. Plus a host of other things so you can get to other things. I am in the last stages of a head gasket replacement due to me not "cycling" the new ARP head bolts the last time I had the heads off. Remember you cannot reuse the factory head bolts.

If you are not an organized person or have access to accurate torque wrenches, you might want to get some assistance from someone you know to be mechanically inclined. The project can be made more frustrating and less fun if you don't do certain things on the front end.

I am not trying to talk you out of doing it yourself, just be prepared and take your time. Stay organized and label everything. My .02 for what it is worth. Good luck.

90Indy

bogus

At this point, unass the $100 and get the damned Helm Factory Service Manual - www.helminc.com.

You can find them for sale either here or eBay.

Blownfuel1

Having just done this yesterday, I can give you a few pointers. First, I agree with Bogus, get a factory manual. I got mine off E-bay, pretty sure I paid $35.00 for it, that being said, it's not the easiest manual in the world to use, just because everythings not in a step by step order in the book, you have to search for it. One available at your local auto parts store will probably get you through this job easier, but they won't have nearly the amount of Diagnostic info the factory one does. Watch out for the vacuum lines, if your car's anything like mine, they'll fall apart if you blow on them. I labeled everything as I took it off, but it didn't really matter that much, cause the few that wern't already broke (there were several), broke as I gently moved them around to gain access to bolts or remove components. As far as I can tell, their not available from the aftermarket, I haven't called Chevy yet, but I seriously doubt their available there, so it looks I'll be making a new harness from scratch! The bolt's on the runners and lower intake are a little hard to get too, I bought a Stainless Steel Alllen Head bolt kit to put mine back together with, so I can use those ball end Allen sockets to put it back together (works like a universal joint without all the flop). You should really purchase a set of Line wrench's (Metric and Standard) if you don't have them for some of the hard lines (ALWAYS use them to break the fittings loose, once there broken loose you can use a standard wrench for better access to finish removing them) and you'll need a set of Torx Sockets (thru T-40 at a minimum), get the short ones for easier access to some of the bolts (I did the whole job with these and some extensions, but the long ones might have made a few things easier), and if you don't have one, a one inch 3/8 extension will save your butt when a socket and 3" is just too long (like the right rear exhaust manifold bolt!) and a deep socket is too short. The only other thing I can think of is if you're not going to do it immediately, drain the cooling system, pull all the plugs, crank it over a few times to blow any water out of the cylinders, then squirt some oil (or spray fooging oil into the cylinders to keep them from rusting (do them ALL, I skiped some because I found watre in two and four, so I assumed that the gasket was blown between them, but it actually failed at the 3 o'clock position on two, and between four and six, so there was still some water in six, which rusted the bore and necessitated a complete rebuild! Even 30 years of mechanical experience can bite you in the @** when you skip the basics because you "THINK" you know whats wrong! Oh well, never to old to learn. Also, you have to remove the air pump / alternator assembly and bracket off the front of the left head, and the A/C compressor off the right head (you don't have to bust the lines and loose the R-12, just remove the bracket fasteners and slide it foward enough to remove the head) to pull them. I think I took more apart on the Alt. Side than I neded too, but I removed the alternator's lower bolt, and the upper bracket to the Air pump bolt (I couldn't figure out how that funky reverse Torx stud on the top of the Alt. comes off, must take a special tool I don't have), and a bolt was missing on my air pump bracket, but I think you may have to remove the AIR pump pulley to get to a mount bolt behind it, and you will need a puller to get it off
(it's an interfearence fit), check yours to see if this is necessary. If this is sounding like an awful lot of tools, you might check with Autozone and their lend a tool program to see what the have. Lastly, buy (or steal them out of the kitchen) a box of Zip Lock ( the sandwich size works fine) Bags and bag and tag everything (I did all the bolts by component) caust there is a lot, and it'll be hell remembering where they all go!

Trog

Get a helms FSM, be prepared for a whole lot of learning.

I'm not sure where 90Indy is at w/ not being able to reuse the head bolts? Some 4 & V6 engines do require new head bolts but I don't think our good old SBC does. Not that upgraded bolts wouldn't be a bad thing, but some require a retorque which can be a bit of work to pull our valve covers due to accessories being in the way. Studs would be nice but I'm not sure you can fit the heads over studs w/ the block in place? Perhaps someone can answer that.

I used the Corteco thin headgasket for a .5 bump in compression & they are designed for our alum heads so hopefully won't scrub & leak due to the diff. in expansion of the alum/iron block.

black88z51

It took me approx. 16 hrs and I've got both heads off. The FSM I ordered last week is still in the mail, alot of good it will do me now other then provide the correct bolt down patterns and torque for the re-install. I am going with Felpro 1010, but these are 4.160" diameter while the L98 bore is only 4", why the extra 0.160" offset? I lost about 1.5-2.0 hrs on a broken exhaust manifold, some idiot mechanic that worked on my car b/f broke the flange and reattached it in some funky manner of mixed & matched nuts and bolts that just free spun . Also, one of the side that had the blown gasket had the head bolts overtightened and they were hard to get off. I was told I should internally polish the intake manifold now that it's off, what do you think? also should I put on a set of Comp magnum 1.6 roller tip rockers while I'm at it? The cam and lifters will remain stock.

aj1988

I found the vac line at O'reilly this weekend. 1/8" OD x 3' made by Vacu-tite, p/n 47417. Carefully cut it with a pair of dykes and it fits into the rubber boots with no problem.

65Z01

If I were that far into it I'd do some pocket porting on the heads and clean up the chambers.

Also a set of 2.00"/1.56" pro valves would be in order along with the 1.6:1 RRs.

Then I'd match up the intake base ports to the heads.