My rebuilt V8 - rolling road report!

Riddler

Riddler

Active Member
Hi folks - you may remember that I recently posted about having the engine rebuilt on my 1972 3500S. Well I have now taken it to a tuning specialist, and I thought you might like to see the figures it produced on the rolling road!
At 4,397 rpm it delivered 151.8 bhp at the engine and at 4,365 rpm it delivered 131.5 bhp at the wheels.
Pretty happy with that!
Attached is the rolling road report/performance graph for those who are interested.

img049 (Medium).jpg
 
did they tune the needles at all? What set up did they start with/end up with?

Looks decent power wise.
 
What cam have you got now? The start of the torque curve seems strange to me, is it a mistake? I suppose it's just the equipment wasn't recording it at those low revs?
Not that it matters, it's about how the car is now driving, which you sound pleased with :)
Here's a Range Rover 4.6 Dyno comparison, which I thought was interesting to show.
Jim

dynograph.gif
 
Ok - well you are talking to someone with very little technical know-how. All I can tell you in response to the above questions is that Tom - who did the rebuild - told me he had fitted a "mild road cam" which he predicted (before I had the rolling road test) would result in a small rise in bhp. I also know that after the re-bore, the car was fitted with over-sized pistons which I understand is normally what happens - I believe the ones used were from the Rover SD1 Vitesse?
 
If they were SD1 or even Vitesse pistons, it would have dropped your CR a bit and lost a bit of power.
 
PeterZRH said:
If they were SD1 or even Vitesse pistons, it would have dropped your CR a bit and lost a bit of power.
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Yes, Tom did warn me about that - though he said unless I was really pushing the car hard (which I don't really do) then I would not notice any real difference. Maybe the uprated cam has more than compensated for that? But, I have no expert knowledge of these matters. I am a driver, not a mender!
 
Makes sense, the mild "fast road cams" tend to give slightly below 20bhp, so take a little off for CR and you get your extra 10.

However changed cams definitely would need rejetting so it'd be interesting what was done on the rolling road session
 
Hmmm . . . don't really know the answer to that. Re-jetting? I presume you are referring to the carbs there? I will have to ask the guy.
 
A 72 could well have KO needles which are pretty tuning tolerant for mild increases in power. Major question is did you have the heads ported as the early cars have one exhaust nearly blocked by the air injection molding. Those graphs aren't particularly useful unless you know how fast the readings were taken as a quick blast up to 5000 is going to give a richer (or possibly leaner) mixture than a slow rise; changing the figures. It does appear that some ones foot slipped off the throttle early on...
 
Ignoring the weirdness at the beginning that is a decent output - seems the combination you have gives a decent torque between 2700 and 4000RPM ish.
 
Out of interest, where's the new cam from? Great result and eagerly anticipated I bet! Has anyone used a Crower CompU Pro Cam? ( before I bite the bullet)
 
A previous 'S' I had was fitted with a 'mild road' cam & SU HIF6s (it originally had an Offenhauser manifold on it instead).

I haven't a clue about tuning; all I remember was that it was fantastic at overtaking, but a little 'lumpy' at lower revs. What's yours like?
 
Hi Phil. Interesting description. I'm planning a top end rebuild and for a few compromises I'm thinking of going for the Crower cam. I'm certainly no tuning expert either but I guess it could run lumpy at low revs too. Just wouldn't mind knowing how others have found it. Well done on yours though.
 
@DeanoV8. Crower do any number of grinds for the RV8/Buick 215 numbered from 50227 onwards, getting progressively more extreme as the numbers increase. I have the 50229 which is the first of the "level 2" camshafts, which I think is the one you refer to. I haven't installed this but it's popular with the Land Rover crowd so it'll be torque focused which would also indicate good idle characteristics. It's recommended for automatic transmissions in fact so you know it'll behave well low down. There are a few youtube videos of this in action but often these are with other mods, so hard to tell. However "Crower 50229" gives you something to search with for info.

Despite being cheap Crower cams have an excellent reputation for quality in the US. Certainly in the Land Rover world they are deemed more durable than Rover OEM which really shouldn't be as much of a challenge as it appears to be in many areas half a century on (aftermarket rocker gear).

If your cam as more than 50k on it anyway you are quite likely to notice improvements whatever you do with new timing gear/cam. The Crower with SD1 heads has got to be good for 25-30bhp over a standard engine if you keep the CR the same and that's pretty useful.
 
@Riddler sorry for hijacking your thread because I was impressed with your results and just wanted to know what your cam was. I'll now look at your rebuild thread for more detail. Cheers

Peter. It is the 50229 I'm looking at but would be interested how it compares to RPIs Piper Torq Max. Mines a manual (BTW 'S' stands for Synchro everybody but I'm a newbie so don't let rip for stating the bleeding obvious)so don't really need low down improvement, or do I? On a budget I think the Crower is going to win unless anybody spooks me. Sorry for being thick, are you recommending aftermarket rocker gear? Pick up SD1 heads tomorrow so will know more about what else I need then. Will start new thread to discuss but have gleaned heaps already on here.
 
DeanoV8 said:
@Riddler sorry for hijacking your thread because I was impressed with your results and just wanted to know what your cam was. I'll now look at your rebuild thread for more detail. Cheers

Peter. It is the 50229 I'm looking at but would be interested how it compares to RPIs Piper Torq Max. Mines a manual (BTW 'S' stands for Synchro everybody but I'm a newbie so don't let rip for stating the bleeding obvious)so don't really need low down improvement, or do I? On a budget I think the Crower is going to win unless anybody spooks me. Sorry for being thick, are you recommending aftermarket rocker gear? Pick up SD1 heads tomorrow so will know more about what else I need then. Will start new thread to discuss but have gleaned heaps already on here.
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You don't need rocker gear unless yours is worn. The point I was making is aftermarket components are not necessarily inferior to OEM, so don't worry about non-OEM cams, many of these US based companies have been around as long as our cars. As Rockdemon says, the only alternative known to be durable are yella terra if you really do need these. (Standard disclaimer: This is what I've read many times and not experienced - roller rockers are nice to have for several reasons but not really an issue for a standard road car).

The problem I found when reading up was that very few people have comparative experience with regards to cams. The main users will be Land Rover fans at one end and TVR owners (or other sports cars using the RV8) at the other. This tends to leave us somewhat in the middle. With an auto you are on safe territory with those talked about by Land Rover owners and obviously TVR appropriate cams are going to be too lumpy and peaky. Having a sporty cam in an everyday car it just a PITA as it is hard to drive in traffic smoothly. I've tried this in a mini once and, no thanks...

As you have a 3500S with a manual box you can go a little more aggressive depending on your taste. The 50229 is a pretty safe option. The worst that can happen is you might need to add 50rpm to the idle speed. Remember the OEM cam is very, very mild. If you look at the cam timing and lift you'll see many of the "fast road" options look somewhat similar.

I chose mine based on what I read, Crower's reputation, the overall lift wasn't too high and is OK with standard valve springs and the fact it was half the price of many of the other options. I'll claim no more expertise than that. Quite a few LR owners have it and I seem to remember at least one P5 did and the owner was happy enough. I hope to install it in the spring. If you can wait a bit I'll let you know...

Like I said if you can get 25bhp+ for £100 worth of cam and some second hand late cylinder heads then that's real bang for your buck if you DIY. The rolling road session you'll need will cost more.

The "S" as far as I can tell in 3500S stands for "not a 3500". Remember the 3500S sold in the US (NADA) was automatic... Just marketing, although theories abound as your's sounds plausible..
 
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