Rebuild - maybe all the way to the bottom?

[djailer]

I need to bounce this off of someone who knows more than I, which is pretty much all of you.

I am about to dive into my top end to check out my pistons..suspicion of hydro lock maybe. #1 has about 40 lbs less compression than the others and the rest of the story is out here somewhere. I had a leak-down test done and the shop said it passed. A friend of a friend who wrenches on Sprint cars says that may not be 100% and I won't know until I get in. I have done my T-belt before and got it all back together once so I am not so leery about that part. It is the pistons that make me wonder.

I got some good pricing for the whole ball of wax from JNZ, partsdinosaur, and ExtremePSI. Yes, I avoided DSMG like the plague it sounded to be. It may be a little above my $500 budget but that depends on what I see once the head is off. If, in fact, #1 does not travel as far as the others then I guess it is a bent rod. That is the rub...getting the bottom end apart. I have read some posts that insist that since you are that far you might as well just take the block out. I don't have access to a hoist and I bet even bare it will be heavy. The other worry is I am not sure about what just taking it out from there consists of. Unhook the tranny, mounts, etc. or whatever. i am a little worried that getting the tranny back on may be tricky. In the ideal world I would love to just drop the crank and pistons, stick new ones in and put it all back together - assuming that is where I end up.

The sticking point is honing the cylinders. I assume that is not negotiable and would surely be easier to take a bare block in to a shop but i really am not keen on taking it out in the first place. Can I hone it with a drill mounted tool and leave the block in place?? I am a little apprehensive and my instinct says when you are apprehensive you may be in too deep. Problem is my budget doesn't allow for apprehension. I can barely afford to buy the parts if you know what I mean. I'd like to hear some opinions and take it from there.

I read the other posts in the Duplicate thread alert and it is not really clearer now than before I checked them out.

 

[Mischif]

If your looking for a bent rod, it will be cheaper and easier to drop the pan and inspect from the bottom. You could always just remove the spark plugs to cylinders 1 and 4 and drop a screw driver or something down there and compare them to each other. 1 and 4 travel up and down together.

The transmission must be removed in order to remove the crankshaft. You have to remove the flywheel/flex plate in order to remove the rear seal housing, which bolts to the block and goes around the end of the crank shaft.

Given your level of experience and your small budget it would probably be better to try and find a used engine and just drop that in instead of trying to rebuild your bottom end. If it is a bent rod you will want the block thorougly checked. The cost of that at a machine shop plus a rod, and a crank and all gaskets and seals and everything else will be well past $500.

 

[djailer]

I found a really good 'minor rebuild' checklist here. So, trading out for a used engine is pretty much the same labor-wise ... I am still messing with the tranny either way. If I end up doing that I might as well take it in and get my own block done. Then I will know where it stands. I saw a post which listed some of the things that might need to be done item by item and minimal stuff shouldn't add more than 1 or 2 hundred. I hadn't thought about the crank...hopefully that isn't messed up cause that is another couple hundred. It is more I really didn't want to get down in that far.

My other option is just to drive it. It drives fine, the tapping is annoying but not terribly loud. I am going to try to measure 1 & 4 as suggested and see if there is a difference in height. I bought a caliper at HF and I assume that will do the job. That is going to tell me a lot I hope. You mentioned taking the pan off and checking the bottom end. What can I see from there that would tell me a rod was bent? i don't imagine you could just eyeball it?? How much bend would account for 40lbs of compression?

 

[My1GLaser]

I've never dealt with hydrolock before but, I think it would have to be pretty bent to account for approx 1/4 less compression in one cylinder.

(Using round numbers plugged into a CR calculator)

So if the stock compression is 8.5:1 and you have lost roughly 1/4 of your compression (40psi) then you would be closer to 6.5:1 in that cyl. If the stroke is 88mm then you would have to lose about 22mm of stroke to account for the drop in compression (all other factors remaining the same.) That seems pretty unlikely if the motor was still able to run! I'd measure to find out what's going on before tearing too far into it! (I realize that cylinder psi doesn't always correlate to a specific CR, but for arguments sake and stockish cams I think it's close enough..)

What do you mean it passed the leak down test? What were the numbers? What's the compression in the other cylinders? Have you taken off the valve cover and inspected the valve train? Maybe Bogus will chime in, cause something doesn't add up!

 

[djailer]

When I checked the compression the others showed 175 each. I didn't get the numbers from the shop, they just told me that the leakdown test didn't show any problem. I have not popped the valve cover off yet....when I do, what am I looking for?

I am curious as well, the more I hear. If it was bent 22mm that is almost an inch. Why would that much bend not just tear the cylinder walls up? As I noted, it runs reasonably well as far as I can tell. It is supposed to be crummy and rain all week so I may not get to comparing 1 & 4 until next week. I will post the difference I find in height through the plug.

 

[BogusSVO]

I doubt you would bend a rod 22mm

The math is off on that. 40psi is a good deal, but trying to figure CR to a compression reading is not the way to go.
CR is a volume measurement, where a compression test is a pressure test.

Now if the rod bent, .010-.020, I can see that causing a 40 psi drop, but a 22mm bend I would be surprised to see anything over 40 psi

With the cylinder head combustion chamber advertised as 47cc, then the volume of the head gasket about 10cc, and the dish of a stock 63DTF1 15cc piston you would have to have 75cc or more of water on top of the piston when it came up on the compression stroke to even think about bending a rod.

Now to get that much water to the back of the valve, it would have to get past the air filter/MAF, fill the IC, get pumped up the outlet pipe of the IC and dumped into the intake, and fill the intake runner of the head and be ready to be dropped on the piston when the intake valves open.

I am not saying you can not bend a rod in a 4g, but it is not common, even the guys with bad blown HG burning water tend not to bend rods.

Now, OP, what makes you think you bent a rod?

I would suggest you perform a leak down test yourself, or just inject compressed air into the cylinder and listen at the TB, exhaust and oil fill cap/dipstick tube.

You should hear a slight hiss from the oil fill/dipstick tube due to ring gap on the piston rings.

A more common cause for your loss of compression would be a worn cam, unlikely but possible, but I would be more inclined to think of a unseated valve, bad guide, or heavy carbon build up on the valve stem.

 

[My1GLaser]

Like I said, something didn't add up! Glad you chimed in here. I think it would be hard to get that much water into only one cylinder and it not have affected the others also!

Using a CR calculator, I just changed the stroke enough to drop the CR to what would be resonable for a 130ish psi compression test and got 66mm and thought WTF how is that even possible!

I was mostly trying to stop unnecessary work from taking place, cause who has time for that!

 

[djailer]

Amen My1G

Well, that's good news. I guess I thought it might be bent because the shop told me the leakdown was good. If the rings, valves and head aren't leaking then the low pressure would seem to imply the rod. I wasn't so sure since it was driving OK but was heading in the direction the shop was pointing me. That is why I posted here...'cause I wanted to be sure. Or at least more sure

So will I be able to tell anything by taking off the valve cover? It sounds like the head will probably have to come off regardless if it is rings. valve, or whatever. Would a fluid test show any of the valve problems you mentioned?

I know I have seen threads describing the leakdown tests so I will look them up and put down a few $$ for a HF leakdown tester? I don't have a compressor but I will find a way..

Thanks for the re-direct!

 

[djailer]

I did not do the leakdown test yet but did measure the piston depth. I measured it in three different positions and got readings of .23, .29, and .29 inch difference. 2&3 are almost identical but 1&4 are over a quarter inch off.

I used a long extension that fit through the plug hole and measured from the top of the plug well to the end of the extension. I measured the lip as well just to be sure and all 4 are the same height. Is 1/4" enough to call it a bent rod or should I do more looking...and if so, what next?

It may not have happened in the puddle...could it have been that way for the past four years? I lost a timing belt about 40k miles back. Could the valves have done this much by banging on the piston a few times?
I don't know that I ever did a compression test...the wells are too deep for my tester and I was never motivated/educated enough to try the loaner tool route. If it lasted that long I suppose it could keep going, right?

 

[djailer]

New plan....I didn't realize my auto insurance would cover this but my agent says it sure will. Whew...I really wasn't looking forward to getting in over my head anyway.

Thanks for all the advice/suggestions/input

 

[djailer]

I guess I can't let this thread die a natural death yet.
Yes, insurance will cover the damage - under my Collision coverage. They are calling i standing water. Good enough for me.

They want me to take it in have a shop do a tear down so they can check out the damaged parts. That is almost exactly my $500 deductible - so far so good.

Three years ago my timing belt took a vacation. Bunch of bent valves but no piston damage that I could tell -or knew to look for. There were some valve-shaped impressions on the pistons but nothing too bad. The car has run great since then. I didn't think...or know...to check the compression in the meantime.

I followed some advice from earlier and measured the difference in distance to cylinders #1 and 4. I measured three different times and got .23, .29, .29 inch diference in height. I used a socket extension that just fit through the plug hole so I am pretty sure I got the same spot on each piston. As I recall when I tore it down last time the pistons didn't have any weird geometry and were failry flat on top. I doubt carbon build up could account for that big a difference. Does that add any fuel to the bent rod assumption?

When I got stuck in the water it died stone cold. Water was just lapping over my floorboards when I opend the door. After I pushed it out and let it set for about 5 minutes I tried to start it. It chugged and chugged really roughly and put out a lot of white smoke fromt the tail pipe. It took quite a few turns but eventually turned over and ran really roughly for a bit. By the time I got home - about 5 miles - it was running reasonably well. It got better and has run well for the past three months. I still have a pronounced lifter? tick and some cold temp accel lag but other than that....? Does that seem consistent with any kind of hydro-lock scenario?

My dilemma is this. When the adjuster sees this would it be more likely he would attribute it to hydro-lock or to the valves knocking into it? That was over three years ago and almost 40K miles. Would this car run almost perfectly for that long with a rod bent that much? Last thing I need is to do the tear-down and have the adjuster determine it was pre-existing. I definitely cannot afford the $2K or so bill for a rebuild. I suppose I would get it hauled home and .. I don't know where I would go from there.

Any thoughts from those who have seen similiar symptoms? I would like to at least have a sense that it is more likely or not before I commit to taking it in.

 

[djailer]

No opinions or suggestions?

 

[TaLN91tsI]

Hydro-lock produces strange damage depending on how much water was ingested to how fast the engine was going. Insurance adjuster may just total the car since the repairs likely will be more than 50% of blue book value.