20v bt wif svt piston

[Sam-Q]

how did you end with such a high compression ratio? did you shave the head?

or perhaps the better question is how did you measure it?

 

[nappx]

workshop secret receipy..

 

[chinozie]

yup...slightly skimmed it a little bit just to compensate the metal gasket...

 

[Sam-Q]

so did you actually measure the chamber size with burette or your just estimating where it's at?

 

[chinozie]

estimate it...

I don't think any engineering shop here do that attention to details...correct me if there's any shop doing that...plus I even a bit skeptical about how they do the full engine balancing...again, attention to details...

I just gave the spec details to my mech...putting my trust on him...and he did delivered it...

 

[Sam-Q]

I also don't know the exact process of how they balance an engine and I am also suspicious because if you send your parts off you can see drill marks but if they assemle the engine who is to know?

I think you will find if you measured your engine it would be 10.5:1, it won'tbe over 12 unless you shaved off something like a whole mm

 

[chinozie]

I also don't know the exact process of how they balance an engine and I am also suspicious because if you send your parts off you can see drill marks but if they assemle the engine who is to know?

I've also never seen it.
The marking just to balanced it out, similar like wheel balancing, instead of adding the balancer, they skim it out...just like the drilled hole shown on picture below :

the method may be the same, but how precise the do it into how many miligrams :D

some info we'll can read :

Engine Balancing By Eddies Performance:Eddies Performance Motors-High Performance Engines, Crate Engine, Racing Engine Builder, Rebuilt Motor:

I think you will find if you measured your engine it would be 10.5:1, it won'tbe over 12 unless you shaved off something like a whole mm

Not just that...it's added by rebore the engine cylinder based on the piston size, hooning it, new psiton rings, skimmed engine head, thinner gasket...well you know it...all sealed thigh...like a virgin...

 

[Veloc]

I've read about this being done in another forum. The reason being they want to turbocharge it and the svt con rods are favoured because of its thickness.

 

[Sam-Q]

chinozie: let me rephrase, I know how they can do the drilling and even add weights if really needed but I don't know how the balancing machine looks. My main point is that you can easily tell if a crank has had some attempt at balancing if you see it before and after however if an engine builder is given and engine and told to do it during the rebuild how would you know or even if it was done after the engine is back together. Or how well it was done? thats what I was refering to when say I get suspicious of it not being done right. All those engine mods you mention are all good, I have them myself but it still won't get you more than 10.5:1. So have you got a good tune on it? it would love a heap of advanced timing.

Veloc: blacktop rods although tiny compared to silvertop are still very solid compared to other rods and I see it being quite unlikely that any level of boost would cause them to bend. Revs kills rods unless it's an engine with a very low redline originally and has miniscule rods to suit it. The local to where I am Ford turbo 4L 6-cylinder is a good example of that. So they had the right intentions but probably an un-nessesary step. Also it brings up the issue of piston stength.

 

[chinozie]

Sam-Q - my bad...I've just called my mech...it wasn't 12...it was 16 !!!...much more higher... :D

he used to overhauled and modded the engine...even finish for 12 hours endurance race...
plus he said...most of the engine he overhauled it...get above 15...

Yes, I would say that the mech did a good tune on it...

 

[Veloc]

Veloc: blacktop rods although tiny compared to silvertop are still very solid compared to other rods and I see it being quite unlikely that any level of boost would cause them to bend. Revs kills rods unless it's an engine with a very low redline originally and has miniscule rods to suit it. The local to where I am Ford turbo 4L 6-cylinder is a good example of that. So they had the right intentions but probably an un-nessesary step. Also it brings up the issue of piston stength.

Maybe they just doing it for safety la... I guess its because they want to boost it but do not want to sacrifice the high revving nature. So better be safe then sorry... They didn't mention the amount of power they were trying to achieve la... But I guess below 300 hp? Because there are 300 hp 4AGE there but they use GZE crank, rods and piston on them.

---------- Post added at 04:17 PM ---------- 6 hour anti-bump limit - Previous post was at 04:15 PM ----------

so did you actually measure the chamber size with burette or your just estimating where it's at?

Wow Sam-Q! You are very scientific man... Why not just use a compression gauge. Will the reading deflect a lot from the actual volume? I guess not. If using a burette, how to drain the water off the combustion chamber after that?

 

[levin818]

Chin, are you referring to the max pressure at the combution chamber?
I think this is diff with compression ratio.

 

[chinozie]

Oppsss...it was pressure at the combution chamber

---------- Post added at 03:32 PM ---------- 6 hour anti-bump limit - Previous post was at 03:26 PM ----------

owh yaaa...forget about those 2 differences... :D

Thanks levin818...

 

[pcmoddingmy]

Guys, there's a formula to calculate the CR: Compression ratio - Wikipedia, the free encyclopedia

Hope it helps ;)

 

[zmays]

roughly if compression ration reduced from 10.5:1 to 10.1:1 how much the hp will be effected?