hey, i got an 89 Trans Am GTA 5.7L TPI. one of my cylinders held no compression at all on the passanger side when i did a compression test. im gona have to replace the head gasket right? is there anything else i should do to the engine while i have everything appart? like certain things that i should check, replace or upgrade? i released all the pressure from the ac canister and im gona have to dissconnect alot of hoses and stuff. if anyone has done this before, can you please offer some tips or pointers to make the job easyer?

 

Well since you're going to have one head off, might as well take both off and take them to have the valves done and new seals put on. Also check the deck surfaces with a straightedge to make sure they arn't warped. Run a 7/16NC tap through all the head bolt holes and clean the bolts good. You could do a valve check by standing the head on edge and pour rubbing alcohol in the ports and see if it leaks through the valves. Have them check the spring pressure or just change them.

It sounds like alot, but why go through the trouble and have it start puffing blue smoke through the seals... or have a valve leak.. later down the road. Most vj's cost around $50 a head last time I had it done (a while ago so i'm not 100% sure)

Be wary of 'head' turnaround operations where you bring your heads in and get 'already done' heads, the l98 iron heads are excellent stockers and anything else could really hurt the performance. Like the guy who traded his 92 700R4 for a rebuilt 85 PLUS alot of $$ I heard of awhile back...

 

so basicaly what your saying is that to "overhaul" the valves myself would be hard and probly take a long time, so i should take them into a dealership and have them fix it? my local GM dealership is well known for their lazy mechanics that do half *** jobs. i dont really want to blow money on them if i can do it myself. but im guessing it would require special tools and stuff right? is there specific places that recondition engine parts? other than dealerships i mean(if they actualy do that at all). finding honest mechanics is nearly impossible where i live so thats why im doin the gasket job myself

 

DO NOT take your heads to the dealer for machine work. Most dealers do not have a machine shop, and just farm out the work to someone else. (and, charge you more.....) Find a reputable machine shop in town, take your heads to them directly. Let them know what you want done. (you can do some phone to check prices, turnaround time, and availability of services before you pick up the first wrench.)

But, please keep in mind, that if you have zero compression on one cylinder, there is a real possibility that you have more going on than just a bad head gasket. Be prepared to find more than that. (mentally, anyway....)

Doing both heads is an excellent idea. You are already going to be most of the way there, so, yank 'em both, and have them cleaned, decked, triple grind valve job, new seals, and, if you have the money, go to larger diameter valve springs, so, when you put in the fat new cam, you don't have to deal with them again.

Good luck.

 

well, that one cylinder is deffinatly holding no pressure, so what do you figure is wrong? when i crank the engine it goes up to like 110 then down to nothing as quickly as it went up

 

You might try shooting some 80/90 gear oil in the cylinder to try to seal the rings temporarly to determine if the valves are to blame. If the heavy oil makes no differance then its probably in the valvetrain. If the oil increases the compression its probably the rings. Good Luck.

 

well its a little too late for that unfortunatly, most of the intake is all ready off the engine and so are most of the hoses. all thats left now is to rip off the heads. now i have been thinking about these corvett aluminum heads everyones talkin about. is it a good idea to switch to them? is it even possible? how and where can i get them? and can i buy them new?

 

It not too late yet. You can still to a comp check with the intake removed. Pull all the fuses(ECM, injectors, ignition, fuel pump), hook up a remote start switch, and re-connect the battery. As long as the valvetrain is still intact this should work.

 

Replacing a head gasket or a head on a TPI is tedious. Iwas involved in helping a friend with a dead cylinder on his Z28. Turned out one intake valve had a hole the size of a dime on the passenger side. You are looking at a 10 hour + job. A set of L98 head off a neighbor's '89 Formula 350 for $80 was purchased, $110 dollar for
complete gasket set Autozone, $40 of cleaners, silicone, oil, oil filter etc.

You must take the whole AC set up, drain coolant, remove plenum, TB, runners,
disconnect fuel rail, remove intake manifold, unbolt the exhaust manifold and of course the head(s). That's the easy part, prepping it up for the gasket and putting the parts back is a PITA. Make sure you dont drop anything in the engine while apart....cover up the top of the enfine with a cloth to keep bolts & nuts away.

Get the torque sequence specs for the heads...highly relevant. Bring a radio, beer, friends to assist and keep you company. Even better with power tools/compressor. Look out for vacuum leaks upon completion. Have fun please keep us posted and an update soon.



------------------
'89 GTA 5.7 TPI bone-stock

 

Since you are yanking the heads if you have the money at least have a pocket port done on the heads should be about $100. If you have more money get a new set of heads. Depending on how much you want to spend there are some good heads out their fairly cheap. Also get a set of thin head gaskets from TPIS. This will bump up your compression about half a point. If you don't have headers now is a great time to put them on.

 

im still learnin about engine repairs... so um... what are headers? the farthest ive ever ripped apart an engine is the intake manifold off my 350TPI(3 times to be exact). but i wana learn more so thats also why im doin the head gasket repairs myself. i wont be working on it till this weekend, but when i do ill keep ya guys posted ill probly need some help when i get down to the exahst runners. thanks for your help

 

hey come on, its a valid question isnt it? i have no clue what headers are, obviously they have something to do with the heads.... all ya gota do is edumacate me once and ill understand.... im a very quick learner when it comes to engines, cuz i have to be

 

Headers are high performance exhaust manifolds with individual tubes for each exhaust port on the heads that converge in collectors on either side of the engine. I would also add a set if you have the money since you'll be taking the exhaust manifolds loose to get the heads out. SLP makes the headers that most people prefer, but they are around $400. Hope this helps.

------------------
1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, MSD coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley AFPR, ported plenum,
Ported Daytona Yellow stock base, Moroso valve covers, other stuff,
Ruger P95DC, hot wife, new oil filter, thick rubber floormats, no cats.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

ah! thanks, ive been wondering that for a long time now. right now ive got the vavle covers off and the whole intake manifold off. i seem to be haveing trouble getting one of the passanger side exahst bolts off. its the one closest to the dash. i tryed useing a wrentch and it was on their so damn tight that i stripped it a little bit. so now im in the process of removeing my A/C system. ive got most of the hoses off and the canister, but i cant seem to get that annoying bracket off. should i take off that big thing that is attached to the dash behind the canister? its really in my way and i want try and fit a socket/rachet on the exahst bolt cuz i dont want to risk stripping it any farther. any advice would be GREATLY apprecated.

 

Ok I'm in the process of changing head gaskets also. My 87 has a 350 not original, and they put the 305 heads back on it, so they didn't seal right or something also I believe this is creating severe blow by has anyone ran into this problem? I'm looking for a set of L98's if anybody knows of a set for sell.

------------------

87 IROC-Z 350 T-tops
"Rock & roll doesn't create psychos it just helps psychos be more creative"

 

has anyone here ever replaced a blown head gasket themselves? if so i could really really use your expert oppinions on this matter cuz i want my GTA to drive again..... i need to know how to unbolt the a/c caseing from the firewall so i can get to that last bolt. its rusted on good and no ammount of dw40 is helping. i need to get a rachet on there or a wrench and i need the room so i can actualy put some muscle into it. i know there must be one bolt somewhere thats holding that a/c casing to the firewall but i cant find it. someone told me that its not gona be on the otherside of the firewall (under the dash) so its gota be under the hood somewhere right?

 

Yes, I have actually changed the heads on my car and no I didn't remover the AC box on the firewall. I used a torch to heat up any stubborn bolts and then got them loose using a breaker bar. Yes you will need to wear gloves.