Baller 2Valve Posted August 15, 2019 Baller Share Posted August 15, 2019 We verified last evening that my buddy's boat has a blown head gasket (350 Chevy block). It's on the starboard side. Was wondering if we can just use automotive gaskets and if it's necessary to purchase new head bolts. If anyone can point me to the torque spec's for the head, exhaust and intake manifolds, I would appreciate it. Thanks, 2Valve Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 15, 2019 Author Baller Share Posted August 15, 2019 I forgot to add it's a '96 MC, non LT-1 engine. 275hp I think. Link to comment Share on other sites More sharing options...
Baller MDB1056 Posted August 15, 2019 Baller Share Posted August 15, 2019 It happens. My 92 Hydrodyne Comp has GM 350 Mercruiser marinization (Magnum). Same issue a few years back at ony 550 hrs. No way to know if orig gasket had a defect or what. Automotive gaskets are fine. I used Victor Reinz gaskets - very good quality. No issues since. Head bolts shoudl be fine. Don't recall torque specs but any machine shop should be able to tell you. Keep skiing Link to comment Share on other sites More sharing options...
Baller thager Posted August 15, 2019 Baller Share Posted August 15, 2019 Check the exhaust manifold riser gasket first. I had water in my oil and was sure it was head gasket when actually exhaust manifold riser gasket. 74 Hydrodyne. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 15, 2019 Author Baller Share Posted August 15, 2019 @MDB1056 Thank you sir! He had a previous problem with the motor going into limp mode because it would overheat. Come to find out, it had two thermostat's installed and one was failing. Apparently, you can install a t'stat in the hose riser assy. above the water pump as well as the traditional location in the front of the intake manifold. I'm thinking, that maybe the engine overheated and possibly warped the starboard head. Something we'll definitely check upon removal. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 15, 2019 Author Baller Share Posted August 15, 2019 @thager good point. We checked the oil Sun night and it appears clean with no evidence of water. thanks, 2Valve Link to comment Share on other sites More sharing options...
Baller BrennanKMN Posted August 15, 2019 Baller Share Posted August 15, 2019 Get new head bolts. They are quite often torque to yield (TTY) bolts meaning they are toast after you've used them once. People do re-use them, but am a torque freak. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted August 15, 2019 Baller Share Posted August 15, 2019 @BrennanKMN i am as well which is why I always install studs and then those are reusable. Link to comment Share on other sites More sharing options...
Baller Jetsetr Posted August 16, 2019 Baller Share Posted August 16, 2019 Go with a permatorque head gasket as well...only need to torque it once... Better make sure the head isn’t warped if it overheated...easy to take a few thousands off to true it up (machine shop). Link to comment Share on other sites More sharing options...
Baller Orlando76 Posted August 16, 2019 Baller Share Posted August 16, 2019 New bolts. Don’t forget to check direction of Eder gasket as one side goes forward and the other opposite. That is if Indmar is same as PCM. Link to comment Share on other sites More sharing options...
Baller MDB1056 Posted August 16, 2019 Baller Share Posted August 16, 2019 Always good advice to have a shop check the head for warp or crack. When my gasket failed- water got in and hydrolocked. I lost one head. Other was fine. I had entire engine rebuilt - and one new head - I reassembled and installed - that was 250 hours ago. New head bolts are cheap insurance if you’re inclined. Always torque to specs and check check check. Victor Reinz gaskets are excellent quality Link to comment Share on other sites More sharing options...
Baller_ DW Posted August 16, 2019 Baller_ Share Posted August 16, 2019 FYI - Marine head gaskets have stainless steel combustion rings, automotive gaskets do not. So if raw water cooled, marine head gaskets are what you want to go with. Automotive ones work, but won't have the corrosion protection. @2Valve - have you verified why the gasket failed, most likely between cylinders 3/5 since the exhaust valves are siamesed and adjacent there. Do a good inspection to the cooling passages to ensure not blocked and limiting coolant flow in the hot zone. Also, make sure you get one that is the same thickness, you can get various thickness options for the SBC. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 16, 2019 Author Baller Share Posted August 16, 2019 @DW We haven't pulled the head. Hope to do that later today. Low compression was seen between cylinders 4 and 6. We'll be checking for warpage on the head and block in that area as well as the cooling passages. The motor over-heated about a month ago but was running fine until last week. Thanks for the head's up on the marine grade SS gasket material. The engine is RWC. Link to comment Share on other sites More sharing options...
Baller MDB1056 Posted August 16, 2019 Baller Share Posted August 16, 2019 Victor Reinz is owned by DANA corp. Go to danaaftermarket.com and Victor Reinz has en entire menu of marine applications including Holman Moody, Indmar, Mercruser, Chevrolet Marine, GMC Marine, Ford Marine, and many more. Reinz gaskets are very high quality. Link to comment Share on other sites More sharing options...
Baller_ DW Posted August 17, 2019 Baller_ Share Posted August 17, 2019 @2Valve - it can take a while after an overheat to cycle the head gasket to failure, and right between the siamesed exhaust ports, 3/5 & 4/6. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 19, 2019 Author Baller Share Posted August 19, 2019 @MDB1056 Thanks for the info. One of our members is an Engineer at Dana, so I'll pass this along. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 19, 2019 Author Baller Share Posted August 19, 2019 @DW So the head gasket is definitely open between 4&6. We measured the head and block and thankfully, there is zero warping. We decided to pull the port side head too and will have both cleaned up before re-installing with marine grade gaskets. There's quite a bit of rust, crud, in the water channels so we figured, clean them up while we have it apart. Link to comment Share on other sites More sharing options...
Baller Jetsetr Posted August 19, 2019 Baller Share Posted August 19, 2019 That’s a good move pulling the other head...all the work is done and it’s just a few more bolts... Your engine will like that... PLUS if it got hot there might be damage on the other side as well...might save you a bunch of work to change the other gasket when you could be skiing. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 20, 2019 Author Baller Share Posted August 20, 2019 Heads should come back tomorrow from the shop. Funny, I tried but couldn't talk my buddy into getting them ported and polished. A Roots Supercharger would have been cool too :) Link to comment Share on other sites More sharing options...
Baller_ DW Posted August 20, 2019 Baller_ Share Posted August 20, 2019 @2Valve - for an inexpensive 'wake it up' option, a ZZ4 camshaft is a pretty nice match for great idle and improved air flow at higher RPM. It has more lift over the marine cam and does not hurt idle quality. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 20, 2019 Author Baller Share Posted August 20, 2019 @DW Thanks for the tip. I love a motor with a silky smooth idle. One of the great sounds is the LS1 in my Vette. Link to comment Share on other sites More sharing options...
Baller MDB1056 Posted August 20, 2019 Baller Share Posted August 20, 2019 Agree 100% with @Jetsetr - it's a given that with headgaskets you always do both if one has been damaged. Always. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 30, 2019 Author Baller Share Posted August 30, 2019 Update on my buddy's boat. Only issue was a blown gasket between 4, 6 cylinders. Checked everything for warpage, and had the heads cleaned up and milled .002". Valves, valve seats, seals and springs were deemed "excellent", so we left those alone. The motor's never burned oil either. Got it all put together last night. Took our time setting valve lash/pre-load on the lifters, which I haven't done since I was a kid on a 327 Impala. I'm used to solid lifters, valve clearances on old motorcycles, so had to re-train my brain how the hydraulic lifters actually work. :) Popped the distributor in and it fired right up. Silky smooth idle, and quiet as a mouse. Set the timing and took it out for a spin. Literally sounds and runs like a brand new motor. Couldn't ski since the lake had whitecaps, but we'll run it through our course tomorrow. 2Valve Link to comment Share on other sites More sharing options...
Baller skihacker Posted August 30, 2019 Baller Share Posted August 30, 2019 It's always a deep sigh when you hit the key and it just...........starts. No popping or noises or looonnnng crank. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted August 30, 2019 Author Baller Share Posted August 30, 2019 @skihacker Exactly. Confirms that you did it all perfect. The most fun was assuming the squat position to set the torque on the 34 head bolts in three stages. :( My legs felt worse than running 8 sets in the course. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted September 3, 2019 Author Baller Share Posted September 3, 2019 One more question for y'all. We got the timing close (as we marked the distributor position on the intake manifold), but idle is a tad high. Under the assumption that the timing is advanced, is the timing mark on the cover marking TDC? (see photo). I'm going to pick up some harmonic balancer timing mark tape today. And I have the CodeMate tool to put the system into base mode, but wasn't 100% sure that the timing mark on the timing cover indicates TDC or the 10 degrees advanced, when setting the timing, as aligned with the slit on the harmonic balancer. btw, my buddy nearly broke his ankle this past Sat morning. Wanted to use his boat in the course, since we got it running. He's first up. Weather conditions horrible, (but we could care less), and he goes out the front around 1. Right now, it's a severe sprain, so just hoping to help him get this completed. Link to comment Share on other sites More sharing options...
Baller_ DW Posted September 3, 2019 Baller_ Share Posted September 3, 2019 Not sure on how your particular timing cover is marked, but if only on notch it just might be the base timing mark. You might look at the flywheel, there is usually a removable plug on the top of the bellhousing and the flywheel may be marked at TDC. Next option would be to grab a TDC stop, pull #1 plug and verify TDC 'the right way' :-) Link to comment Share on other sites More sharing options...
Baller 2Valve Posted September 4, 2019 Author Baller Share Posted September 4, 2019 @DW thanks for the advice. We were in such a rush to get it running that we never bothered to determine if that mark was true TDC or the base timing mark (10 degrees BTDC). I'll look for the bellhousing plug tonight, but I'm thinking it's just easier to pull the plugs and get #1 on TDC, as you suggest. Thanks, 2Valve Link to comment Share on other sites More sharing options...
Baller_ DW Posted September 4, 2019 Baller_ Share Posted September 4, 2019 @2Valve - since you are marking the damper with a timing tape, you may as well document full advance, which is the more important parameter. Should be 32-33 deg BTDC for a GM small block. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted September 9, 2019 Author Baller Share Posted September 9, 2019 @DW, good point. I'm guessing that full advance occurs around 3k rpm? Thanks, 2Valve Link to comment Share on other sites More sharing options...
Baller_ DW Posted September 9, 2019 Baller_ Share Posted September 9, 2019 @2Valve - it all depends on the timing curve and 3k is a good estimate. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted September 9, 2019 Baller Share Posted September 9, 2019 96 prostar has mefi so you need to make a tool to put it in timing mode and then it's timed to -10 I would caution against trying to time to TOTAL advance - because MEFI uses the RPM as well as values from the MAP sensor so total advance can be between say 28 and 35 degrees depending on the input from the MAP. Basically its hard to know what advance the MEFI is asking for unless you have some way to read the sensor values and access to the background tune so that you could check that for at 4000 rpm the tune is asking for X amount of advance when there are 46 KPA of manifold pressure etc. Instead you want to place it in timing mode and then set base timing - or go with your mark and try a tiny fracture more/less rotation on the distributor until the running attributes are as you desire. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted September 9, 2019 Baller Share Posted September 9, 2019 https://www.rinda.com/acro/codemate.pdf You can buy the tool from michigan motorz, ski dim, rinda etc. Or you can use an LED and a paper clip stuffed in the port - Or I personally made one using one of these https://www.ebay.com/itm/10-Way-Aptiv-Delphi-Metri-Pack-150-Series-Connector-Pigtail-12045808-6-inch-Wire-/283516169356?hash=item4202e16c8c along with an LED and a switch. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted September 10, 2019 Author Baller Share Posted September 10, 2019 @BraceMaker I have the CodeMate. It's not 100% clear about the base timing instructions but I believe the Code mate is installed, engine off. Start motor and turn the Code Mate on, which would put the engine in base timing mode? Then set to -10 degrees BTDC. Thanks, 2Valve Link to comment Share on other sites More sharing options...
Baller chrislandy Posted September 10, 2019 Baller Share Posted September 10, 2019 just bridge A&B on the connector with a paperclip and start the engine (or you can do it when the engine is running), then set to 10deg BTDC, the timing mark is usually TDC. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted September 10, 2019 Baller Share Posted September 10, 2019 As Chris pointed out - bridging the A&B on the DLC will set service/timing mode - but if you're going to do this please put some sort of fuse in it. A Code mate is literally just a 10 way Metri-Pack 150 series connector with an LED that bridges F/E and a Switch with a fuse that Bridges A/B. If you stuff an LED into F/E on the connector it should light up when you turn the key on and turn off when you start the boat - if that LED blinks or stays on when running you have a fault stored. You then turn off your ignition and stuff a paperclip across A/B and turn the key to the on position it will start blinking out your trouble codes. If you start it with it bridged you're in timing mode. Link to comment Share on other sites More sharing options...
Baller 2Valve Posted September 10, 2019 Author Baller Share Posted September 10, 2019 @BraceMaker Got it. So I'll install the CodeMate with engine off, switch it to On and then start the motor and time away. :) Thanks very much. I'm a points and condenser, dwell meter kind of a guy, so this new fangled electronics stuff is very new school. Appreciate it. Still another month of skiing left up here in the North. Link to comment Share on other sites More sharing options...
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