Blown engine and rebuilding my 308

Your hp goal is going to be quite a strech for natural aspiration...a full race prep might get you to 300rwhp, but with carbs on it, it won't be very street freindly IHO....300-320 is what a 360 makes, 320-350 is a CS. They do it with 5 valves, 8700 rpm, and a state of the art intake design. Your going to have your hands full. Carb'd 2v 308 race cars make about 320 crank, so 275 rwhp. Switching to an 8 throttle body EFI system would add 20-30 hp to that getting you to your goal and make it streetable. Rob at www.force-efi.com told me a couple days ago they now make a weber replacement throttle body for about $600.

To your question, A friend of mine had his heads done at Norwood. They said they bumped the flow up about 10%. Nick's websight also had porting listed, you might give him call too.

Boost is probably by far the cheaper and more streetable way to make the numbers your talking about. I can tell you that by simply putting an eaton MP90 supercharger on my QV it made 304 rwhp at 10 psi, no intercooling. I now have a lysholm screw type blower and an intercooler an I think it is about 500 rwhp, I'll be dynoing it soon. There are a couple guys with Norwood turbo cars on this sight who make 400+ rwhp on street cars (308, 348) and a 300 rwhp daily driver mondial.

 

Hi Dan

My, that is a mess !!

We can supply you engine parts from stock. Even brand new OE cylinder heads if you like.

Prepared to be very competetive if required !

 

Uhhhh....I think you need to switch to Royal Purple, bro.

And maybe change it a little more often!!!

Get in touch with Caribou Engineering. They are working up a 308 engine for Forza with tech articles. You are not going to get past 300HP in a street engine without losing drivability, but I'll let them tell you that.

That said, in your car (210 -240HP stock), 260 - 280 should give a noticable kick in the pants!

Now go steam out that block!

 

Hi Dan
Sorry to see this
Was this a sodium filled valve that let go?
John

 

Dan:
Cool..I am doing the same thing right now and so far you are winning the biggest frickin mess on the floor competition, but in a day or two I should be there!! I am going to follow your thread here for some vicarious (big word for me) advice. I would suggest Nick's Forza Ferrari (sponsor) here for some good advice and practical knowledge, and parts source. He has been very helpful to me so far.

 

Why were you running a 7500 RPM red lined engine at 8,000 RPMs?

A) you need to change the oil about 2X as often as you were changing the oil.
B) you will need a new head, new liner, piston, con rod, and a bunch of other parts.
C) as long as you are in there, you should micrometer every journal bearing and every clearance if you want a 300 HP engine to live for more than the first dyno run.

Modern gas (last year) was good for 11:1 with excellent combustion chanber shape and careful fuel injection and knock sensor advance control. With carbs and manual advance, stay under 10.0:1 unless you want to learn how to tune Webers daily.

The DCNF 36's will limit you airflow to under 300 FWHP.

If this were my engine: and in consideration that one piston has already let go, I would consider the con rods, wrist pins, pistons and cylinder liners to be junk. With a substantial upgrade in target power, and the age of these parts, just put in all new bottom end (less crank). Don't forget to check the indexing of the crankshaft and micrometer the journals, and align bore the mains. If 300+ HP is a realistic goal, consider building the bottom end with titanium con rods and converting the engine to dry sump.

On the top end, you should replace very valve, every guide, have the cam checked for wear and timing/cylinder. Have the cam journal bearings align bored. I believe that there is an upgraded set of cam seals available.

You are looking at a $15K rebuild at least, and if 300 HP is a goal, figure $23K after tuning.

 

1. If I was in your shoes I would buy a rebuilt bottom end from T.Rutlands (7500.00) specifying the 10:1 pistons and spend the rest(?) of the money on extensive head work, P4 cams and carburetor rebuilds/mods. You might get 240 at the rear wheels this way.

2. If you want 300+ at the rear wheels I would go with a mild form of supercharging similar to Mark E's set up. Plenty of power and still retaining drivability and longevity.

3. An alternative to 300 HP at the rear wheels (almost);
Sell the 308 to me for 6,000.00, then take the money in items 1 & 2 and buy a good used Testarossa.

DJ

 

LOL, Spasso!

You gonna "collect" 308GTBs, like me???

 

How, pray tell, are you going to fix all those divots in the combustion chamber of the piston that let go? (So that it has the same shape and volume as the others?)

 

I would start with another complete engine. No telling how much crap got flushed through that engine! The shock of blowing a piston isn't just limited to the damaged parts but to most of the surrounding parts. My guess is the head is done too, cracked possibly.

Judging from the looks of the internals of that engine in general (very dirty) I would also guess that it would need a complete blueprinting, total remachining throughout and rebalancing of the rotating assembly. $$$$$$$$$



Speedy,
God forbid I should start collecting 308's! Maybe I should take my own advice and cash in for a TR.

DJ

 

i dont see how you could replace just 2 rods, on the same bank no less and expect to get any performance out of the remains sitting on the floor. all the rods and pistons should be replaced, just to get them to balance under load. get a crate motor and put a super charger on it. you will be back on the road in no time. otherwise its going to take time, more time and $$$$$$$ to get it the way you will be happy with. sorry to read about this though, least i have pics of the guts for when my 308 gets here. ouch!

 

Custom pistons...1500, they come eith rings,pins,pin bushings
Custome rods.....1000.More if titainium,,but not nessacasry
Reapir cylinder head(yes it is possiable) abot 600-1000 depending how much work is needed
New valves ,guides, seals, about 500
New bearings rod and mains about 500
Gaskets figure about 700
engine balancing about 3-500
Cylinder sleaves..get custome ones made.

You can build one of these motors for a reasonable price. You just have to do your research, and be willing to mreak out the measuring tools.

 

If your wanting 300+ rwhp your going to spend BIG bucks for normally aspirated. Your going to need really trick rods (carrillo or pauter), ARP rod bolts and head studs, trick pistons and matched liners, custom larger valves, ported/polished heads with a serious valve job, full racing cams, racing headers and good muffler, a more powerful ignition system and lots of expert time spent on carb setup. Too bad there is no way to twin plug the 2v cars. Your also going to needs lots of good machine shop time to balance the entire rotating mass. I would expect power at 7000rpm to 9000rpm, and it will be a dog below 4k. Expect to spend $20K.

Or..... buy a rebuilt STOCK compression long block from trutlands for $7500, Then spend perhaps $6K on a supercharger install and have 350hp and a more streetable car.

Or you can do what I did if you really want to go fast around the track: buy a Porsche!


Terry

 

I spoke with Nick a while ago and he told me that the 308 engine can take 8000 rpms no problem.

 

Looking at what's sitting on the floor, I think we found one example that couldn't take 8000 rpm.

I'll up the offer, $6500 for the mess.

 

As long as a valve doesn't let go!

 

7,000...........................

 

Dan, please forgive me, because I'm not trying to be insulting,
but that is about the nastiest 308 engine I have ever seen.

A stock 308s cams fall off just before 7000 RPM.
Every dyno pull I have seen shows this.
Can you take a stock 308 up to 8000 RPM? Sure, but why?

And Ditto on what the tech heads have said, your not going to get the HP you are after NA without VERY DEEP pockets.

 

7250 but no more unless I get to inspect it in detail.

 

YOU GUYS ARE NUTS, I PAID LESS THAN $10K FOR MY 308 AND IT DOESNT NEED A DARN ENGINE! ( and yes it has a clean TITLE ) nanny nanny boo -boo!

 

Dan:

Just a note:

You may have read the following, but if not there may be information within that will help ...

"FORZA The Magazine About Ferrari" in Number 43, February 2003, and Number 44,April 2003 have a good article regarding the rebuild of a 308 engine. There is some discussion regarding cams and the like.


Best wishes

 

My dyno chart. 1978 308 GTS. Crane ignition. Ansa exhaust. No cats. The max HP is 6400 to 6600 RPM. I ran mine to 8k on one run and it didn't skip a beat. Kind of pointless after I saw the RPM, peak HP.
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