Ai 185cc CNC Heads - First Impression
01-26-2008, 11:42 PM
#1
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Thread Starter
Join Date: Jan 2004
Location: Downey, CA
Posts: 1,406
Ai 185cc CNC Heads - First Impression
Everything has been fine with the installation of the heads, intake and SLP shorty's except
for the coolant line that runs against the header. I've finally got it to the point that I'll
live with it and had a chance to flog the car a little today.
The SOTP meter says WOW! The power band has shifted slightly just as you would think with the
addition of the headers and heads. Lost some torque down low and it just screams up high with
no sense of it laying back at 6k. The most noticable difference is the cold start and manners
before the water temp gets to 160. It's much more finiky now until it gets up to temp, but at
temp it's just like it was before except for the different sound from the SLP shorty's.
I went a different direction with valve springs since I have never liked the spring rate for
the Crane 99893 springs that are recommended on the cam card (Crane 104227). At 391#/in. the
open pressure for the 99893's seemed unnecssarily high to me for a baby cam. I went with the
Crane 96872 spring which has a rate of 326#/in. and about the same closed pressure at 140#.
I switched from 26918 springs with Ti retainers so you can't really do any comparison since
the beehive springs are designed for the lighter LS1 (8 mm) valves and corresponding hardware.
Based on my initial impression this spring combo is working just fine. This spring is ideal
for installed heights in the 1.80 to 1.85 range.
I was surprised to find that when I checked my fuel pressure it was way high @ 50#.
I guess it's something that I'll need to check about once a year. Last time I adjusted
the pressure I set it to 45#. I reset the pressure to 44#.
I'd like to be out driving around but it's raining like a MF out there right now. We'll see how
things go on the dyno in a couple of months, but I'm hopeful for 360 rwhp.
for the coolant line that runs against the header. I've finally got it to the point that I'll
live with it and had a chance to flog the car a little today.
The SOTP meter says WOW! The power band has shifted slightly just as you would think with the
addition of the headers and heads. Lost some torque down low and it just screams up high with
no sense of it laying back at 6k. The most noticable difference is the cold start and manners
before the water temp gets to 160. It's much more finiky now until it gets up to temp, but at
temp it's just like it was before except for the different sound from the SLP shorty's.
I went a different direction with valve springs since I have never liked the spring rate for
the Crane 99893 springs that are recommended on the cam card (Crane 104227). At 391#/in. the
open pressure for the 99893's seemed unnecssarily high to me for a baby cam. I went with the
Crane 96872 spring which has a rate of 326#/in. and about the same closed pressure at 140#.
I switched from 26918 springs with Ti retainers so you can't really do any comparison since
the beehive springs are designed for the lighter LS1 (8 mm) valves and corresponding hardware.
Based on my initial impression this spring combo is working just fine. This spring is ideal
for installed heights in the 1.80 to 1.85 range.
I was surprised to find that when I checked my fuel pressure it was way high @ 50#.
I guess it's something that I'll need to check about once a year. Last time I adjusted
the pressure I set it to 45#. I reset the pressure to 44#.
I'd like to be out driving around but it's raining like a MF out there right now. We'll see how
things go on the dyno in a couple of months, but I'm hopeful for 360 rwhp.
01-27-2008, 10:00 AM
#4
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Thread Starter
Join Date: Jan 2004
Location: Downey, CA
Posts: 1,406
to seeing your car at the dyno.
All in all the head swap went really well. The only hitch was the SLP/coolant line
issue. In hindsight I should have bought some 3/4" aluminum tubing and just bent my
own custom line when the heads were off.
The only surprise I had was related to the oil pump drive. After I pulled the intake
I went to check the bolt and it was only finger tight. The drive was fine, and I'm sure
that I torqued the bolt to 13 ft-lbs so it did not make me happy to find it loose. From now
on the oil pump drive bolt goes in with blue thread locker.
At 49 years old I ran out of steam tightening the head bolts. It was pretty funny
because there were a few that I gave it all I had and just barely got the click out of
the torque wrench. By the 30th bolt I was all sweaty and my arms felt like mush.
The Impala head gaskets are not marked "THIS SIDE UP" like the stock ones and there
is no consensus on which way is up for them. I installed them with the PN facing up
based on info from a knowledgeable LT1 engine builder. I also had to set the intake
twice since I blew it the first time. Been there and done that before. No big deal,
just clean everything up and try it agin.
After lots of reading about thread sealants I decided to go with the GM 12346004 for
the head bolts. I had ARP sealant on hand and that is what I used on the rocker studs
so I'm hoping that they will be fine. I'm glad that I did use the ARP sealant on the rocker
studs because I ended up loosening them after the heads were installed to adjust
the guideplates. With the 7.05" pushrods you are closer to the end of the slot in the
guideplate so I set them as far down as possible to provide the most room.
And speaking of guideplates the GMPP parts that were on the stock heads were
not hardened! I checked the new GMPP guideplates and they are hardened, so
the story that was going around regarding a batch of GMPP guideplates that were not
hardened is true. I had close to .050" wear in some locations and this is after only
5k miles. No wonder I had an increased amount of metal powder on the oil drain magnet.
Jeff Creech did a great job with his tweaks on the PCM for the new setup and Phil/Ron
at Ai were great support during the installation. I can't say enough about the quality
of the workmanship on the heads and intake.
01-27-2008, 11:52 AM
#6
Registered User
Join Date: Mar 2002
Location: Ocala, Florida
Posts: 3,245
Glad to hear its up and running and you are statisfied. Definatly keep us updated on the results. And I wouldn't use the APR sealent on the rocker studs, it was starting to let oil seep through on my old setup.
01-27-2008, 12:21 PM
#7
Registered User
Join Date: Jul 2002
Location: San Diego, CA
Posts: 1,193
I hope all goes will with your stripped gears on the oil pump drive. I'm looking forward
to seeing your car at the dyno.
All in all the head swap went really well. The only hitch was the SLP/coolant line
issue. In hindsight I should have bought some 3/4" aluminum tubing and just bent my
own custom line when the heads were off.
The only surprise I had was related to the oil pump drive. After I pulled the intake
I went to check the bolt and it was only finger tight. The drive was fine, and I'm sure
that I torqued the bolt to 13 ft-lbs so it did not make me happy to find it loose. From now
on the oil pump drive bolt goes in with blue thread locker.
At 49 years old I ran out of steam tightening the head bolts. It was pretty funny
because there were a few that I gave it all I had and just barely got the click out of
the torque wrench. By the 30th bolt I was all sweaty and my arms felt like mush.
The Impala head gaskets are not marked "THIS SIDE UP" like the stock ones and there
is no consensus on which way is up for them. I installed them with the PN facing up
based on info from a knowledgeable LT1 engine builder. I also had to set the intake
twice since I blew it the first time. Been there and done that before. No big deal,
just clean everything up and try it agin.
After lots of reading about thread sealants I decided to go with the GM 12346004 for
the head bolts. I had ARP sealant on hand and that is what I used on the rocker studs
so I'm hoping that they will be fine. I'm glad that I did use the ARP sealant on the rocker
studs because I ended up loosening them after the heads were installed to adjust
the guideplates. With the 7.05" pushrods you are closer to the end of the slot in the
guideplate so I set them as far down as possible to provide the most room.
And speaking of guideplates the GMPP parts that were on the stock heads were
not hardened! I checked the new GMPP guideplates and they are hardened, so
the story that was going around regarding a batch of GMPP guideplates that were not
hardened is true. I had close to .050" wear in some locations and this is after only
5k miles. No wonder I had an increased amount of metal powder on the oil drain magnet.
Jeff Creech did a great job with his tweaks on the PCM for the new setup and Phil/Ron
at Ai were great support during the installation. I can't say enough about the quality
of the workmanship on the heads and intake.
to seeing your car at the dyno.
All in all the head swap went really well. The only hitch was the SLP/coolant line
issue. In hindsight I should have bought some 3/4" aluminum tubing and just bent my
own custom line when the heads were off.
The only surprise I had was related to the oil pump drive. After I pulled the intake
I went to check the bolt and it was only finger tight. The drive was fine, and I'm sure
that I torqued the bolt to 13 ft-lbs so it did not make me happy to find it loose. From now
on the oil pump drive bolt goes in with blue thread locker.
At 49 years old I ran out of steam tightening the head bolts. It was pretty funny
because there were a few that I gave it all I had and just barely got the click out of
the torque wrench. By the 30th bolt I was all sweaty and my arms felt like mush.
The Impala head gaskets are not marked "THIS SIDE UP" like the stock ones and there
is no consensus on which way is up for them. I installed them with the PN facing up
based on info from a knowledgeable LT1 engine builder. I also had to set the intake
twice since I blew it the first time. Been there and done that before. No big deal,
just clean everything up and try it agin.
After lots of reading about thread sealants I decided to go with the GM 12346004 for
the head bolts. I had ARP sealant on hand and that is what I used on the rocker studs
so I'm hoping that they will be fine. I'm glad that I did use the ARP sealant on the rocker
studs because I ended up loosening them after the heads were installed to adjust
the guideplates. With the 7.05" pushrods you are closer to the end of the slot in the
guideplate so I set them as far down as possible to provide the most room.
And speaking of guideplates the GMPP parts that were on the stock heads were
not hardened! I checked the new GMPP guideplates and they are hardened, so
the story that was going around regarding a batch of GMPP guideplates that were not
hardened is true. I had close to .050" wear in some locations and this is after only
5k miles. No wonder I had an increased amount of metal powder on the oil drain magnet.
Jeff Creech did a great job with his tweaks on the PCM for the new setup and Phil/Ron
at Ai were great support during the installation. I can't say enough about the quality
of the workmanship on the heads and intake.
Sounds like a good time. Whenever I get deep into a motor, it's always the small tasks that take the most work. I was glad my motor was out of the car when I put my head bolts in, they are no fun when you are contorting inside the engine bay. I've been there with miss setting of the intake manifold. I don't even try it alone anymore, I have to call friends for that.
01-27-2008, 02:07 PM
#9
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Thread Starter
Join Date: Jan 2004
Location: Downey, CA
Posts: 1,406
It's a TPIS regulator.
Last edited by truedualws6; 01-27-2008 at 04:38 PM. Reason: Corrected ICL to LSA
01-27-2008, 03:16 PM
#11
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Join Date: Apr 2006
Location: O'Fallon, MO
Posts: 1,083
01-27-2008, 10:49 PM
#15
Registered User
Thread Starter
Join Date: Jan 2004
Location: Downey, CA
Posts: 1,406
That brings back memories of a night back in 1982 when a good friend of mine
was all pissed off because his girlfriend broke up with him and he was driving
his 1969 Cougar down my block and decided light them up as he passed, only to
go into a drift right into my 1968 GTO. He plowed the front drivers side and
kept going right into a crepe myrtle tree, which he also knocked down.
When I saw the photo of the C6 it was like a flashback to the boom, when
the Cougar hit my GTO. Amazing how things jog your memory. The C6 looks a
lot worse though, and a 1968 "A" body is a tank in comparison. In addition to
paying for my car my buddy had to pay $800 for a replacement tree. Hopefully
things will work out between CAM and the C6 owner.
was all pissed off because his girlfriend broke up with him and he was driving
his 1969 Cougar down my block and decided light them up as he passed, only to
go into a drift right into my 1968 GTO. He plowed the front drivers side and
kept going right into a crepe myrtle tree, which he also knocked down.
When I saw the photo of the C6 it was like a flashback to the boom, when
the Cougar hit my GTO. Amazing how things jog your memory. The C6 looks a
lot worse though, and a 1968 "A" body is a tank in comparison. In addition to
paying for my car my buddy had to pay $800 for a replacement tree. Hopefully
things will work out between CAM and the C6 owner.