Where to do Engine Modification

[Qr25vet]

can become K26A....

[Vesfreq]

The sky is the limit.

[Qr25vet]

aiyah end of the day...the REAL chevy IMO is the corvette and the camaro...

[Qr25vet]

regrinds...thats if done poorly...i have heard of many cams which are reground in race engines and have no problems whatsoever...depends on which shop u bring it to...for singapore...no one can do it...but which machine shop is reputable for crankshaft balancing?

i wanna balance mine together with my crank pulley and flywheel...

[Viceroymenthol]

<<>>

 

Are you sure you attended Texas A&M University (TAMU)?

 

Texas A&M stands for Texas Agricultural & Mechanical University. Can't believe anyone who attended any university wouldn't know the full name of his alma mater.

 

There is no such Texas Austin University! I believe you are referring to University of Texas at Austin (UTA), a totally unrelated university to Texas A & M. Texas Austin University maybe exists in one of those fake diploma mills printing out fake degrees.

 

So now you know, better luck next time!

 

But seriously, get your facts right before you bullsh1t people in a public forum.

 

Other than that, your knowledge of engines is fine.

Edited April 28, 2008 by Viceroymenthol

[Smhomie]

To clear any doubts, yes it is A & M that I attended in 2004 (fall intake). I stayed with my sponsor family in Rockingham Valley (if I can still recall correctly). It was a 5 week structured course with a practical exam at the end.

 

It was a continuing development program offered then from a tie-up with Toyota University and UTI that was conducted on A & M grounds.

 

I apologise if I have loosely used Austin, A & M interchangably and to cause this misgiving. If its correct, the Austin University campus you mentioned is probably about 150km away from each other? Never had the chance to go there though, heard from course mates the football and synchronized swim girls were hot looking

 

But coming back to the topic, often there are cross programs and tie-ups offered by universities or varsity of the university. I may have made a faux pas but should it imply naturally that there is a lie due to inconsistency? Maybe, as this is the 1st thought that comes to mind.

 

Well, that's why I had to explain my position or risk being labelled a liar on a public forum. Besides, I think individuals w/o formal guidance who are able to modify their cars and keep them running are probably smarter than me

 

I had to pay to learn...

 

So that's all for clarification on my part. It is up to you whether you believe me or not, its your perogative

 

Happy modding

[DarkLord]

haha.. its a good lesson to be learnt..

 

So what did you learnt so far?

 

P.S. Time for a rematch soon?

[DarkLord]

LTM?

Why lehz?

[Smhomie]

Sorry, I do not know of any local shop capable of performing such tasks the grams that are shaved off + eventual shape cut may affect the harmonics in the I4 motors ie. Latitudinal, transverse layout. The concern in proper balancing is with the balance weights. They are the part which tuners like to knife-edge.

 

Knife edging practice is based on the claims of rotational efficiency and faster speed when 'cutting' through the oil and of course being slightly augmented in revolution speed.

 

Do you have balance shafts in your motor? They are in-built as counter weights to suppress vibration and noise that is inherent in the engine design. Eg. some Toyota engines have it.

 

My apologies again for not being able to help you on this topic. Are you willing to spend more $$ to get the items done maybe in Australia? Freight would be cheaper than going States but do take into consideration the higher exchange rates

 

Happy modding

[Qr25vet]

nope my car does nto have counter rotating balancing shafts which is a good thing as these things just make yr engine poor in terms of power/efficiency....i'm gonna lighten my crank but no TOO much as it'll lose momentum and that'll make driving in jams very difficult and it'll weaken the crank by a considerable amount...for me i'll be balancing the crank with the pulley,flywheel and clutch pressure plate as one piece....as i want the tolerances to me minimised and my engine to rev higher and freely...besides my new engine is kinda setup for the track

[Xiaogary]

Hi,

 

thanks guys for the wondeful sharing. I learn a lot from your comments. These are knowledgeable comments which are rare to come by in a normal forum.

 

I had given up the hope to knife edge the crank shaft, partially becos not able to find one in Singapore. And also not willing to send the whole engine overseas to balance. Plus do not wish to weaken the structure of the crank shaft in its original state.

 

As for camshafts, they are being professionally done up at UK. I am not sure whether that tuner is going to make a billet one for me from blanks or regrind the new camshafts I sent them. They reccomended 285 duration max since I am not on quad trottle bodies which allows me to go 300 or 320 duration. But such high duration is too hot for the cams and would not be stable during idling. Its for race or rally use only.

 

I found performance Carbon/Kelvar Clutch Kit for my ride (custom made from US) available in 3,4,6 plucks with and without sprung hub. Only ordered the normal full rounded carbon/kelvar with sprung hub since its good for up to 35ohp already. The 3,4,6 plucks are good for 650 hp but without sprung hub and made driving very harsh.

 

Also found cometic gasket which claimed to be stronger than stock gasket and is available in any thickness customisable. Shoule I get same thickness as original gasket?

[Smhomie]

Since you have sent them over, my guess is that it would be regrinds. 285 degrees in/ex is indeed very high Have they advised you on the streetability of this setup?

 

Cometic MLS and their crush seal ring makes for a good seal. Get the same thickness since your intention is not to lower compression ratios (I assume you are talking about head gaskets?). Adding thicker head gaskets also changes your camshaft timing as evidenced by the timing chain markings, dependent on thickness.

 

I'm using Cometic manifold gaskets, triple layer steel. Solid seal even on pitted flange surfaces.

 

Happy modding

[Xiaogary]

Yes. I meant head gasket. Yes, they advice me to go 285 degree max for non quad trottle bodies.

 

Most slightly is a grinding. But they do from blanks too. They have not get back to me whether its possible to grind to 285 with the existing cams.

[Imuya]

Can someone enlighten me:

 

How do you regrind an existing set of cams to a longer duration without making the lift lower?

 

I have no experience in cam regrinds, just thinking out loud from a common sense point of view...

[Turbonetics]

you are the first NA Chevy i heard with big dreams.

keep it up.

success to you.

you should be happy with 110whp at the redline of 7.5krpm unless you can rev your car above 8000rpm.

[Smhomie]

If you look at the side profile of your regular lobe, it resembles a pear or teardrop shape. When you grind the profile, it would be a elongated squarish (lack of a better word). This is what increases the duration for the valves to stay open a little longer.

 

Tuners or performance owners use higher profile camshafts to eliminate or diminish reversion of the exhaust gases during the exhaust stroke. Overlapping of the valves in FI is not desirable. Reversion 'pushes' exhaust/spent gases back into the intake track instead of out to the exhaust runners, this limits the draw of fresh air into the chamber before the compression stroke. For FI, this phenomenon is worse as the exhaust impeller and compressor housing (hotside) represents and contributes back pressure which further accentuates reversion.

 

Camshafts typically gain 15% more power from mid-high range with supporting mods. They do not work well alone.

 

I hope this simplistic explanation allows you to understand the desire of car owners to have different camshaft in degrees.

 

Happy modding

Edited April 29, 2008 by Smhomie

[Imuya]

Hi,

 

I understand the workings of camshaft and also that FI engines need little or no overlap for build up of compression during the intake stroke.

 

I was asking about CAM REGRINDS that the TS as talking about initially.

 

Grinding from blanks is a no brainer but...

 

1.) How do you REGRIND a set of cams without decreasing the lift as material from the lobe has been removed?

 

2.) a 285deg cam will mean it's opened for 75deg of crank movement (a 1mm lift or whatever amount of lift the manufacturer measures). Wouldn't it mean that a 260deg cam is "hotter" than a 300deg one? Cos the TS was talking about getting more "aggressive 300deg cams that need ITBs. Am i right in the understanding of the "degrees"?

 

Thanks!

[Smhomie]

1) If I understand your question correctly, then I would say: No, you can't. Lift has a direct impact on the duration. Both go hand in hand. You shave material from center lobe, the lift would naturally correspond. Factory Indexing is required but is very intensive work. Maybe by adding shims to the bucket to adjust or compensate for longer duration?

 

2) Not necessarily so. It has a direct and correlating relationship with the lift you have. ie. 0mm lift = 360 degrees, ??mm lift = 264,285,300 degrees. What's the factory index to begin with? You need a minimum of 1.27mm to induce lift on a regular 4 cylinder car. Duration of the valve opening is whats happening here. 260 degrees would perform an earlier seal compared to a 300 degrees lobe contact radius since it would behave like almost having the valve perpetually open for that one revolution, this would indicate a very high revving engine concentrating on further improving airflow rate from higher mid to redline application, in my opinion. ie 4800 to 6300rpm. A limited window but facilitating greater flow from its trac velocity.

 

Camshaft selection is important because of its mechanical control properties over timing events in the combustion process. It must be well matched to give you the desired outcome.

 

Not sure if I had answered your questions but hope it explains a little that I know in this aspect.

 

Happy modding