update on my 3.7

[aussie]

ok i do understand about the counter balance shaft Mitsubishi had them on there 4 cyl run by a small timing belt and it broke and wasnt timed propley it would make the car vibrate in a funney way almst like the muffler was gone .thanks for that i havent spoken to him but ill do some research on it and i only want 5000 rpm or close enough i want a torque engine with the carby i dont like the small primaries and large secs and i have never rejted one i do all my fine tuning using a oxy sensor to get the fuel and air ratio correct thanks for your advice

[aussie]

Originally Posted by spareparts

the issue with balancing a 4 cylinder engine is that you can't completely balance one with using a balance shaft. I had my machinist explain it to once, but i still didn't understand what he said. It has something to do with harmonics or something. Most four cylinders are balanced close, but not perfect like you can with a V8. Same thing with some of the V6's, that's why they had the shake issue between 1400 rpm and 2500 rpm. They installed balance shafts on The V6's and it fixed the issue. Some overhead cam engines have weights on the cam shaft to help smooth the engine out. On your 3.7L they shake quite a bit to begin with, I think stroking it is going to add to the issue. Personally, I'd run the 4bbl intake with a Quadrajet(I like them), put the edlebrock head on with a good set of rocker arms. I don't know whats available for a cam shaft, but just running something better than the stock rockers should give you more lift than came from the factory. I think you'll be surprised how well it runs with this set up

spares i spoke to my mate at the shop and he said theres no reason why it should vibrate more only if i do a crank swap

[aussie]

ok the stroking part has been droped but i am going to buy some good conrods there not much more than doing your own---i finally took the timing cover of camshaft and crank so there all waiting to get machined and balanced --with the harmonic balancer i tried a cleveland one on it it fits fine and it even feels a little heavier i will buy a new one that has the removeable conterweight as these engine are internal balanced--i also need to ring crow cams about grinding the cam into a solid profile--i did try and get a unmachined cams from some cam places in the us but they didnt want to sell me one so im stuck using a regrind which im not to keen on---im going to have the old cam read to see what the specs are on it so i have some idea what it had---these are the specs im thinking of using its a comp cam 270s grind

Comp Cams #249-12-222-4

Magnum 270S Mechanical Flat Tappet Camshaft
Lift: .468"/.468"
Duration: 270°/270°
Lobe Separation Angle: 106°
RPM Range: 1500-5500

these are the head flow rates



i might increase the lift to 550 or 600 to get the flow benifits of the head but ill see what crow cams suggest and i will get a secound opion from wade cams too

im still thinking of cutting off the water pump shaft of the camshaft and getting the hole in the timing cover welded up and using a electric water pump as for the delco alternator thats going in the bin i got a 60 amp bosch that will do the job

the engine compartment is going to be painted in color flec and i have put the paper air filter under the bench and i am getting a flame arrestor one as you guys sugessted

will be posting pics and more info as its done and with the harmonic balancer it looks like all the lugs on the timing cover that held the old charging system will need to be machined off to fit will add pics when its done

[aussie]

11

[aussie]

After a week of emailing Eagle I got 4 connecting rods and it looks like ill be using Summit as the shipping is $80 cheaper than Jeggs and the sales rep when he rang ask for 4 but didn't tell eagle that it wasn't to match another 4 that it was for a 4cyl application so tomorrow morning ill be up at 4am to make the order


PROBLEMS pistons the block I have has 30+ pistons and I checked the bore no ridge marks up the top and still had hone marks in it so bye the eye it looked good enough to just hone but I decided to go 40+ as it had the wrong pistons in it 460 smog (I think that's what you call them )
my mate rang me and said theres a problem with the bore at 40 it wont clean up I thought im stuffed now as I only saw 40+ for them .Who ever bored it machined them like funnels omg--He ended up honing the bore while I was there and the bottom of the bore wasn't clean you could still see the light glaze I said it will have to do I have no choice and finding a block here id impossible .Then my mate suggest getting the shirts coated which will give them a little more size $100 to do all 4 so im getting them done and now I need to check the ring gap when its done may even have to buy file backs of those zero rings

With the crankshaft I cant get it machined until I have the connecting rods so that's on hold to now my mate has offered to clean up the ports on my new head im not sure if I want to pull apart a new head he said it will improve the flow rate it will be done for free

[smokeonthewater]

I'm NOT an expert on the subject but I would be VERY hesitant to mess with the porting in the head.... there are bad things that CAN come from that such as fuel not staying atomized at low rpm (IE loading up at idle or low speed) or losing low end torque (which is vital for a boat) to gain top end and you are building a lugger not a 1/4 mile screamer..
just my .02

[aussie]

I don't want to loose low end power this guy is a well know engine builder here its only around the guide boss that needs a clean up as edelbrock don't touch the casting around the guide boss as it takes time and will have a affect on the retail price . I should off said clean up as people know porting as making the ports larger todays its changing the shape of the port that's important not size--that's why these new style v8 go well the heads make the power

[smokeonthewater]

Actually you DID say "clean up" and I knew what you meant.
I've seen it go both ways ..... Both with a "well known" fellow doing the work.
As long as he really does have a good understanding of what works well for a marine engine you are likely ok but sooo many people want to build a boat engine the same way they would a dragster. Just saying be careful mate.

[aussie]

Originally Posted by smokeonthewater

Actually you DID say "clean up" and I knew what you meant.
I've seen it go both ways ..... Both with a "well known" fellow doing the work.
As long as he really does have a good understanding of what works well for a marine engine you are likely ok but sooo many people want to build a boat engine the same way they would a dragster. Just saying be careful mate.

I don't really want a race boat I need good idle and bottom end to get the boat on the plain with my wifes fat *** in there
lol really I want a good idle don't want it thumping when I engage it into gear or doing 5mph at idle

[smokeonthewater]

personally I'd most likely leave it alone.. edelbrock makes good stuff right out of the box... MIGHT be worth a call to edelbrock tech line to discuss their thoughts on your planned mods tho