Valves for 300 heads??

DaviesDJ · Post by **DaviesDJ** » Wed Jan 09, 2013 6:46 am

Think if I can't source a p75 gasket I will modify a river one. In terms of compression ratio, thinking and planning, looking at the efficiency grafts the curve flattens out after 10 or so, but still gains to be had- some eales engines like Andy race's TVR griff (Tuscan series) run 13 or more? What do you think is ideal guys, for fast cross country.

Robrover · Post by **Robrover** » Thu Jan 10, 2013 7:48 am

Here you go

http://www.ebay.com.au/itm/Inlet-Manifo ... 3f1e856656

Wotland · Post by **Wotland** » Thu Jan 10, 2013 8:47 am

You can also purchase parts here : http://www.roverparts.com.au/inc/sdetail/824

DEVONMAN · Post by **DEVONMAN** » Thu Jan 10, 2013 9:13 am

I thought the P76 block was taller and the inlet gasket will be too wide for other RV8 blocks. Please correct me if I'm wrong. (I suppose you could cut it and over lap it and seal it).

Regards denis

kiwicar · Post by **kiwicar** » Thu Jan 10, 2013 12:31 pm

Hi
You are correct the P76 block is quite a bit taller and the gasket is wider.
Struck me as a bit of an odd aproach when I read it too.
Best regards
Mike

Robrover · Post by **Robrover** » Thu Jan 10, 2013 10:11 pm

You are right, the P76 4.4 is taller and wider apart at the top. I simply cut the manifold gasket in half then tacked it back together so it fitted the Rover V exactly.

DaviesDJ · Post by **DaviesDJ** » Mon Jan 14, 2013 8:23 pm

What is the best way to tack together the inlet gasket? Adhesive?? Would you say that the leyland p76 gasket is the best way to go?? I suppose better to cut in the middle then cut each port portion.

DaviesDJ · Post by **DaviesDJ** » Sat Feb 02, 2013 10:20 am

Have had a chat with John Eales - about my 300 heads and valve selection etc - he seemed very negative about 300 heads and stated that there is nothing you could get out of a 300 heads that you couldn't get out of a rover??? He also said that using 1.77 inlets would do more harm then good as the over shroud the bore? This didn't seem to make sense to me? With the obvious good results with TA and wildcats?? I did not expect him to be brimming with enthusiasm for something he did not sell, thought I could by some valves off him, but didn't expect that sort of negative outlook. I have read a great deal of established data and experiences with 300 heads that are positive? What do you recon guys?

DaviesDJ · Post by **DaviesDJ** » Sat Feb 02, 2013 8:31 pm

Again it always seems a shame when people are so reluctant to praise anything other then their own products

kokkolanpoika · Post by **kokkolanpoika** » Sun Feb 03, 2013 8:17 am

Well, maybe MR.Eales is right. If you compare wildcat and TA heads to ROVER/BUICK heads.
Valves is more centerrline on the bore with cats and TA heads.. This will help bore shrounding symptons. Also valve angle is better those two type heads.. + also consumption champer shape is quite optimal..

And my question is why/where do you need 1.9-2" inlet valve? Do you mean that smaller like 1.7" valve will resist your top end power?

I do not see any point to use 1.9-2" inlet valve. If you´r power level is under 5-600hp. Smaller valve give exactly same results if we spoke 400-440hp readings. 1.7" valve flows near 440hp..

And even 2.0-2.3l 4-cylinder engine with 1.7" valve will give you 230-250hp. So why your small V8 need such big valve?

DaviesDJ · Post by **DaviesDJ** » Sun Feb 03, 2013 9:42 am

Didn't really want that size valve, just wanted the best out of my 300 heads when I put them together, think I will go for merlin valves as they are reasonably priced and easy to source

kokkolanpoika · Post by **kokkolanpoika** » Sun Feb 03, 2013 10:57 am

I wont touch Merlin valves if i was you. They are not good design. Valve shape is very poor, and they are very heavy items. + stem diameter is too big.
I will go for Volvo items or similar Ford OHC + etc.. Valve stem diameter is smaller 8mm vs 8.73mm. Shape is good and they are same lenght as original Rover items ~117mm, 3 groove locks witch is mutch better for high performance use than any stock 1 groove..

Here is our Finnish suplier.
http://www.hm-osatuonti.fi/upload/view_ ... duct=25110

I think they are Volvo B200?/Ford OHC/VW beetle items..

DaviesDJ · Post by **DaviesDJ** » Sun Feb 03, 2013 6:06 pm

Yes- that's a thought, volvo valves seem to hit the spot, what engine are they originally from??

kiwicar · Post by **kiwicar** » Sun Feb 03, 2013 9:03 pm

"They are not good design. Valve shape is very poor,"

interesting statment.

When it comes to valve shape there really aren't any absolutes. . . the valve shape is chosen to match the port and the port's shape is matched to the valve shape. . no valve is a "Good" or bad unless it does not match the port it was intended for likewise putting a valve in a head it was not intended for is likley to be a bad match.
Best regards
Mike

kokkolanpoika · Post by **kokkolanpoika** » Mon Feb 04, 2013 7:11 am

kiwicar: Have you ever seen a merlin heads or merlin valves on live?

I do not see any point to use 8.73mm valve stem such´s a small valves. You can go ~8mm stem to get more potential. Same price, better results..
And inlet valve is not that bad like exhaust witch will look like inlet valve. Inlet valve shape is not designet to work exhuast side..
And why they are so heavy items? Make no sense to me. I undesrtand that many customers who use Merlin´s will have issues of weak valve spring or valve bounching high rpm??