I think my motor is on it's way out :(

[99FiveOh]

I know my motor has a lot of miles on it. The guy I bought my donor car from said the odo had just stopped at 187k when he bought the car 6 years prior. He also said he 1/4 miled it regularly and put at least 100k more miles on the car in those 6 years. Even thought the dealer he bought the car from said it received a rebuild on the engine, when I freshened up the motor with new gaskets and put the intake on I could tell that motor had never been taken apart in it's life!

The engine ran pretty good since the conversion up until about a week ago. Over the past week it's feeling "lose" for lack of a better term. I can feel more vibrations and hear more tapping going on. And I think I hear a little bottom end knock when I first start the car in the morning as well.

So I think what I'm going to do is use this lower mileage explorer short block I have, throw a set of GT40 heads on it and maybe a cam and put it in my car. I was hoping this motor would last until I had a 351 built for it but it's looking like that won't be the case.

I went on a short road trip yesterday and ran the motor at highway speeds a lot. It already felt out of sorts then, but this morning when I fired it up to go run some errands it was making some wierd noise I can only hear from the inside. Noise sounds kinda like water trickling or being forced through a small opening. It sounds like it's coming from the bellhousing area and doesn't change with the clutch in or out. Can anyone tell me what a bad crank bearing would sound like?

 

[screamin5oh]

well if its clanking when you fire it up for the first couple seconds thats a sign of a rod bearing, if its more of a slapping that can be piston slap, you should see a big change in oil pressure if either is getting bad, i will tell you on my old 85 that motor had well over 200,000 miles and knocked at start for years but i beat the piss out of it for years like that

 

[99FiveOh]

The vibrations are getting worse every day though. I know something is going to give soon.

 

[revhead347]

Damn, and you just put that engine in the car.

Kurt

 

[99FiveOh]

I know, it's a bummer.

 

[wheelyman19]

I'd say if u got a 351 on hand build the bottom end up and put it in then when funds allow do your hci combo that way u don't hav to keep pulling the motor out lol

 

[99FiveOh]

I don't have a 351. I did have a short block but had to sell it last year. I'm shooting for a lower mileage lightning motor income tax time. It will already come with GT40 heads and the tubular intake. I'll put some springs on the heads, throw a cam in and drop it in the car. Then I'll boost it! I may just see if I can baby this one around until then. I have a Maxima for my daily driver so the stang can sit!

 

[BlackVert]

sorry to hear it.

after everything else, at least this time is should pretty straightforward.

 

[Green 94 5.0]

Sounds like the problem is much deeper than this but have you checked the easy things like the balancer as a cause for the vibration?

 

[revhead347]

I'm having trouble seeing why you would want a 351 with iron heads.

Kurt

 

[99FiveOh]

I replaced all that before I installed the motor. It's spinning true and straight as it should since it's only a couple months old. Besides, I know what a bad balancer feels like, it's a "sharper" type of vibration that will vibrate the fillings from your teeth! This is more like something is loose, like things slapping around inside the motor. Problem with these 'stangs is we put loud exhaust systems on them and it's hard to hear a low end knock over the exhaust noise.

The only other thing I am considering is that maybe something came loose from the pressure plate. Since I am hearing a noise from the bellhousing area and there is this vibration it makes sense that perhaps a spring or retainer came loose. Only one way to find out though! lol

 

[99FiveOh]

I'm having trouble seeing why you would want a 351 with iron heads.

Kurt

$$$$$$$$$$$$$$$$$$$$$$

sometimes what I "want" is irrelevant! And when I cram 15 psi down it's throat the car won't mind the extra 100 lbs either!

 

[revhead347]

$$$$$$$$$$$$$$$$$$$$$$

sometimes what I "want" is irrelevant! And when I cram 15 psi down it's throat the car won't mind the extra 100 lbs either!

I guess with a lot of boost it will compensate. I still think you are better off with a 302 and aluminum heads rather than a 351 with iron heads. Should be about the same cost. I don't know about 15psi though. That much boost on iron heads is going to cause some detonation problems. It's not even 100lbs difference. I think it's more like 40lbs difference.

Kurt

 

[BlackVert]

I still think you are better off with a 302 and aluminum heads rather than a 351 with iron heads.

I still don't get why you don't understand that a 302 based solution has limitations that a 351 does not.

If one has to re-do the foundation anyway, why not go with a foundation that is known to be superior?

 

[99FiveOh]

A 302 with aluminum heads will still sign off at 500+ hp. I'm going for the lightning motor because it's a descent package for the money and is almost drop in ready besides the little crap. Then I can boost the crap out of it and know it will survive. I'm not looking for a 9 second strip terror, but maybe more like an 11 sec street warrior. The windsor will get me there reliably. I want to compete with terminators and coyotes.

 

[Zero Signal]

Problem with these 'stangs is we put loud exhaust systems on them and it's hard to hear a low end knock over the exhaust noise.

Hey. Not the car's fault there.

I wouldn't bother with the 351. It's WAAAY too much work. Just get a quality rebuild on the factory block and plan something out for it. It won't cost much more if any more to do a stroker. You can put the factory heads back on until you can afford proper equipment. I would suggest a basic rebuild of the heads though. That's the boat I'm in. I'm running a nice 347 but with the crappo factory heads since it was my only option (long story). The big difference is that I know I will never be able to afford proper heads before I get rid of the car.

I also wouldn't shoot for competing with anything new until you address the terrible factory suspension. A bone stock 2011 will easily blow away a 500hp SN95 with factory suspension.

 

[revhead347]

I still don't get why you don't understand that a 302 based solution has limitations that a 351 does not.

If one has to re-do the foundation anyway, why not go with a foundation that is known to be superior?

I pushed 600hp through my stock block 302 for 10 years. There's no hard number for when the stock block will crack. With a turbo you can push it a little farther. A 351 is not necessarily better than a 302. It has a longer stroke, but it also has heavier internals which costs you power. The bottom line is, with iron heads, you will likely hit the detonation point before you reach the 500hp mark anyway. Aluminum heads dissipate heat quicker, and are almost essential in high hp builds. Especially when that high hp is coming from high combustion pressures, a.k.a boost. I considered doing a 351 when I built my last engine. The cost of swapping to a basic 351 was actually more than going to another 347 with a 4 bolt main block. I'd go with the 4 bolt main block over a stock 351 block.

Kurt

 

[99FiveOh]

Hey. Not the car's fault there.

I wouldn't bother with the 351. It's WAAAY too much work. Just get a quality rebuild on the factory block and plan something out for it. It won't cost much more if any more to do a stroker. You can put the factory heads back on until you can afford proper equipment. I would suggest a basic rebuild of the heads though. That's the boat I'm in. I'm running a nice 347 but with the crappo factory heads since it was my only option (long story). The big difference is that I know I will never be able to afford proper heads before I get rid of the car.

I also wouldn't shoot for competing with anything new until you address the terrible factory suspension. A bone stock 2011 will easily blow away a 500hp SN95 with factory suspension.

But I don't want a "built" motor. I don't want a motor that will beat the crap out of me when I drive it daily. I want a smooth running motor with gobs of power from a blower or turbo. I wanna be able to turn up the boost and not worry about when the block is at it's limit.

And Kurt, a stock block 351 can handle 300-400 more hp than a stock block 302. I know you got away with it, but most don't. I don't want to take a chance on it. If I can find an aftermarket 302 block on the cheap I'll get it, but i'm not spending 2 grand on just a block and another 2 grand to have it built.

Also, I'm not sure where you're getting this "detonation point" nonsense. I pushed 15 psi through my iron headed 302 in my old 95 and it was fine. The 351 won't be any different. A thicker block with increased stroke is just what the doctor ordered.

 

[revhead347]

You've got some very good points. I still think you are better off with the 8.2" block, especially if you want to save money. If you are interested, there are 4 bolt blocks all over the corral classifieds in the range of $700-$1000.

Kurt

 

[99FiveOh]

If I can score one for that price when I'm ready I'll go that route. What that'll allow me to do is build a mild combo on this other block of mine and get it in the car, then get a 4 bolt block and transfer everything over to it. So many choices to make... my head is spinning! Anyone wanna buy a 5.0 converted New Edge? lol