The engine of my 350cui 1968 FB leaks quite a lot and, since at least one exhaust manifold is cracked (RH) and as it turned out 2 bolts of the other exhaust manifold a broken off. Thus, it is now time to address these topics and the engine will come out.
Currently, I have got one used exhaust manifold to replace the cracked one. Since I live in Germany and parts are not as readily available as in the USA and a shop will do the work it is better to order parts in advance to keep turn around time at bay. Gaskets are no problem. Exhaust manifolds, however, are. Would you rather buy a complete set of: https://www.ramairrestoration.com/p...-long-branch-d-port-factory-headers.html to be hassle free compared to used ones that might crack (I would have to obtain a used LH via eBay in case the currently installed on has also cracks)? Since the thread of the oil pan is apparently worn out something needs to be done here, too. Is there a repair kit (metal piece to be welded inside containing a new thread) available or is the Canton 15-389 oil pan the better choice despite having the plug on the side?
You have a lot going on here. Not sure either one requires removing the engine but you may have more going on than just these items.
You said your engine leaks? That can mean many different things? But since you list a few I'll give it a shot.
You have many exhaust manifold options. You can replace with stock log type which will not require any modifications to your existing exhaust. You can also upgrade to longbranch set as you mentioned. They are a nice upgrade but not cheap. You may need an oil filter re-locator and need to adapt to your current exhaust. You can also go with headers but they have their own set of issues and may require additional fit work. You should gain a few horses with longbranch or headers.
As for the oil pan... I can't tell if you are talking about the drain plug or the bolts holding the pan in place but either one should be a relatively easy fix for any mechanic to retap and not require a new pan unless the drain plug hole has been already repaired before now beyond repair. They even sell oil drain plug fix kits just for that occasion.
Actually, I want to keep the FB as stock as possible. The link I posted regarding the ramairrestoration headers would require additional changes to the exhaust system as I’m aware of now. So I prefer to find a LH exhaust manifold to add to my replacement RH side one, which has been lying dormant for 6 years. I meant the drain plug thread and there are time sert kits available. However, depending on previous work on the thread you may need different kits - this can’t 100% be decided before removing the pan. I know there was a flange available for C2 Corvette oil pans facing the same problem: GM #3723008 or you can make it by yourself: 1/4”- 3/8” flat steel about 2 x 2” and a thread 1/2-20 in the center, which is then welded in the pan. This is something I can prepare in advance. Since at least one stud of the LH manifold is broken and it needs to be drilled out I was told the engine has to be removed. Most probably more will shear off while removing the manifolds.
You should be able to find an exhaust manifold pretty easy. Check ebay or used Pontiac parts stored online. Frank's Pontiac parts etc. come to mind. I can think of a long list of projects to tackle while the motor is out. Great chance to have access to the entire front end too.
As for the oil pan I would find it hard to imagine you can get it repaired fairly easy. Especially if the pan is removed.
@Ron: thanks for your offer. However, I was was able to obtain one on eBay. If its condition is bad I’ll come back to you. @uconn86hgiv: also thanks for your input.
Unfortunately, this is a project that my limited experience and tools prevent me from doing on my own. So the only thing I can do is to order used parts in advance and gather information on which companies to choose with respect to new gaskets and quality.
I’d like to know which engine sealant kits are recommendable. Summit Racing offers one. But I would choose Bop for the divided rear main seal (Viton) and one piece oil pan gasket and omit respective parts of the sealant kit. What do you think? I suppose the suitable down pipe bolts and exhaust manifold bolts can be ordered arbitrarily - or is there also a company preferable? Thanks in advance.
And how about the rear main seal? Is a Viton one as offered by BOP the least troublesome - or is this plain marketing? I heard stories by my garage that sometimes a replaced rear main seal leaks just after 700 mls again.
Fel Pro makes nice gaskets and ARP makes nice bolts and studs. I don't think anybody will argue those.
Rear main seals can be quite a bear but as you are pulling the engine you should be ok. The originals were made of rope but more options now. Lots of opinions on the best products and courses of action. Some have had good luck with a product only to have it sworn off by others. Lots of threads here you can look up on the topic. Viton is a popular choice.
I’m undecided ... I have never done a comparable task. Some people here in the forum did it without any previous experience, too, and were successful. I’m currently looking what tools I would need: an engine stand - not too expensive. An engine crane can perhaps be borrowed. Regarding the nuts and bolts that are rusted and, thus, hard or not easily to open, I would buy an induction heater instead of using a flame. For the labour costs in the shop a lot of tools could be bought :-)
So here is my 2 cents on "do it yourself". Some things are worth it... and some things not. There is no doubt you can do it. Thousands before you have done it. Whatever it is. You just need to consider "What is the worst thing that happens if I screw this up?" Depending on the repair that can vary.
If you take your engine apart to replace the rear main seal my guess is that you will properly be able to put it back together. With some help and a good shop manual of course. Worse case scenario is things are not repaired and a lot of oil continues to leak. However if you are not careful in reassembly things could go very bad. The up side is you will learn a lot along the way and if you do it properly save a good deal of money. Make a big mistake and you will be looking for a new engine! What you will be missing out on is that a good mechanic might be able to tell you a good deal about that engine while they are in there!
Here is where you get into the fun of an old car. While you have that engine out and torn open there is a list of about 100 things that you should probably look into doing. It's all about time and money. It's not just about the engine... you now have wonderful access to the front end too. See what I mean!
As far as your exhaust manifolds go those rusted bolts can be a real pain in the butt! You may find that you hit them with some penetrating oil and let them soak and then some heat and they come out. You win. But you might need to drill them out or worse have the hole retapped. Better to leave that to a pro. It's worth the few dollars.
Here are two pictures of the holes with the missing/broken bolts. Still nothing removed just used a tiny USB camera for a smartphone. More bolts will most probably break. These broken bolts have been my biggest concern so far because experience is the key factor. Regarding the rear main seal I would use the divided 3” Bop Viton seal so that the crank case can be left in place and only the main cap anti rotation holes require high temp silicon. For removing the old rope seal there is this sneaky pete tool. I think i need an exit strategy, i.e. when to hand over to a pro. This can be when the holes need to be retapped and/or the crank case needs to be loosened or removed in case the Viton seal doesn’t work.