[5m7m2j]

Help. The shop that handled most of my 7M-GTE conversion started my car for the first time today. Unfortunately, oil was not getting to the head and the engine seized as the engine was running for the third time. They were trying to diagnose a pegged oil pressure guage and dead tach. No, they didn't bother to remove the oil cap and look inside before starting it, again, and again.

Don't know where the problem was yet, but they or the machine shop will be eating the bill. I had the engine rebuilt already with .20 overbore JE pistons and rings, HKS MHG, new valves and springs,...

What parts do I demand that they replace with new? Up to and including the entire effin short block. Turbo damage?

Thanks for any expert advice. I don't want to get screwed by a half-ass redo.

Clark

 

[Deanfun]

everything. that's just stupid. whatever isn't damaged... get the bore checked out by another shop if possible.

 

[82Spearco]

Geez, if you are in Atlanta, you should be having Jeff Tamulis doing your 7mgte conversion!!! He lives just outside Atlanta. Another list member from Kansas City is having his done right now.

 

[WadeT]

Holy *&^*!!! Those guys should have built up oil pressure by priming the pump first. Not sure how the thing seized but perhaps they used the wrong oil pump or oil pump pickup.

To get the oil pressure guage to work, use the original 5m oil pressure sensor - not the one on the 7mgte harness. To get the tach working your going to have to splice the tach signal which (mine's at the igniter). At that point you can get the MSD tach adapter or swap a 7mgte tach chip in place of your MKII tach chip. Using the 7mgte chip will cause the engine RPMs to read about 500rpm higher than actual rpms.

-wt

 

[Dave A.]

tach. chip? Where is that located?

 

[5m7m2j]

Thanks for the reminder on the 5m Oil pressure sensor. At this point I don't recall if that was swapped.

I guess what I am looking for is advice on what the machine shop needs to do when rebuilding a seized motor that is above and beyond what they would do when rebuilding a working motor?

 

[DKJones96]

if it seized up wouldn't the whole engine have not been getting oil? because if it was just the head it might have locked the cams but the pistons should still move and tear the timing belt a new a like my freinds carolla did one time when we forgot to take out the screw in one of the cams.

i'd say make um replace the whole thing. cuz if the whole thing wasn't getting oil and it was actually running the bearings prollymelted into the rods and all kinds of stuff depending on how much it actually ran.

 

[Dave A.]

Unless the engine seized from the oil passage in the head being blocked from using the wrong head gasket (possible, though not likely unless you're completely illiterate) then a complete rebuild or longblock is in order. Someone obviously screwed up royally and now has to pay the price for the mistake.

 

[WadeT]

tach. chip? Where is that located?

There's a small circut board on the back of all MKII/MKIII tachs and they are interchangable. Not really recommened now that MSD has an adapter.

 

[5m7m2j]

Update

I'm not sure how they diagnose this 2 days after pulling the motor, but the shop is saying that they crossed the oil lines to the remote filter, thus oil didn't get through the filter. That screw-up not withstanding, the engine was rebuilt back in January and they didn't take measures to prime or verify pressure in the oil system. Relying on 6 month old packing grease in the pump to create vacuum.

 

[jdk_ii]

Clark-

That's amazing they didn't prime a new rebuilt engine and check for oil pressure.

There is enough documentation relating to starting a dry motor
and the damage it does.

Even motors that have been sitting for a while require a re-prime.

Trying to fix only the things that are siezed is a gamble, since everything
will need to be reinspected. Arguably, siezed bearings may be workable.
Though I suspect the piston rings may have scored the cylinder walls.

As for the turbo, an inspection is required. They are very tough
and worst case is the bearing is toast (repairable).

I hope they do the right thing, as it's obvious they missed a key step.

 

[jtamulis]

I just happened to be online on my vacation, and noticed this thread and
popped in. I'm up in Marietta, and if you need help with stuff for the
7M-GTE, let me know. I'll be back in town sunday or so. Gimme a call.

Jeff
[email protected]
(770) 289-6716

1983 7M-GTE MKII
1986 7M-GTE MKII (work still in progress)
1985 7M-GTE MKII 400+rwhp joint project car
1990 1jz-gte MKIII
1985 GMC extreme duty suburban 2500 series 4x4 3/4 ton 6.2 diesel
(tows 9500 lbs

 

[5m7m2j]

Machine shop findings

I went and saw the mostly dissasembled engine. They coat everything with a setup oil when assembling. This appears to have saved most of the engine. No scarring on the cylinder walls, pistons, rings. The crank has a few surface scratches at the journals, as the engine appears to have seized at the crank bearings. They already had the new crank bearings ready to go.

The head was still together. They speculate that the cam may have scored the head, in which case they plan to true the cam guides in the head and install cam bearings. I can't decide if this is something I should be concerned about. Any help/insight would be appreciated.

P.S. - apologies if any of my terminology is wrong :?

 

[suprathepeg]

I would have another mechanic look everything over. IF you aren't doing this swap yourself that probably means that you aren't completely comfortable around an engine. Have everything checked cause I'll bet if is grenades 20k miles later they wont fix it. Who knows there could be stress crackes etc depending on how "well" it seized. Overheating could warp the head and on and on.

I feel for ya. good luck.

 

[CRF_Rider]

I would make sure they magnaflux the crank to check for cracks.

 

[5m7m2j]

further update

Ok, they dissasembled the head. Timing gear damaged on the the intake cam, as well as head damage. They cannot line bore the head because it is closed on one end, preventing alignment. Thus, no cam bearings. So, I get a "new" re-built head.

What is the life expectancy of a cam, under normal conditions? i.e., If my original cams had 70k on them, and these "new" ones have 140k on them...? I guess I should ask for the runouts on both, eh?

They "x-rayed" the crank.

 

[suprathepeg]

I don't think it is too comon to have to replace the cams, Usually the seals and bearings will go long before the cams.

 

[artm]

Have them check out both sets of cams and use the best - the MK2 can show siginificant cam wear with low miles if you don't use the car daily I used to start mine only once a week and mine were shot (out of spec) at 40,000 miles. Cams are a long way from the oil pump and can be starved from a cold start.

Art

 

[Dave A.]

Cam bearings? None of the M-series engines have cam bearing inserts. Both cams ride directly on the aluminum journals machined on the head surface. How about the bottom end of the engine?? If the cylinder head was starved for oil than surely something is fouled up in the short block! The shop should foot the bill for another complete engine IMO.

 

[5m7m2j]

It's alive

Well, the engine is back. I got a new 'used but unworked' head, and the same block. In the car and running , but running rich . Posting Q's about that problem in the &MGTE section...

Thanks to all for the info and support.