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Author Topic: Camshafts  (Read 1414 times)

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Doctor Gollum

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Re: Cmashafts
« Reply #30 on: 03 April 2018, 00:50:31 »

A proper gearbox makes even a 3.2 estate a sub 7 second car... Presuming you know how to drive it... ::)
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TheBoy

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Re: Cmashafts
« Reply #31 on: 03 April 2018, 17:55:38 »

A proper gearbox makes even a 3.2 estate a sub 7 second car... Presuming you know how to drive it... ::)
Shame GM never fitted a proper gearbox to any Omega-B, just a relic from one of Dr Beechings leftover signal boxes...

...which makes the archaic autobox seem modern ;)
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laney101

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Re: Cmashafts
« Reply #32 on: 05 April 2018, 02:56:06 »

i always chase more torque .. low to midrange is the best as were you use it the most...  but gaining BHP also helps... mild reprofiling cams wont make drastic changes just help a little.

ported heads, manifolds etc again aid airflow and increase torque and bhp

raised compression again more power albeit very small amount considering only raising to 10.8/11.1 depending on what i feel like

none of mods will drastically loose low end power yes will obvioulsly move slightly  by product of tuning unless cc increase or using forced indcution but be ok
as said if can get another 40bhp (peak) that means through out rev range should increase power leading up to peak outputs.

for troque n/a cc is king. hence a tuned 2.5 as stated can put out 200bhp but still wont feel as torquey as a 3.0 becuase it isnt.. the torque peak be higher and more peaky.
would be great if could get oversized pistons for 3.2  and get to 3.3/3.4... who knows maybe further down road something to look at hahaha


apologies on later vecs running 4xA Cams  cheers for correcting

you want to start with the best cams you can for regrinding as the profiles are all slightly different. so sending j instead of a cams may yeild a slightly different re profile shape due to the original shape.

Just a thought. Any benefit in changing the pistons?

The 3.2 ones have indentations in the crowns to reduce compression .... (part of the green save the trees brigade etc)


ive not mentioned pistons not sure what your actually asking.. i already have 3.2
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aaronjb

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Re: Cmashafts
« Reply #33 on: 05 April 2018, 08:44:10 »

I think James is suggesting a switch to flat-top pistons (3.0?) for increased compression ratio
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JamesV6CDX

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Re: Cmashafts
« Reply #34 on: 05 April 2018, 09:51:02 »

ive not mentioned pistons not sure what your actually asking.. i already have 3.2

The 3.2 has a big dish in the piston which is intentionally there to lower compression.

The 3.0 model doesn’t have this.

I was suggesting that if you could source a suitable set of pistons without the dish, it would be an easy compression gain

It would also be a good opportunity to clear out the sump and replace the big end shells - ideal moves if you’re trying to max out performance
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tunnie

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Re: Cmashafts
« Reply #35 on: 05 April 2018, 10:51:14 »

ive not mentioned pistons not sure what your actually asking.. i already have 3.2

The 3.2 has a big dish in the piston which is intentionally there to lower compression.

The 3.0 model doesn’t have this.

I was suggesting that if you could source a suitable set of pistons without the dish, it would be an easy compression gain

It would also be a good opportunity to clear out the sump and replace the big end shells - ideal moves if you’re trying to max out performance

If I had the ability/knowledge to be changing pistons on an engine for more performance, I'd put the V6 in the bin and source a LS1 V8 to go into the engine bay instead.  8)
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Re: Cmashafts
« Reply #36 on: 05 April 2018, 10:58:40 »

Its a dish, not big by any means, and easily addressed by using ported heads from a 2.5/2.6 with smaller squish area.

Laney is going the right way, worthy of note is that the G cams have a slightly longer opening duration than the other cams and a slightly more aggressive opening/closing profile, hence them being the better option (although its very questionable if it makes an impact on the exhaust side given the dynamics of the exhaust stroke......although with tubular manifolds there maybe some gain to be had).

All the 3.0/3.2 cams have the optimum lift, increasing this wont give a benefit unless you were to fit larger valves as it results in a curtain area that equals (its actually slightly larger) the valve seat area. The 2.5/2.6 was effectively throttled by using a smaller inlet port and lower lift cams (hence the fitting of 3.0 cams and inlet divider plus some part matching brings 20ish bhp benefit on these).

Exhaust manifolds have always been crap, the pressed steel items from the 2.6/3.2 are better than the cast versions on the 2.5/3.0.

The best 'from stock parts' was always a 3.2 block with 2.5/2.6 heads (ported) with 3.0/3.2 inlet manifold, 2.6/3.2 exhaust manifolds, 2.5/3.0 front pipes and 3.0 engine management on G/A cams, any improvements based on this starting point are going to yield better results.

Crack on I say as it will be cheaper than any other option and far more interesting.
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deviator

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Re: Cmashafts
« Reply #37 on: 05 April 2018, 11:13:33 »

Crack on I say as it will be cheaper than any other option and far more interesting.
This ^^.  :y

Might I add, I have seen mentioned adjusting the timing a tooth or two has had a positive effect on a rolling road, I just can't find it now. Please note, I don't recommend this unless you know exactly what you are doing.
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Nick W

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Re: Cmashafts
« Reply #38 on: 05 April 2018, 15:30:59 »

Crack on I say as it will be cheaper than any other option and far more interesting.
This ^^.  :y

Might I add, I have seen mentioned adjusting the timing a tooth or two has had a positive effect on a rolling road, I just can't find it now. Please note, I don't recommend this unless you know exactly what you are doing.


Having all four cams 1 tooth advanced certainly does affect the power: doing so reduces it and the fuel economy quite noticeably. I suspect that 20XE adjustable pulleys will fit, but I don't fancy paying for them, let alone adjusting all 4 cams to whatever timing is required and with the correct belt tension.
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LC0112G

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Re: Camshafts
« Reply #39 on: 05 April 2018, 15:55:06 »

I think James is suggesting a switch to flat-top pistons (3.0?) for increased compression ratio

You can't put a 3.0 piston in a 3.2 block. Well you could I suppose, but  3.0 pistons are +/-86mm diameter, and 3.2's are +/-87.5mm diameter, so compression is going to be a bit on the low side and they'll slap a bit :D

You're going to be searching for 87.5mm pistons with the correct wrist pin and crown height, and getting accurate info out of anyone is difficult.
« Last Edit: 05 April 2018, 16:19:18 by Fuse 19 »
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Andy B

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Re: Camshafts
« Reply #40 on: 05 April 2018, 16:36:00 »

....

You're going to be searching for 87.5mm pistons with the correct wrist pin and crown height, and getting accurate info out of anyone is difficult.

Gudge0n pin ......  :-X 

I thought the admin had grown up & removed the filter ......
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LC0112G

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Re: Camshafts
« Reply #41 on: 06 April 2018, 00:59:01 »

....

You're going to be searching for 87.5mm pistons with the correct wrist pin and crown height, and getting accurate info out of anyone is difficult.

Gudge0n pin ......  :-X 

I thought the admin had grown up & removed the filter ......

That is what I wrote, but ..... ::)
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laney101

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Re: Camshafts
« Reply #42 on: 06 April 2018, 02:16:52 »

Its a dish, not big by any means, and easily addressed by using ported heads from a 2.5/2.6 with smaller squish area.

Laney is going the right way, worthy of note is that the G cams have a slightly longer opening duration than the other cams and a slightly more aggressive opening/closing profile, hence them being the better option (although its very questionable if it makes an impact on the exhaust side given the dynamics of the exhaust stroke......although with tubular manifolds there maybe some gain to be had).

All the 3.0/3.2 cams have the optimum lift, increasing this wont give a benefit unless you were to fit larger valves as it results in a curtain area that equals (its actually slightly larger) the valve seat area. The 2.5/2.6 was effectively throttled by using a smaller inlet port and lower lift cams (hence the fitting of 3.0 cams and inlet divider plus some part matching brings 20ish bhp benefit on these).

Exhaust manifolds have always been crap, the pressed steel items from the 2.6/3.2 are better than the cast versions on the 2.5/3.0.

The best 'from stock parts' was always a 3.2 block with 2.5/2.6 heads (ported) with 3.0/3.2 inlet manifold, 2.6/3.2 exhaust manifolds, 2.5/3.0 front pipes and 3.0 engine management on G/A cams, any improvements based on this starting point are going to yield better results.

Crack on I say as it will be cheaper than any other option and far more interesting.



thankyou very much for comment.

currently engine is std 3.2 v6 with 3.0 downpipes.

ive gone for 3.0 heads only due to being able to get easily.. going to be ported.. back cut on valves ..new guides  valves and chambers coated through CAMCOAT warrington .... heads are going to be skimmed. (unsure what amount by need to work out want to push it slightly past std 3.0 compression maybe 11.1)

i need to find a set of g and a cams from 3.0 and have shipped to newman cams for fast road re profiling. He said he has done them in past a few times mainly on vectras and seen good results so we shall see..

im also going to port std inlet upper and lower and match to head (may do throttle body unsure yet)

just purchased a spare set of 3.2 later exhaust manifolds. going to make a jig from these and try and make tubular stubby manifolds. not ideal however should be better than the log design of std. (thats the plan anyways)

management been looking at getting a unichip dastek ecu to allow remapping of parameters as currently cant find anyone who can remap my 3.2. 
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