Rebuilding 3800 L67

So recently I had the intake manifold gaskets blow out on my 98 Riv with about 200,000 kilometres on it. Opening up the intake I wasn't surprised to see that they're made out of plastic and they finally died, great idea General Motors. The engine developed a knock and I replace the lifters and the con rod bearings hopefully to solve the issue. However this didn't solve the problem and upon further inspection of removal and dismantle of the engine I found the two pistons on the left side or the front of the engine as it sits in the car missing the crown all the way down to the first ring land on the first two Pistons. My gut is is that these first two Pistons are struggling to get the exhaust out because of the restrictive exhaust ports that these cars have on the manifolds especially the front manifold and I think that at the time that the intake went I ended up with severe detonation. Anyways the engine still ran but developed a pretty significant knock. The block and heads actually are still in good shape; the cylinders didn't get damaged despite the Pistons losing little chunks of aluminum that eventually ended up going out the downpipe likly lodged in the cat. I'll post a few pictures here of the engine dismantled and I'll let you now how things go. I have a couple of questions if anybody's rebuilt one of these: what head gasket do most of you guys use, multi-layer steel or composite. I priced out the parts on rockauto.com. They currently dont Have a full engine gasket set but I can piece together the gaskets that I need. I also ordered the replacement bolts that I need from ZZP including an ARP stud kit for the heads and the mains. I was looking at forged pistons however they're quite expensive so I'm opting to go to hypereutectic pistons for about one-third to cost. I've also got new LS1 lifters , pushrods and upgraded rocker arms from zzp..1.9:1 vs 1.6...the gaff is " It is a lightweight replacement rocker arm, (over 27% lighter than the OEM rocker arms!) however this is the higher 1.9 ratio version, the stock rockers are 1.6 ratio. These are intended to maximize the performance of the stock camshaft by increasing the lift of the stock cam lobe. Increasing the lift of the valve will improve airflow through the heads resulting in about 5-7% more horsepower. They will reduce the boost a bit in supercharged applications which will reduce knock."
I was shocked to see how restrictive the stock front exhaust manifold is with it having a pretty decent restriction as soon as the exhaust hits the guts of the manifold so I will put a power log on the front... the rear actually is pretty well made from the factory so I think it will remain in place. I believe that I'm going to add an oil cooler to it and a 180F t-stat and then maybe at some point I'll look at getting an intercooler kit from ZZP as well ...they're out of stock right now and I haven't quite figured out how the actual heat exchanger is going to mount as it's just kind of large for sitting anywhere on the front end of a Riviera ...I'm wondering if anybody tried this intercooler route on the Riviera and what they use for the heat exchanger.. here are some photos so far...


NOTE ... the cylinders are really shiny so the picture shows the reflection of the damage piston area making it look bigger. The top of the first compression ring is visible..

PM Aaron (AA).  He rebuilt his and found a guy that did a great job.  His high mileage engine was damaged from detonation, the rod bearings were hammered by it.  The PCM can only protect the engine so much with KR.
Hyperutechtic pistons are even more susceptible to detonation

A Plog would be great, but you will get joy *just* from porting the front cast exhaust manifold. I did that.

It'll be nice to see what you do about a heat exchanger for your intercooler.  I'd probably mount something behind the front air dam with the plumbing coming through the drivers side front in vicinity of the existing air box.  You could get some space (and noise) going to a mustang-type cone filter for the air intake and bung the air sensor into the existing air horn somehow.  I've never tried that, however, no interest, but it's fun to think about for a moment.

LARRY70GS wrote:

PM Aaron (AA).  He rebuilt his and found a guy that did a great job.  His high mileage engine was damaged from detonation, the rod bearings were hammered by it.  The PCM can only protect the engine so much with KR.
Hyperutechtic pistons are even more susceptible to detonation

Ok thanks i will contact him

Hi Dave. We used fresh OE cast aluminum pistons (L67). These are fine for running quite a bit of boost. I was at 13-14 PSI, and have run up to 16. Problems occur when you go lean and severe knocking ensues, which is what happened to mine.

For what it's worth, I've read hypereutectic pistons are brittle, and not recommended for boost, but there may be exceptions here.

Diamond makes a set of forged pistons for a pretty penny, which can tolerate lots of knock, but a downside is they have piston slap when cold. It's just something I read numerous times from those running them. Not a huge deal for a race car, but not something I wanted for my daily.

Also the OE head gaskets are very good in the L67. We used these and of course the updated OE metal LIM gaskets for the rebuild.

If you've never had your fuel injectors cleaned and flow tested, this is a good time to do so. https://www.mrinjector.us/

Love the extra mid/high power from 1.9:1 rockers. One of my favorite mods for these engines!

I ended up with hyper pistons, and I will dial the boost back a bit for longevity. I bought 6 new injectors as well.
I'm still working through this rebuild project but I've kind of hit a bit of a stumbling block. I had the Machine Shop install the cam bearings that I bought and when I went to put the camshaft and I could not get the cam to go past during number four bearing. So I took the cam and engine block back to the machine shop and left it with him, after showing  the issue. He spend some time playing around with it and he managed to get the cam in and it spins okay unless you let the cam slide back into the block, then it gets a little bit tight. In other words if you pull the cam forward a little bit it spins freely but if you push the cam back into the block a little bit it gets tight. So that to me is improper clearances. Almost like one of the bearings is tapered but my gut is is one of the bearings is actually damaged from the install. I don't know what side he started installing first but just judging by the tightness I would almost say he was installing them from the back side of the block. So I'm not sure I want to do any business with this machine shop anymore.  What I was thinking to do was just order another set of cam bearings and then reinstall them myself after I buy the tool. It doesn't look very difficult to do I probably should have done it myself to begin with. My question is bearing selection. I didn't really pay attention when I ordered the bearings before but now I see there's a first design second design and they talk about the actual bore size in the block. I'm curious if anybody's gone through the selection process and what they discovered. The bearings are not expensive to buy even if I had to buy both sets 2 be sure. The tool is more expensive than buying ten sets of bearings from what I can see. Unless I buy GM OEM bearings which look like are both $50 each bearing which is ridiculous. So if anybody's got some input on this I would really appreciate it

Sorry for double posting . This forum is a pain to post post from my phone it seems

Read through this thread on V8buick. It deals with the 455, but the tight cam can be an issue with any engine for various reasons. Yes, I would try another set of cam bearings. Look at post #18.

https://www.v8buick.com/index.php?threads/tight-camshaft.313240/#post-2604524

Thanks. I played around with it a little bit today, polish the cam up quite a bit measured it all out make sure it was inspect I just can't measure the bearings cuz I don't have the proper tools yet but they're on their way. I ordered another set of cam bearings I'm just going to pound these ones out when my tool shows up and measure the journals and then install the bearings and see what happens. I was playing around with it today and I was spinning the cam with a drill just to see what would happen and I can actually see rub marks on the bearing surfaces where the cam is tight the. It's like it has a slight bit about around but I can't really turn the cam with my fingers within the block unless I slide it halfway out of the bearings so something's not right. The cam is tight going in when it hits the second bearing

I received the new cam bearings and I will install them on the weekend.  I notice the #1  and  #4 bearings have  small  grooves cut into them . My thinking is these are meant to squirt a small stream of oil onto the back of the cam thrust plate at the front of the block and at the rear I am not sure what its purpose is

I set this bearing to lube the cam of course and squirt oil behind the thrust plate. I bought a universal cam bearing tool and removed the previously installed bearings and installed the new ones. Now i can turn the cam with two fingers easily.
Tomorrow I will file my rings to spec and get the cam and crank in and the rear cover on. I don't have the rear seal install tool so I will improvise

Ran into a snag... the single roller chains crank sprocket wont slide onto the crankshaft....bought from ZZP ... I might try baking it in the oven for 45 min at 350F the see if that makes it expand enough to slide on .

dbriviera wrote:

Ran into a snag... the single roller chains crank sprocket wont slide onto the crankshaft....bought from ZZP ... I might try baking it in the oven for 45 min at 350F the see if that makes it expand enough to slide  on .

Mmmmkay... while you are at it, pack a quart size (at least) ziploc bag with crushed ice and salt (any salt will work... rock salt, table salt, sidewalk ice melt, what the heck ever) and pack it on that crankshaft end. Change out the ice bags when they have melted too much (see below). By the time that crank sprock has baked that shaft end will have shrunk somewhat and you'll have a minute or 2 to press the sprock onto the crank.

The trick would be to make up 3-4 of those salt water ice bags and while one is on the crank hold the others in the freezer, swap them every 10 minutes or so. Why? In the freezer those bags will sit at your freezer's set point, which should be between 0 deg F and 10 deg F for a household freezer. Out of the freezer, the salt will quickly melt the ice BUT the slurry will be well below freezing (32 deg F). The slurry will conform well to the crankshaft end. You also might want to use gloves to handle those bags because they will be d-mn cold.

Zzp video is to use a piece of pipe and hammer it on.He then says the oil pump drive slides on, however he does not show doing this as it too is hammered on . I don't like hammering on a crank even they it isn't much. Plus I felt like it was going to mark up the crank. So my solution to the problem ways to put 2 pieces on a pan and put them under the boiler in the oven for about 20 min and then they just slid on without any issues at all. Within about 1 second they cooled and were solid in place. The engine work is in progress in the garage and its about 10C so pretty cool.

One thing I never understood was why I see people putting the camshaft in after installing the crank and pistons ..I found it much easier to put in the camshaft being able to reach in the bottom of the engine to help guide it through the bearings with ease and accuracy.

dbriviera wrote:

One thing I never understood was why I see people putting the camshaft in after  installing the crank and pistons ..I found it much easier to put in the camshaft being able to reach in the bottom of the engine to help guide it through the bearings with ease and  accuracy.

I agree with you on heating the cam gear to fit it.  I could not be there to measure the cam and the gear hole with a caliper; however, with those measurements and knowing the coefficient of expansion of the metals, it's easy to tell if freezing that shaft is even necessary (obviously not necessary in your experience).  Without the measurements, the ice bag thing changes the effort from a "will probably work" to "sure thing."  That's all, really...

As for the camshaft, my guess is it's the difference of experience. And maybe OHC vs valve in head (like the 3800) engine.

OHV is valve in head . Did you mean OHC?

dbriviera wrote:

OHV is valve in head . Did you mean  OHC?

fixed... thanks...

This is quite the learning experience. I suspect all GM engines after the mid nineties are like this;
Almost every fastener is a a single use tourqe to yield.

It's easier just to list off the bolts that I didn't "have" to replace. The intake manifold and the supercharger bolts are reusable and some of the accessory Drive bolts like the power steering and the alternator and air conditioning bolts are reusable, all the little bracketey bracket bolts around the engine and the exhaust manifolds are reusable, the oil pan bolts are reusable and there's a few others I'm probably not thinking of right now like some heat shield bolts and maybe the EGR bracket bolt and the EGR bolt .

However, all the major bolts between the tourqe converter and water pump are all torque to yield bolts that require being tossed-basically single use fasteners designed to permanently stretch. The factory service manual is full of warnings about not reusing these bolts.
I went to a bolt Fastener supplier today and got all new bolts for the rear cover which are not torque to yield but they were stronger than the factory bolts rated at 10.9 rather than the 8.8 or 9.6 that those bolts were . I already forgot. These replaced the rear cover bolts and the mains bearing cross bolts(10.9). I bought all of the other engine bolts for the internals from ZZP; ARP stud kit for the mains and the head and ARP bolts for all the rods, and the 1.9 rockers came with reusable bolts. And of course the cam bolt, crank bolt, torque converter bolts and flexplate bolts.

While I was at a nut and bolt place today, I also got myself some dressy stainless steel hex socket bolts and stainless washers for the supercharger and some of the things that bolt onto the supercharger like the pcvalve cover, the bolts for the vacuum fittings, and a few others. I have to reuse the one stud but I got a stainless steel washer and a Nylock for it. Tomorrow I'll get a few more fasteners for the front cover with the exception of the studs that need to stay in place for the crank sensor sheild, and some water pump bolts and also I'll get some stainless hex sockets and washers for the intake, which I should have thought of that when I was there.
I may get stainless hex sockets for the valve covers, I'll see...
I was going to polish this supercharger but then I thought since I live close to the ocean in the car sits for a long time out in the salt air, all the aluminum is just going to get shity looking over time ( like it is now). So instead I bought some silver paint that's meant for headers, and I painted the front cover and the oil filter adapter and I will also paint the supercharger in the intake manifold with it as well. I don't run the car with the plastic " fuel injection sight sheild" in place; I like to see the S/C when I open the hood and hear its little whine. I did a restoration of the alternator
with the nice silver paint as well ... the trick I learned there was to paint everything silver including the pulley ( painting the front without removing the pulley) and then once the silver paint dried I slipped thin cardboard cut in half with a hole in the middle under the pulley and painted it black using the cardboard to mask off the alternator. Turned out pretty good. The silver looks like very metallic aluminum, almost a sandblasted look.. but it looks better than crusty old aluminum... I also found some VHT engine paint made for plastic surfaces, so I scrubbed the set of ugly gray plastic valve covers and painted them silver. It doesn't look like tacky fake aluminum silver; looks like a nice silver color. I think it'll look good since I also bought the Power log from zzp.
I intend on assembling it fully for photos and then i will remove the necessary "R and I" parts to install it. Intent is to be driving it before March 31st.

I also wanted to seal of the coolant supply to the throttle body from the intake using screw in plugs so that's up next.. I will run a lower temp stat ( 180) and an oil cooler as well to keep this engine cooler inside to keep detonation at bay.

I am used to allot of knock sneaking in around 3000 rpm when the cylinder pressure are high so I bought new knock sensors and injectors to bring everything back into new engine spec. The seeping intake crossover may have helped the knock appear.
Somebody suggested having the injectors sent out and cleaned but because the place that does that is in the states, I am in BC, when I did the math, it was cheaper for me just to buy new injectors so that's what I did. I also anticipate that with the 1.9 rockers and a stock cam ZZP says that thos setup will bleed off a little bit of boost in the low mid end so that should can help with knock, so we'll see. I also was trying to overdrive the supercharger a little bit too much with a 3.3 pulley so I'm going up to a 3.6, in thinking of longevity for this engine non- intercooled engine. If I get an intercooler later, I will drop the 3.3 back in.

albertj wrote:

A Plog would be great, but you will get joy *just* from porting the front cast exhaust manifold. I did that.  

It'll be nice to see what you do about a heat exchanger for your intercooler.  I'd probably mount something behind the front air dam with the plumbing coming through the drivers side front in vicinity of the existing air box.  You could get some space (and noise) going to a mustang-type cone filter for the air intake and bung the air sensor into the existing air horn somehow.  I've never tried that, however, no interest, but it's fun to think about for a moment.

The exhaust ports are smaller than needed so i don't see porting adding much relief.

I have an open element cone style aid filter presently. The sound is of the S/C rotors so sort of a whine rush of air which sounds pretty cool. Sounds great in a tunnel under the highway nearby.

I struggled a bit installing the pistons today. The oil control rings and the oil control expander ring were being bitches. The expander ring on a few pistons kept climbing on top of itself at the gap was one issue and the oil control rings fucked up on 2 pistons during install into the block. I did get it all put back together though and I discovered a way to make sure that once the Pistons installed that there's no binding of the oil control rings. Basically with the Piston at top dead center I would just put pressure on the inside dish and work my finger around in a hard Circle and you can actually see the Piston moving around in the cylinder from wall to wall following your finger. For the one piston that had the oil control expander ring climb on top of itself it was kind of stuck to one side inside the cylinder. But having not checked there's no way that I would have known. So I removed the Piston, realigned the control ring expander and replaced one of the oil control rings which had a slight kink in it from jumping out of place as it was going into the cylinder.

dbriviera wrote:

albertj wrote:

A Plog would be great, but you will get joy *just* from porting the front cast exhaust manifold. I did that.  

It'll be nice to see what you do about a heat exchanger for your intercooler.  I'd probably mount something behind the front air dam with the plumbing coming through the drivers side front in vicinity of the existing air box.  You could get some space (and noise) going to a mustang-type cone filter for the air intake and bung the air sensor into the existing air horn somehow.  I've never tried that, however, no interest, but it's fun to think about for a moment.

The exhaust ports are smaller than needed so i don't see porting adding much relief.

I have an open element cone style aid filter presently.  The sound is of the S/C rotors so sort of a whine rush of air which sounds pretty cool. Sounds great in a tunnel under the highway nearby.

The porting gets rid of adverse reflections of the shock waves from the head, which is what gives you the relief. As you know, you don't enlarge the tube you get rid of the reflecting surfaces. The thing that blew my mind is I'd read about this stuff in fluid dynamics and could work the math but I did not believe it would really make a difference until I actually did it. For the rest of you reading this and getting curious: See https://www.hilarispublisher.com/open-access/analysis-of-exhaust-manifold-using-computational-fluid-dynamics-fmoa-1000129.pdf.

Running an office center must leave you with a lot of free time on your hands.

Closer... heads on and valve train in place. Getting more now fasteners tomorrow.
I am going to cap off the coolant ports from intake through the throttle body. I see ZZP does this mod and it makes sense. Theres so much heat going into the intake from hot coolant to EGR heat. I have checked the temp of the supercharger case after a drive and its been around 140f at the top around the middle.
I have bern reading and researching engine oil coolers. I think I will add one with a thermostat in the oil filter sandwich. I see i can get one with sender fittings so i could add a oil temp gauge and oil pressure gauge. I was thinking to install them in the spot where the cd storage was, as its gone from there. Maybe even a vacumm/ boost gauge as well.

Jack the R wrote:

Running an office center must leave you with a lot of free time on your hands.

I have evenings and weekends open, usually, for myself and family. It *looks* like I have a lot of time probably because I try to structure it well. Does not always work, of course.