Replacing Head Gaskets this morning. Question though....
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Replacing Head Gaskets this morning. Question though.... On the Fel Pro 1074 head gasket instruction sheet, it touches on a few things. One is an additional water hole the gasket provides and mentions that you should drill this hole in your block if you don't have it. The reason being is that this is a failure prone area due to overheating since two exhaust valves are beside each other (Cylinders 3/5 on the drivers side, 4/6 on the passenger). Drilling this additional hole helps cool down that region. The literature goes on to state that all LT1 heads have this hole but not all blocks have it. I bought my standard '93 block from a guy on the internet so it probably doesn't have this hole. Oh well. But, then next thing it mentions is that, generally, electric water pumps do not flow enough coolant to remove the heat produced by the engine. This is the one that has me wondering. I've ran electric water pumps since 2000, having used both the Meziere and the CSI iterations. They engine stays cool according to the temp gauge but with the turbo, maybe it's getting overly hot in localized areas such as the aforementioned adjoining center cylinders during boost. Your thoughts?
never heard of it but i never had an lt1 car long enough to change gaskets, call fel pro for more information but they wouldnt go through all the trouble of putting the hole in and doing the instructions without it being helpful.
i know old school small blocks ( 400s i think) had this problem, there was a little spot in the heads that would get hot and keep water boiling. GM put a litltle "steam hole" in the head to keep hot spots from happening, and let off pressure if it did happen. only reason i remember this is because your suppose to drill this hole if you put heads from a smaller CI sbc on a 400 block.
That said i would drill the hole like the paperwork says
That said i would drill the hole like the paperwork says
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Well, Got the turbo off, the turbo log exhaust manifolds off, drained the block and got all the miscellaneous stuff out of the way ready to pull off the intake, then the heads. Just on a whim, I set the click type torque wrench to the base/stock setting of 65 ft lbs to see if any of the head bolts had loosened since I first brought the engine home. About a fourth of them required a bit more turning to get the 'click', and this is just at 65 ftlbs. The ARP spec for these bolts says
"Following the manufacturers recommended torque sequence tighten the bolst in three equal steps to 75ftlbs with ARP MOLY ASSEMBPLY LUBRICANT or torque to 85ft lbs with 30 wt motor oil."
I know you that after you fire up a motor with new head gaskets, you're supposed to let it reach full operating temperature, then let the motor cool completely, then re-torque all the head bolts in order to retain full clamping force. I didn't do this back when I got this motor, and it looks like I'm paying the price for that laziness. Not this time!!! Lol...
Also, just as a note to others. When you retorque the head bolts, don't just go in with the torque setting and try to tighten the bolt right away. Back it off a bit then retorque it.
"Following the manufacturers recommended torque sequence tighten the bolst in three equal steps to 75ftlbs with ARP MOLY ASSEMBPLY LUBRICANT or torque to 85ft lbs with 30 wt motor oil."
I know you that after you fire up a motor with new head gaskets, you're supposed to let it reach full operating temperature, then let the motor cool completely, then re-torque all the head bolts in order to retain full clamping force. I didn't do this back when I got this motor, and it looks like I'm paying the price for that laziness. Not this time!!! Lol...
Also, just as a note to others. When you retorque the head bolts, don't just go in with the torque setting and try to tighten the bolt right away. Back it off a bit then retorque it.
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Here's a pic of my block. I got lucky and this 93 block has the hole already!
Now here's something puzzling. My engine builder said he was going to use the FelPro 1074 head gaskets. However, the gasket I pulled off there doesn't look like the 1074's I just bought. Maybe he used an old version of a 1074 but I *think* this gasket has a different number stamped on it. Here they are side by side. I've highlighted the hole I mentioned the 1074 literature mentioning. Notice it's not on the 'old' gasket.
The old gasket, at least on the drivers side, doesn't have an actual 'break' in the gasket material but it looked a bit eroded nearest Cyl#1 where the gasket ring nears the large cavity on in the 10:30 postion.
Now here's something puzzling. My engine builder said he was going to use the FelPro 1074 head gaskets. However, the gasket I pulled off there doesn't look like the 1074's I just bought. Maybe he used an old version of a 1074 but I *think* this gasket has a different number stamped on it. Here they are side by side. I've highlighted the hole I mentioned the 1074 literature mentioning. Notice it's not on the 'old' gasket.
The old gasket, at least on the drivers side, doesn't have an actual 'break' in the gasket material but it looked a bit eroded nearest Cyl#1 where the gasket ring nears the large cavity on in the 10:30 postion.
Looks like GMPP head gaskets were used at rebuild. They are all black like that.
Look at this one.... and check out the outer shape. Totally different than the Fel-Pro
http://paceperformance.com/index.asp...&ProdID=180531
Look at this one.... and check out the outer shape. Totally different than the Fel-Pro
http://paceperformance.com/index.asp...&ProdID=180531
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Tomorrow with the better light, I'll squint and turn the gasket a few ways to see if I can identify that nearly obliterated part number imprinted on the gasket.
Looks like GMPP head gaskets were used at rebuild. They are all black like that.
Look at this one.... and check out the outer shape. Totally different than the Fel-Pro
http://paceperformance.com/index.asp...&ProdID=180531
Look at this one.... and check out the outer shape. Totally different than the Fel-Pro
http://paceperformance.com/index.asp...&ProdID=180531
