looks like im pulling the motor apart already

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Sounds like someone needs to know, do some measuring, for piston depth at tdc.
 
ou812 said:
If it's detonating he'll be doing this again!
Click to expand...

I dont know what happen Brian, but the pistons are not in the hole. He had 9.7 compression with a 260@50 cam. Running 91 octane at 7.2-7.7 DCR, I really doubt he was detonating..I ran this exact cam with 10.7 compression and ran 91 and didnt blow a head gasket. I honestly think he did not torque the head bolts correctly, but if he detonated then I have no idea why with that little compression at zero deck and that big of a cam.
 
With -17.5cc dish pistons, zero deck, 62cc chambers, and typical .040 gasket his compression is 10.5:1 which is more than enough to detonate with ANY camshaft if he got a bad batch of pump gas or old gas...
And that's if his timing was perfect. Guys don't realize with iron heads once you go over 10:1 even with good quench you have the potential for detonation using PUMP gas. And where the cam was installed has an impact on that as well.

You say his machinist told him it's zero decked...CHECK it yourself!!

I'm just sayin.....
 
ou812 said:
With -17.5cc dish pistons, zero deck, 62cc chambers, and typical .040 gasket his compression is 10.5:1 which is more than enough to detonate with ANY camshaft if he got a bad batch of pump gas or old gas...
And that's if his timing was perfect. Guys don't realize with iron heads once you go over 10:1 even with good quench you have the potential for detonation using PUMP gas. And where the cam was installed has an impact on that as well.

You say his machinist told him it's zero decked...CHECK it yourself!!

I'm just sayin.....
Click to expand...

Sounds good Brian, You are the man, I was just going off the build that MRL built for me with a 360 and figured it would be less effect for him because its a 410. But Im sure he will go through it correctly as the machinist also put the bottom end together for him. He just NOW wants to go to a .040 gasket because the ones he blew out were .053
 
ou812 said:
With -17.5cc dish pistons, zero deck, 62cc chambers, and typical .040 gasket his compression is 10.5:1 which is more than enough to detonate with ANY camshaft if he got a bad batch of pump gas or old gas...
And that's if his timing was perfect. Guys don't realize with iron heads once you go over 10:1 even with good quench you have the potential for detonation using PUMP gas. And where the cam was installed has an impact on that as well.

You say his machinist told him it's zero decked...CHECK it yourself!!

I'm just sayin.....
Click to expand...

Had a guy come up to me at a gas station yesterday and said I had a good sounding car. He went on to ask if I was running race gas. Nope. He said a local (not such a good IMO) speed shop had built him a 11.5-1 CR engine with alum heads, ferd or chebby I didn't pay much attn. I mentioned the price of 110 race gas and told him how well the fish runs on 93. Kinda let the wind outta his sails. Poor guy.

Funny how a purple 508 cam and 3" flowmaster 40s will bring them out.
 
I hear the strokers like to run32* is this a true statement?? with a locked dizzy ?mine isn't locked but plan on it I'm going to check the deck height to make sure it's at 0 if not I'll have to make up for it with thinner gasket (also have a talk with my machinist) .i mean 100 is like$7+ here I run 91 all day and ran it in my belvedere wat are some signs of detonation?
 
If you lock it out, it will want to detonate easier! I'd make sure you end up with as close to .040 piston to head clearance as possible, leave the advance curve in it, don't up the compression just clean the heads with as light of a cut as possible.
Anywhere from 32-34 total advance is fine, just make sure you rev it up high enough...I've seen MSD dist. and MP dist. need as much as 3800rpm before they quit advancing!!

Make sure you chamfer the chamber where it meets the deck all the way around the chamber...lightly.
What plug are you running?
 
moper said:
Run a tap in all holes put a very small amount of oil on bolt threads this helps the torque read right. also the torque sequence is critical.
Use a good torque wrench that is calibrated.

Measure and measure again if you are getting your heads resurfaced witch I suggest you do that will change the clearance.

Head bolts do stretch good bolts are very important.
Click to expand...
 
ou812 said:
If you lock it out, it will want to detonate easier! I'd make sure you end up with as close to .040 piston to head clearance as possible, leave the advance curve in it, don't up the compression just clean the heads with as light of a cut as possible.
Anywhere from 32-34 total advance is fine, just make sure you rev it up high enough...I've seen MSD dist. and MP dist. need as much as 3800rpm before they quit advancing!!

Make sure you chamfer the chamber where it meets the deck all the way around the chamber...lightly.
What plug are you running?
Click to expand...

I'm running the fr5 plugs. So what head gasket thickness would you rec , if I'm at 0 deck?? And your saying to not lock it out and leave it how it came?
 
Ridge said:
Run a tap in all holes put a very small amount of oil on bolt threads this helps the torque read right. also the torque sequence is critical.
Use a good torque wrench that is calibrated.

Measure and measure again if you are getting your heads resurfaced witch I suggest you do that will change the clearance.

Head bolts do stretch good bolts are very important.
Click to expand...

Are you saying use oil instead of the stuff that came with the arp bolts?
 
If you drive it hard, I'd run a bcp6es plug. I'd run a .039 felpro if it's true zero. Yes leave the timing curve in the dist. I like to use the light silver and light blue together in place of the heavy silver springs.
And yes check that the bolts don't bottom out in the block.
 
ou812 said:
If you drive it hard, I'd run a bcp6es plug. I'd run a .039 felpro if it's true zero. Yes leave the timing curve in the dist. I like to use the light silver and light blue together in place of the heavy silver springs.
And yes check that the bolts don't bottom out in the block.
Click to expand...

Is that.039 crushed thickness??
 
those 8553pt gaskets are .045 compressed and run.
I ran 165-170psi cranking ' 9.9 static' with those head gaskets and had no issues.
I used 91 octane, quench domes w/open chamber heads around .037 q/d and 24* initial & 32* total timing.

140psi is weak, but the cam is bleedin it too..., so doesnt mean it cant detonate up top...but just maybe the tune was crap.
 
1wild&crazyguy said:
those 8553pt gaskets are .045 compressed and run.
I ran 165-170psi cranking ' 9.9 static' with those head gaskets and had no issues.
I used 91 octane, quench domes w/open chamber heads around .037 q/d and 24* initial & 32* total timing.

140psi is weak, but the cam is bleedin it too..., so doesnt mean it cant detonate up top...but just maybe the tune was crap.
Click to expand...

When I did the first compression test my rings weren't even seated yet, not sure how big a difference that makes I'm sure to some extent it does
And car wasnt really professionally tuned either
 
ou812 said:
If you drive it hard, I'd run a bcp6es plug. I'd run a .039 felpro if it's true zero. Yes leave the timing curve in the dist. I like to use the light silver and light blue together in place of the heavy silver springs.
And yes check that the bolts don't bottom out in the block.
Click to expand...

Hey so I measured my deck and it is at 0 , also got my heads back from shop yesterday,he took off.004 and checked all valves to make sure they were sealing up all the way, now is that .039 a compressed thickness ? Also what bore diameter would I need if my cylinder bore is 4.040? Would you recommend a different camshaft? Cause the one I have is bleeding out pressure?? Want to make sure this is the last time I have to do this for a long time thanks


Also Brian I'm using the bolts you sent me with the heads so they shouldn't bottom out right??
 
dustya_383 said:
Also Brian I'm using the bolts you sent me with the heads so they shouldn't bottom out right??
Click to expand...


Each block can be different. You should check to make sure they don't bottom and make sure the threads are cleaned and tapped prior to assembly. On the lubricant - I would either get a torque spec from ARP, or use 30wt oil on the bolts and the factory torque spec/sequence/steps. The ARP lube will allow the bolts to preload more before they reach the spec than 30wt oil will. Also make sure if washers are used on the head bolts that you lube the washer on both sides too.
 
dustya_383 said:
Hey so I measured my deck and it is at 0 , also got my heads back from shop yesterday,he took off.004 and checked all valves to make sure they were sealing up all the way, now is that .039 a compressed thickness ? Also what bore diameter would I need if my cylinder bore is 4.040? Would you recommend a different camshaft? Cause the one I have is bleeding out pressure?? Want to make sure this is the last time I have to do this for a long time thanks


Also Brian I'm using the bolts you sent me with the heads so they shouldn't bottom out right??
Click to expand...

Why not just use ARP studs....they are stronger AND you don't have to worry about them bottoming out causing false torque issues.
 
dustya_383 said:
Hey so I measured my deck and it is at 0 , also got my heads back from shop yesterday,he took off.004 and checked all valves to make sure they were sealing up all the way, now is that .039 a compressed thickness ? Also what bore diameter would I need if my cylinder bore is 4.040? Would you recommend a different camshaft? Cause the one I have is bleeding out pressure?? Want to make sure this is the last time I have to do this for a long time thanks


Also Brian I'm using the bolts you sent me with the heads so they shouldn't bottom out right??
Click to expand...

Personally I think it was detonating. Now if you go with the 1008 felpro gasket, you'll have proper quench and that should take care of that. Leave the advance curve in the dist., set total timing at 33°, use the bcp6es plug (stock #4930), and set lash hot at .018 and see what she does.
 
flyfish said:
Why not just use ARP studs....they are stronger AND you don't have to worry about them bottoming out causing false torque issues.
Click to expand...

Yeah but in the car the brake booster can get in the way.

True, some studs have a hex on top so you can tighten-remove them easily.

He really should no need studs for a street engine on pump fuel. 12--13 to 1 compression, yes studs are a good idea.

They might not have trouqe the heads down-right or enough, that is why mine blew
 
ou812 said:
Personally I think it was detonating. Now if you go with the 1008 felpro gasket, you'll have proper quench and that should take care of that. Leave the advance curve in the dist., set total timing at 33°, use the bcp6es plug (stock #4930), and set lash hot at .018 and see what she does.
Click to expand...

Ok the cam spec for lash is .022 is it ok to close lash to.018?? I'll get the 1008 gaskets and and those plugs get timing set right then hopefully this will solve my problem
Thanks guys
 
closing to .18 will give more cranking compression and lift
 
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