yes, but you need to remove the valve rockers to do it. This means retiming. You will have to reset each valve's lash which means turning the engine over several times.
Be sure to get the both kinds. the exhaust side needs to be heat resistant more
I have a related question... My 86GT 2.8L has positive valve seals on the intake side along with another seal on the stem that is like an o ring. The exhaust side has only the o ring. Is it possible or is it a good idea to add positive seals on the exhaust valves? One of the comments on this post mentions seals that can take higher heat and I am wondering if this is a reference to positive seals. Are there any downsides to putting a positive seal on the exhaust valves? I'm replacing the seals now and I want to do the best thing while the head is off and everything is apart. Thanks.
The intake valves are always low pressure (sucking air into the cylinders), and the exhaust valves are high pressure (pushing exhaust out)...so the seals are different. I would keep it the way the engine designers built it.
Quick question and suggestions. Are you having a oil burning issue on startup?? If so I have had luck with a simple remedy. Try using 1 quart of lucas engine oil stabilizer. I was burning up to 2 quarts of oil in a oil change. I started using it with every oil change, and I might use a pint of oil now. If you choose to do the seals with the heads still on, a tool for the 3.1/3.4 pushrod can be used. It allows you to remove the rockers without loosening the rockers. You do have to roll the motor over to get them out. Saves a lot of time adjusting the rockers. The tool is available at any parts store or a tool truck..Mac, snap-on, or Cornwell. Hope this makes life a bit easier Brian
Thanks Brian/bkw88... the heads are already off. I had spark plugs in the front head break off so I needed to disassemble anyway. I wish I would have known about the tools beforehand it would have made it unnecessary to remove the rocker arms and worry about adjusting for lash upon reassembly. (Does anybody have any Fiero specific tips for rocker arm adjustment?) I saw a Lisle tool in anotehr post that might be similar to the ones you mentioned. I only had a little oil burning at startup and no appreciable loss of oil over the span of an oil change (the car and engine have only 36K miles). As long as I was taking everything apart I was using this as an opportunity to change the valve seals.
Does anybody have any Fiero specific tips for rocker arm adjustment?
As a matter of fact I do. I had installed 1.6 ratio roller-tip rockers recently in my Formula, but my method will certainly work with stock rockers as well.
I wanted to take this opportunity to discuss the methodology of adjusting valve lash. The last time I adjusted valve lash was back in 1977 after I swapped a lumpy camshaft with solid lifters into my big-block 396ci Chevy.
This is the first time I've ever adjusted the valve lash on a 2.8 engine. I've read all the numerous posts about which rockers to adjust when, and "spinning" the push rods while tightening the rocker nuts until the push rods start to bind. Then there's the debate about how many turns of the nut after finding zero lash. I gotta be honest... I didn't feel a lot of those posted methods were very convincing. Here's how I did it....
First, for each cylinder I determined when it was at TDC of the compression stroke. This was done by rotating the crank using a wrench on the front pulley (with the spark plugs out it's easy) and seeing when the exhaust valve is closing and the intake valve is opening. That's TDC, but on the exhaust stroke. Turn the crank 360° (watch the timing marks go by... stop on the third one), and this is TDC on the compression stroke.
With the rocker nut loose, grab the rocker at the valve end tip and lift it. You'll notice the play. You don't even have to see it, you can feel it. Slowly start to turn the socket wrench on the rocker nut and you can feel the play becoming less and less. And now I've got something critical to add...
Do not get fooled by a lack of play due to your socket wrench putting pressure on the rocker ball.
Lucky for me, I noticed this very quickly, but I can certainly see how an inexperienced mechanic could get completely fooled by this! It is very important that the socket wrench is taken right off the rocker nut when lifting the end of the rocker to check for play. (A deep socket rests on the rocker ball, and the wall of the socket can also push against the inside of the rocker, both of which can prevent the rocker from easily moving.) Otherwise it's way too easy to come to the conclusion that you've reached zero lash when in reality you could still be way off. Using this method I was able to determine zero lash to perfection.
And now the lifter pre-load. I gave each rocker nut exactly 1 1/2 turns after finding zero lash. I suspect why some people suggest less pre-load is because the "spinning" push rod method to find zero lash is so imprecise that many people would probably have already gone beyond zero lash. Therefore, adding another 1 1/2 turns would be exceeding the recommended lifter pre-load for this application (if the rocker nut was tightened too much while setting zero lash).
Before I removed the original rockers, I checked to see what the pre-load was. It was all over the place, but it seemed like 1/2 turn past zero lash was the usual. That's not enough.
This is wonderful Patrick! Thanks a million! I saw one video online (for a new build-up that wasn't a Fiero engine) that implied that the pre-load would be different depending on whether your hydraulic lifters were new and dry versus existing ones with oil already in them. Do you think that matters? Were your lifters new or not?
Another archived comment that is not directly a reply to this thread, but which I think warrants repeating is this one, which I found to be incredibly useful in valve seal replacement:
I saw one video online (for a new build-up that wasn't a Fiero engine) that implied that the pre-load would be different depending on whether your hydraulic lifters were new and dry versus existing ones with oil already in them. Do you think that matters? Were your lifters new or not?
My lifters were not new, as I was just swapping out the stock 1.5 ratio rockers for 1.6 ratio rockers (although I did install new push rods as well).
You bring up an interesting point though. Let me make it clear that I don't know for sure, but I suspect the pre-load, and the method used to get there, would be the same with new lifters. However, it might be prudent to submerge the new lifters in oil and pump them full of it prior to installing them.
[This message has been edited by Patrick (edited 09-16-2015).]
I installed a valve stem seal set on the 2.8L engine in my 1986 Fiero GT. I noticed that the o-ring seal on the valve stem is pushed down out of the groove when I compress the spring to re-install it. I'm not sure that I could pry it back up into the groove with the spring/keepers reinstalled because access to stem is only available at the insert opening. Is this a problem? Will the o-rings re-seat themselves when the engine runs?
My lifters were not new, as I was just swapping out the stock 1.5 ratio rockers for 1.6 ratio rockers (although I did install new push rods as well).
You bring up an interesting point though. Let me make it clear that I don't know for sure, but I suspect the pre-load, and the method used to get there, would be the same with new lifters. However, it might be prudent to submerge the new lifters in oil and pump them full of it prior to installing them.
If hydraulic lifters, definitely soak in oil prior to install.
I had installed 1.6 ratio roller-tip rockers recently in my Formula, but my method will certainly work with stock rockers as well.
