| Author | Message | ||
     Ed Hsu (Ed_h) New Member Username: Ed_h Post Number: 7 Registered: 04-2003 |
I need a valve job for my 96 disco with over 110,000 miles. Instead of doing a valve job, I would like to just buy the high performance heads on the market that will increase the power for this old engine. As you can see, I don't know that much about the engine. If it is a stupid question, sorry. Thanks. | ||
| Brad Noviski (Bradnoviski) New Member Username: Bradnoviski Post Number: 29 Registered: 02-2003 |
Ed Not sure of any high perforamce heads, I think you will see some improvemnt in performace from the valve job. I did. Or I like to think that I did. The following site may help you out. http://www.rpiv8.com A single new head assembly from Rover North is $1000. I would expect a high performance head would be even more, that is if they exist. If you can do the work yourself, a complete valve job is around $350. That does not include gaskets or anything else you need | ||
| todd slater (Toddslater) Senior Member Username: Toddslater Post Number: 283 Registered: 08-2002 |
Ed, You may want to talk to these folks www.aluminumv8.com about your hipo head questions. | ||
| Jared Schnelle (Jared) Member Username: Jared Post Number: 92 Registered: 09-2002 |
I was quoted 2500 for a valve job from a local shop. If you can do it yourself, do it that way. | ||
| Ed Hsu (Ed_h) New Member Username: Ed_h Post Number: 8 Registered: 04-2003 |
The way I look at it is this. If I am going to spend that much money, I might as well spend a bit more to get some additional performance out of it. | ||
| Christopher Dynak (Adtoolco) Member Username: Adtoolco Post Number: 207 Registered: 08-2002 |
Get them ported & polished. It'll cost you a few hundred extra but you'll gain 15-20 horse. Add headers and free flow exhast add another 15-20 and now you got 220 someodd ponies. It'll feel real peppy. While your there you might as well do the 4.6 conversion. Once mine is off warranty I'm going to do all the above...I can't wait! -Chris | ||
| Roland Kutasi (Disco1) Member Username: Disco1 Post Number: 113 Registered: 10-2002 |
It largely depends how much performance you want. Stage 2 or 3 heads would be all I would go for if you want a reliable motor with lots of grunt, however, be warned, if you go the stage 4 heads you will end up with a real beast that will be hard to keep at idle at the lights. Jared: For $2500 you sould be able to get Stage 3 heads not just a valve job. | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 167 Registered: 10-2002 |
Oh man... I don't believe that throwing a set of "ported and polished" heads on your rover with out many other mods will improve performance and may,in fact, ruin performance. I don't claim to be an expert on rover heads (or any heads for that matter), but I wouldn't be anxious to pay someone to do more than a "mild" port and polish on my heads unless I was doing a lot more to engine (camshaft), intake and exhaust systems and FI to enhance performance. By "mild" I mean simply cleaning up rough areas on intake ports and a slight polish on exhaust with a quality three-angle valve job. I'd only trust someone who knew their stuff with a flow bench(not your corner rebuilder). My bigger concern is whether the head builder used quality valve guides and seals that are going to last for years. I would be suspicious of any head builder that tried to talk me into alot of expensive head work. Remember we're talking 4wd rover here and not street/strip machine. Typically my rover spends most of it's time in the lower RPM ranges and I want torque from my engine not really looking for higher HP. Hogging out the heads will usually hurt port velocity and if there IS a benefit (usually not) it will generally be in the higher RPM ranges. Does anyone remember the 70's when anyone with a drill started "porting and polishing" their heads? Port matching and "indexing" were the sexy words of the day and people hogged out their heads, intake manifolds, and exhausts/headers and found them unusable on the street. People who polished their INTAKE ports discovered that this removed needed turbulence in intakes and also killed any performance benefits. Remember the Chevy big-block D-port heads? A smaller, different-shaped port (and smaller valves) enhanced flow AND port velocity. Slightly milling heads will give more performance gain due to higher compression but then you run into potential detonation probs. You may be able to solve that with timing changes and recurving distributor. Why not just get a quality head rebuilding and if you want more performance for the $(read torque) increase displacement with a 4.6 block and reprogrammed ECU and maybe a cam with higher lift (but short duration so as not to screw up EFI system)? $2500 for head work alone?? Dammit, I swore I wouldn't write a tome (too late) and I'm too lazy to rewrite. Now I'll be in a flame war with anyone who spent $$ on head work and thinks it's solved all their personal probs. Oh well... IMHO, My $.02, etc. | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 168 Registered: 10-2002 |
BTW, "indexing" above refers to spark plug indexing where "open" area of a standard plug electrode faces towards center of chamber for maximum efficient combustion. When I grew up "everyone" was indexing their plugs and I'm really not aware of any great benefits on a street engine. And yes, I know that there is a SBC D-port (Pontiac too). | ||
| Anatoly Vasiljev (Gaiver) New Member Username: Gaiver Post Number: 4 Registered: 05-2003 |
May be You need to think about supercharger? I installed it 2 years ago. now I have 120,000km and 20,000 with EATON 90. Disco run greate - 7.8c for 0-100km/h Anatoly | ||
| Christopher Dynak (Adtoolco) Member Username: Adtoolco Post Number: 208 Registered: 08-2002 |
Greg, all valid points. I didn't want to give the impression that port & polish alone will make dramatic improvement. Your right that doing that alone might actually hurt performance. I'm going to do the 4.6 conversion with a "street" port & polish(matching heads & intake) exhaust work, and chip reprograming. I'm hoping for 250 horse, and good torque from the 4.6 stroker(Thats what I call it). From all I have read and from my own personel experience this would be the best performance I could expect while keeping the engine reliable. -Chris | ||
| Roland Kutasi (Disco1) Member Username: Disco1 Post Number: 117 Registered: 10-2002 |
250hp? Are we talking about hp at the flywheel or at the wheels. If we are talking about 250hp at the rear wheels you will need a bit more than the above. | ||
| Greg Hirst (Gregh) Member Username: Gregh Post Number: 169 Registered: 10-2002 |
Chris- Ignore my ranting above. I was up most of the night with a sick kid and I was in a foul mood this AM. Anyway, I agree with you on displacement increase as giving reliable torque increase (I don't really care about HP increase). Someday (when I win the lottery) I'm going to build a 5.6 litre engine and solve all my problems. Until then I'll also just upgrade to a 4.6 block (with requisite mods) when the 3.9 gives up. Of course, if gas prices continue to climb, that IH 2.8 diesel conversion starts sounding attractive!  | ||
| Christopher Dynak (Adtoolco) Member Username: Adtoolco Post Number: 209 Registered: 08-2002 |
Yes Roland, at the flywheel. No prob Greg, helluva rant -Chris |
