Need some engine advice....

[HEMI-ITIS]

30 with a little and 50 degrees with a lot. For the detonation problems described that runs fine cold and starts to show up when the secondaries kick in...30 degrees should be a big difference. Could probably even run on 89.

1st you need an IAT probe in the intake manifold which I have. Even 50* does not put me where I wish to be with the IAT.
I used 2 fogger nozzles front & rear with a 50/60 nitrous shot under each carb.I'm told the IAT will drop at least 100*

 

[Nate S]

I took the numbers you gave on the sheet and made two assumptions: flat top pistons, .020 head gaskets
I then calculated your compression ratio.
4.638 in^3 = 76cc chamber
.297 in^3 head gasket volume
.149 in^3 piston below deck volume
61.645 in^3 cylinder displacement
Total volume up = 5.083 in^3
Total volume down = 66.728 in^3
66.728/5.083...
This gives 13.1:1 CR

go to a thick .039 gasket and you're at a mere 12.5:1

add in 8cc's of valve clearance pockets maybe? and you're at 11.5:1

No wonder you're knocking!

 

[hunt2elk]

Didn’t you already say it doesn’t ping when the motor is cold?

No, I didn't say that. I never run any of my cars till they are up to operating temp. It pings all the time as soon as the secondaries open. Motor runs at a constant 190 degrees.

 

[hunt2elk]

If you requested a pump gas motor what does the engine builder say? I cant see 180psi ever running on pump gas.
Doug

He won't talk to me, so I don't know what he would say.

 

[hunt2elk]

I took the numbers you gave on the sheet and made two assumptions: flat top pistons, .020 head gaskets
I then calculated your compression ratio.
4.638 in^3 = 76cc chamber
.297 in^3 head gasket volume
.149 in^3 piston below deck volume
61.645 in^3 cylinder displacement
Total volume up = 5.083 in^3
Total volume down = 66.728 in^3
66.728/5.083...
This gives 13.1:1 CR

go to a thick .039 gasket and you're at a mere 12.5:1

add in 8cc's of valve clearance pockets maybe? and you're at 11.5:1

No wonder you're knocking!

These guys on here figure it has .080 head gaskets. Sure wish the builder would talk to me to confirm.

 

[hunt2elk]

Only drive it in the rain with the scoops open Joel! Free water injection.

Hope you get it sorted out, sounds like a lot of good knowledge here helping you forward... while your engine builder hides.

Yeah, I sure do appreciate all the comments. This place is the greatest.

 

[33 IMP]

Your build sheet says: deck height (minus) -.010, cylinder head to piston clearance, .090 . So depending on how you read it, it either has a ten thou positive deck (out of the hole) and a .100 gasket, or it has the normal .010 deck, in the hole, and an .080 gasket. Either way, no effective quench to worry about losing.
(The way i understand practice, a piston that is down in the hole, say .050, is expressed as a ".050 deck height." Therefore a negative deck height has the piston HIGHER than the deck. Supposedly, some late 60s 340s and 383s were factory-built in this manner.

 

[PRHeads]

the only time I could hammer it without knocking with 91 octane was when the engine wasn't up to temperature

I guess that was Kern Dogs build.

The OP’s would likely be the same.

Either way, no effective quench to worry about losing.

Right. It doesn’t matter how you ended up with .090” p/h clearance...... iiwii.

 

[Nate S]

These guys on here figure it has .080 head gaskets. Sure wish the builder would talk to me to confirm.

Recalculated with .080" gaskets, back to flat tops = 11.3:1
with 8cc eyebrows = 10.5:1

 

[hunt2elk]

Your build sheet says: deck height (minus) -.010, cylinder head to piston clearance, .090 . So depending on how you read it, it either has a ten thou positive deck (out of the hole) and a .100 gasket, or it has the normal .010 deck, in the hole, and an .080 gasket. Either way, no effective quench to worry about losing.
(The way i understand practice, a piston that is down in the hole, say .050, is expressed as a ".050 deck height." Therefore a negative deck height has the piston HIGHER than the deck. Supposedly, some late 60s 340s and 383s were factory-built in this manner.

So what are the exact measurements I should ask him if he ever does bother calling me back?
Head gasket thickness?
Is the piston .010 in the hole, or sticking up .010 out of the hole?
What else?

 

[hunt2elk]

I will tell you guys a bit more of the build. Motor arrived with absolutely no paperwork, no dipstick or tube, no breather that I had shipped directly to him from Mancini, and no MSD springs or bushings. He eventually sent me everything except refused to send the MSD stuff, saying that when he sets up a motor he doesn't want anybody changing the distributor advance rate or timing. He finally did send this as well after I called him the first time complaining about the rattling.
The motor was shipped without oil of course, so after it was in the car I dumped in the 6.5 quarts that he recommended. Steady trickle ran down the rear of the passenger valve cover. He had cometic gaskets on it and I could tell just by looking at it that it would never seal decently on these heads. So he calls Mancini and they recommended the blue Moroso's which he had sent to me.
Then as I was raising and lowering the car on the hoist (still not been fired up yet) I notice oil leaking out of a factory weld on the very expensive Milodon Road/Race pan that he talked me into. He says he didn't have a drop of oil leak out of either place when the thing was dyno'd. I called Milodon and they claim they will fix it for free if I send it to them. Told them maybe I would send it to them this winter so they recommended slobbering JB weld on the leak. I did. Looks terrible, but it is dry.
Then the best part. I stipulated that I wanted Harland Sharpe rockers from the beginning. It is in the first couple of emails back to me with his price. Guess what I found when I pulled off the valve covers to replace the gaskets? No Harland Sharpes, but PRW instead. And you guys think you have bad luck...... It is amazing I just don't sell all my junk and buy a Hellcat.

 

[Nate S]

Your build sheet says: deck height (minus) -.010, cylinder head to piston clearance, .090 . So depending on how you read it, it either has a ten thou positive deck (out of the hole) and a .100 gasket, or it has the normal .010 deck, in the hole, and an .080 gasket. Either way, no effective quench to worry about losing.
(The way i understand practice, a piston that is down in the hole, say .050, is expressed as a ".050 deck height." Therefore a negative deck height has the piston HIGHER than the deck. Supposedly, some late 60s 340s and 383s were factory-built in this manner.

I'm glad you called this out. In my ratio calcs I assumed it was down the hole. The numbers are confusing. Add a 1/2 point for above (roughly).

 

[HEMI-ITIS]

He won't talk to me, so I don't know what he would say.

What kinda BULLSHIT is that??

 

[hunt2elk]

What kinda BULLSHIT is that??

View attachment 958483 View attachment 958484 View attachment 958485 View attachment 958486

Exactly. He would always answer the phone or call me right back, until he was paid in full. Still can't believe how great my experience was with him on the first motor he built for me and how absolute terrible this one turned out to be. Kind of crazy that he won't at least email me the couple of dimensions that we are looking for.

 

[dadsbee]

So who got your motor that he ran and dyno'd?.. and who's did you get? Could be his mess and he doesn't have the balls to admit it..

 

[451Mopar]

If you have a bore scope you could look through a spark plug hole to see if the piston is a flat top, and if it is above or below deck at TDC.

 

[hunt2elk]

If you have a bore scope you could look through a spark plug hole to see if the piston is a flat top, and if it is above or below deck at TDC.

I just have a cheap one that hooks to my phone. Couldn't tell much except that there are valve reliefs.

 

[hunt2elk]

So who got your motor that he ran and dyno'd?.. and who's did you get? Could be his mess and he doesn't have the balls to admit it..

That would be interesting wouldn't it?

 

[69 GTX]

Joel I feel your pain! If you have room the Snow performance injection, it might be the cheapest fix. I would put a 160 stat in it just for giggles and try it. Also anything you can do to lower the under hood temp. And finally anything you can do to reduce the fuel temperature. Cool can or insulate fuel lines & phenolic spacer for the carb, to lower carb temperature. Wish I had a week off to come up and help you.

 

[HEMI-ITIS]

Just skimmed through your post. I am surprised that Brian is treating you that way,maybe there is more to that.........
IMO there are now 2 choices,water/meth injection can lower your IAT by up to 50* or a baby shot of nitrous can drop your IAT over 100* on a 90* day!
That is the route I am taking. W/m might be your best bet if nitrous is out of the question. A 50/100 hp is not that much. A cast piston/crank engine can handle that with no issue.