engine problems, replace? rebuild? stroke?

OK so on the way down the highway the otherday i think my engine finaly gave up the ghost, while i didn't fully granade it i caught it before that it has started to make a really aweful grinding, banging noise from inside the cylinder head. My step dad looked at it and he said that it sounds really bad, he thought that it might be that one of the rocker arms was broken and bouncing aroung, and he was hoping for that. but we pulled off the valve cover and every thing looked find but the noise was even louder. he says that it sounds like a piston pin or a pison rod it broken, he thinks at least one of the pisons it free moving up and down and since it happened on the highway, i am guessing it may have caused some signifigant damage to the engine. but in the end he said that we will proubly have to replace the engine or at a minimum take the cylinder head off drop the pan and replace the pistons. but im not sure what to do. what do u guys think? totaly replace the whole engine? take one i have and rebuild it? how much would it cost do u guys think it would be to take my current engine rebuild it and stroke it?

Well you could have bent a valve, and it is hitting the top of the slug. Or it is sticking and when the slug hits it, it pushes it shut.

I have been working on the stroker thing for some time now and it is like doing a lift kit. The parts you want to use list, just gets longer and longer. I have gone through 3 cranks before getting the one I will use. I have a set of pistons that are 0.060 over that I am not going to use, getting a set of different 0.060 over slugs.

My crank (turned new) was $175
Rods (have to get used, arn't made anymore) $65
First set of slugs around $200
First set of rings $70 +/-
all valves $150
Cam, lifters, springs, retainers aprox $400
Next set of slugs and rings $200
Head gasket can't remember
head abolts $125
Headers $400
Push rods $7
Still need rocker arms, fab up roller rockers around $200
High valume oil pump, haven't even looked at yet
Cam bearings, no clue, shop is getting them
$500 so far to shop
$220 to bore block
$125 valve job
$35 a releaf to cut down for valve springs (12 total)
About $150 to clean intake and have machined out to 69 mm
$365 for a 68 mm TB
A TB spacer, and to have it machined out
That is not including the higher rate fuel injectors still needed, and fuel delevery system, still need to put together
electrical gadgets like adjustable MAP sensor, relocating the AIT to a cooler spot, and fine tuning the TPS. Contaplating the Jet stage 3
Bought a turbo for it, and need to get all the other gadgets that go along with it. A 2 1/2" exhaust with high flow cat and mufler. As well as fab up a 3" intake system with a cold air intake. (not intercooler)
Oh, and $100 for donor block from junk yard. Destroyed last motor but the heads. (everything on the bottom end was toasted)

how many miles are on the motor? after enough miles the cylinders won't be round anymore, they take an oval shape you i'd get it checked before you put new pistons in it, that is if ya decide to take the easy route. If you choose to rebuild it then get the cylinders bored to the smallest possible overbore until they are round again. I guess it all matters on how much ya can spend, ya know.

my engine has 170 thousand miles on it. my step dad has been a mechanic for 30 years and i would think that he would be correct and another mechanic that is local agrees with him after listening to it, we need to pull the heads and really take a look at the internals we just haven't really gotten that far yet.

no no, what i meant was when you put new pistons in it dont' just throw them in at that amount of miles because the bores won't be round anymore. I'm saying when ya replace them if i was you i'd have the block rebored.

Eric

...after listening to it, we need to pull the heads and really take a look...

Click to expand...

"heads"? are we talking an old V6 or typo.

If you are talking stroking the 4.0 it depends on how you do it.
It comes down to two main methods, cheap and expensive, and in this case cheap is only a relative term.

The "cheap" method uses the 4.2L crand AND rods with a 4.0 slug. It works but is very difficult to set up quench and keep compression tolerable. I would only consider this method if you run a renix based engine (non-HO). The second method uses the same 4.2L crank but uses 4.0L rods and custom pistons. The pistons alone can set you back the price of a 4.0 complete rebuild kit. As M Lake said,

The parts you want to use list, just gets longer and longer...

Click to expand...

I went top shelf on my parts selection (stainless valves, true roller timing chain, HESCO water pump, Borla header yada, yada, yada...) and it came out over $3.5K ($2.2K in just internals and injectors). Add to that a new head 1700 miles later and now a new cam and bearings and I'll be well over $4.2K. I like the power but it doesn't come cheap.

If you are serious about a stroker talk to Mike at Accurate Power (http://www.accuratepower.com/Jeep/) and sign up for the strokers newsgroup on Yahoo (http://autos.groups.yahoo.com/group/strokers/) as there is a ton of info there.

Good Luck,

Bones
#6

How old is your Jeep, what condition is it in, and how much do you want to invest in it? A stroker is not much different from a full rebuild of a stock engine -- it just happens to use a stock crankshaft from a different engine. (Or a different version of the same engine.) To do it right, you're looking at probably $2000 to $3000 to build a stroker engine.

Unless you really need the additional torque a stroker will generate, your most economical route would be to buy a low-mileage late-model engine out of a junkyard and just drop it in. If your old block hasn't been trashed by a rod through the cylinder wall, then you'll have a "spare" engine that you can use to build up a stroker at your leisure. The stroker is not an off-the-shelf solution and few if any have ever run right upon installation. If you need your Jeep to run NOW, skip the stroker and buy a used engine.

Good advice Bones...proper combustion chamber set-up is often ignored. there is a vast difference between "runs" and "right".