| ||||
| ||||
| Moderated by: Greg Fletcher |
|
||||||||||||||
| New Heads | Rate Topic |
| Author | Post |
|---|
| Posted: 09-02-2005 01:27 am |
|
1st Post |
|
jensen4u Member
|
Just purchase a head with the following valve sizes - Intake 1.41" / exhaust 1.28" . Can anyone give me some insight as to how well this are sized for a nice streetable performance engine. Thanks! Last edited on 09-02-2005 02:08 am by jensen4u |
||||||||||||||
| |||||||||||||||
| Posted: 09-02-2005 03:00 pm |
|
2nd Post |
|
Judson Manning Member 
|
jensen4u, What you've got there is what we tend to refer to as the 'big-valve' conversion, which was pioneered by Richard R. at West Coast Racing Cylinder Heads. The Intake valve measurement is stock. However, the exhaust valves puportedly are modified motorcycle valves which are ~.06" larger than stock. I'm pretty sure the JHPS store now stocks these valves. Richard is the guy who is the most famous for producing 907 heads/engines that flow enough to produce 220-240hp. The only problem is that if you are interested in competition, the big valves are illegal to use (but who's gonna know? lol). Generally speaking, big power gains on the top-end come at the expense of low-end torque and drivability. However, this is generally not true about modifications made to the exhaust portion of the engine 'equation'. In practice, anything you can do to 'un-cork' the exhaust will produce power gains all through the rev-range. Take advantage of the bigger valves and install a free-flowing exhaust system. For additional perfomance gains, the #1 thing you can do is install pistons with a realistic c/r. The new head gasket nets about 8.0:1 on stock pistons. With stock cam duration, I'm running close to 11:1 on pump gas, and the car has tremendous torque from 2500-6000rpm. Use the bigger valves, free-flowing exhaust, and higher c/r pistons as a basis for your performance upgrades. Later you can try different cams and carb configurations to fit your driving style. Let me know if you need someone to build you an engine! Judson Manning DLC Motorsports Atlanta, GA
|
|||||||||||||
| ||||||||||||||
| Posted: 09-03-2005 12:38 am |
|
3rd Post |
|
jensen4u Member
|
Thanks Judson! I actually have a set of 45 mm dellrotos for my car already. This car is not ready for the rebuild yet. I am just being patient and trying to obtain the items I want to include in the rebuild. I am after a very nice performing streetable engine that is fairly dependable. I will not drive her often but would prefer once I am done to drive her more than I repair her. I appreciate your insight on the heads. Just out of curiosity what would be a good buy for this head? Just want to see if I got a deal or ripped. By the way I too am in GA so I will definitely keep you in mind during my jensen journey. Regards, Brad
|
||||||||||||||
| |||||||||||||||
| Posted: 09-05-2005 12:07 am |
|
4th Post |
|
mike92782 Member 
|
I recently had my head done by Richard Reyman. Here is the work I had done and the costs:
Mike
|
|||||||||||||
| ||||||||||||||
| Posted: 09-05-2005 01:34 am |
|
5th Post |
|
Judson Manning Member
|
As Mike so kindly details, a competition style set-up will cost you ~$2,500.00 (which is exactly what Huffaker quoted me). No doubt Mike's beast will be capable of producing well over 200hp at perhaps 7,500rpm???? (http://www.lotusbits.com publishes a dyno report for a similar set-up) On identical engines, Richard's magic can be worth an extra 40hp. However, you won't see much of it below 5,000rpm (right where the stock set-up starts to lose steam). Alternatively, for $250.00 you can get stock valves and guides. Find a local machinist who does work on modern 16-valve engines, and you'll get charged $200.00 for a basic valve-job. With a hand grinder, do some port matching 1" in and presto: The Poor Man's higher-flowing head solution. Richard is a wizard, and by all accounts does fantastic work, however, I don't suggest his services if you have a street car. For a street car, the 2.2 stroker kit makes the car much more 'streetable' if you have to chose where to put your money.
|
||||||||||||||
| |||||||||||||||
| Posted: 09-05-2005 09:58 am |
|
6th Post |
|
Harkes Member 
|
Brad, I agree with Judson: if you are not thinking of using your JH for the track but as a hot streetable car, then i think BHP is less important then torque. You would want a fat torque curve that gives you lots of power from 2000 rpm till 6000 rpm. I mean in a 30 year old convertible..who dares going faster than 200 km/hour? Also peak BHP is mostly around 6500/7200 rpm, but on the street you hardly live in those rpm ranges..at least i don't. Same goes for peak torque; you would want the peak torque at 5500 rpm or even lower than that. Judson's engine sounds very good and torquey. 11:1 c/r on gas pump is indeed very good. Judson; i would love to know your peak BHP and peak torque. My new 2.2L engine build by Garry Kemp is also 11:1 c/r on gas pump. That is a great basis to work on. (my pistons are JE's). Now comes head, cams, carbs etc.. the dyno plot Judson referred to has a peak power of 220 BHP at 7246 rpm and a peak torque of 171.1 lb ft at 6232 rpm. This is a 2.2L engine with 10.9:1 c/r and 104 on both inlet AND exhaust. This is a great example: with the 104's on inlet and exhaust you loose low end torque. My engine uses a 107 cam on the inlet and a custom cam (similar to the 104) for the exhaust (i would have to ask Garry for the specs). My engine has a peak power of 210 BHP at 6250 rpm (peak power is much lower!!) and a peak torque of 178 lb ft at........5000 rpm!! (more torque at a much lower rpm). It has 135 lb ft at 2500 rpm! the stock JH (with dellortos) has peak torque of 140 lb ft at 5500 rpm. I run 45E dellortos and they have been rejetted by Garry with 38mm venturis. I used to run 2.0L with 2 x 107 cams and 45E with 36 venturis. It all comes down to your driving style and purpose. In the much congested little country i live, i won't be able to drive much faster than 170 km/hr and i don't think if i could i would considering the respectable age and design of the car. Does anyone know how the JH performes when driving on or over 130mph?? good luck in your choices erik harkes Last edited on 09-05-2005 10:04 am by Harkes |
|||||||||||||
| ||||||||||||||
| Posted: 09-06-2005 03:38 pm |
|
7th Post |
|
Judson Manning Member
|
I'd be really interested to know the specs on the cam Garry put on your exhaust. For years the 'trick' solution was 104 intake and 107 exhaust...sounds like Garry has found another solution that seems contrary to previous thinking.....hmmmmm.... I'm running 36mm chokes and an interesting 'flavor' of 107 cams...no one seems to know where these things came from but they have 272^ duration (same as stock) and .388" lift. The official Turbo 107 cam is more like 252^ and .378" lift. While my car isn't perfect below 2500rpm, once it passes this mark it really takes off...I may need to try a 'spec' 107cam one of these days....
|
||||||||||||||
| |||||||||||||||
| Current time is 10:49 am | |
| > Jensen Healey & Jensen GT Tech > Engine & Transmission > New Heads | Top |
