Blown Head Gasket

[Snoopy]

There are diferent bolts. The old classic one can reused and must controlled after some miles and the others cant be reused and are not allowed to controlled again (in germany Dehnschrauben) there are looking similar to torx... and the classic like normal screws...

[Zippy]

The head has been machined. All the gaskets have been replaced and I set the head on the block. I cleaned and coated all the bolts and have done the first torque at 30 Ft Lbs. I decided to check the manual for the final torque and was surprised to find that in the 3 different manuals I have, there are 3 different torque specs. The Chilton Manual says 54, the Clymer says 56 unless it is an 1800cc, which it is, then 62 and the Haynes manual says 56. Any opionions out there?

Thanks,

Al

[majicwrench]

Zippy,
Not sure on the torque, but a lb or two is not gonna make a big diff. Do you have a click style torque wrench?? I would be tempted to do 60. If I get a chance I will look in some old manuals I have.
Mark is right as he so often is, the gasket blew for a reason. High compression engines can ping, and blow head gaskets. Did the car ever ping when it was running?? At the least, I would be tempted to run a highest octane fuel you can get at teh pump. Hope you cleaned out the head bolt holes well too.
You're asking a lot of good questions, hope all goes well, keep us posted!
Keith

[Zippy]

Keith,

Yes, pinging was a problem until I put some time into tuning the car and had the carb rebuilt. The mechanic that took the valves apart said there was evidence of pinging. Burn marks on the head between all the cylinders.

Anyway, yes I cleaned out the bolt holes, I cleaned off the bolts and put anti sieze on the threads. I have everything back together except the T fitting because one of the holes stripped, the oil because the autoparts store gave me the wrong filter and the final torque on the head, wating for a consensus.

Al

[Zippy]

Wow, can't believe it's been a year since I started this post and my repair of the head gasket. Time for an update I guess. Thanks for all the help and suggestions with this project. You folks are the best.

I took pictures of everything I did. I put tape on both sides every electrical and plumbing connection with a description of what it was. As I was putting it back together I looked at the pictures to make sure it was going back in the reverse of the sequence I took it apart. Now I know you experienced mechanics are laughing right now but I don’t care. I learned a lot and feel much more confident about what I am doing. Just imagine what would have happened if I hadn’t taken those pictures or done that labeling and there was a crisis that took me away from the project for several months. My 60 year old brain would never have been able to figure out how to get it back together.

I did a little more research on the pinging issue. Guess the proper term for this is detonation. When I had the car back together and tuned up I took her for a test drive. She performed real well. Lots of power like before the head gasket gave out. And yes, pinging. I have tried adjusting the timing to find that spot between pinging and dieseling. I use 92 octane all the time. I can only hear the pinging at above 4500 rpm during hard acceleration. Usually as soon as the secondary opens. If I back off it goes away. It actually sounds more like a clicking or rattling noise than pinging and believe me as a former sonar technician I know the difference between a ping and a click. It is obviously detonation though.

So at 10 BTC it is very noticeable. At 0 I don’t hear it at all but then the engine runs rough and sputters on acceleration and diesels at shut down. I set it at 5 BTC and I could still hear it quite a bit. I am now at 2 ½ BTC and like I said it is only when I accelerate hard and above 4500 rpm. As a side note I have noticed that the closer to 10 BTC the easier it is to start the farther away the harder it is to start.

So now I am wondering what else to check.
Could it be the advance, or maybe lack of advance if the dizzy isn’t working right? I have a single point distributor with no vacuum advance. Does that mean it is a centrifugal advance?
How about fuel? Could not enough fuel cause this?
What about the coil? Do I need a stronger coil because of the high compression pistons?
Any other ideas of what to do?
Also, if there is noticeable pinging at high rpm does that mean there is always detonation even at lower rpm? I don’t want to blow another head gasket.

Thanks again for all your help. Sorry for the long post.

Al

[majicwrench]

Al,
An engine with high compression is going to be prone to pinging/detonation. Is a good reason NOT to have an engine with high compression for a driver. Milling the head made compression higher.
That said, now you have to control it.
IF distributor is advancing too much, that can create the problem. Total advance should be somewhere around 36deg i would bet. Yes, your dist is strictly centrifical advance.
In theory, not enough fuel can cause ping/detonate. Realisticly probly not an issue here.
You do not need a stronger coil

Dieseling is not caused by timing at all. With your ignition off, there is no spark, thus timing not relevent. Dieseling often caused by too high of idle

Not sure what to suggest for a fix without lowering compression. If you are certain the noise is a ping/detonate, you have to stop it or you will damage the head gasket or worse.
A qualified shop may be able to recurve your distrib, but this would be hit and miss.
Some 0f the regulars here have racy motors, hopefully they can help.
Keith

[roanokeSpider]

Try a lower octane

[BEEK]

Try a lower octane

reverse that, higher octane! check ignition timing, make sure mixture is slightly rich. good starting point

[Zippy]

Okay, so I did a little research on octane. I searched the web and found the quote below attributed to Chevron Fuels Technical Service.

“The Antiknock index is defined as (RON+MON)/2 (RON + MON divided by 2). The RON is typically 97.5 for 91-92 AKI premium gasoline. MON for premium is about 87.3.”

Chevron uses the AKI rating on the pump. What this tells me is that I’m at 97.5 RON octane when I buy Chevron gas with a pump rating of 91 AKI
The manual in my glove box for the 1800 Spider says to use 91 Octane (Research Method) That’s RON.

I found a chart on Wikipedia that shows the relationship between AKI and RON
An AKI of 87 equals a 91-92 RON so should we all be using regular in our cars? Am I missing something here? Does this mean I need a 100 or 110 octane fuel for my high compression engine?

Source of Chevron Quote http://forums.nasioc.com/forums/archive ... 92996.html

Source of octane chart: http://en.wikipedia.org/wiki/Octane_rating

“regular” gasoline in Canada and the US RON 91-92 MON 82-83 AKI 87

Any ideas or suggestions

Al

[BEEK]

you can run a 9.8-1 motor on 92 octane aka premium, just be mindful of ignition advance, if you still have aspark knock, back the timing down a degree or 2