Need Quick Help Going to Look at an Engine!!!

Adam95GT · Mar 16, 2007

Ok im going to look at a 306 today... the guy that posted it for sale said it was a 308 at first but i called him and he said its actually a 306... its got TFS heads hardened Push Rods an e cam and some other stuff... My question is... he said it was bored .030 over and they used low milage stock pistons from a 92 ho.... and used bigger rings to fit the 306.... is this common... or is this just asking for problems... i asked my friends and couldnt get a strait answer....is this what people normally do for a 306????

thanks,
adam

1slow95 · Mar 16, 2007

I don't know how bad of an idea it is, but I wouldn't do it.

1TallMF · Mar 16, 2007

hhmm I always thought they used oversized pistons in 306's. Has this engine been ran like this at all?

Adam95GT · Mar 16, 2007

no its pretty fresh the bottom end has new bearings and the rings are new... everything was freshened up... ive talked them down to $1200 with new mounts.... im just unsure weather to do it or not... im really worried about the bottom end.... but .030 isnt that much....

Therian · Mar 16, 2007

unless '92 pistons happened to be .30 over (and I don't believe they are...might want to look into it) I wouldn't feel comfortable running that bottom end. I don't like the thought of my pistons having 'wiggle room' in the block.

306 kits aren't uncommon, but they always have 306 specific pistons. Most engine builders insist on having the pistons before doing any boring, simply because there are often tolerance issue that must be addressed.

I'd also want to know why he's selling it.

94-302-vert · Mar 16, 2007

For $1200 buy it, pull a head and check to see if the pistons are right or not... the heads alone are worth the $1200...

Adam95GT · Mar 16, 2007

well he said they used bigger rings so they fit.... i dont have money to spend like that...
here is the specs that i do know:
94 302. forged pistons 9 5 1 comp. low mileage on shortblock. tfs heads. crane 1 6 roller rockers. e cam. victor 5.0 intake, brand new. heads have 5k on them. rockers same. hardened pushrods. all new gaskets. 94-95 timeing chain cover and water pump. selling with all assc. off a 94 cobra minus smog and ac. 1800obo will not separate. located in jersey

But when i called him he said the bottom end is from a 92 ( pistons, rods, Crank) with 30,000ish miles.... im just unsure that even if they did use bigger rings... that they might fail if your relying on them for compression to much...

Therian · Mar 16, 2007

buying a used engine is always a tough call man. I didn't notice that it was a long block before though...if you can get it for 1200 I would do it.

the heads + intake could be sold for 1200 probably...

Adam95GT · Mar 16, 2007

he said 1200 minus the intake manifold but i was going to try to get him to do 1200 + my gt40manifold for his complete set up... i was just wondering if anyone has heard of using stock 302 pistons and bigger rings in a 306 ....????

final5-0 · Mar 16, 2007

It just don't work that way Trav

Stock size slugs would be wallerin around big time in holes 30 over

You must have been mistaken about what that guy said

Grady

Adam95GT · Mar 16, 2007

thanks grady... im trying to get ahold of the guy again... but he said he sent it to a shop and had his motor bored to a 306 and the guy put in stock forged 92 302 pistons in the 306 with bigger rings to make it work right...

if you know anything about this please let me know... im calling him up again tonight....

The Green GT · Mar 16, 2007

I cant see that working at all. I mean think about what it would do to the compression with a gap on the sides of the pistons.

HISSIN50 · Mar 16, 2007

I'm with Grady here - you'd have some slap and control issues, especially with a forged slug.

I'd add that in the 92 model year run (though generally considered to be late in the run), they changed to hypereutectic pistons. When boneyard hunting, a crude generality that often works as a clue is that if the oil pan was grey, it was forged. If the pan was black, it had hyper pistons. None of that would probably be helpful in your case though.

Good luck.

trav_19 · Mar 16, 2007

....hmm we sold engine rebuild kits at the parts store with .30 rings for a stock piston people bought them up pretty commonly so i know it has been done before..

HISSIN50 · Mar 16, 2007

Trav, do you know if the bores were punched over or just honed? You can get away with a hone and fresh rings on a stock piston.

Grn92LX · Mar 16, 2007

I'd pass on buying someones used train wreck, save your pennys and have an engine built the way YOU want it.

blksn955.o · Mar 16, 2007

I would not do it.

If the setup is running a "factory" replacement .030 piston then it could be true. However, there is NO way a stock piston will fit in a .030 overbore. Rings that would make up that kind of size diff. dont really exist, remember rings fill like a .003 or .006 type toll. If someone was to even be able to get a ring package to make up the diff. rings are not setup to handle the load that would be put on them.

Either the guy does not know what he is talking about and selling something that a shop took him for a ride on.

or

he has a said trainwreck from not knowing what to run or is making up an excuse as to why it will not run when you get it.

trav_19 · Mar 16, 2007

hmm its been a long time since i sold them lol maybe it was for a honed block....hmmm now im curious....i would probley never buy a used motor from someone like that its prolbey a 302 with stock pistons and never rebuild just got new heads on a high miliage block and then it started pulling oil lol if you cant hear it run dont buy it....my friend got taken for a ride in kinda the same boat supposibly it was a 347 and all that wiht everything new and all this it had a good set a heads with stock rockers and stock bore so beware he had to completly build it...his excuse was well it was a friends that i was selling it for thats what he told me it was after that conversation he couldn't be reached...

reddy351 · Mar 16, 2007

Run! Run far away and FAST! This guy is waiting for a sucker! He's talking some bullsh1t! The parts may be worth $1200, but what has he done to them to ruin them? If they took stock bore (4.000") pistons and put .030" over rings in there, it won't run for more than a few minutes before it takes itself apart. (recommended piston clearance is .0012"-.0028". .030" is WAY too much.) Back in the day, we put a 351w together that had about .008" of play (didn't realize it, when we were re-ringing it.) the skirts of the brand new pistons were broken off in less than 5000 miles. It was a disaster. If he cobbled the short block chances are he cobbled the heads and everything else. I would MUCH rather pay $600-$800 for a 50,000 mile OE longblock than somebody elses (correctly put on an earlier post) trainwreck.

Adam95GT · Mar 17, 2007

Alright guys i just talked to the kid and he talked to his brother who had the work done... and he said that it was honed not bored 30 over like he thought.... and they put in new rings and bearings.... so i guess that means its still a 302 which is cool.... now do you guys think this is an ok deal????

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