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XN1 camshafts

Bob D

Member
I put a note in a book I think posted by Dave McVean on AF maybe 10 years ago.
It went along the lines that "a pre 1975 504 camshaft is more lively, smoother running with better fuel consumption."
So does anyone know if there is such a difference between early and late camshafts ?
Between round and square port heads maybe was what the note was inferring ?
I know Ti and twin carby models have a different profile.
Bob
 
Yes Ti cam or twin carb cam with square port head is the go. Only difference between these 2 cams is twin carb cam has extra lobe on it to drive the fuel pump (some TI cams may also, but not all).
 
I think what I was talking about by "pre 1975" camshaft is a pre 75 TI camshaft. I think (but not 100% sure ) the difference is one cam is advanced more than the other, but timing and lift are the same. 73-74 504 TIs are known for being able to make 6800rpm in top gear (120mph).
 

GRAHAM WALLIS

VIP Sponsor
A bit earlier than the 504 but early 404 cams have more lift than the later ones, later ones have more timing though, and would be the same as an early 504.
 

Bob D

Member
Thanks Dave and others,
I think that was probably correct that you were talking about Ti cams many years ago.
It sounds as if most round port and square port cams are the same except for the XNA one.
And I do have such a cam marked XNA sitting on the shelf, which I can use with the square port head.
Before I proceed I would be interested if anyone has done this and whether there is any downside to the conversion ?
eg does fuel consumption jump up ?
Thanks Bob
 

ThanosK

Member
The Ti cams rev well, the idea is to not rev past the powerband as you are just making noise, not power. I am attaching the dyno sheet of an XN2 engine, pretty standard except for skimmed and flowed head. Power numbers are at the wheel. Makes no sense to rev it past 5800 rpm even with a set of really good extractor, there is no power to be made. If you go through the trouble of changing a cam, you might as well get a regrind, like the Wade 112 (Wade is out of business, but others have similar profiles). You can get higher compression now with the better fuels, and a mild regrind can take advantage of that.
 

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Bob D

Member
Thanos,
Thankyou. The motor I am putting together is for a 404 ute with a camping body. It weighs 1750 kg with the roof top tent etc. The current 1800 motor is a positively delightful motor but it is a bit overwhelmed coping with the weight, particularly on hills and with low revs such as trying to get on a set of car ramps. An impossible feat !
The ute has a 4.2 LSD which in hindsight could have better utilized a 404 wagon diff at 4.6.
I have all the parts to put a 2l motor together and basically I am after something that pulls well and rarely revs above 3000rpm.
A stock XN1 maybe the simple approach but the XNA cam is of interest especially as I have one. The exhaust is a twin engine pipe unit but after that it needs to be replaced with something bigger. I will stick with a good stock Solex as I have been through the Weber era and didnt find the advantages of that much benefit.
Bob
 

GRAHAM WALLIS

VIP Sponsor
I've found the XC7, 1600 404 motor after 1970, to have a great camshaft. Try to find one in Australia though! The car that I lent to Brian Amey for the 2005 Ampol Rerun was a 1600 with one of these cams. Nobody would believe that it was just a 1600. I built another 404 with 1800 plus XN6 (505 Sli ) cam and this wasn't as good.
 
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