Well I did it, 3 trashed pistons in my car, on a new engine. I have been attempting to sort it out. The engine was very mild, 91 Iroc cam, 350 .060 over. 305 heads nothing fancy, stock ECM with 24 LBS injectors. So I am very perplexed as to why???. I was only running about 6-10 degress of intial timing at the crank. Stock is 6. So I am not happy.

So I am looking for 8 new piston, 350 0.060 over. the psitons that were in there were Sealed Power L2417 but I can't find that number any where looks like they are discontinued. Otherwise I would would just get 3 and weight match them.

If anyone a s a good deal on pistons or a used short block let me know

thanks
Steve

 

left side

 

right side #2

 

Damn, good luck fixen it.

I was hoping to see that car run at Mosport next week.

 

Can you get a closer shot of the gasket edges around the messed cylinders? Also what do the plugs from those cylinders look like?

 

ME TOO!!! LOL!

Sports Car Revolution will be filming this weekend on Sat AM TOO!!!!!

I just need pistons now.

Steve

 

Better figure out WHY you need new pistons first!

 

Oh yea , I know that!LOL!! something , timing, AFR etc is off, I will have to get it back together and spend some time on the dyno sorting out.

Thank
Steve

 

Good luck with it, you don't want to have to dig in a third time!!

 

That's some pretty impressive destruction for a near stock engine

I have a set of almost new .030 over pistons hanging around. It's too bad they wouldn't work.

 

What about sticking a carb on it. Might be easier/cheaper to sort out and should make more power.

 

I have been seriously thinking of that. The TPI is very restictive after 4500-5000 RPM and I would like to make power to around 6000. and move my torque higher up in the rev range. This woul makeit much easier to drive out of corners,.i.e hooking it up.

I am defianelty going with bigger cam. My heads are 081 castings, 305 heads small valves. apporx. 1.85. If I can find a better set of heads that need reworking 1.94 or bigger I'll put them on. I'd swap the heads I have now, which have VERY little time on them, they have new valves, springs, guide plates, screw in studs etc. SO if you know anyone with some heads bare or assembled let me know, Carbs and manifold too, i.e. Torker etc single plane and 750 DP for example.

thanks
Steve

 

Take those "305" heads and stick them back on the 305 they came off of.

Those heads will limit your power above 4500 or so....they're junk & not worth putting $0.01 into.

Get some 350 heads with a 64cc chamber & decent size valve 1.94/1.50 or whatever depending on what pistons you end up using.

As for the pistons, now may be a good time to invest in some Federal Mogul/TRW forged pistons if you can afford it, or even better a lighter forged piston (SRP, Wiseco, JE, Ross, Etc...)

Put some good ARP Waveloc bolts in those stock rods & have them resized.

Do it right, not twice & thats the best info i can offer you.

 

Thanks I agree, the pistons are Sealed power forged pistons L2417 and the bottom end was done right. It only had maybe an 1-2 hours fo run time. But the tuning was NOT,.........

I will put forged back in again , and will verify the weight against of the new psitons against the old ones, to see I have to rebalance. I will probably do it anyway if I can't get the same psitons. (I believe the L2417 are discontinued).
ANy suggestions? I was thingking going with a slight doem to raise my compression ratio a bit, it is a track only car, raod racing.

I agree on the heads! The 305 heads are better suited for a tow vehicle.LOL!

Thanks for the advice

steve

 

Any idea what compression you were running?? 305 heads being 58 cc would have jumped the compression way up and then I see you were bored 60 over. What piston were you using. I would put the compression at through the roof. Was it a flat, domed or dished piston that you were using. From pics it looks like flat which would coincide with the stock comment.

Anybody got the calculator to figure out compression on this??

 

Seems odd.

I think it's been mentioned but you really have to find out what caused that o/wise you might be doing it all again after another 1-2 hours of run time.

What about the shop that built it - have they got anything to say apart from "30 seconds or 30 feet" I was considering that car at one point and if I'm not mistaken the engine builder's name was mentioned in the ad.

 

I haven't contacted the engine builder yet. I didn't have them build the engine. Here is what was told to me by the former owner. "The car wasn't running right, not all injectors were firing. I took it up to Strudwick motors ( they have raced camaros and corvettes for 20+ years) and they replaced the injectors,24lb. Accel, MAF and ECM. ran great afterwards."

Umm.. 58 CC chambers in teh 305 heads.... I thought they were 64CC........ Well.....
The pistons are labeled flat top but they have a single valve relief so they can run on either side of the block. Not the typical 4 "eye brow" style we see in stock ones. The pistons are sealed power L2417 forged.

My feeling is that is was either fuel delivery or timing. It could have ran lean. fuel pressure maybe ? It has an adjustable regualtor and it was set for 43 psi. Idle. and would increase when rev'd.

At first I had a combination of some old gas and lots of fresh gas with octane boost, FI cleaner etc. the last time out I had sunoco 94 octane with otance boost. I could not hear any "rattling" when driving, load exhaust and helmet on?


I still have to rebuild the bottom end first. I will probably go to a bigger cam and better flowing heads. and replace the fuel pump to be safe. As far as the induction system, I am not sure if I want to stay with EFI or go with a carb set up. Either way some dyno time with a wide band O2 sensor is in order. I would like approx 400 Hp and be able to pull to 6000-6500 RPM.
The TPI is doesn't like to make power above 4500-5000 and the heads are also a limiting factor. An Accel stealth ram maybe? any one running one of these?

thanks for all the help!!

At least is ti a SBC chevy, aprts are cheap!! I can buy an entire SET of pistons for it for the same price as 1 psiton costs for my Mercedes 6 cyl diesel!!!!!!!!!! LOL!!!! pistons are $2500 !!!! Rods are $1800, everything else is fairly reasonnable.

thanks and regards!
Steve

PS any ideas, thoughts, or comments are always appreciated.

 

Here are my worthless two cents.............

1. That wasn't caused by a bad tune. If it was, it was a severe lean condition caused by some sort of mechanical failure. You can actually see one of the hot spots in one of the pics.

2. 400HP will require a new cam, heads, and intake. A Holley Stealth Ram would do the job as far as intakes go but so would a carb and intake. I'd combine the HSR with some AFR's (or Fastburns / E-tecs), and one of the new Comp XFI cams. But i'm also an EFI honk

 

This is what I was referring to..........

In pic 3 it looks like the piston is smashed from detonation

 

the very dark black spot you ahve circled? or the chunks missing over the rings?

I my earlier statem about a state of tune, a severe lean condition would fall under a bad tune. I.e it leaned out, why I don;t know!!

thanks for the great input, I like the AFR heads too.!!

I would rather go EFI personally,


thanks
Steve

 

In theory, all the injectors are going to spraying the same amount of fuel. A programming issue wouldn't cause that damage. A failure in the fuel system would though.

The spot I circled looks like a melted divot in the piston to me.

 

true about the injectors.

Part of wht you see is the vailve relief in the psiton but you are correct the piston did start to melt there also. In addition, the edges on 3 pistons were smashed away includign the top ring!!

but this was only in 3 cylinders 5,7, & 2, the other 5 look perfect- failing or clogged injectors? or wiring? I wll have have to test them to make sure. Cylinder 5 is the worse.

Are these batch fired or "true" MPFI, sequential fired systems?

thanks for the insight!
Steve

 

They are batch fired. A failing injector will usually dump fuel before starving it. They could be clogged I guess, but 3 of them to cause that much damage....I don't know, having them tested will be a must in this case before you fire this thing up again!!

 

Sorry to see that happening. Do a search on TGO for Accel Injectors, may have had something to do with the issue.

RBob.

 

Since your pretty much starting from scratch, i'd find a 283 crank, a 327 block, a decent set of heads and valvetrain, and carb it. You now have an easy 7000+rpm road course monster. Will be tonnes more fun than EFI ever could be on a road course.

EFI on anything but a street car= eternity of damnation in fire-y region

 

It would be pretty hard to find a 327 small journal block for that 283 crank to fit in!

 

I've seen clone 302 short blocks on ebay back when i bought the 383. They were a little pricey then. But a roller valvetrain, and a good balancing and those motors sing like crazy.

 

I'd rather have a 350 or 383

 

or a BBC thats spins up to 7000 RPM

 

I have been thinking about a dropping in a later lorge journal 327 crank in the 350 block, any thoughts??? Pistons might be tough , not sure if I would have to have a custom pin height. just some food for thought. It is a track car and not a steet car.

Pistons are cheap for this engine, $235 US for forged selaed power + rings.

Any one know of a place in the GTA to get injectors tested?

thanks
Steve

 

I wouldn't bother with any kind of "different" engine combo. Just stick with the 350 or 383.

You can get your injectors serviced at www.racetronix.com . They're in the GTA.

 

This seems almost like I guy I know named Jack with a buick GN. Shop in the woodbine/steeles area. Is that him by any chance? I forgot the name of his shop. Was there when he was putting it together a couple of years ago.

 

I agree; particularly for a track car.

Get something simple that puts out about 350 HP and can be easily tuned at the track using machine age technology such as a screw driver.

A carbed 350 should be adeqate and will meet the above criteria.

 

yup thats him..Jack owns racetronix

 

I only half read it so sorry if someone else already told you but with 081's and flat top's the 58cc head will put your compression way too high for cast heads on street fuel.

I would surmise that is the reason for your trouble's.

 

thanks!! I didn't build the engine I got it that way. FYI I was running Sunoco 94 with octance boost. the psitons actauly were flat tops but are close, they do have a full width valve relief. Bascially it was a 350 +0.060 with 305 heads! I fgure around 11-11.5 :1 compression ratio. anyother guesses?

Anyway, anyone got any 350 heads they would liek to part with?

thanks
Steve

 

I dont, but you can buy my shortblock for $3500

https://www.thirdgen.org/techbb2/sho...14#post2487414

 

Awesome motor. Now why couldn't you have posted that a year ago when I was looking?

 

Yup it was your compression then, you cant run more then 10.5:1 on pump gas with cast heads or BOOM just like you got.

You need to retard the timming to run 11:1 with Alum heads even.

 

Hey Hawk, I agree, this was my comment from much earlier in the thread. That was all I needed to know before it would have been easy to see that the compression was way to high for any street gas, even 94 gold. The compression here has to be high 11's which would have caused the damage that we see pictured. dished pistons and some 64cc heads would make this setup work

 

I looked up the specs on teh pistons i have and they are rated at 9.72:1 compression ratio with a 64CC chamber. Even with 58CC chambers I shouldn't see more than 10.5: 1 compression ratio. I will get the injectors tesed and see why I leaned out or if teh timing was way off.

thanks
Steve

 

Well I am in the process of rebuilding the engine. I am going with the 350 4 bolt main block I have with flat top Prob forged SRS pistons 0.060 over with powerhouse ultralight rods with a 350 forged chevy crank and a Findanza aluminum flywheel. I want a bullet proof bottom end.

I am running world castings S/R torquer 76CC with uprated Manley springs good for .600 lift. hese are the 2.02/1.60 heads. I got hese and the crank from my machinist.

This will give me 9:1 compression. I am going after a very broad, wide torue curve.i.e pulls like a frieght train from 2500-6000.
carb to start-750 DP on probably Torker II (I have one).

Camshaft is hydraulic roller, I haven't settled on a final grind yet. I have ZZ4 cam that I was going to use on a steeet project, thats why I have a Holey 750 DP and a Torker II. LOL!
But I am looking at a bit more agressive grind. Anyone have any experience with the ZZ4 grind?

Dyno simiulation give me just under 400 HP with the ZZ4 (396HP) and apprix 420 HP with the bigger cam. 24 more HP, but is peak 24 HP worth $240 US fo rthe cam? The ZZ4 has a broader torque curve and pulls vnicely to 5500 the bigger cam pulls to 6000.

Thanks and looking forward to getting it back on the track.
Steve

 

Steve if you can, avoid that Torquer II intake because it really is one the worst intakes ever designed & has a problem distributing fuel evenly.

If you can fit it, an Edelbrock RPM intake would be a much better joice i think

That probe flattop with a 3.48" stroke will give you 8.8:1 with a 76cc head.....why dont you mill those heads down to ~70cc and get that compression up again.

-Carm

 

Hi Carm,
Thanks for the feed back!

Just an FYI according the Probe data sheet with a 0.060 over bore they go to 8.99 to 1. I have skimmed the block and head just to clean them up, but nothing major. I don't want to run race gas and after last years fiasco with the detoantion issue I am little gun shy.

I want to get everything back from the machine shop and assemble one rod and piston combo and mock it up so I can check the piston to deck distance. I am running a 6.0 rod piston combo. I'll know more what to do once I get it mocked up.

The heads won't be on there too long. I'll replace them next year-hopefully. I'll go aluminum an get REAL serious!!

Only so much $$ to play with this year!!

I am thinking of the RPM Air gap or the Professional products "Clone" Crosswind.

I have the Torker II from another project that has a real low hood. The Torker II is nice and low.

Thanks
Steve

 

April 29 at the DDT - do you think you'll be at that one.

 

no prob....those Pro Products intakes are pretty decent for the $. I've used them before (Hurricane) and im intending on using it again this season (polished Hurricane).

From what i've seen just need a slight cleanup in the runners just like the Edelbrock's and they're good to go. Heck, you can bolt them on out-of-the-box but im a little picky

I just pulled up an SRS 350 Probe flattop when i said 8.8:1 so i was close :P

When you do change to your aluminum heads though, you can order up a smaller chamber ~64cc and get that compression up.

Just curious why you decided to go with the Probe stuff? Don't know many Chev guys using it, lots of Ford's though

 

George- April 29 DDT I sure hope so, fun little track, elevation changes and I had a spin out at speed on the kink in the straight about 60+MPH in my Jaguar. Without R compounds that car would like to come around on me, did it at Shannonville too. Were looking you for a bolt in Players roll cage? I can't remmebr if it was you or Scott. I know some one who has one, he thinks.

I went with the probe due to price to quality, they have a very good reputation and the prices through Powerhouse were awesome!

Check out www.enginekits.com, I bought- Pistons, rods, Clevite 77 H main and rod bearings and a SFI rated harmonic balancer for $982 US. Exchange rate is very good right now!! :-)

Probe has 3 levels of pistons.: FPS SRS and RSR?, I went with the middle ones- Sportsman Racing Series. Flattop,

My machinist/engine builder does the BIG offshore racing engines, he is in Orillia, 500+ HP boat motors etc. small custom shop, Mercruiser hP warranty shop too. He had 2- matched pair of 502 Mercuriser Chevy BBs out off a 34' Donzi -$300,000 boat, he was them "freshening up".

I'll go aluminium 210CC or larger, 64 CC chamgers etc, the car is not a street car. don't real low end.

Steve

 

Lol..I've seen a few people go off there - gets to be a bit of a ploughing match sometimes.

Should be a good day though and it's on a Saturday too - supposed to be a barbeque afterwards. Not bad for $135.00.

I wasn't looking for a cage as my car is still a road car and if I cage it then I'll need seats and a harness etc. It's starting to concern me a bit though as I got the car completely sideways last year in the rain coming up the hill to Moss; I was thinking "well, it's going to be a track car now after I back it into the tyre wall" but I managed to gather it up somehow and kept going as if nothing happened..lol.

I expect there will be a few f-bodies there from TFBM on the 29th; one of our guys bought a Player's car last year. I see that there's a blue one for sale on casc - Catherine Teasdale's old car - too bad I have no room to store it.

 

I agree on the performer rpm intake. I fit the air gap version under my stock 91RS hood with a Holley 770 and a 14x3" drop base air clearner. Just barely mind you!
What are you running exhaust wise... unequal length or stepped headers are known to broaden/flatten a torque curve as well... Same thing with crossovers if you're running a dual exhaust.

 

Buy my motor - it was built for my solo 1 car, but I am no longer interested in racing. Rather get the house fixed up this year.

I think you can build a much better motor for the same $$ amount if you change a few minor things. If you already have the parts, then I guess you are using them.

I would change the block or at least have it sonic checked. 60 over is too far for road racing for 90% of the blocks. You want at least 0.150 thickness in the walls, with thicker in the trust area. Too thin and you will get cracks in the bores from them flexing.

In your pic's - you detonated it to death. The smashed ring lands are an easy giveaway.

Those heads you have are not very good. I would spend about $1000 cdn and pic up a new set of Dart Pro-1's in aluminum with 180-200cc intake ports. The smaller ones will actually make your car faster on a road course because of superior torque.

The heads you have only have a 165cc intake port and flow about the same as a factory fuelie head. They are designed as a stock replacement and flow like it. They chambers on them suck also. Are they the ones Andy at straightline had for sale?

If you are on a budget - the Vortec are kick *** heads for the money also - but after the needed upgrades, its only a few hunded more for the aluminum Darts. For the same price as the Torquers you could have gotten Iron Eagles. 64cc heads are the way to go with th aluminum ones and build the motor with a tight quench.

If you are using the stock hydralic lifters, you might need to change the springs on the heads you have because they are really heavy and really are not happy above 5500rpm. They need heavy springs to keep em' from floating or a rev kit. When they start jumping off the peak the roller shatters and you get to build a new motor again. I would limit engine speed if you can, build for torque, and gear it appropriately.

Engine load increases linearly with cylinder pressure which creates torque, but geometrically with RPM.