Replacing the Head but I need serious help

[alohaman]

We're planning on having a mechanic we know swap out the old swirl style head for a '76 direct port head that has already been rebuilt and planed, for around $340. Plus new gaskets of course which is going to cost me around $110. Then we plan on getting someone else to do a custom exhaust using the dual exhaust manifold. I thought about a real dual exhaust setup using the manifold, but I am not entirely sure there is enough room below.

I'd also like to know if this would fit a Chevette: cgi.ebay.ca/Weber-carburetor-32-36-DEAV-carb-Vw-toyota-Samurai-NR_W0QQitemZ200341413078QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item200341413078&_trksid=p3286.c0.m14&_trkparms=72%3A1215|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

I have a couple of questions regarding the block, and the pistons.

The chevette we are working with is an 1984 4 door, and I was wondering which type of pistons these models had. I heard they used flat tops for this year, but I cannot say for sure without taking things apart (of which I am nervous about). Anybody know for sure?

I am really on the fence about this, I am not really confident that I could take the engine out of the car and rebuild it myself without screwing something up, but I cannot afford to have someone do it for me either ($2500-3000 would buy me a fleet of Chevettes...or a paint job). The biggest engine I ever rebuilt was a rototiller engine, and I managed to kill the compression by breaking the piston rings. Hell, I am just having trouble replacing the timing belt due to a stubborn crankshaft pulley bolt, and my not wanting to accidentally turn the thing counter clockwise any further than I have already done. We did manage to swap the automatic tranny out for the T5 last year, despite the difficulties, still though, I had a lot of help when it came to the muscle work. And the tranny had to be rebuilt eventually anyway due to bad bearings and rust on the gears.

Herein lies a problem, I would like my Chevette to be the best it can be without going crazy on it. 85 to 90 HP plus maybe aluminum alloy floor pans, and the right tires and wheels would be plenty. It runs well enough at over 96,000 kms (it hauled over 700 lbs of cargo and got up to and ran at 110 kph for over an hour long trip last year) and is managing an excellent 7.6L/100km in the city right now (so it's all tuned right), but I can see the rust forming on the block, the manifolds, the bolts and threads, the rest is starting to show its age, and it makes me think that even if I have the new head put on, I will just have to have it removed later on in the future if something goes wrong, costing me more money. The car had sat for many years before I got it, and I have only put in a little less than 9000 kms on it. It probably is not that worn on the inside, but I am guessing it really needs a clean-out if it is to perform its best. I am just afraid I may break something again or improperly tune/align/time something and make things worse.

The car is no longer a daily driver, my 91 Integra has taken over that duty. Am I just making a mountain out of a molehill, is rebuilding the Chevette as complicated as I make it seem, or are my concerns genuine?

[zackbandyr12]

That carb Will bolt right to the intake. Why are u fooling with the crank pulley to get the timing belt off???

[rad15E]

none of the vette motors i no of had flat top pistons,the 84 has a slightly dished piston,do a compression test before you do anything

[alohaman]

May 17, 2009 22:24:43 GMT -5 zackbandyr12 said:

That carb Will bolt right to the intake. Why are u fooling with the crank pulley to get the timing belt off???

The timing belt was never changed before, so all the covers are still on. The crank pulley holds the bottom cover in place in front of the crank sprocket and prevents me from sliding the belt on.. I cannot get the new timing belt on until the pulley and the cover with it are removed. I think it might be possible to get an impact wrench in there if I carefully lift the radiator a few inches, but I cannot seem to find my torque wrench to put it back on, so it would be pretty pointless of me to remove the thing just yet.

Is there a list of which Weber carbs will fit the Chevette? How much better would the one in the link be? I have never used a Weber carb before so I wouldn't know. I know of the Holley 5210 and 6510 and the Rochester 1bbl (useless piece of junk), frankly I wish they were mechanical instead of vacuum powered, though they get the job done, they are not very good for performance.




So you are sure the pistons are dished? I have seen a few blocks with flat tops in the junker before (newer models only though). The parts book say they are flat with a circular groove with a smaller diameter than the piston on the top surface. I know for sure the older models are dished, but I could be wrong. Guess I will find out eventually when things are removed.

[hydroli]

Hey there, you want to switch the heads, change the timing belt and put a bigger carb.

A good procedure woiuld be the following: Compression test and mark the results on a paper that you will keep after dismanteling the head (it will let you know if there's something wrong with the block and you will be able to do something about it if needed), with this done, remove the accessories and plastics in front of the block then loosen the timing belt by unscrewing the binder, remove the timing belt, now remove the cam and head and diagnosis bad cylinders and corresponding head/valve/valve seat to figure out what's wrong before you install the other head cause you don't want to build it up with bad rings sealing, clean the surfaces and install your FRESHLY REBUILT HEAD (it really is sad when you realize after all this work that a few valves are not sealing tight).


For the weber carb, if you have a manual transmission, you could use a mechanical secondary which is synchronised on this carb brand. Both open at the same time via a set of two gears. you will find it on the weber 38/38. This carb is a little big if you run stock cam but it will work if you're manual trans. If you're automatic, stay with the vacuum secondary 32/36 cause the 38/38 will bug on take off unless you're very gentle with it. That means you may not be able to stump on the gas to take off as the torque converter is applying. You can still make the 32/36 more nervous by drilling the tiny hole (progressively) on the vacuum actuator and I would try plugging it on a direct vacuum source. I should say that I never drilled the vacuum actuator gapping hole but it's a common modification on the rochester quadrajet and it's supposed to help alot.

I'm not a professionnal builder but what I said is to give you a good idea of what I would do.

another thing, I would not touch the fuel pump unless it's broken. My experience is that you will loose oil presure because of how the oiling system is made and because of a common issue with the fuel pump's push rod vs. block sealing. You may need to add a fuel presure regulator to keep fuel presure a little lower, it's because the weber carb wants 4psi precisely, it's a frequent missed detail from my reads.

Good luck

[alohaman]

She runs the 5-speed Borg-Warner. Used to be an automatic, but we converted everything. The problem I find is that there are many 32/26's and 38/38's from the Weber line, but do they all fit or are there certain part numbers to look out for that will bolt to the stock intake? I will probably run the stock cam, it runs around the 1500rpm-3000rpm range, at least I think it does, and that's good enough for around town and on the highway. Most of the external parts work fine, other than the choke. The block and head seem to be rusted together a though.

Oh quick question, here's a 38/38 Weber with a manual choke, would it fit, there are no part numbers displayed so I do not know: cgi.ebay.ca/New-Weber-38-38-manual-choke-carburetor-hi-performance_W0QQitemZ280301945917QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item280301945917&_trksid=p3286.c0.m14&_trkparms=72%3A1215|66%3A2|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A50

Is there also a way to clean out the engine block without removing the engine? The car sat for over a decade before a couple years ago when I got it, being ran maybe once or twice a year if lucky. It has built up a lot of crap on the inside. And I notice it always performs better after it has had a fast run on the highway at passing speeds (120-130 kph, bloody well needs an alignment though, the steering wheel vibrates so much that one would think the car is falling apart).

I got the pulley off, put on the timing belt and tensed it up. Though I am having trouble bolting the pulley back on. I have a torque wrench set to 85 ft/lbs but it just ends up turning the crank (and subsequently moving the car). I tried using a wrench to hold the cam but that was no good, it just made the belt slip a bit and made me have to readjust the thing again. I am guessing I should try using the impact wrench again to tighten it then finish it off with the torque wrench, right?

[hydroli]

The carb you pointed out is ok but I would go with a 32/36 cause it is alot cheaper than the 38/38 and you won't benefit from a too big carb. Degreaser to clean the engine on the outside. Don't care about the indside if it runs fine as it is. No engine flush! Just put regular detersive oil in it, such as 5w30 or 10w30 and change the filter, crap will make its way to it. Yes you should use the impact, you may adjust it to not break something.

[alohaman]

Got the timing belt on and the car runs as smooth as my Integra (which for a Chevette is saying something lol). Still I am going to be wary of it because while the pulley is on tight, it may not be the right amount of torque. So the car is only going to be used for one short trip to the mechanic that I am taking it to where he can do the proper adjustments himself. Definitely a felt sense of accomplishment when that car fired up and ran though Almost felt like yelling "It's alive!" and laughing maniacally. Would have been a nice change from cussing every 5 seconds lol.

So a 32/36 DGV carb would be probably the best all round choice then. I see there are a few on eBay for around $270 or so like this one: cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=280260506257

After the head is put on, the only things left to do with the mechanical end will be exhaust, carb, maybe the intake pipes themselves, and a good wheel alignment. Then I can start saving up for the bodywork and interior (found a custom interior with dark blue upholstery, one of the seat's brackets is broken, but heck, that can be replaced).

Thanks for all the help guys!

[hydroli]

You can look for a good used 32/36 for less than this. The 38/38 is rare and those who buy it will sell the 32/36 they had on for cheap. You can cut more than $100 on the price you gave by doing a good search.

You're welcome