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  View original topic: Sad day, I could use some advice..........
skyguy Thu Oct 04, 2007 1:13 pm

I am an unhappy camper right about now..................... When I bought this Baja I thought that the push rod tube seals were leaking, after much effort I have determined that it is not the tube seals at all.

It is indeed the fit between the top of the jug and the head :cry:

I pulled the head got a good look at the mating surfaces. Not good at all. Whoever put this together knew it would leak and sold me their problem. The top of one piston has a ton of nicks in it, the jug looks like it got dropped. I think there may have been some head damage and the guy just repaired and or slapped on a new head. The rocker arm studs are heli-coiled............ I am an idiot.

I have spent a ton of time looking up answers for various things but this forum is huge, I am pissed off and can not stomach the thought of five more hours of searching various terms. Please be patient with me as I have what may be some noob questions. I have a 1964 bug with a 1641dp, single solex carb

1. how do I identify the various items used in this build (head, cam, pistons)?

2. Can a machine shop repair this kind of stuff?

3. Given the amount of leakage and the dinkers in the top of a piston (cylinder walls are nice looking) should I just throw the top end in the garbage?

4. I am thinking jugs, pistons and one new head at the moment. What size piston is usually used in a 1641?

5. Should I pull the pistons, jugs and head and just go down to a bug shop and ask for replacement stuff?

6. Can I replace just the jugs and head on one side of the motor as the other does not leak? Would this be stupid to do given the cost of pistons and jugs?

7. What pistons and jugs should I avoid?

8. Are "total ring seals" worth the money?

Let me add I want to keep this an easy to maintain, street able bug that gets good mileage. I am not looking for a horsepower monster.

Thanks for any and all help anyone may provide, my GF is not happy with me right now so I need to keep repairs as cheap as possible without buying garbage. lol.

grimace007 Thu Oct 04, 2007 1:35 pm

unless there are huge chunks missing from the jugs you can "lap" them in with some valve lapping compound. and clean up the cyl to head mating surface. ive done it a few times.

but if you want to be 100% sure you can get a set of Mahles 85.5 mm pistons for a displacement if 1584(1600cc) or 87mm for 1641cc
alot of people dis the 1641 but there are MANY people on these forums who have used them without any trouble.

just make sure are your cooling tins are in place and everything is properly dialed in and you should have no problem.

unless the heads are abused and beat theres no reason to replace them.
a good machine shop can do a tiny flycut to cleanup the mating surface and also perform a good 3angle valvejob that will clean things up on the head and you should be set

just my .02

nextgen Thu Oct 04, 2007 1:55 pm

I agree, As for the heli coil, well I hate the idea but it is not a high stress area and should be fine. If you have the head off just rip out the coils and put in the inserts, and you will be good as new. Keep in mind how much you take off the head in a flycut. You want matched CC's, for each head. Actually seeing that the last guy was playing a game with parts, you better take the other head off and match them up. One may be flycut way to much. Also if something was broken it can fly through the manifold to the other head, so it may have damage also. That I personally have seen.

Joe

bpritchert87 Thu Oct 04, 2007 6:48 pm

1. most parts will be stamped therefore the heads for instance will have a 043 stamp or maybe 044 heads.... etc.... "mofoco"

2. depending on the damage created would both determine whether first you need to take it to a machine shop and where or not they can do something about it.

3. personally depending on the damage.... maybe just a new piston or some head work could fix it...

4. the piston used for the 1641 is a 87mm piston

5. would really be the best route but not the cheapest.... but i would recamend getting the heads cc'd to make sure they are both the same...

6. others have done it... havent heard of any issues as long as both are setup up the same as far as cc's/CR

7. as of right now many would say stay away from AA's not sure if they make 87's but i would stick with forged mahles....

8. not sure good question... (aka i dont know either lol)


i would also wonder why those little dinkers are there... did ya drop the oil yet?? if chunks of metal in oil there might be a larger problem (hate to tell ya)... if it was me i would personally rebuild the entire engine... put it.. recheck head cc's clearances... and possibly go to 90.5's.. but this would cost both time and $$$ possibly a few hundred for parts of a 1776... depending on if the parts you have are good....


this is just my ,02... take it for whats it worth...

skyguy Thu Oct 04, 2007 6:59 pm

Thanks for the thoughts............

It just occurred to me that if I am getting oil out from between the jug and the head then oil must be passing the rings in significant quantity.

I think I will get new pistons and jugs from a local bug place and have them matched to my heads. I would prefer to avoid machining the case. Would that be even be needed (I think I read it would) to upgrade to a 90.5 piston?

Oh and then of course the bigger carb, distributer etc etc.... It never ends does it? lol.

For now I just want to get it on the road without leaving an oil slick behind me. Although if I have to spend money and do the work I would prefer to only do it once.

bpritchert87 Thu Oct 04, 2007 7:11 pm

yes 90.5 require machine work to the case..... "only doing once is why i suggested 90.5's lol :wink: :wink: but yeah at a price... for now i would say new pistons 87's or 85.5 pick your posion.. if cooled proplery 87s should be fine.(aka i have had many friends that havent a problem with 87's becuase their engine where setup right)... And possibly new head but I WOULD make damn sure that they are cc'd the same.... other wise you will have issues... so i say buy one new head if the current one cannot be used... and then take the other off and bring to a machine shop.. tell them your delma and i would say stick around 7-8:1 CR... also i believe you need to measure your deck height in order to figure out CR and what the heads should be cc's to...

skyguy Fri Oct 05, 2007 10:41 am

I just ordered a set of Mahle cast pistons and matching jugs. It is only a 1641 so I did not go forged and feel ok about it.

I think I can just lap my existing head to my cylinders. I was thinking about fly cutting them .040 and adding .040 spacers at the bottom of the jug.
The heads look pretty good though, so perhaps lap and forget will work and save me some machine money.

I am going to patch up this motor and start a new one from scratch this spring. Of course I will have this website and all you fine people to blame for my new addiction. Without this site I would not bother to build my own motor. After all the reading I have done here it sounds like a better option than a turnkey.

I suspect this website is really owned by a super secret conglomeration of bug part suppliers and has a nasty virus attached to it. It makes me want to buy and build stuff................................................................

Eric_S Fri Oct 05, 2007 12:09 pm

You could add .040 copper head gaskets between the head and barrel instead of between the barrel and case too. Might be a better seal.

bpritchert87 Fri Oct 05, 2007 1:14 pm

skyguy wrote: I just ordered a set of Mahle cast pistons and matching jugs. It is only a 1641 so I did not go forged and feel ok about it.

I think I can just lap my existing head to my cylinders. I was thinking about fly cutting them .040 and adding .040 spacers at the bottom of the jug.
The heads look pretty good though, so perhaps lap and forget will work and save me some machine money.

I am going to patch up this motor and start a new one from scratch this spring. Of course I will have this website and all you fine people to blame for my new addiction. Without this site I would not bother to build my own motor. After all the reading I have done here it sounds like a better option than a turnkey.

I suspect this website is really owned by a super secret conglomeration of bug part suppliers and has a nasty virus attached to it. It makes me want to buy and build stuff................................................................

yup that is what we are good for.. lol :lol: :lol: so far ive been trapped for about 4-5 years now lol... and im 19!!!! lol

and maybe the samba is run by parts dealers.... :roll: :roll: :roll: :roll:

vwracerdave Fri Oct 05, 2007 3:05 pm

Don't halfass the job to save $50. Have both heads CC'ed and made the same. Then flycut them .020" to be safe and have a good seal. Then measure your deck height and set compression accordingly.

Juanito84 Wed Jan 21, 2015 9:12 pm

grimace007 wrote: unless there are huge chunks missing from the jugs you can "lap" them in with some valve lapping compound. and clean up the cyl to head mating surface. ive done it a few times.

I did this to the cylinder to case mating surface. But is it ok to do to the cylinder to head mating surface? Or am I better off getting tye heads fly cut?

The reason I ask is I noticed a small scratch on a step in one of the heads where they cylinder seats. It goes straight across the step. I must have set something with a sharp edge in there. How big of a problem is this? Is leaving it alone ok? PS, #3 cylinder.

Jerry Hundley Wed Jan 21, 2015 9:15 pm

This thread is almost 8 years old

Juanito84 Wed Jan 21, 2015 9:27 pm

Jerry Hundley wrote: This thread is almost 8 years old

And my heads are over 40 years old. But the lapping paste I bought is only a few months old.

Can I use lapping paste on the heads or not?

modok Wed Jan 21, 2015 9:39 pm

a tiny scratch probably will not cause a problem. Scrathces have a way of looking deeper than they really are. Lapping the cylinders will show you if there are any low spots. Don't over-do it!

Juanito84 Wed Jan 21, 2015 10:27 pm

Ok. Thanks! It's very small. Looks like just on the very surface.

mark tucker Thu Jan 22, 2015 9:41 am

go through the entire engine and make it right.or it will leave you walking and spending a lot more money chasing your ass in a circle,small circle as you will be walking in oil puddles.do it.

Juanito84 Thu Jan 22, 2015 8:12 pm

mark tucker wrote: go through the entire engine and make it right.or it will leave you walking and spending a lot more money chasing your ass in a circle,small circle as you will be walking in oil puddles.do it.

Sometimes when something is "ok" and I try to make it perfect I end up making it worse. :shock:

I'll twist them just a couple turns with lapping paste. If that doesn't get rid of the scratch I guess it'll be a sign I should take it to a machinist who can fly cut them.



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