Help!!!!! no compression in motor

[jfrank133]

Hello, a while back my head gaskets on my 305 went out, so instead of paying someone that knows what thier doing, I decided to go the cheap route and do it myself. What I did not know was that the heads were suppose to be torque down. Now I know. Now here I am with a little more knowledge, however my question is, now that I have to do the heads again do I have to take everything out, like the intake maifold to correctly torque down the heads and do i need to do anything else so it will work properly. please help me out.

[86swb]

I am not sure but do not understand why you would have to take the intake back off. Looks like you should just be able to back them off and then tork them down. I will let someone with more engine know how tell you if this is right or wrong. Not really sure-for sure

[82c10]

you will have to take your valve covers off, your exhaust manifold, or header, i can't remember but you also may have to take your rockers off, then tighten them all to 35 lb. pounds from the center out, then go to 50 lb. pounds, and then go to 65 lb. pounds then put everything back on, use this to torque down the rest of them http://www.ecbrcnj.com/id13.html

[82c10]

don't know about the rest, thats just for torquing the cylinder heads down

[jfrank133]

thanks, now i was told that i would have to get some new screws for the heads, because the old ones usually bent, and would not torque down they way they should. Is this true?

[86 GMG]

personally i would just completely redo the head gaskets b/c you could have tightend them down to much and damaged the head gasket so yes remove the intake as far as the head bolts i dont think the are hurt bent is alittle far fetched but stretch is a factor still not real normal. the torque spec will be in any manual you might have a have always lick haynes due to the way they are wrote they make it simple to understand

[jfrank133]

question about my intake, when i replaced it the first time, it only had on gasket in the back and some kind of seal on the front and all away around is this normal? is this because there is not to much pressure underneath the intake manifold. if i damaged the head gasket because i overtightend them, woulnt i know already?

[82c10]

i don't know about the gasket in back, but mostly everyone uses rtv silicone to seal the front and back, so it doesn't leak

[jfrank133]

82c10, thanks for all the help, but let me just say that i changed the gaskets withouth tourqing to spec I then ran it for about 3 mos without any compression on the motor. is it ok just to loosen up the bolts to the heads and then torque them down to specs. Reason im asking is because I was told by the outo part man that I needed to change the gaskets, but I dont know if i should trust him or not, makes me believe he just want to make a sale. what do you think.

[Paso76GMCstepper]

Dude,

Like has been suggested. This is a perfect oprtunity for a " Do Over" You havent done any damage yet and you have learned a bunch so far. Now start over. get new head gaskets. The bolts or studs (not screws) should be ok. I wouldnt sweat it unless there is obvious damage. Get a manual. Even the cheapest ones at Kragen are better than nothing, and It will pay for itself very quickly. Personally I would replace the head and intake gaskets. U use RTV on the front and rear of the intake. Its better than the ones they give u. I even RTV the sides a little to keep em in place. Do the heads right this time and you wont have to screw with it again for a long time hopefully. Most everything on these trucks have a torque spec. They will all be in your book. I would not trust those old head gaskets. TAKE YOUR TIME. One other thing dont believe everything you are told by "your buddy" or the "auto part dude" I know from first hand experiance the people on here have helped me more than you know. Everything I have said to you is stuff gleaned from here and from practical experiance.

I am ready to be put in my place if I gave crappy advice

[superchevy]

Do yourself a favor and buy a Chiltons or Haynes manual. How to remove/install everything, torque specs, etc are in the manual...they're only like $12...although it's too late in this case, it's a hell of a lot cheaper than having to re-do everything the next time you do it yourself.

[82c10]

buy new gaskets, and take the whole top end off

[jfrank133]

Thanks guys for all the information, I have started redoing the heads, everything is looking good. Thanks again.

[piecesparts]

I agree (DO OVER) The motor has had the heads installed and tightened to god knows what. The 305 is a picky little piece of POS when it comes to the heads, anyways. The heads on the 305 yend to crack easuier than their counterparts on the 350. Many guys around where I live kabosh tthe 305 and put in the 350 the first opportunity they get. More Hp, more torgue and better components. The intake should be removed to relieve any stress that it will give for torquing the heads and the head gaskets on the first install will be questionable on their seal, so take them off and go for the quality head gasket, intake gasket, and header gaskets. I would pitch the intake front and rear gaskets and invest in some quality RTV (Silicone sealer) for the proper sealing of the intake. Make sure that you overlap the sealant up onto the intake to head gasket, so that there is no leakage at the corners where it meets the heads. This little investment of time will give you a more assurance that you won't have to do it on a really bad day when you need the truck badly.