86 engine block questions


Active Member
whats up fellow members so I have a question regards to an 86 engine block I might dibs on …… it looks like a complete block except for intake and everything above that has heads , water pump oils pan etc , I’m told it ran fine at the time just has high mileage, what can you guys suggest for me to look at to see if it’s worth taking it? I’ve never really dealt with something like this so not sure what to look for and know if to take it or walk away ? Any tips or suggestions are highly appreciated ill try and get pictures


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You don't mention an asking price so it is hard to say. Looks like a decent starting point. Cam look like it is in good shape? Timing set been replaced? A pull of a rod and main cap or all to see the bearing and crank journals? Does it have the rolled fillets that a turbo crank will have?Does it have the valve train under those valve covers?
Thanks for that info still trying to negotiate price honestly , just wanting to get insight on what to look for those are good starting points valve train should be there since it was running at some point I’m guessing
oil pan has been off recently. blue felpro gasket is aftermarket replacement. factory was gray.

timing cover has been off recently. missing hardware and crank seal

concern that oil pan gasket has pushed forward and out from timing cover & oil pan. looks like 20-bolt gasket but mis-alignment with timing cover could be a couple things...

either some hardware is missing like the three smaller bolts that fasten the 20-bolt oil pan to timing cover and the gasket is just mis-aligned OR

it's a timing cover for use with the earlier 14 bolt oil pans (mid-85 production and earlier). 14 bolt oil pans used timing covers that only had two smaller bolts in that triangle area vs 86-87 (and late production 85's that used the 25524140 block) that for the 20 bolt oil pan provision used a more pointed timing cover at the oil pan to permit use of 3 bolts.

main caps 2 + 3 and rod caps 5 + 6 would be ones to pull to show what wear exists on bearings. because of the design of the oiling system, mains 2 + 3 would be good to pull.

I'd remove cylinder heads to look at bores for scoring and pitting. also can then see top of pistons to view any marks on top of pistons to show oversize - that engine was previously rebuilt and what the block was previously bored.

rotate the crank with a crank socket. saw the crank key is in place.
Don't guess. Bring your tools and ask nicely to do some disassembly to verify what you are getting. If they won't let you disassemble my offer would decrease accordingly. I've seen 109 blocks with four digit asking, but that seems like a lot to me. I'd bring at least a caliper but a couple mics would be better. If they won't let you pull a/both head(s) maybe a camera that plugs into a phone to look down the plug holes to see the piston tops, cylinder walls and such could help with inspection.

It is essentially a core at this point and if the crank has been cut , the cylinder been bored , or if the block is cracked it can be a boat anchor in a hurry.
Remove the two center caps and a couple of rod caps. These engines are usually detonated all to fuck...and the bearings will be down to the copper or scored all to fuck. If he won't let you inspect them...don't walk...run away.
if it's been rebuilt before and is already 0.030" over standard bore, i'd pause as we don't know what your plan is for this engine. are you doing a complete rebuild with whatever engine you buy? how much power you want to make? A 0.030" over turbo-use block now three decades old where there is no knowledge of how the engine was used (street cruiser its entire life or 25+psi boost, 1/4 mile at a time) could be pause for thought. a rebuild where cylinders just need a hone to clean up is fine once the block proves ok via magnaflux for crack check in main webbing 2 & 3.

boring to 0.040" over and wanting to make 500+ hp => not worth the cost of the build. probably wont last. but stock hp level might be ok. same concept with crank. at 0.010 / 0.010 and maybe a polish, ok. crank needing to go 0.020 / 0.020 => nope.
If you're gonna throw the boost at it...if it's .030 over or more walk away. For daily cruising it should be okay.
still trying to negotiate price honestly
can't discuss price until you confirm what you might be starting with...all that's been posted above...

yes, a bare 109 block that has been cleaned via hot tank / jet wash; magnafluxed OK; and perhaps had cylinder walls ultrasonic checked OK is fetching in the $1100 range today for what I've seen sold. then the machine work can begin or maybe just a hone of the cylinders for a clean up lick.
Thanks so much for all ur info and input I’m not to convinced for the asking price lots of stuff missing and misaligned like some of u mentioned if they drop the price significantly maybe I’ll consider it and take the risk but not for 4 digits
At this point we aren't even sure those are 8445 heads. Lota of unknown and it sounds like the ask is quite a bit it.
Just looking at it in these pix I might offer $300, but as the pieces get identified and can be confirmed usable the offer can go up. Good block, good crank, good heads can bring that offer over the four digit area. But that is a pig in a poke if you don't know the history.
this engine has been disassembled down to just the block (with the expected rotating assembly still inside) or a long block (leaving the heads still attached to the block)

there's 4, maybe 5, bolts holding the timing cover to the block - not a full set. so that's easy to check out as it's already been apart.

same for the water pump. most water pump bolts are missing.

I see another head sitting on the floor in one pic. seller has other pieces and parts to turbo buick engines.

seller should welcome the opportunity to show you what's happening with this already disassembled and then partially re-assembled engine.

since seller has other engine parts laying around, need to verify the parts. don't want to find the engine did have a blueprinted TA Performance timing cover but that was swapped out with what you see there now. is that a GM timing cover or a Chinese cover with misaligned bore for the cam sensor causing the cam gear and drive unit gear to wear excessively. how bad is the quarter sized wear divot from the cam thrust button on the inside of the timing cover. if it's a gm cover, milling that wear area flat and maybe adding an epoxied wear surface plate like in the Buick PowerSource book is the solution.

with the water pump barely attached, what was there before? to remove the timing cover, one does not need to remove all the little bolts that just attach the water pump to the timing cover. maybe there was a better water pump, maybe even a FlowKooler high flow unit, that was taken off for this sale.

Again, since it's already been disassembled and partially reassembled for this sale, seller should have no problem showing you all the parts for inspection since they're barely attached with minimal fasteners.

it's not as though it's a complete engine that's never been opened before and you the buyer wants permission to take that unopened engine apart. this thing is already apart. you just don't want to discover or learn later that the good parts that were on this engine were swapped out with scrap parts laying around to make it more complete. that's an expensive lesson. where's the rest of the hardware, balancer, flexplate, headers, accessories, etc. once you get a better idea of the components and condition and history, you can go up in offer as Rich noted above.
This is not running in a car for a reason.
Quickest non-invasive way is to cut open the filter, or in this case, open up the oil pump filter adapter. it will show you all you need to know.
Exactly. Expect the worst. Easier to plan on replacing everything.