304 304 tickle up

[Deuce]

So it is a standard stroke motor and not a factory stroker?

being a 195i standard I would say so.

but if he has shaved heads .020" than 9.2 or 9.3:1cr may be what it is at. thinner head gasket may bump it up a little again too. so maybe 9.6:1 at a guess??

 

[Cava454]

Porting and polishing heads doesn't effect compression. 0 decking the block, piston change, thinner/thicker head gaskets and milling heads, which alters the combustion chambers, change the overall compression.

The 195i isn't the stroker either it's a 304. The vt roller 304 had a bees dick more compression then the non roller. Pretty sure it was 8.8 vs 8.4

 

[383 hatch]

MY ENGINE---- View attachment 150930
As mentioned before I have the Crane 888241 in my 304. If I don't have that sort of compression ratio how come the specs on the cam demand that. See below.

https://shop.rocketindustries.com.au/products/CR888241

Part No:
CR888241
Description:
Hydraulic Roller Camshaft - Holden with EFI Heads
226/230° @ .050", 110 LSA, .569"/.580" Valve lift w/1.65 rocker arms
Fair idle. Moderate performance usage. Good mid range torque & horsepower. Street & bracket racing. Auto trans with 3000 + converter. 9.5 - 10.5:1 comp. BASIC RPM 2800-6200

Just because the cam specs specify what sort of compression you NEED to work at its optimum doesn't mean your engine has 10:1 compression.

As Cava said, porting and polishing won't bring the compression up. However, it can lower the compression slightly if the chambers are cleaned up as material would have been removed. My guess would be that the compression would be in the low to mid 9 region, if there has been no bottom end work done i.e. flat top pistons. Even 9.5:1 would be a stretch by just shaving the heads. Shaving heads is also a half arsed way of raising compression anyway IMO.

 

[97VTSS]

Just because the cam specs specify what sort of compression you NEED to work at its optimum doesn't mean your engine has 10:1 compression.

As Cava said, porting and polishing won't bring the compression up. However, it can lower the compression slightly if the chambers are cleaned up as material would have been removed. My guess would be that the compression would be in the low to mid 9 region, if there has been no bottom end work done i.e. flat top pistons. Even 9.5:1 would be a stretch by just shaving the heads. Shaving heads is also a half arsed way of raising compression anyway IMO.

Oh dear Oh dear. There is always someone out there trying to shoot you down in flames isn't there. So you are saying machining or milling heads serves no purpose at all unless the heads are warped or damaged in some way and in that case they are probably ready for the scrap heap anyway. I know porting and polishing wont bring up the c/r. I just mentioned that as part of the work that has been done.

 

[Cava454]

Oh dear Oh dear. There is always someone out there trying to shoot you down in flames isn't there. So you are saying machining or milling heads serves no purpose at all unless the heads are warped or damaged in some way and in that case they are probably ready for the scrap heap anyway. I know porting and polishing wont bring up the c/r. I just mentioned that as part of the work that has been done.

No one is shooting u down. We're just merely mentioning that u don't have the comp u think u have with the mods u have done.

His saying people with stock 304's who shave 60,70,80 thou or what not to bump the comp up are just doing it the dodgy way. Which they are. If ur running a cam that needs 10:1 comp its rebuild time. Simple as that.

 

[383 hatch]

Oh dear Oh dear. There is always someone out there trying to shoot you down in flames isn't there. So you are saying machining or milling heads serves no purpose at all unless the heads are warped or damaged in some way and in that case they are probably ready for the scrap heap anyway. I know porting and polishing wont bring up the c/r. I just mentioned that as part of the work that has been done.

I didn't say shaving the heads serves no purpose at all. I just said that to me, shaving a heap off the head surfaces isn't the right way to go about raising compression. The right way to go about it is to rebuild the engine with a set of flat top pistons, 0 deck the block then mabye just take a light skim off the heads to get the comp exactly where you want it. That way, atleast the heads have another rebuild or two left in them. Taking heaps off the heads just wrecks a perfectly good set of heads as there will be no room for further rebuilds (especially if down the track you decide to do it properly and fit flat top pistons).

I'm not trying to shoot you down at all.

 

[97VTSS]

Found out a bit more about the car. Apparently the person who owned the car before me had the top end done. He had the block 0 decked bigger throttle body and so on and modified heads as well. But he reverted it back to stock before he sold it so he could use the heads and other parts on another project. Obviously he couldn't de-deck the block, so I was the winner there. As far as I know the pistons are standard. So obviously the C/R is alot higher than normal.

What would it cost to stoke it. Crank, Pistons and so on.....????

 

[ajvx01]

Seems odd they didn't swap the pistons out as they 0 decked the block?

 

[97VTSS]

Yeh does seem a bit odd doesn't it. But as i said, thats as far as I know. Maybee he ran out of cash. Maybee he's a donkey. Maybe they are flatties I don't know. One of lifes little mysteries. Maybe i got lucky and he left 'em in if they are flatties, but i'm not about to pull the heads off just to check that. Not in the foreseeable futre anyway. haha.
I will up load a video of it idling tomorrow on this thread. Tell me what you think of it.

 

[Cava454]

If there is one thing I've learned about work done to vehicles by previous owners is never assume the best.

Sounds suss that he has pulled it back apart. Logic behind it is point less...you won't know unless u pull it apart.