I tore down the engine in my 86 mutt yesterday and got to play detective.

This all started after I finally got my 86 to run (thanks to everyone on this forum). It was running fine (after many answered questions and a lot searching) but there was a knock after it came up to temperature. I thought it was a rod knocking so I dropped the pan and changed the bearings. This seemed to help but after about a week I noticed the knocking again. It was hard to hear but you could definitely feel the rhythm if you placed your hand on the block and I would have sworn that it was cylinder #4. I also had a ton of blow-by. I was getting oil coming out of the dipstick if I revved the engine and lots of smoke out of the valve cover oil hole all of the time.

So I pulled the engine and went looking with all intentions of upgrading to a 383 and adding a modified LT1 intake.

If anyone remembers or if you care to reread my old posts - my vette has been a source of constant surprises. Supposed to be an early iron head. It has a roller cam engine with aluminum heads - a 128 and a 113. Definitely a mixed mutt of a vette - but my vette none the less and I will never give up on her (I hope that she is listening).

Anyway, here are some pics of what I found:

Cylinder #3


Head for #3


Piston #3


Cylinder #3


Piston #7 and #3


Every one of the top compression rings on every piston was broken, some into several pieces.

The block appears to only have a sort of wavy smooth area at the top of the #3 cylinder. I hope that the .030 overbore will take care of it.

My new bearings appeared to be in great shape so I am still not sure what was knocking. I did not find any of the ring pieces in the cylinder or the pan and the valves looked good as far as damage is concerned. When I ran a compression check they were all a little low but nothing crazy and my vacuum gauge was at a steady 16. If you ask me it all looks like long term damage (only guessing).

I never would have guessed the damage that I found. I am also surprised that it was able to run at all.

I will provide pics as the 383 transformation continues.

One quick question: when I upgrade to the 383 / LT1 intake, will the injectors that I just purchased from FIC (stock for the 350) work or will I have to upgrade?

 

I'm no machinist or engine parts super expert but, similar damage equals uniformity in my book. How are the rest of the pistons? Cracks or similar signs? Its interesting how both pistons got similar damage.

We got few guys in here that do their own machine work and they will be able to give you a solid answer. I got to follow this one for my own personal knowledge.

Keep us updated on your 383 project...you'll love the torque

 

The other pistons look fine with the exception of the broken top rings (all of them). Maybe the ridge broke the others during removal but there was not really any ridge that I could feel. None of the pistons were cracked and the engine was running when I pulled it. The plugs looked fine and there was no smoke out of the exhaust. She was a little rough when cold, but was pretty smooth when warmed up. I have video but not sure how to post those.

I will be asking for recommendations for cams (dear lord help me) and such as the build continues and I really hope that the modded LT1 intake is as good as I hear. I scored a stock one locally for next to nothing, complete. Sorry I just cant justify the cost of any of the purpose built manifolds. I am a single father of 4 little ones and this is just my "project". I do all of my own work (except machining) due to cost and the personal satisfaction.

Regarding the Torque - how long can I expect the 4+3 to last. It was working fine also, but I have no service history on anything regarding my vette. Just going to replace all the fluids and clean it up while I have it out. I already put the short throw shifter arms on (before the pull out).

 

wow,never seen that before,and its the first time i've seen a car with mixed heads

i bet the 113 was the passenger side head, so the original might be the 128
Do you have identical exhaust manifolds ? from what i remember the 113's had
D ports ...

 

The 113 was on the drivers side. I never compared the exhaust manifolds when I removed them to put on the long tube headers.

I discovered this earlier and purchased a single pass side 113 head (from a forum member) to put on when need be - but after researching upgrading and rebuilding and self porting the heads - I think that I am going to go aftermarket.

According to the RPO codes I am supposed to have iron heads and roller blocks weren't out yet - so any guess is as good as mine. I am guessing it is an 88 due to the fact that I have the ugly a** base wheels from an 88. I got a pure MUTT but she is my mutt and mutts usually make the best pets.

 

Ahhh....if its an 88, the 128 head (passenger side) is what's out of place
check your vin ..its 86 or 88 ??? seems like an 88...and your problems are on the driver's side..hmmm

 

can we assume the pistons, were not hitting the head ? were they all down in the hole ? was the block decked ? did the pistons stick out above the deck surface on the block ?

if the damage wasn't mechanical interference, was the timing way off, at least during some part of its life ? was the fuel air ratio way too lean ?

these are questions I'd try to get some answers to before investing in a 383 build, only to have the same things happen again, only faster ?

 

The pistons were not above the deck surface and the engine was no problem turning over by hand with the spark plugs removed - nothing was hitting as far as I could tell. The numbers cast on the front pass side are visible but they do not match the car - so it more than likely was not decked. Again - it was running fairly well when I removed it and the plugs all looked good - especially on that side (1-3-5-7).

I have no idea about its life - NONE - I just know it was a hard one.

 

 

Little update - the weather here in Louisiana has not been cooperating for us "non garage" folks but I finally got the block over to the machine shop yesterday. I brought along my two damaged pistons so he could give me a diagnosis.

The machinist stated that the damage was due to - Detonation. Damn, it must have been pretty severe. The pistons will make cool ashtrays though.

Anyway, he said the block should be done next week but he is not sure if .030 overbore is going to be enough. May have to go .040. No big deal as far as I know.

Then the parts ordering can begin. He stated that he will try to price match what I find on the internet and I would rather deal face to face, but we shall see.

Also - about finished with the LT1 intake conversion. Found one local for next to nothing so I could not pass it up. That is about the only thing that I could get accomplished due to the constant rain around here - but we are having a rain free weekend and I have Monday off due to the holiday. Time to yank the tranny and start the cleanup of the engine bay.

 

Finally got the block back from the Machine Shop on Saturday. They had to bore it .040 over to get rid of the scoring, deck the block and I had them clearance it for the stroker crank. Cost a bit more than I expected, but what can I do? Now its time to order the internals and heads - Money Time.

Painted the block, oil pan, and timing cover after massaging the dents out of the oil pan.

Also continued cleaning and painting the engine compartment. Fixing all of the wiring and putting new conduit on. Getting ready to put the BMA spring in with the lowering wedges and replace the steering rack.

 

I almost did the same I also just purchased a set of new set of Injectors from FIC before I pulled my motor two months after do my rebuild and hop ups.

Just give him a call and tell him whats up FIC traded my out for a set of 24# Bosch injectors for my hopped up motor .

Let him know compression cam set heads ect he well tell you what best for you set up.

I had to pay a small price to swap them out not much he take care of you.

Don't forget about getting a chip burned for the new motor set up Tell them everything about the car to get the best burn for you car.

 

gotta love this pics !!!

 

Just something to think about is get rid of the stock POS fuel lines that run under and though the A/C compressor My leaked once again after I got the new motor to run this was the 3rd time they leaked on me under th A/C compressor I went to SS braided line little pricey but at least I routed them so you can see them if they do start to leak so you can fix it before you ends up having a fire ball cruising down the road.

 

Called Jon @ FIC. He sold me some 32# injectors at an incredible price for the rebuild. I am going to sell the whole TPI setup with the mostly new 22# injectors when I am finished. Gonna put a whole lot of parts up for sale.

 

 

I planned on changing the fuel lines to braided lines with AN fittings and rerouting them away from the long tubes (they were really close before). I am going with a modified LT1 intake so the routing will have to change anyway. I was planning on trying to go from the fuel rail straight to the filter area on the frame. Anyone done this? Good idea? Any pics?

 

I am thinking about PCMForLess for the new chip. Any other suggestions? Anyone less expensive? This thing is costing quite a bit, but I am determined to do it correctly.