- Oct 18, 2008
- 949
- Boat Info
- 1989 340 EC
- Engines
- 7.4LX2 Hurth 630A Drives
6.5Kw QS Genny
I had previously asked for recommendations on exhaust manifolds for the old 7.4L. I was hoping to avoid paying the high price for the OEM Merc set. This is my $.02 on what I have learned, bear with me if I go too long.
I purchased 2 complete sets for my newly remanned 7.4L's. They arrived with the lightweight cardboard beat up. When I inspected them, I found that the riser flange on the manifold was mushroomed on the corner as if it had been dropped (they also still had sand in the water passages, some painted over). I took a machinist straightedge and small file and went to work until I got it dead straight. For good measure I did the same on all the like surfaces where the riser and manifold mate to avoid possible leaks. Of the 8 surfaces(4 on each set) I had to straighten the previous manifold spot and an additional spot on 2 of the risers.
I used the mercruiser riser gaskets with the metal shim stock sandwiched in, I used the blockoff version because I have freshwater cooled manifolds and raw water in the risers. I started both engines on land with a freshwater flushing adapter, both ran quiet, didn't overheat, and appeared to pass the proper amount of water flow.
After about a week of use it was apparent that the port engine was getting freshwater back into the cylinder (slightly delayed startup and some steaming) I checked surfaces and replaced 3 more sets of riser gaskets and even tried riser retorque after a heat soak and cooldown to no avail. I was fed up with the wasted time, money and hassle and decided to just get the OEM manifolds for the port engine to verify in my mind that they were the issue. Installed the OEM manifolds and ran for the rest of the season with no issues. You can immediately see and feel the difference in material and manufacturing quality.
I contacted the seller concerning the GLM warranty and was told the following "GLM will do a pressure test on your manifolds to determine if they are leaking. A pressure test can be done by any local Mercruiser dealer for a minimum charge. I suggest that you have the manifolds pressure checked locally before you make the effort to return them. If GLM finds that they do not leak you will be responsible for all shipping costs.Most manifolds returned for warranty consideration because of leakage do not fail a pressure test (do not leak) and are returned to the customer without warranty."
In a followup email I asked that I be reimbursed my money since I had already purchased the right manifold set and was told that that was at GLM's discretion and more than likely they would only replace them with replacement manifolds.
About a month later the same issues began on the S/B engine and I purchased the OEM Mercs for that side as well. Some may have had good experience with GLM's, but, as you can tell, I have not.
An additional note: all the manifold and riser surfaces I checked and filed on were kept together on the S/B engine to be sure in my mind I hadn't messed something up. They were painted with red paint on the water nipples so I could remember which ones I had "massaged"
The moral of this story for myself was: The money I saved on the initial purchase was lost, as was the total purchase price of the manifolds (which I gave the better set to a coworker who had the same issues and threw them in the trash) and I ended up putting up the money to buy the right parts I should have bought in the first place. I also learned that the warranty is only as good as the company, and reseller, that stand behind (or don't) their products. I have told as many people as would listen to Stay away from GLM manifolds at all costs.
I purchased 2 complete sets for my newly remanned 7.4L's. They arrived with the lightweight cardboard beat up. When I inspected them, I found that the riser flange on the manifold was mushroomed on the corner as if it had been dropped (they also still had sand in the water passages, some painted over). I took a machinist straightedge and small file and went to work until I got it dead straight. For good measure I did the same on all the like surfaces where the riser and manifold mate to avoid possible leaks. Of the 8 surfaces(4 on each set) I had to straighten the previous manifold spot and an additional spot on 2 of the risers.
I used the mercruiser riser gaskets with the metal shim stock sandwiched in, I used the blockoff version because I have freshwater cooled manifolds and raw water in the risers. I started both engines on land with a freshwater flushing adapter, both ran quiet, didn't overheat, and appeared to pass the proper amount of water flow.
After about a week of use it was apparent that the port engine was getting freshwater back into the cylinder (slightly delayed startup and some steaming) I checked surfaces and replaced 3 more sets of riser gaskets and even tried riser retorque after a heat soak and cooldown to no avail. I was fed up with the wasted time, money and hassle and decided to just get the OEM manifolds for the port engine to verify in my mind that they were the issue. Installed the OEM manifolds and ran for the rest of the season with no issues. You can immediately see and feel the difference in material and manufacturing quality.
I contacted the seller concerning the GLM warranty and was told the following "GLM will do a pressure test on your manifolds to determine if they are leaking. A pressure test can be done by any local Mercruiser dealer for a minimum charge. I suggest that you have the manifolds pressure checked locally before you make the effort to return them. If GLM finds that they do not leak you will be responsible for all shipping costs.Most manifolds returned for warranty consideration because of leakage do not fail a pressure test (do not leak) and are returned to the customer without warranty."
In a followup email I asked that I be reimbursed my money since I had already purchased the right manifold set and was told that that was at GLM's discretion and more than likely they would only replace them with replacement manifolds.
About a month later the same issues began on the S/B engine and I purchased the OEM Mercs for that side as well. Some may have had good experience with GLM's, but, as you can tell, I have not.
An additional note: all the manifold and riser surfaces I checked and filed on were kept together on the S/B engine to be sure in my mind I hadn't messed something up. They were painted with red paint on the water nipples so I could remember which ones I had "massaged"
The moral of this story for myself was: The money I saved on the initial purchase was lost, as was the total purchase price of the manifolds (which I gave the better set to a coworker who had the same issues and threw them in the trash) and I ended up putting up the money to buy the right parts I should have bought in the first place. I also learned that the warranty is only as good as the company, and reseller, that stand behind (or don't) their products. I have told as many people as would listen to Stay away from GLM manifolds at all costs.
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