using iron head gaskets for alum heads on a 2.8/3100 hybrid

[sil]

[post edited]
possible ?
boost compression ?

if so, by how much, pros and cons na/turbo/boost? hp increase ?

im running a cam with (if i can locate my 1.6 roller tips) .469 lift

are there any modifications that i will need to do to the gasket ?

thanks in advance for all the help you guys are giving me
my first swap, so its kind of shady :P

[Doubt_Incarnate]

it depends on the pistons used, if the pistons are the low output pistons, .036" down the bore at tdc, then you might be ok, but you have to use the aluminum head gaskets for the 3.1 fwd or 3X00 motors or your compresion will be well over 12:1. if you can get the pistons from a 2.8 with aluminum heads, you'll be safer, and can use the steel heads gaskets. that would be somewhere around 9.3:1. the fwd 2.8's with aluminum heads had a 8.9:1 i think and that would be friendly for boost if you plan to go that way later.

[Rhedalert]

iron heads?

[v6h.o.]

Is it an Iron head block or an alum head block?

You will have no issues with piston to valve clearance with the thinner gasket even with that amount of lift.
I have much higher lift and I use the Iron head gasket with my severly milled down alum heads with no issues.

The change from the .060 thick gen2/3 gasket to .040 thick gen1 gasket is worth about .3-.4 or so compression change.

[sil]

it depends on the pistons used, if the pistons are the low output pistons, .036" down the bore at tdc, then you might be ok, but you have to use the aluminum head gaskets for the 3.1 fwd or 3X00 motors or your compresion will be well over 12:1. if you can get the pistons from a 2.8 with aluminum heads, you'll be safer, and can use the steel heads gaskets. that would be somewhere around 9.3:1. the fwd 2.8's with aluminum heads had a 8.9:1 i think and that would be friendly for boost if you plan to go that way later.

yes i have the 2.8 with aluminum heads and dome pistons




now im confusled

when i had my 2.8 (out of a 1988 olds) rebuilt last summer, the machine shop told me that in order to use the 1.6 roller tip rockers i needed to get the pistons custom ground to make clearance for the valves.

he also told me that i needed to get custom length pushrods and had to go with the "adjustable" rocker bolts, he said the geometry would be off or somthing.???

and comp cams said that was the biggest cam i could fit in that motor due tolow tc stall, but if i had higher stall tc, or a standard tranny he said i could go bigger.

do you guys have problems with piston to valve clearance on the 2.8 aluminum heads, with dome pistons??

somthing is not adding up here

also, the reason why i had to take the 1.6 roller tips off was becuase the pushrod guides bent and nearly wrecked my topend, they slid off the valve stem on a couple valves.

i had the comp cam double springs installed as well.

is there anyone from winnipeg that wouldnt mind looking at it to see whats up, this is frustrating me

[v6h.o.]

Dome or Dish pistons?

I have yet to see a Dome'd aftermarket off the shelf 60v6 piston.

A domed piston with Alum heads would give you stupid CR, as flattops with the small chamber alum heads gives you over 13:1

You have the same amount of clearance from Piston to valve with Dished as you do with flattops on aluminum heads as the splayed valves will contact the outer edge of the piston.

in the area's in red:


I run a camshaft with 1.6's that gives me .469 inch lift. I have .020 thinner head gaskets and .040 was taken off my heads (long story, I know they should only be cut .018 Max)
Still had heaps of clearance.

As well the new performance cams for the 3400's coming out have over .540 inch lift with stock pistons. you will be fine if you are using flattop or dished pistons.

[sil]

i'll take a picture of my pistons in the block at tdc for you guys

the area taken off was the area where you marked the picture in red

perhaps the 3x00 heads give more clearance than the 2.8 heads, which is why im confused

[sil]

pics (click for fullsize)

measured in the cutaway


highlighting the cutaway

Dome or Dish pistons?

i guess they are dished, my bad

I run a camshaft with 1.6's that gives me .469 inch lift. I have .020 thinner head gaskets and .040 was taken off my heads (long story, I know they should only be cut .018 Max)
Still had heaps of clearance.

ya my bad.
im running:
comp cam k-16-233-4-260H
260/260 AD - 212/212 @ .050 - 440/440 lift - 110* ls
with the 1.6 roller tips it makes it:
260/260 AD - 213/213 @ .050 - 469/469 lift - 110* ls

As well the new performance cams for the 3400's coming out have over .540 inch lift with stock pistons. you will be fine if you are using flattop or dished pistons.

who will be making these cams ? and will they be compatable in a 2.8 block ?

[Doubt_Incarnate]

i dont think 3x00 cams will work in the older block, i think the lobes and races dont line up properly.

with those pistons, you can use the 3x00 heads with iron head gaskets and get about 9.3:1 cr

[farmerz24]

so who makes the .540 lift cam???? also i thought the valves move in towards the center of the piston as they go down?

[bszopi]

You can go through Milzy Motorsports or get the cam directly from Cam Motion if you design your own profile.

[v6h.o.]

so who makes the .540 lift cam???? also i thought the valves move in towards the center of the piston as they go down?

Yeah Milzy's motorsports has that cam Chris.

The valves are angled in such a way that they do angle inwards on the cylinder but due to the placement of them and the location of where they angle the valve hits the outer edge of the piston right at that spot first.

[v6h.o.]

As well the new performance cams for the 3400's coming out have over .540 inch lift with stock pistons. you will be fine if you are using flattop or dished pistons.

who will be making these cams ? and will they be compatable in a 2.8 block ?

The 3X00 roller cams do not work in the old blocks due to the oiling system between gen2 and 3 is setup different. Gen3 blocks have the proper oil galleries to run hydraulic Roller lifters.

On our gen2 blocks we can only run flat tappet Hydrualic lifters Or, solid roller lifters from Crane.