Engine Rebuild? Have you done a 412 1.7L build up?

vwbill · Post by **vwbill** » Mon Aug 07, 2006 11:24 pm

Sorry to create another motor rebuild post but was wonder how many people have done a complete rebuild of the 1.7L motor and how it went and what they used as a set up and what work did they do and what work did they send out? Did you do the measurements and compression calculations? Would you do the rebuild yourself again or have it doen by a machine shop and pre-run? bill

raygreenwood · Post by **raygreenwood** » Tue Aug 08, 2006 4:55 am

I have done a few. I am in the middle of one now....yeah ...have been for a couple years

. Work has been killing me!

I am doing everything myself except for teh machine work...obviously. Re-size rods. grind and polish crank, valve seats, valve job, light port work on exhaust, polish intake tract, machine work to domes on pistons, complete balance work and bore and hone cylinders to .5mm oversize....all went out.

New cam, new gear, new crank gear, new lifters......all will come from Jakes store. Work on double thrust cam bearings rocker geometry and pushrods I will do. Oiling system and squirters I will do. All assembly Iwill do. All calculations I will do.
Yes I highly reccommend building yourself but do your homework. Ray

vwbill · Post by **vwbill** » Tue Aug 08, 2006 9:03 pm

So, do you think for a stock setup going with the web cam 73 and a matched set of lifters and new cam gear, rebuilt heads or new, reman pistons and rods or new jugs and pistons and reman rods, New rings(what make?), reman crank, new bearings, new oil pump. Do you think it's better to start with a small block rebuild and build the long block yourself or just do all the assembly yourself? Do you assemble and prerun the motor or complete the motor and car fit and run and adjust and then remove and retorque and reinstall and resetup? What type of rebuild do you think a amatuer can reach vs. a shop and do you think dyno is needed after the rebuild to test the quality of the build? I know the cost is alot more having the motor rebuilt at a shop but what do you gain in time and quality? bill

raygreenwood · Post by **raygreenwood** » Wed Aug 09, 2006 4:21 am

If you are having the correct machine work done (heads, crank, case and balancing) and you take your time....you can do as well as anyone.

I think you should always rebuild from the ground up. Even if you buy a built short blcok from someone you will need to disassemble it to make sure of the tolerances. Unless you buy from someone like Jake.

Its hard to say on pistons and cylinders. Personally with the quality issues in new cylinders right now, Iwould use the best new German or old German domed pistons I could find and the best used cylinders I can find...or optimally.....have new pistons made for rebored German cylinders.
The 1.7 needs t o be as finely balanced and as tightly built as possible to be the excellent engine is was designed to be. Ray

vwfye · Post by **vwfye** » Wed Aug 09, 2006 4:40 pm

let me know if you can not find NEW 1.7L pistons and cylinders... i have a set here at the house with zero miles on them. i paid 325+ shipping new for them but no longer need them.

vwbill · Post by **vwbill** » Wed Aug 09, 2006 11:54 pm

Hey vwfye, what is the deal with the 1.7L set? Are they domes, what make? I am interested! Hey, checked out your website and wow some great stuff goin on!! Your Estate is looking so sweet!! How is the squareback? My brother has a 70 that I only just got to get the oil cooler replaced last time I was in south florida.... At first I thought the two mount bolts were stripped in the case, but duh they have wrench bottom access!! I think my back hurt for a week after the climb to get the tin screws and reach the intake stuff... Thanks bill
p.s.The Race Bug"Yard Find" has some great history!

vwfye · Post by **vwfye** » Thu Aug 10, 2006 6:42 pm

these are not the dome pistons... i supposedly bought (at the time) the last set of them in the USA (again, according air-cooled.net). we were rebuilding my father's 1.7L in his bus and upon putting the heads back on and putting the rockers on it, the stud pulled out of the head. so, assuming the engine had been extremely hot, we decided to just go all new and did a hybrid 2.0L instead. so, the brand new, only been on the engine long enough to find out we weren't gonna use the engine, pistons and cylinders are available.

sorry for the novel

raygreenwood · Post by **raygreenwood** » Fri Aug 11, 2006 10:42 am

These days...if they are original Kolbenschmidt or Mahle dished pistons....keep them around. Even good quality dished pistons are getting rare. Word of warning though....in the 1.7L for 411/412....if you are going to run D-jet....the low compression gives a very poor running engine. The dished should be used with carbs only where they run very well...but with about 12 hp less. Ray

vwfye · Post by **vwfye** » Fri Aug 11, 2006 10:16 pm

hmmm, well, they are the dished pistons... so, nevermind i guess

hoodsy · Post by **hoodsy** » Fri Aug 11, 2006 11:41 pm

I have rebuilt many engines of all types shapes and sizes, most of the time I prefer to do 90% of the work myself except for some machining. I have though done builds from short bklocks and long blocks that were done by other shops as well. I suggest familiarizing yourself with the techniques enough to do as much of the job yourself as possible, just because you pay a bunch of money to a shop to do a job, does not mean it will be done right. I have had to pull many an engine out because another shop we had shipped work out to had done a second rate job. in fact I have seen engines fail with less than two hours on them. fact is if you send it to a shop you have no idea what was done internally and if corners were cut. As one who rebuilds engines professionally myself I can tell you that when you are working in industry, under time constraints etc. you are pushed to cut corners and simply do what is deemed good enough. If you do it yourself you have the time to measure everything and get it right so that you can have the confidence that the job is done right. if I do a build at the shop it rarely takes more than a couplre of days unless it is an extremely bad case, if I do a build at home where I can take my time, it can take easily five times as long or longer, but I know that with any build if I have done all the work, and everthing is done to spec. I am confident it will run fine, with out worry.

raygreenwood · Post by **raygreenwood** » Sat Aug 12, 2006 5:31 am

Vwfye....that is not to say that the dished pistons are bad. They are specific for an application. Most specifically...they are what you need to have in a correct bus 1.7 rebuild. The bus with its gearing and load does not do well with teh higher compression domed pistons. If they are Kolbenschmidt or Mahle....even if they are dished they are valuable. Ray

vwbill · Post by **vwbill** » Sat Aug 12, 2006 8:38 am

Question about after the build, what about retorqueing and how long and what about dyno? Do you do a car first run and then retorque or do a out of car run and then retorgue? What about condition of the rebuild check? Do you do a compress test? What specs are acceptable for the first drive period? bill

vwfye · Post by **vwfye** » Sat Aug 12, 2006 9:32 am

i know there value, i just didn't want vwbill to be dissatisfied if he purchased them from me. as i have a 1.8 in my 412, 2.0 in my pop's bus and type 3 power in everything else i have no use for these pistons/cylinders now so i thought i could be of some help...

raygreenwood · Post by **raygreenwood** » Sat Aug 12, 2006 1:05 pm

Re-torque of the heads is always a debate. Its a large pain in the neck....but I beleive you should re-torque immediately after break-in. That way if any particular stud is stretching a bit a loosing tension you can catch it before it destroys the seating surface between the head and cylinder.
I also retorque all of the studs. Yes, this means that I pull the runners and tin. Its worth it just to pull the whole engine. Four hours of pain for 100K of good driving.
It will be a bit different on this current build. I am using all long studs to equalize the stretch. That means that I am in the process of designing vovers for teh holes I need to make in the tin....as well as aluminum spacers with forged washers for the longer studs. But....it will also allow me to be able to retorque all of the studs without removing the engine, manifolds or tin. Ray