Elusive engine miss revisited to New Motor

[purpleRac3r]

Many thanks to those who have offered suggestions for tracking the miss I experienced. I have performed most of the tests suggested and added a couple members of Boone Trail Corvette Club mentioned. I fear the heart has stopped beating. :cry The miss indicated in my previous thread advanced to engine ticking, then quickly to barely run at all with pedal mashed to floor. A compression check results in 55-85 lbs. in 5 of 8 cylinders (I'm told they should be around 125 to 140 lbs.), and a whopping zero in the remaining 3. Yes, that is definately no compression whatsoever. I triple checked each cylinder, and the gage itself. The three zeros were consistantly the same cylinders. Strangely, no oil in antifreeze and vice versa. Also no loud bangs one would expect to hear with catastrophic failures. <sigh> ;squint: I'm now looking at a new motor. My total engine replacement budget will be around $2000; I'm considering the GM Goodwrench 290hp/326ft-lbs 350cid crate motor (Jeg's part number 809-12499529) with the Edelbrock Performer manifold I just put on the fried motor in the spring and a freshly rebuilt Quadrajet matched to the intake. This seems to be the best bang for my bucks at the moment. However, I am open to suggestions....

 

[Bob Chadwick]

Sorry to hear about the bad news. I've been scoping out that motor as well and it seems like a sweet deal for what you get.

Before you get it check with Sam at The Last Detail. He told me that he sells them for marginally above cost and could save me some money. Of course I'm in Atlanta with The Last Detail so I wasn't going to have to pay shipping, which could have been a big part of the savings.

Good luck.

 

[WayneLBurnham]

Sorry to hear that guy....I had really good service

out of the ultracheapy GoodWrench engine....unlike this POS I have now that we still haven't found the problem of.... The next few steps up one you're looking at seems to be a very good deal.

If that thing of yours is down already.....and sitting somewhere happy in a garage or driveway, have you considered ALSO going ahead and popping the heads and, if necessary, later pulling the pistons to see what's going on?

I didn't follow your earlier thread, but so many severely dropped comps are likely head gaskets, multiple valve seat problems or terrible rings (or a combination) - things that, while severe, might actually be fixable. It's less likely you have huge block damage, although the bores could be scarred up. Even if they are scarred up some, you might be able to re-ring, reassemble, throw the thing back together and drive it while waiting for your reliable fresh engine, and maybe for only $500 or so. It's not impossible all your probs are in a mess of sticking valves - we just found a bad one on my heap - I'm not saying it's that likely, but it is possible.

Only some thoughts if you have some time and want to drive the monster before next spring. At least with an engine you just sorta strapped back to life waiting for a real one, you don't have to worry about babying it and you keep your other moving systems fresh by keeping it in service.

I think your engine choice is a good one for really fixing the problem permanently.

 

[vette-dude]

Me thinks you might have a bad camshaft. Sounds like the lobes went south on a few cylinders. Just a guess.

Randy

 

[gmjunkie]

Me thinks you might have a bad camshaft. Sounds like the lobes went south on a few cylinders. Just a guess.

Randy

Thats my Gess!! when the lobes start past the Hardend part they go purdy Fast!! gmjunkie!!

 

[goertz]

i would place money on a bad camshaft. I had the same problem years ago with a 454 in a truck. It would barely run, you could mash the pedal to the floor just to keep it running. did a compression check, and sure enough, some had no compression, some had a little, none were great. pulled the intake to look at the cam, and all the lobes were bad. installed a new cam, and she ran like a champ.

 

[goertz]

especially being that he said he heard ticking noises before it really went south. It's a bad cam. go to PAW and get their "SSI" brand for about 100 bucks with lifters.

 

[purpleRac3r]

Thanks, Bob, I'll check with The Last Detail before ordering a new engine. For those of you who missed the previous thread, I don't think the cam is the entire problem. I imagine it is partially to blame: however, the valves are moving more or less like they should, so I doubt any seriously rounded lobes. I would think also that by putting a thumb or finger over the plug hole I would feel at least a little air movement from the piston's motion, but there is absolutely none on three cylinders. That leads me to believe the pistons aren't moving. I could be wrong. Also, looking into the exhaust ports with an inspection mirror shows me some rather sad-looking valves, lots of carbon crud build-up and such. Last, the motor was rebuilt with a 0.040 overbore about eight years ago, and they had experienced several problems while doing so - the heads were mis-machined the first time around at the valve seats, the piston rings were incorrectly installed twice, and for all intents and purposes, ended up rebuilding it twice. I was told it was because it was an inexperienced mechanic working on it: I think the guy just didn't give a s--t. It may be possible to rebuild this motor again, but I sure don'y want to be the one to do it. Besides, a fresh more powerful motor, freshly rebuilt carb and upgraded cooling system will make for more competitive autocrossing. I do plan on disassembling the old motor to see if someone could salvage it down the road.

 

[fine69]

I found a fully rebuilt and assembled 4-bolt main 350/325 HP Chevy engine for less than $2K that you might be interested in. The guy is offering free shipping and has good feedback.... hope helpful.

Here'e the link:
http://cgi.ebay.com/ebaymotors/CHEVY-350-325-HP-4-BOLT-HIGH-PERF-BALANCED-CRATE-ENGINE_W0QQitemZ7987791293QQcategoryZ33615QQrdZ1QQcmdZViewItem