Blown head gasket / causes

[majicwrench]

No offense intended to anyone. There is just so much "wheel-spinning" in most auto repair, I hate to see folks wasting time doing things that are not neccessary. And checking cranking compression... honestly is not gonna help. What number is he gonna compare his reading too?? How much is too high?? What are the numbers gonna tell him?? And the pressure in a cylinder spinning at cranking speed has little relationship to the pressure at road speed.

Yup, I use a modified spark plug as a piston stop and then split the difference. Gets it dead on. Would be interesting to try the screwdriver method, then the piston stop method, and see results.
Haven't lost my manners, not slamming anyone. Just keeping it real.
Keith

[TulsaSpider]

Thanks for the suggestions guys. I appreciate the help. Yes we did put a drop of 50 weight oil on the threads and under the head bolt washer as well. I think the method I will use is pull off the aluminum pulley put on the old pulley, line up the marks then put the aluminum pulley back on and make my mark that way. I can check it withe the screwdriver method to verify I am close.

[So Cal Mark]

it sounds like you are assuming the stock pulley is perfectly marked

[TulsaSpider]

Good point Mark. Yep I was doing just that. I'll just get it as close as possible using the methods described here. Majicwrench I would like to read your plug/piston stop method as well.
Update. According to everything I know it is timed correctly as it sits. piston is at top, my original mark is on the longest finger of the pointer...

[majicwrench]

Here goes, in rough form:
Old spark plug, knock out all porcelin. This is tougher than it sound. Chip chip.
Get 1/4 20 thread- all or long bolt and (2)1/4 20 nuts .
Thread-all into plug, nut on each end. Leave about an inch sticking out of threaded end of plug. This is adjustable.
Nut on threaded end of plug will be too big. You need to grind of the edges of the flats to make it round.
Insert plug tool.
By hand, slowly, gently turn over engine. Piston will come up, hit thread-all (or bolt) and stop. Make mark on balancer.
Turn engine other direction. Piston will come up, hit thread-all (or bolt) and stop. Make mark on balancer.
Halfway between two marks is TDC.
Most factory balancers I have checked have been within 3-4 deg.
Hope the above makes sense!
keith

[manoa matt]

When Bayless was in Marietta Georgia before they moved to Columbus Ohio they used to sell a performance head gasket that was thicker than the standard one. The price was around $20. I can confirm later tonight when I get home the thickness differences, but I believe it to be around 0.5mm. The only downside to the performance gasket was the lack of a pre-formed silicone gasket around the perimeter.

I don't see it listed on their website, maybe call and ask them, they might have it.

[TulsaSpider]

Ok well after going out and trying a few things I found one of my spark plug wires had come away from the cap that's why it began running poorly. I played around with the timing until I got MOST of the ping to go away... so some progress!...
I have been told that my plug is probably too hot (Champ RN9YC) to try a colder plug RN8YC. Opinions?
What do you guys think about the jetting?
jet next to cam tower 140
jet next to fender 137
Opinions...
Thanks

[manoa matt]

Tulsa wrote: "I have a 34/36 carb. " Do you mean a Weber 32/36 DFEV?

Tulsa wrote: "The top one, that pokes out farther is 0 correct? then 5 btdc then the bottom one is 10 btdc."

Nope, opposite way. 0 deg is the furthest down, 5 in the middle and 10 at the top. That's why when you adjusted the timing it got worse, go the opposite way. I would set the max advance at 32 deg at 3600rpms and not worry about the initial advance.

What type of distributor are you running? If you are running the Marelli Plex distributor it may provide too much advance and too early for a high compression motor. The dual points model may be a better suited advance curve.

[So Cal Mark]

the timing pointer is different on a 2L and 1800. Matt's description is of an 1800. The 2L pointer is on the right side of the engine and is just as Clark described. I was also thinking the advance curve isn't correct. Was it pinging at all rpms under load? Or just at certain rpms? Was it pinging under light load or heavy load, or both?

[pastaroni34]

Grrr why can't the vendors mark their aluminum pulleys...

We normally do not mark our pulleys as it is always more accurate to do it on the assembled engine. It also complicates things that there are different timing marks for different engines, even though their pulleys are interchangeable. Many of our customers don't even use the OEM timing markers!

Anyway, we will happily mark them upon request!

As far as plugs, I agree, you should go colder. There isn't much harm doing so unless you start fouling.

[TulsaSpider]

Yep 2L sorry yes 32/36. Yes I am running the Marelliplex (electronic, no vacuum advance). This is interesting and if it turns out to be the case could I swap out anything like the weights and springs to remedy this? Truthfully I loathe points. I had all kinds of bad luck with them in the past in different cars and in this one too.
It is pinging under load only for example 4th gear with my foot 3/4 in the gas it will ping or in third it will slightly if I have it mashed down. So Mark, heavy load only. Like when the secondaries kick in.
I'll try the colder plugs when I get paid next week. My buddy Kent said try the NGK's in a colder range, recommendation there?
Thanks so much!

[Fiatmonkey]

Yes an NGK V-Power plug would be great! Remember NGK is backwards of other plug brands. The go up in number for a colder plug.

[baltobernie]

I'm running Champion RN6YC (now on sale at Rock Auto for $0.81) in an engine similar to yours. Stock motor uses RN8YC.

[TulsaSpider]

Hmmm well I am running the 9's now. I hope changing them out makes a good improvement!

[SanRafaelFaz]

Instead of starting a new "blown head gasket" thread, I thought I'd just ask here. Got a call today from my mechanic. Said the h/g was indeed blown (I had figured as much), on my '78 1800 Spider, and that he could put it back to gether and "see if it runs". Or my other options are to rebulid or replace. I have only about 40K on this NOS engine over the past 15 years. It sat for several years unused and I'm just now in the process of evaluating if I want to spend the $$$s to restore it.
So, assuming that the car was running otherwise well when the h/g blew, what other problems could there be which would make him even question whether it would run or not after the h/g is replaced? (Head will be shaved as well). I'm not technically astute enough to notice any tiny nuances, but AFAIK, it ran well until the h/g went. I'm $500 in already, and am willing to go another grand to get it back to engine spec.
Thanks for any suggestions/advice/insight.