1991 Plymouth Laser Base

[Redrocketlaser]

The only righteous repair is to have the block decked. That passageway between the top of the bore and the water jacket has gotta be milled away. I know that's a hard pill to swallow and a buncha work but from the other issues you've mentioned along w/the pics I'd say your rings have problee seen better days so the engine needs to visit the machine shop.

My 92 Laser w/a 4g37 and only 140k on the clock just died last night so I feel your pain man. When I say died, it was an ugly, smoke filled, oily death complete w/ some of the most horrendous mechanical squeeks, shrieks and groans you can imagine ... before it finally locked up. Was tryin to nurse it the 30 miles home and it made it to within a mile and 1/2 of the casa.

Did a buncha research this mornin and found few used 4g37s I'd take a chance on. Gonna just stuff an NA 4g63 in it.

We’ll thankfully the blocked had nothing wrong where it wore into the head, thank god. I picked up another 4g37 from a local jy that supposedly just had a broken timing belt but turned out to have a seized cam the cam seizing resulted in 2 bent valves, some shitty can journals and a bottom end absolutely full of glitter. I was planning on cleaning that block and head and dropping it in until I realized that the main bearings and rod bearings are toast too. My new plan is to finish rebuilding this head with 2 new valves and seals annd drop it onto the running block. When I pull the head I’ll pour atf in the dead cyl and water in the combustion chamber of the head to see where my compression is going. If the valves leak water into the ports that’ll tell me I only need to install the head. If the head olds water but the atf in the dead cyl drains then I’ll be dropping the oil pan at the same time and taking a piston and rod from the junkyard engine and putting it into the engine in the car(cleaned throughly with a new rod bearing of course).

Was planning on ordering parts for the head this week but my car decided it needed a new battery, so maybe next week or so. I’ll post again once I have either blown it up or fixed it

 

[wrenchspinner]

We’ll thankfully the blocked had nothing wrong where it wore into the head, thank god. I picked up another 4g37 from a local jy that supposedly just had a broken timing belt but turned out to have a seized cam the cam seizing resulted in 2 bent valves, some shitty can journals and a bottom end absolutely full of glitter. I was planning on cleaning that block and head and dropping it in until I realized that the main bearings and rod bearings are toast too. My new plan is to finish rebuilding this head with 2 new valves and seals annd drop it onto the running block. When I pull the head I’ll pour atf in the dead cyl and water in the combustion chamber of the head to see where my compression is going. If the valves leak water into the ports that’ll tell me I only need to install the head. If the head olds water but the atf in the dead cyl drains then I’ll be dropping the oil pan at the same time and taking a piston and rod from the junkyard engine and putting it into the engine in the car(cleaned throughly with a new rod bearing of course).

Was planning on ordering parts for the head this week but my car decided it needed a new battery, so maybe next week or so. I’ll post again once I have either blown it up or fixed it

Can definitely appreciate your tenacity and remember well being married w/kids and having to keep stuff on the road. Still have issues keepin stuff goin!

If the block isn't badly scored in any of the cylinders you can hone it w/a stone or ball hone and a drill to help seal the bores but a fresh set of file fit rings would help too. You can pick up a set of rings pretty cheap from Rock Auto ($32 for a set). Take some green scotchbrite and solvent and clean up the pistons (especially the ring lands) file fit some new rings to the honed bores and slip 'em onto the pistons and you'll have a poor mans rebuild! Doin this simple stuff will add many miles to your Laser!

 

[Redrocketlaser]

So I've talked the wife into letting me get a parts car and if I can find one for sale withing a few hours from here in late feburary than ill be ditching the current junkyard block and head I have in favor of the donor vehicle engine. There's one for sale right now that's 3 hrs away 94 talon 2.0 nt for 1k obo, if that's still there when I have the money I'll be going to grab it. Will.i be able to use a 94 ecu/harness in a 91 car? And had anyone ever ran a flat hood with a 4g63? Maybe with the timing cover off?


I'll attach a picture. As of now the car is still running and getting me to work every day on 3 cyl. I still have issues with the mpi kicking off but since I figured turning the ignition switch kicked it back on it's not really been a problem. I'll post again when I have an update.

 

[Redrocketlaser]

Oh also, I found a red 1g toy car at walmart so I picked it up, I got so excited when I found it

 

[wrenchspinner]

So I've talked the wife into letting me get a parts car and if I can find one for sale withing a few hours from here in late feburary than ill be ditching the current junkyard block and head I have in favor of the donor vehicle engine. There's one for sale right now that's 3 hrs away 94 talon 2.0 nt for 1k obo, if that's still there when I have the money I'll be going to grab it. Will.i be able to use a 94 ecu/harness in a 91 car? And had anyone ever ran a flat hood with a 4g63? Maybe with the timing cover off?


I'll attach a picture. As of now the car is still running and getting me to work every day on 3 cyl. I still have issues with the mpi kicking off but since I figured turning the ignition switch kicked it back on it's not really been a problem. I'll post again when I have an update.

View attachment 783670

You could swap the engine bay harness and ECU into your Laser but the flat hood on your Laser won't clear the 4g63 cam pullies. Never tried it but I doubt even takin the upper timing cover off will help it clear.

Any idea what kinda shape the Talon is in? Might be better to just build that one.

 

[pauleyman]

You could swap the engine bay harness and ECU into your Laser but the flat hood on your Laser won't clear the 4g63 cam pullies. Never tried it but I doubt even takin the upper timing cover off will help it clear.

Any idea what kinda shape the Talon is in? Might be better to just build that one.

I thought the flat hood was 1990 only.

 

[Redrocketlaser]

You could swap the engine bay harness and ECU into your Laser but the flat hood on your Laser won't clear the 4g63 cam pullies. Never tried it but I doubt even takin the upper timing cover off will help it clear.

Any idea what kinda shape the Talon is in? Might be better to just build that one.

sadly the talon has no title otherwise I would. I guess I'll have to be on the lookout for a hood too, or I'll modify this one to fit. I saw where one guy slotted the hood for the cam cover, if I absolutely have to I can do that. Hell maybe I can make my own bump in the hood to clear it, I do work in a body shop now.

 

[Redrocketlaser]

I thought the flat hood was 1990 only.

My car is a 91 and has a flat hood

 

[CrackedDSM]

Harness, electronics, etc will all work for a 91. The transmission if it's a manual is the same between the two engines, so don't feel like you gotta swap in the '63 trans.


But, take it from someone who did this (4G37 to 4G63 n/t swap) don't expect any kind of noticeable power increase. I'd really honestly only bother doing this swap again if I planned to turbo it right from the jump. Add the 5 wires to the n/t 4G63 harness before putting it in the car, source a turbo FWD transmission/clutch, throw in a turbo ECU, stock injectors/pump/FPR/turbo setup and enjoy the almost 110HP gain and stock reliability.

 

[Redrocketlaser]

Harness, electronics, etc will all work for a 91. The transmission if it's a manual is the same between the two engines, so don't feel like you gotta swap in the '63 trans.


But, take it from someone who did this (4G37 to 4G63 n/t swap) don't expect any kind of noticeable power increase. I'd really honestly only bother doing this swap again if I planned to turbo it right from the jump. Add the 5 wires to the n/t 4G63 harness before putting it in the car, source a turbo FWD transmission/clutch, throw in a turbo ECU, stock injectors/pump/FPR/turbo setup and enjoy the almost 110HP gain and stock reliability.

I'm more so chasing part availability and wanting to boost it sometime in the future. The 4g37 can be a bi*** to find parts for sometimes because no one wanted it when these cars came out so there just aren't as many floating around.

It's also nice that there are so many off the shelf/factory parts that I can find and use to turbo an na 4g63 rather than having to fab up my own manifold+downpipe if i wanted to boost the 4g37.

So you've done the exact swap I'm wanting to do? Is there a write up anywhere? Or is it pretty straightforward? Did you have to pull the dash to swap the dash harness or anything?

 

[Redrocketlaser]

Update: So I have been driving the car to and from work every single day since the last time I posted and as of now days ago it is JUST NOW running on all 4 cyl again. I never ended up getting a parts car, we simply didn’t have the funding I expected to have. So the new game plan was to just limp the car around on 3 cyl until I can swap my rebuilt cyl head and a donor piston, or it blows up and I’m forced to rebuild my engine I bought from the junkyard that’s full of glitter. Some how the car made it until I had a 3 day weekend to swap the head, and a donor piston and rod from the junkyard engine with new rings and a rod bearing(I assumed cyl 3 cyl wasn’t firing because of blown rings from hydro locking). As it turns out I was wrong and right at the same time the piston had a crack just below the oiling ring and I assume that’s where my compression was going. Any who I got the car back together and accidentally clamped the pcv hose between the head and block when reinstalling and messed up the gasket causing it to blow within 3 starts. Finally a week later and I have another gasket. I swapped it out and I’ve been driving for 3 days now all over the place and other than some smoking(previous blown hg left tons of oil and coolant In intake tube and manifold) I’ve had no issues at all. The car runs great and has as much power as a 4g37 can and for now I’ll be happy with that. I’ll update again if any major changes happen

 

[wrenchspinner]

Certainly appreciate your tenacity and all the effort you've put into keepin your Laser goin dude. Reminds me of how I had to keep my rides on the road many years ago.

When I finally yank my 4g37 to drop the new 2.4 in I'll see what I have that you might find a use for. Have a box of new parts I had bought for spares that I won't be needin for sure. Just off the top of my head I know I have a new set of lifters, rear main seal, distributor cap n rotor, think I even have a fresh head gasket.

Doubt there's much on my engine that's much good judgin from the horrendous noises comin outta the engine bay before it finally seized up. Expect the crank and head are likely shot, so really only the block is of any use to anyone. I do have an almost new distributor w/cap n rotor that's fine, less than 500 miles on it, same for the timing belt tensioner pulley. Also have a 4g63 adjustable cam pulley I won't be using.

 

[Redrocketlaser]

Certainly appreciate your tenacity and all the effort you've put into keepin your Laser goin dude. Reminds me of how I had to keep my rides on the road many years ago.

When I finally yank my 4g37 to drop the new 2.4 in I'll see what I have that you might find a use for. Have a box of new parts I had bought for spares that I won't be needin for sure. Just off the top of my head I know I have a new set of lifters, rear main seal, distributor cap n rotor, think I even have a fresh head gasket.

Doubt there's much on my engine that's much good judgin from the horrendous noises comin outta the engine bay before it finally seized up. Expect the crank and head are likely shot, so really only the block is of any use to anyone. I do have an almost new distributor w/cap n rotor that's fine, less than 500 miles on it, same for the timing belt tensioner pulley. Also have a 4g63 adjustable cam pulley I won't be using.

I might take you up on that distributor sometime, the car is still randomly losing tach signal occasionally and the only 2 possibilities left are the distributor or the ecu

 

[wrenchspinner]

Good chance it's the distributor or wiring causin your issue but it could be the ECU too. I'll have both available.

The wiring to the distributor was bad so I replaced it w/a longer lead and used bullet connectors on the wire ends since I had broken the flimsy connector at the distributor while changing the timing belt tensioner pulley. Wrench slipped and destroyed the connector!