how much power can a Rover V8 bottom handle?

sven410 · Post by **sven410** » Sun Jun 27, 2010 8:23 pm

Hi, new to the Rover V8's, but I have a few of them kicking about...

I am thinking about rebuilding a 3.5 low comp ratio engine with new shells, pistons and so on and supercharge it

my question is then, how much power can I push out of it, before the bottom end will be too weak? someone with experience in this area?

thanks

Sven

unstable load · Post by **unstable load** » Mon Jun 28, 2010 7:27 am

You will want to find one of the cross bolted blocks for that to be a worthwhile undertaking, I would say.
I won't post about figures cos there's folks here that know far better from first hand experience what you will be able to do.

topcatcustom · Post by **topcatcustom** » Mon Jun 28, 2010 8:13 am

Tbh I think a 2 bolt mains with ARP studs will handle at least as much as the stock pistons and rods could take in a 3.5, a rover is never going to make silly power anyway so I dont think it's as much of a worry as if you were going to supercharge a sbc or similar which could kick out 700 ponies!

TVRleigh · Post by **TVRleigh** » Mon Jun 28, 2010 8:50 am

Unless you need to run a 3.5, you better off getting a 3.9 or bigger to start with, they are going for silly money currently, so a bit pointless spending a lot of money on a 3.5

kiwicar · Post by **kiwicar** » Mon Jun 28, 2010 9:33 am

To be honest the heads even with as much porting they can take will limit you to about 550 bhp on petrol even with a blower. Apart from the pistons the bottom end can take this with ARP studs and a bottom end brace. Going for more capacity over a 3.9/ 4.2 set up just adds to the budget as you start needing top hat liners and all it does is move the power to lower revs and makes it even more likley to go bang.
If this is a serious max power engine then go for a 4.2 with merlin heads and a good thick main brace and decent pistons, shot peen the standard rods and fit ARP rod bolts, if you have the cash add a set of chevy H-beam rods with the sides narrowed and chevy 305 pistons.
Best regards
Mike

ian.stewart · Post by **ian.stewart** » Mon Jun 28, 2010 2:33 pm

Rovers are fairly strong, with 2 obvious faults, you need to fit ARP rod bolts, possilbly advisable to fit injection rods as well,
The big problem with the bottom end is the ability of the mains to walk about, even with ARP studs, normally found more in high revving engine 7k+, but supercharge/turbo engines will suffer similar problems if the power is turned up, I would suggest 275hp as a max before the engine gets to a point where the caps are coming loose, There lies one of the reasons Rover opted to build a 4 bolt engine, again basically a better engine, but suffers from liner problems which is well documented elsewhere on this site

mgbv8 · Post by **mgbv8** » Mon Jun 28, 2010 4:42 pm

As Ian say's!
275hp is about all I would give it on a stock bottom end. I ran my 3500 stocker up to 260hp for a year or so at the track, and it was only pistons that kept letting me down. Hence my upgrade to 4.6 now

Cobratone · Post by **Cobratone** » Wed Jun 30, 2010 11:05 am

mgbv8 wrote:As Ian say's!
275hp is about all I would give it on a stock bottom end.

I'm surprised mine ran then

r2d2hp · Post by **r2d2hp** » Wed Jun 30, 2010 12:14 pm

Think Ime going to be having trouble soon then

JP. · Post by **JP.** » Wed Jun 30, 2010 4:01 pm

Think me will have some trouble soon too then................

stevieturbo · Post by **stevieturbo** » Wed Jun 30, 2010 5:43 pm

Wind the boost up and never worry about it. It'll be dead on

mgbv8 · Post by **mgbv8** » Wed Jun 30, 2010 11:41 pm

OK OK!!

I gave up on my 3500 at 260hp!

What have you guys run your stock 3500's to ?

It wasnt the bhp I was concerned about though. I was pushing nearly 400 ft/lbs with the old 3500 on gas??

My bigger 4.6 will run well over 550 ft/lbs on gas and hasnt complained yet

bigaldart · Post by **bigaldart** » Thu Jul 01, 2010 6:06 pm

WE have run ours over 400 bhp and counting, only fitted studs over the winter and still not managed a full pass this year, lots of niggly problems nothing to do with the engine.

Google Gene Adams in the states and his exploits with the early Hem, go back to the sixties. His recommendation is to smear lanolin on the mating surface between the caps and the block and let them move where they want. It stops the metal transfer which is what scraps the blocks. Studs will pretty well register the caps, but you can tighten them up with a chisel if it makes you happier. You probably won't find this published in the open but I subscribe to a forum that he pops up on. 354 early hemi injected on methanol and in the 6 second zone, pretty impressive, also placed third in Engine masters challenge with an early hemi against LSi, SBC, BBC, BBF, SBF etc.

Alan

mgbv8 · Post by **mgbv8** » Thu Jul 01, 2010 6:21 pm

Thats good news Al!!

My old 4600 may have a bit left in her then

I have to admit that this RV8 is a really good platform for tight budget diy racing, like wot I do

bigaldart · Post by **bigaldart** » Thu Jul 01, 2010 10:21 pm

We don't even have a budget, LUXURY, you lucky B***ard. After the last blow up we find we have zero good blocks left, the decision became fix the block that lost a bottom rear corner which is relatively unstressed, or fix a block mating surface. We went for option one and it seems to be terrific. Cut the damage back to a square slice and then cut a matching piece from a scrap block.Then we glued it together with Belzona , perforated metal as a reinforcement. Seems bloody good, next job is the mating face for the head on another block. Fantastic stuff but bloody expensive at £56 for 400 grammes. Mind you this repair only took about 60 grams so it evens out.
Stuff has a five year shelf life too.

Alan