Engine swap yes or no?

[68isgreat]

I've got a frame off 68 short stepper that I'm about halfway through the restoration. I've put in a 1990 350 tbi out of a Suburban that I was told only had about 90k miles on it. I have a 700r4 that isn't hooked up to it yet. I put a new Painless harness in it and a new distributor, plugs and wires and it runs well enough, but has a lopey idle. Both injectors seem to be working fine. The check engine light on the harness isn't on or flashing. I did a (cold) compression test and most of the cylinders are 125psi, and cylinders 3 and 5 (driver's side in the middle) are weak, around 100 and 110 psi). Plugs in 7 and 8 in the rear are also oily, and one or two others as well. It sat on its side for a while before I bought it, and there was water in the top of the left head under the valve cover from rain seeping in. I turned the engine upside down on a stand to get all the water out, but I wouldn't be surprised if the valves are a bit rusty. There is no water in the oil, so that's good. A couple of the push rods have a bit of surface rust on them. Very minor oil seepage at one spot at the rear of the intake, which is common with these apparently. I'm not a mechanic, but it seems like it obviously needs a valve job (which maybe is causing the lopey idle?) and new intake sealant, and who knows if the rings are letting oil seep in.

Given all that, and the expense associated with head work, and the fact I would like to use this as a long term daily driver, would I be better off just spending another 2k for a stock crate long block, or just try to drive it as is for a while? I like reliability, and don't like tinkering with engines. I just want them to run well, out of sight and out of mind.

This is my first time doing this, so any advice is appreciated. Thanks!

P.S. - sorry for the double post. I didn't see an option to delete it on the edit screen. Mods, please delete the older post.

[guyryan100]

Do you enjoy the hobby aspect of changing engines after your body panels are in place, or would that be a big frustration? Some of us do these projects so we can do more, others so they don't have to do it ever again.

[68isgreat]

Originally Posted by guyryan100

Do you enjoy the hobby aspect of changing engines after your body panels are in place, or would that be a big frustration? Some of us do these projects so we can do more, others so they don't have to do it ever again.

I do enjoy it when it comes together and everything works as it should. When I first got it running, after installing a rear mounted EFI tank and pump, and new harness, I was ecstatic and whooping with joy. I just don't want the engine to break down on the side of the road. That part I don't enjoy. I'd like to be able to take it on long trips, especially since I'm considering converting it to 4x4 down the road, and would like to take it on long hunting trips, as long as it gets ok mileage. That's one of the main reasons I went with the tbi/700r4 setup. Having never owned one of these however, I'm not sure how long they will last with not great cylinder compression, etc. If it would run like this for a long time, then maybe I'm worrying too much?

[weq92f]

.

Could it be that running the engine would improve the weak compression? Maybe do a leak down test on it and if it passes that...send it!

https://shop.advanceautoparts.com/r/...d-how-to-do-it

-Kevin

[72SB]

I don't think you will find a crate engine for $2k. My Blueprint Engine was $3600 a few years ago, now same one is around $4200 (no intake, carb, dizzy, damper or flywheel)

Just machine work on block, heads, crank is about $2k these days

[68isgreat]

Originally Posted by 72SB

I don't think you will find a crate engine for $2k. My Blueprint Engine was $3600 a few years ago, now same one is around $4200 (no intake, carb, dizzy, damper or flywheel)

Just machine work on block, heads, crank is about $2k these days

I found a shop locally in Portland that will do a complete rebuild for $1995. I'm going to fiddle with it some more, re-set the timing and see if running it for a while as mentioned above will help loosen it up and improve compression. $1995 to start with a fresh motor is very tempting though, especially since it's frame off right now and I don't even have the tranny hooked up yet.

Thanks for the replies!

[70cst]

Why two threads?

[68isgreat]

Error, and couldn't see a delete button on the edit screen.

[68isgreat]

In case anyone is interested, I got a timing light to make sure the timing was set at 0 degrees tdc, disconnected the fused brown/black wire from the distributor to the computer so it wouldn't receive inputs, and much to my surprise, the timing was WAY off. The timing mark wasn't even showing on the balancer at first. I had to move the distributor almost an inch to get it to top dead center. As soon as I did though, it ran smooth as a baby's butt. I turned it off, reconnected the fused wire so the computer would re-set to 0 degrees, and she runs great now, with a bit of surging at idle is all, probably due to a vacuum leak at the throttle body and not having everything hooked up yet. Going to replace the throttle body gaskets and check the IAC. Anyway, no wonder it was running rough. I thought my starter needed to be replaced too, because it was binding at startup due to the timing being so far off. Now it turns over effortlessly. I ran it for a while, and checked one of the cylinders that had weak compression, and it improved back into the 120+ range, same as the others. Awesome. I guess I don't need to swap it after all. At least not now.

[Shifty One]

Glad I could help...

[68isgreat]

Originally Posted by Shifty One

Glad I could help...

I need all the help I can get.

[HO455]

Originally Posted by 68isgreat

I found a shop locally in Portland that will do a complete rebuild for $1995. I'm going to fiddle with it some more, re-set the timing and see if running it for a while as mentioned above will help loosen it up and improve compression. $1995 to start with a fresh motor is very tempting though, especially since it's frame off right now and I don't even have the tranny hooked up yet.

Thanks for the replies!

If your going that route then I highly recommend that you supply the gasket set to the shop. At that price point you're going to get the cheapest gaskets available and after 20 or 25k miles the oil leaks will start getting out of hand. Ask the shop if they will upgrade you to a Felpro or other QUALITY set and if not see if you can provide the gaskets. Just the voice of experience here.

I would also ask for new rocker arms. The shop will reuse whatever one's they have around and some of them may have 200k miles on them. I have a $1500 SBC 350 rebuild in my Burban from a shop in Portland and these are my experiences. Nothing against the shop, the engine is still running good but, it leaks everywhere. The shop was also good to me when the rocker arms failed.

Neither one of these items will change the price by a lot but they should give you some of piece of mind.

The link has more information on my rocker arm experience. Starting at post 372.

http://67-72chevytrucks.com/vboard/s...698377&page=15

[68isgreat]

Originally Posted by HO455

If your going that route then I highly recommend that you supply the gasket set to the shop. At that price point you're going to get the cheapest gaskets available and after 20 or 25k miles the oil leaks will start getting out of hand. Ask the shop if they will upgrade you to a Felpro or other QUALITY set and if not see if you can provide the gaskets. Just the voice of experience here.

I would also ask for new rocker arms. The shop will reuse whatever one's they have around and some of them may have 200k miles on them. I have a $1500 SBC 350 rebuild in my Burban from a shop in Portland and these are my experiences. Nothing against the shop, the engine is still running good but, it leaks everywhere. The shop was also good to me when the rocker arms failed.

Nether one of these items will change the price by a lot but they should give you some of piece of mind.

The link has more information on my rocker arm experience. Starting at post 372.

http://67-72chevytrucks.com/vboard/s...698377&page=15

Great info, thanks. After re-setting the timing yesterday, it's running great. Just a minor oil seepage at the back of the intake, so I'll be re-sealing that soon. Going to hold off on the swap for now.