View Full Version : Camshaft Timing.?
ive never personally fitted an aftermarket cam so ive not really got the understanding regarding them.:scratch:
what is the best setup for the piper 285 cam?
advance or retard? by how much? why?
engine freshly rebuilt.
engine will be std compression.
turbo is a T25. cold side .48, hot side .49 which will push 18psi max
carb will obviously be rejetted etc to suit.
now im not one for chasing big power figures. nor am i one to take the engine all the way to the redline! id say 6k rpm max.
i would actually like the turbo to spool up quicker but obviously not as quick as a std t2 and be able to pull nice and hard through all gear changes.
Eugein Offord
03-09-2011, 23:02
dont take it the wrong way......... but your gonna spend dough on an engine and you dont want it to be quick?????why not leave the car at 12 or 15 psi and go on oliday with a couple of tarts with your money..........save yourself the effort........................in my opinion......................:)
Alastair
03-09-2011, 23:05
dont take it the wrong way......... but your gonna spend dough on an engine and you dont want it to be quick?????why not leave the car at 12 or 15 psi and go on oliday with a couple of tars with your money..........save yourself the effort........................in my opinion......................:)
:worship:
:laugh::laugh::laugh:
dont take it the wrong way......... but your gonna spend dough on an engine and you dont want it to be quick?????why not leave the car at 12 or 15 psi and go on oliday with a couple of tarts with your money..........save yourself the effort........................in my opinion......................:)
ok ok:cartman: yes i do want it to be quicker but what i meant was im not really interested in max bhp figures, but yes i do want it to be quicker or i would not be fitting the 285 cam with a t25.:)
I would just time it at what piper recommend I think it's 112 degrees, I timed mine to 116 degrees retard for max hp high up the revs but my car runs stupid boost and is primerly set up for the strip.
Has anybody ever advanced the timing of a 285?
Markey Mark (BD)
04-09-2011, 16:18
Has anybody ever advanced the timing of a 285?
I'm not 100% on this although someone may clarify but when Bushy (don't know if people remember him) done his 11.9 at pod i heard Mike Spencer had set the cam to 108deg on his engine, he was running full T25 too.
I ran an advanced 285 on the Raider before swapping it with an RT200, which, bar the lumpy idle (which I 'enjoyed' anyway), I found to be a better cam overall.
Retarding the cam would only make a difference with a larger blower, as you'd naturally want to raise the power-band. Absolutely no point with an o.e T2 or TomCat/T25 variant.
Mike's MSM-285 that he used to sell were full lift @ 108deg'. Wonder where he got that idea from...
Someone say something ???
:wasntme:
The compression ratio and turbo size I suppose are key when it comes to timing the cam then and of course the general use of the engine once built.
Was bushys engine high comp?
Markey Mark (BD)
04-09-2011, 19:59
The compression ratio and turbo size I suppose are key when it comes to timing the cam then and of course the general use of the engine once built.
Was bushys engine high comp?
No don't believe it was thinking about it, i even think it started out as a BB Tuning engine originally so either was standard or low comp
Having watched that car run the day it did the 11.9 the outstanding thing for me was how it got off the line and first to second gear with pretty much no power loss/lag. I always assumed he was higher comp than standard. Interesting to know an advanced 285 has also produced a high terminal speed from a c1j.
So raj, maybe you could get away with advancing the timing a little, if you are only revving to 6k it may be worthwhile.
Dave Reed
06-09-2011, 09:40
I run mine on the marks my cam maker suggest.. Always seems to go well :D
Your only going to move the power band, not get anymore power. So I'd just dial it in to what they say.
does advancing lower the power band and retarding increase it ? or have i got this the wrong way around?
:scratch:
Yes that's correct raj in terms of how early/late in revs I'm not all that sure, that's why turbo choice affects cam timing choice
My cam has been advanced by 4-6 degrees and as you can see my power starts dropping off at the top end. but that suits me as I don't like over reving my poor push rods.
http://i3.photobucket.com/albums/y89/L0GGTT/New%205%20GTT/th_209.jpg (http://i3.photobucket.com/albums/y89/L0GGTT/New%205%20GTT/209.jpg)
My cam has been advanced by 4-6 degrees and as you can see my power starts dropping off at the top end. but that suits me as I don't like over reving my poor push rods.
http://i3.photobucket.com/albums/y89/L0GGTT/New%205%20GTT/th_209.jpg (http://i3.photobucket.com/albums/y89/L0GGTT/New%205%20GTT/209.jpg)
ah ok, so i could in theory advance mine a tad bit more as i wont be revving anywhere near 7k..?!?
Phil, bushy ran a T25 which is why it looked lag-free. His friend, whoever it was that drove it, was a handy driver too. I think he posted 115mph at one point, which is flying, so it made plenty of power too :)
markey b
07-09-2011, 01:49
Phil, bushy ran a T25 which is why it looked lag-free. His friend, whoever it was that drove it, was a handy driver too. I think he posted 115mph at one point, which is flying, so it made plenty of power too :)
i think i know who drove it... karts spring to mind
whatever happened to him anyway? i need a carb setup again, and it was pukka last time said driver did it
Okaaaay!
im going to have a gander at sorting this cam timing today...
Have i got the following correct.......
* using a dti gauge, Set crank @TDC.
* set the timing disc and pointer up.
* Rotate the crank using the timing disc to the desired number.
* using a dti gauge on no#1 inlet follower, Check the cam is at full lift at the desired number on the timing disc and adjust accordingly.
is no#1 cylinder the waterpump or flywheel end? i keep forgetting:confused:
I want to set my cam up with a bit of advance as im not one for redlining.
But by how much do i advance the cam .?
At what degree should i set the crank while the cam is at full lift?
im not at all familiar with aftermarket cam timing, so help is muchos needos
:)
would make for a nice article if you were to take some good pics etc when you do it.. As i also have no experiance with aftermarket cams.
And then i just looked and realised we already had one!
Okaaaay!
im going to have a gander at sorting this cam timing today...
Have i got the following correct.......
* using a dti gauge, Set crank @TDC.
* set the timing disc and pointer up.
* Rotate the crank using the timing disc to the desired number.
* using a dti gauge on no#1 inlet follower, Check the cam is at full lift at the desired number on the timing disc and adjust accordingly.
is no#1 cylinder the waterpump or flywheel end? i keep forgetting:confused:
I want to set my cam up with a bit of advance as im not one for redlining.
But by how much do i advance the cam .?
At what degree should i set the crank while the cam is at full lift?
im not at all familiar with aftermarket cam timing, so help is muchos needos
:)
it's all in the wrist Raj... ;)
it's all in the wrist Raj... ;)
lol:D cheers for popping over and sorting this for me, much appreciated:agree:
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