The V8 Owners Forum -

Hi there.
Here some pictures of my V8 heads
What do you think about this heads? Can i only clean and polish the valves or i have to put new oneS?

can you clean them up a bit and pull a valve so we can see if the seats have receeded?
Best regards
Mike

Hello bakuuu,

No disrespect, but did you ever change the engine oil? If so how often, and what type of oil was it?

How many km has the engine seen please if you don't mind me asking?

Ron.

Hello
I had bought this engine on ebay to make a fully rebuild. This is not my engine.
The block is already fully rebuilded, and now it´s time to rebuild the heads.
i have cleaned the heads with petrol and now they are with a better look.

I think the best thing to do is change everything. I´m looking put the 4.6 valves, it is possible?
The rocker shafts maybe are worn/bad but i haven´t sure.

How is possible someone keep one engine so bad :O :O

im looking buy these stuff
http://v8tuner.co.uk/product.php?id=706

with an upgraded camshaft, 4.6 valves and new rocker shafts and a STD fully rebuilded block and MAGNAFLOW muffler, i´m looking to 220HP, is possible?

Bakuu,

If I remember correctly you are the guy with a nice clean RangeRover.

If the engine you have is a 3.9 and it's worth double checking, what is the engine number whioch you can find on the block next to the dipstick hole.

The 3.9 engine should have waisted stem valves so the same size as 4.6 valves.

Paul at V8 Tuner is good for parts and will give fair prices.

for the heads, strip and clean them as much as possible and then find someone who can properly chemically clean them, after cleaning check the oil supply holes to the rocker gear which are under the front and rear rocker pillars, you may need to use a drill to clean all the hardened muck out, new valve springs obviously will need to be fitted.

The rocker gear on the heads shown is likely to be badly worn so will need replacement, but if the roocker gear on your existing engine is in good condition you can use that, but it will need to be checked carefully.

If the heads are this bad then the block will also be in a similar condition and will need the same treatment as the heads.

Once everything is properly clean the crankshaft can be checked for wear, and if necessary be reground and the bores checked for wear, it may need a rebore and new oversize pistons.Also new cam bearings will need to be fitted.

After that if you want more power the first place to start is to have a stage one heads mod, this is to fit the valve guides you have seen from V8 Tuner and to have the valve seats opened up to actual seat size and the area below that opened up and smoothed down into the bowl area.

With standard size waisted stem valves this will give approx 30+ BHP with a standard new 3.9 cam and lifters, so close to your suggested 220BHP.

You will need new all steel timing gear and you will need to check that your distributor is in good operating condition, most are not and optimising timing will release quite a bit of power.

If you want to fit an upgraded cam then it will depend on how you use the vehicle and whether it's manual or automatic gearbox.

Are you using fuel injection and if so which system do you have?

Kevin.

ello CastleMGBV8,
Yes, that´s right. I have one white Range rover V8 on 35" from Portugal.

My engine is a 3.9i...The block was fully rebuilded in past week.....Now it´s time to rebuild the heads

I will buy parts at v8tuner (Paul). He is a very experiente guy.

The 4.6 valves is plug and play on the 3.9?
I think it´s better put a new rocker shafts and new springs too. It´s not a lot expensive and by this way i have 100% sure that it´s new.
The camshaft that i´m looking is : http://v8tuner.co.uk/product.php?id=637
Cam Data
Power Idle - 5500rpm
@ 0.50" In 206
@ 0.50" Ex 206
Lift with std Rockers (1.6:1) In/Ex 0.433"
Lobe seperation 108 Degrees.

my range rover is MANUAL and i want power in low RPM (from 1000 to 4000 RPM).
I´m using Fuel injection ( 3.9i EFI STD).
how can i see if the distributor is OK or dead?
So with 4.6 valves and upgraded camshaft i think 220HP are possible.
Sorry my english and all these questions but in Portugal there are no information about this engine

Bakuu,

Cam sounds interesting but lobe centre angle of 108 deg. surpises me for standard Hotwire EFI use.

In my opinion it is always better to modify the heads first otherwise you would be better off using a standard cam.

To explain, to get more air and fuel into the engine you need to remove the obstructions in the standard cylinder heads.

If you put a hotter cam in an engine with standard heads you will lose power at lower revs and possibly have a very small gain at the top end of the rev range because the heads are blocking the performance of the hotter cam.

4.6 Valves are same size as 3.9 which is what you have, so no gain in power. You will get more power with the mods I suggested than just fitting larger valves anyway.

Check out Peter Burgess site for econotune Rover V8 heads.

http://www.mgcars.org.uk/peterburgess/page18.html

A small gain in compression ratio up to 9.8/1 will increase power and torque.

What did you do to the block when you rebuilt it?

Once you get engine installed and running you can check the distributors advance curve with a timing gun that will show advance through the rev range or on an electronic tuning set up like a Crypton, come back for further advice later.

Kevin.

I think that cam would work well with the valves you are going for and a good clean up of the standard casringstaper the valve guides where they stick into the port if they arnt already done), open up the valve seats by 1.5-2mm and give them a 3 angle valve job, and then just blend the seats into the heads, clean up the castings to an 80 grit finnish and just blend everything you can get at easily but don't open up the ports and definatly don't match the ports to the gaskets, match them to the manifold as it is if you are going to go that far but you don't want them any bigger.
Best regards
Mike

Thank you for the info. My engine is almost ready
i bought Viper Cyclone Hydraulic Camshaft "Use 3 degrees extra advance, and a "cone" style free flowing air cleaner. In dyno tests, we
obtained 26bhp extra at 5000rpm, with an extra 27ft lbs of torque at the same rpm. Rpm Range @ .050" Lift-1.60 Rockers Lobe Sep
Idle-5500rpm In.206 Ex.206 In; .433"Ex; .433" 108 degrees"; New timing chain and new cam followers, KN filter, headman headers and a magnaflow exhaust.

the heads are cleaned and tested. Ready to fit. i don´t buy new rockershafts and valves. I think they are OK.
I´m looking for 210HP with these stuff.

thank you